This manual is for GNU Automake (version 1.9.4, 18 December 2004), a program which creates GNU standards-compliant Makefiles from template files.
Copyright © 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled "GNU Free Documentation License."(a) The FSF's Back-Cover Text is: "You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development."
Automake is a tool for automatically generating Makefile.ins from
files called Makefile.am. Each Makefile.am is basically a
series of make variable definitions1, with
rules being thrown in occasionally. The generated Makefile.ins
are compliant with the GNU Makefile standards.
The GNU Makefile Standards Document (see Makefile Conventions) is long, complicated, and subject to change. The goal of Automake is to remove the burden of Makefile maintenance from the back of the individual GNU maintainer (and put it on the back of the Automake maintainer).
The typical Automake input file is simply a series of variable definitions.
Each such file is processed to create a Makefile.in. There
should generally be one Makefile.am per directory of a project.
Automake does constrain a project in certain ways; for instance it
assumes that the project uses Autoconf (see Introduction), and enforces certain restrictions on
the configure.ac contents2.
Automake requires perl in order to generate the
Makefile.ins. However, the distributions created by Automake are
fully GNU standards-compliant, and do not require perl in order
to be built.
Mail suggestions and bug reports for Automake to bug-automake@gnu.org.
The following sections cover a few basic ideas that will help you understand how Automake works.
Automake works by reading a Makefile.am and generating a
Makefile.in. Certain variables and rules defined in the
Makefile.am instruct Automake to generate more specialized code;
for instance, a bin_PROGRAMS variable definition will cause rules
for compiling and linking programs to be generated.
The variable definitions and rules in the Makefile.am are
copied verbatim into the generated file. This allows you to add
arbitrary code into the generated Makefile.in. For instance
the Automake distribution includes a non-standard rule for the
cvs-dist target, which the Automake maintainer uses to make
distributions from his source control system.
Note that most GNU make extensions are not recognized by Automake. Using
such extensions in a Makefile.am will lead to errors or confusing
behavior.
A special exception is that the GNU make append operator, +=, is
supported. This operator appends its right hand argument to the variable
specified on the left. Automake will translate the operator into
an ordinary = operator; += will thus work with any make program.
Automake tries to keep comments grouped with any adjoining rules or variable definitions.
A rule defined in Makefile.am generally overrides any such
rule of a similar name that would be automatically generated by
automake. Although this is a supported feature, it is generally
best to avoid making use of it, as sometimes the generated rules are
very particular.
Similarly, a variable defined in Makefile.am or
AC_SUBST'ed from configure.ac will override any
definition of the variable that automake would ordinarily
create. This feature is more often useful than the ability to
override a rule. Be warned that many of the variables generated by
automake are considered to be for internal use only, and their
names might change in future releases.
When examining a variable definition, Automake will recursively examine
variables referenced in the definition. For example, if Automake is
looking at the content of foo_SOURCES in this snippet
xs = a.c b.c
foo_SOURCES = c.c $(xs)
it would use the files a.c, b.c, and c.c as the
contents of foo_SOURCES.
Automake also allows a form of comment which is not copied into
the output; all lines beginning with ## (leading spaces allowed)
are completely ignored by Automake.
It is customary to make the first line of Makefile.am read:
## Process this file with automake to produce Makefile.in
While Automake is intended to be used by maintainers of GNU packages, it does make some effort to accommodate those who wish to use it, but do not want to use all the GNU conventions.
To this end, Automake supports three levels of strictness--the strictness indicating how stringently Automake should check standards conformance.
The valid strictness levels are:
foreign
NEWS file, it will not be required in
this mode. The name comes from the fact that Automake is intended to be
used for GNU programs; these relaxed rules are not the standard mode of
operation.
gnu
gnits
For more information on the precise implications of the strictness level, see Gnits.
Automake also has a special "cygnus" mode which is similar to strictness but handled differently. This mode is useful for packages which are put into a "Cygnus" style tree (e.g., the GCC tree). For more information on this mode, see Cygnus.
Automake variables generally follow a uniform naming scheme that
makes it easy to decide how programs (and other derived objects) are
built, and how they are installed. This scheme also supports
configure time determination of what should be built.
At make time, certain variables are used to determine which
objects are to be built. The variable names are made of several pieces
which are concatenated together.
The piece which tells automake what is being built is commonly called
the primary. For instance, the primary PROGRAMS holds a
list of programs which are to be compiled and linked.
A different set of names is used to decide where the built objects
should be installed. These names are prefixes to the primary which
indicate which standard directory should be used as the installation
directory. The standard directory names are given in the GNU standards
(see Directory Variables).
Automake extends this list with pkglibdir, pkgincludedir,
and pkgdatadir; these are the same as the non-pkg
versions, but with $(PACKAGE) appended. For instance,
pkglibdir is defined as $(libdir)/$(PACKAGE).
For each primary, there is one additional variable named by prepending
EXTRA_ to the primary name. This variable is used to list
objects which may or may not be built, depending on what
configure decides. This variable is required because Automake
must statically know the entire list of objects that may be built in
order to generate a Makefile.in that will work in all cases.
For instance, cpio decides at configure time which programs are
built. Some of the programs are installed in bindir, and some
are installed in sbindir:
EXTRA_PROGRAMS = mt rmt
bin_PROGRAMS = cpio pax
sbin_PROGRAMS = $(MORE_PROGRAMS)
Defining a primary without a prefix as a variable, e.g.,
PROGRAMS, is an error.
Note that the common dir suffix is left off when constructing the
variable names; thus one writes bin_PROGRAMS and not
bindir_PROGRAMS.
Not every sort of object can be installed in every directory. Automake will flag those attempts it finds in error. Automake will also diagnose obvious misspellings in directory names.
Sometimes the standard directories--even as augmented by Automake--
are not enough. In particular it is sometimes useful, for clarity, to
install objects in a subdirectory of some predefined directory. To this
end, Automake allows you to extend the list of possible installation
directories. A given prefix (e.g. zar) is valid if a variable of
the same name with dir appended is defined (e.g. zardir).
For instance, installation of HTML files is part of Automake, you could use this to install raw HTML documentation:
htmldir = $(prefix)/html
html_DATA = automake.html
The special prefix noinst indicates that the objects in question
should be built but not installed at all. This is usually used for
objects required to build the rest of your package, for instance static
libraries (see A Library), or helper scripts.
The special prefix check indicates that the objects in question
should not be built until the make check command is run. Those
objects are not installed either.
The current primary names are PROGRAMS, LIBRARIES,
LISP, PYTHON, JAVA, SCRIPTS, DATA,
HEADERS, MANS, and TEXINFOS.
Some primaries also allow additional prefixes which control other
aspects of automake's behavior. The currently defined prefixes
are dist_, nodist_, and nobase_. These prefixes
are explained later (see Program and Library Variables).
Sometimes a Makefile variable name is derived from some text the
maintainer supplies. For instance, a program name listed in
_PROGRAMS is rewritten into the name of a _SOURCES
variable. In cases like this, Automake canonicalizes the text, so that
program names and the like do not have to follow Makefile variable naming
rules. All characters in the name except for letters, numbers, the
strudel (@), and the underscore are turned into underscores when making
variable references.
For example, if your program is named sniff-glue, the derived
variable name would be sniff_glue_SOURCES, not
sniff-glue_SOURCES. Similarly the sources for a library named
libmumble++.a should be listed in the
libmumble___a_SOURCES variable.
The strudel is an addition, to make the use of Autoconf substitutions in variable names less obfuscating.
Some Makefile variables are reserved by the GNU Coding Standards
for the use of the "user" - the person building the package. For
instance, CFLAGS is one such variable.
Sometimes package developers are tempted to set user variables such as
CFLAGS because it appears to make their job easier. However,
the package itself should never set a user variable, particularly not
to include switches which are required for proper compilation of the
package. Since these variables are documented as being for the
package builder, that person rightfully expects to be able to override
any of these variables at build time.
To get around this problem, automake introduces an automake-specific
shadow variable for each user flag variable. (Shadow variables are not
introduced for variables like CC, where they would make no
sense.) The shadow variable is named by prepending AM_ to the
user variable's name. For instance, the shadow variable for
YFLAGS is AM_YFLAGS.
See Flag Variables Ordering, for more discussion about these variables and how they interact with per-target variables.
Automake sometimes requires helper programs so that the generated
Makefile can do its work properly. There are a fairly large
number of them, and we list them here.
ansi2knr.c
ansi2knr.1
compile
-c and
-o at the same time. It is only used when absolutely required.
Such compilers are rare.
config.guess
config.sub
ftp://ftp.gnu.org/gnu/config/> before making a release.
depcomp
elisp-comp
install-sh
install program which works on
platforms where install is unavailable or unusable.
mdate-sh
version.texi file. It examines
a file and prints some date information about it.
missing
missing
prints an informative warning and attempts to fix things so that the
build can continue.
mkinstalldirs
mkdir -p, which is not
portable. Now we use prefer to use install-sh -d when configure
finds that mkdir -p does not work, this makes one less script to
distribute.
For backward compatibility mkinstalldirs is still used and
distributed when automake finds it in a package. But it is no
longer installed automatically, and it should be safe to remove it.
py-compile
texinfo.tex
make dvi, make ps
and make pdf to work when Texinfo sources are in the package.
ylwrap
lex and yacc and ensures that, for
instance, multiple yacc instances can be invoked in a single
directory in parallel.
Let's suppose you just finished writing zardoz, a program to make
your head float from vortex to vortex. You've been using Autoconf to
provide a portability framework, but your Makefile.ins have been
ad-hoc. You want to make them bulletproof, so you turn to Automake.
The first step is to update your configure.ac to include the
commands that automake needs. The way to do this is to add an
AM_INIT_AUTOMAKE call just after AC_INIT:
AC_INIT(zardoz, 1.0)
AM_INIT_AUTOMAKE
...
Since your program doesn't have any complicating factors (e.g., it
doesn't use gettext, it doesn't want to build a shared library),
you're done with this part. That was easy!
Now you must regenerate configure. But to do that, you'll need
to tell autoconf how to find the new macro you've used. The
easiest way to do this is to use the aclocal program to generate
your aclocal.m4 for you. But wait... maybe you already have an
aclocal.m4, because you had to write some hairy macros for your
program. The aclocal program lets you put your own macros into
acinclude.m4, so simply rename and then run:
mv aclocal.m4 acinclude.m4
aclocal
autoconf
Now it is time to write your Makefile.am for zardoz.
Since zardoz is a user program, you want to install it where the
rest of the user programs go: bindir. Additionally,
zardoz has some Texinfo documentation. Your configure.ac
script uses AC_REPLACE_FUNCS, so you need to link against
$(LIBOBJS). So here's what you'd write:
bin_PROGRAMS = zardoz
zardoz_SOURCES = main.c head.c float.c vortex9.c gun.c
zardoz_LDADD = $(LIBOBJS)
info_TEXINFOS = zardoz.texi
Now you can run automake --add-missing to generate your
Makefile.in and grab any auxiliary files you might need, and
you're done!
Of course, GNU Hello is somewhat more featureful than your traditional two-liner. GNU Hello is internationalized, does option processing, and has a manual and a test suite.
Here is the configure.ac from GNU Hello.
Please note: The calls to AC_INIT and AM_INIT_AUTOMAKE
in this example use a deprecated syntax. For the current approach,
see the description of AM_INIT_AUTOMAKE in Public macros.
dnl Process this file with autoconf to produce a configure script.
AC_INIT(src/hello.c)
AM_INIT_AUTOMAKE(hello, 1.3.11)
AM_CONFIG_HEADER(config.h)
dnl Set of available languages.
ALL_LINGUAS="de fr es ko nl no pl pt sl sv"
dnl Checks for programs.
AC_PROG_CC
AC_ISC_POSIX
dnl Checks for libraries.
dnl Checks for header files.
AC_STDC_HEADERS
AC_HAVE_HEADERS(string.h fcntl.h sys/file.h sys/param.h)
dnl Checks for library functions.
AC_FUNC_ALLOCA
dnl Check for st_blksize in struct stat
AC_ST_BLKSIZE
dnl internationalization macros
AM_GNU_GETTEXT
AC_OUTPUT([Makefile doc/Makefile intl/Makefile po/Makefile.in \
src/Makefile tests/Makefile tests/hello],
[chmod +x tests/hello])
The AM_ macros are provided by Automake (or the Gettext library);
the rest are standard Autoconf macros.
The top-level Makefile.am:
EXTRA_DIST = BUGS ChangeLog.O
SUBDIRS = doc intl po src tests
As you can see, all the work here is really done in subdirectories.
The po and intl directories are automatically generated
using gettextize; they will not be discussed here.
In doc/Makefile.am we see:
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
This is sufficient to build, install, and distribute the GNU Hello manual.
Here is tests/Makefile.am:
TESTS = hello
EXTRA_DIST = hello.in testdata
The script hello is generated by configure, and is the
only test case. make check will run this test.
Last we have src/Makefile.am, where all the real work is done:
bin_PROGRAMS = hello
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
hello_LDADD = $(INTLLIBS) $(ALLOCA)
localedir = $(datadir)/locale
INCLUDES = -I../intl -DLOCALEDIR=\"$(localedir)\"
Here is another, trickier example. It shows how to generate two
programs (true and false) from the same source file
(true.c). The difficult part is that each compilation of
true.c requires different cpp flags.
bin_PROGRAMS = true false
false_SOURCES =
false_LDADD = false.o
true.o: true.c
$(COMPILE) -DEXIT_CODE=0 -c true.c
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -o false.o -c true.c
Note that there is no true_SOURCES definition. Automake will
implicitly assume that there is a source file named true.c, and
define rules to compile true.o and link true. The
true.o: true.c rule supplied by the above Makefile.am,
will override the Automake generated rule to build true.o.
false_SOURCES is defined to be empty--that way no implicit value
is substituted. Because we have not listed the source of
false, we have to tell Automake how to link the program. This is
the purpose of the false_LDADD line. A false_DEPENDENCIES
variable, holding the dependencies of the false target will be
automatically generated by Automake from the content of
false_LDADD.
The above rules won't work if your compiler doesn't accept both
-c and -o. The simplest fix for this is to introduce a
bogus dependency (to avoid problems with a parallel make):
true.o: true.c false.o
$(COMPILE) -DEXIT_CODE=0 -c true.c
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -c true.c && mv true.o false.o
Also, these explicit rules do not work if the de-ANSI-fication feature is used (see ANSI). Supporting de-ANSI-fication requires a little more work:
true_.o: true_.c false_.o
$(COMPILE) -DEXIT_CODE=0 -c true_.c
false_.o: true_.c
$(COMPILE) -DEXIT_CODE=1 -c true_.c && mv true_.o false_.o
As it turns out, there is also a much easier way to do this same task.
Some of the above techniques are useful enough that we've kept the
example in the manual. However if you were to build true and
false in real life, you would probably use per-program
compilation flags, like so:
bin_PROGRAMS = false true
false_SOURCES = true.c
false_CPPFLAGS = -DEXIT_CODE=1
true_SOURCES = true.c
true_CPPFLAGS = -DEXIT_CODE=0
In this case Automake will cause true.c to be compiled twice,
with different flags. De-ANSI-fication will work automatically. In
this instance, the names of the object files would be chosen by
automake; they would be false-true.o and true-true.o.
(The name of the object files rarely matters.)
Makefile.inTo create all the Makefile.ins for a package, run the
automake program in the top level directory, with no arguments.
automake will automatically find each appropriate
Makefile.am (by scanning configure.ac; see configure)
and generate the corresponding Makefile.in. Note that
automake has a rather simplistic view of what constitutes a
package; it assumes that a package has only one configure.ac, at
the top. If your package has multiple configure.acs, then you
must run automake in each directory holding a
configure.ac. (Alternatively, you may rely on Autoconf's
autoreconf, which is able to recurse your package tree and run
automake where appropriate.)
You can optionally give automake an argument; .am is
appended to the argument and the result is used as the name of the input
file. This feature is generally only used to automatically rebuild an
out-of-date Makefile.in. Note that automake must always
be run from the topmost directory of a project, even if being used to
regenerate the Makefile.in in some subdirectory. This is
necessary because automake must scan configure.ac, and
because automake uses the knowledge that a Makefile.in is
in a subdirectory to change its behavior in some cases.
Automake will run autoconf to scan configure.ac and its
dependencies (aclocal.m4), therefore autoconf must be in
your PATH. If there is an AUTOCONF variable in your
environment it will be used instead of autoconf, this allows you
to select a particular version of Autoconf. By the way, don't
misunderstand this paragraph: Automake runs autoconf to
scan your configure.ac, this won't build
configure and you still have to run autoconf yourself for
this purpose.
automake accepts the following options:
-a
--add-missing
config.guess is required if configure.ac runs
AC_CANONICAL_HOST. Automake is distributed with several of these
files (see Auxiliary Programs); this option will cause the missing
ones to be automatically added to the package, whenever possible. In
general if Automake tells you a file is missing, try using this option.
By default Automake tries to make a symbolic link pointing to its own
copy of the missing file; this can be changed with --copy.
Many of the potentially-missing files are common scripts whose
location may be specified via the AC_CONFIG_AUX_DIR macro.
Therefore, AC_CONFIG_AUX_DIR's setting affects whether a
file is considered missing, and where the missing file is added
(see Optional).
--libdir=dir-c
--copy
--add-missing, causes installed files to be
copied. The default is to make a symbolic link.
--cygnus
Makefile.ins to follow Cygnus rules, instead
of GNU or Gnits rules. For more information, see Cygnus.
-f
--force-missing
--add-missing, causes standard files to be reinstalled
even if they already exist in the source tree. This involves removing
the file from the source tree before creating the new symlink (or, with
--copy, copying the new file).
--foreign
foreign. For more information, see
Strictness.
--gnits
gnits. For more information, see
Gnits.
--gnu
gnu. For more information, see
Gnits. This is the default strictness.
--help
-i
--ignore-deps
Makefiles; see Dependencies.
--include-deps
--no-force
automake creates all Makefile.ins mentioned in
configure.ac. This option causes it to only update those
Makefile.ins which are out of date with respect to one of their
dependents.
-o dir--output-dir=dirMakefile.in in the directory dir.
Ordinarily each Makefile.in is created in the directory of the
corresponding Makefile.am. This option is deprecated and will be
removed in a future release.
-v
--verbose
--version
-W CATEGORY
--warnings=categorygnu
obsolete
override
portability
syntax
unsupported
all
none
error
A category can be turned off by prefixing its name with no-. For
instance -Wno-syntax will hide the warnings about unused
variables.
The categories output by default are syntax and
unsupported. Additionally, gnu is enabled in --gnu and
--gnits strictness.
portability warnings are currently disabled by default, but they
will be enabled in --gnu and --gnits strictness in a
future release.
The environment variable WARNINGS can contain a comma separated
list of categories to enable. It will be taken into account before the
command-line switches, this way -Wnone will also ignore any
warning category enabled by WARNINGS. This variable is also used
by other tools like autoconf; unknown categories are ignored
for this reason.
configure.acAutomake scans the package's configure.ac to determine certain
information about the package. Some autoconf macros are required
and some variables must be defined in configure.ac. Automake
will also use information from configure.ac to further tailor its
output.
Automake also supplies some Autoconf macros to make the maintenance
easier. These macros can automatically be put into your
aclocal.m4 using the aclocal program.
The one real requirement of Automake is that your configure.ac
call AM_INIT_AUTOMAKE. This macro does several things which are
required for proper Automake operation (see Macros).
Here are the other macros which Automake requires but which are not run
by AM_INIT_AUTOMAKE:
AC_CONFIG_FILES
AC_OUTPUT
Makefile if there
exists a file with the same name and the .am extension appended.
Typically, AC_CONFIG_FILES([foo/Makefile]) will cause Automake to
generate foo/Makefile.in if foo/Makefile.am exists.
When using AC_CONFIG_FILES with multiple input files, as in
AC_CONFIG_FILES([Makefile:top.in:Makefile.in:bot.in]), Automake
will generate the first .in input file for which a .am
file exists. If no such file exists the output file is not considered
to be Automake generated.
Files created by AC_CONFIG_FILES are removed by make distclean.
Every time Automake is run it calls Autoconf to trace
configure.ac. This way it can recognize the use of certain
macros and tailor the generated Makefile.in appropriately.
Currently recognized macros and their effects are:
AC_CONFIG_HEADERS
AM_CONFIG_HEADER
(see Macros); this is no longer the case today.
AC_CONFIG_LINKS
configure generated links on
make distclean and to distribute named source files as part of
make dist.
AC_CONFIG_AUX_DIR
install-sh, in the directory named in this macro invocation.
(The full list of scripts is: config.guess, config.sub,
depcomp, elisp-comp, compile, install-sh,
ltmain.sh, mdate-sh, missing, mkinstalldirs,
py-compile, texinfo.tex, and ylwrap.) Not all
scripts are always searched for; some scripts will only be sought if the
generated Makefile.in requires them.
If AC_CONFIG_AUX_DIR is not given, the scripts are looked for in
their standard locations. For mdate-sh,
texinfo.tex, and ylwrap, the standard location is the
source directory corresponding to the current Makefile.am. For
the rest, the standard location is the first one of ., ..,
or ../.. (relative to the top source directory) that provides any
one of the helper scripts. See Finding `configure' Input.
Required files from AC_CONFIG_AUX_DIR are automatically
distributed, even if there is no Makefile.am in this directory.
AC_CANONICAL_BUILD
AC_CANONICAL_HOST
AC_CANONICAL_TARGET
config.guess and config.sub
exist. Also, the Makefile variables build_triplet,
host_triplet and target_triplet are introduced. See
Getting the Canonical System Type.
AC_LIBSOURCE
AC_LIBSOURCES
AC_LIBOBJ
AC_LIBSOURCE or AC_LIBSOURCES.
Note that the AC_LIBOBJ macro calls AC_LIBSOURCE. So if
an Autoconf macro is documented to call AC_LIBOBJ([file]), then
file.c will be distributed automatically by Automake. This
encompasses many macros like AC_FUNC_ALLOCA,
AC_FUNC_MEMCMP, AC_REPLACE_FUNCS, and others.
By the way, direct assignments to LIBOBJS are no longer
supported. You should always use AC_LIBOBJ for this purpose.
See AC_LIBOBJ vs. LIBOBJS.
AC_PROG_RANLIB
AC_PROG_CXX
AC_PROG_F77
AC_F77_LIBRARY_LDFLAGS
AC_PROG_FC
AC_PROG_LIBTOOL
libtool (see Introduction).
AC_PROG_YACC
YACC in configure.ac. The former is
preferred (see Particular Program Checks).
AC_PROG_LEX
AC_SUBST
Makefile.in. See Setting Output Variables.
If the Autoconf manual says that a macro calls AC_SUBST for
var, or defines the output variable var then var will
be defined in each Makefile.in generated by Automake.
E.g. AC_PATH_XTRA defines X_CFLAGS and X_LIBS, so
you can use these variables in any Makefile.am if
AC_PATH_XTRA is called.
AM_C_PROTOTYPES
AM_GNU_GETTEXT
AM_MAINTAINER_MODE
--enable-maintainer-mode option to
configure. If this is used, automake will cause
maintainer-only rules to be turned off by default in the
generated Makefile.ins. This macro defines the
MAINTAINER_MODE conditional, which you can use in your own
Makefile.am. See maintainer-mode.
m4_include
configure.ac using this macro will be
detected by Automake and automatically distributed. They will also
appear as dependencies in Makefile rules.
m4_include is seldom used by configure.ac authors, but
can appear in aclocal.m4 when aclocal detects that
some required macros come from files local to your package (as opposed
to macros installed in a system-wide directory, see Invoking aclocal).
Automake includes a number of Autoconf macros which can be used in
your package (see Macros); some of them are actually required by
Automake in certain situations. These macros must be defined in your
aclocal.m4; otherwise they will not be seen by
autoconf.
The aclocal program will automatically generate
aclocal.m4 files based on the contents of configure.ac.
This provides a convenient way to get Automake-provided macros,
without having to search around. The aclocal mechanism
allows other packages to supply their own macros (see Extending aclocal). You can also use it to maintain your own set of custom
macros (see Local Macros).
At startup, aclocal scans all the .m4 files it can
find, looking for macro definitions (see Macro search path). Then
it scans configure.ac. Any mention of one of the macros found
in the first step causes that macro, and any macros it in turn
requires, to be put into aclocal.m4.
Putting the file that contains the macro definition into
aclocal.m4 is usually done by copying the entire text of this
file, including unused macro definitions as well as both # and
dnl comments. If you want to make a comment which will be
completely ignored by aclocal, use ## as the comment
leader.
When a file selected by aclocal is located in a subdirectory
specified as a relative search path with aclocal's -I
argument, aclocal assumes the file belongs to the package
and uses m4_include instead of copying it into
aclocal.m4. This makes the package smaller, eases dependency
tracking, and cause the file to be distributed automatically.
(See Local Macros, for an example.) Any macro which is found in a
system-wide directory, or via an absolute search path will be copied.
So use -I `pwd`/reldir instead of -I reldir whenever
some relative directory need to be considered outside the package.
The contents of acinclude.m4, if this file exists, are also
automatically included in aclocal.m4. We recommend against
using acinclude.m4 in new packages (see Local Macros).
While computing aclocal.m4, aclocal runs autom4te
(see Using Autom4te) in order to trace the macros which are really used,
and omit from aclocal.m4 all macros which are mentioned but
otherwise unexpanded (this can happen when a macro is called
conditionally). autom4te is expected to be in the PATH,
just as autoconf. Its location can be overridden using the
AUTOM4TE environment variable.
aclocal accepts the following options:
--acdir=dir--help
-I dir.m4 files.
--force
--output=fileaclocal.m4.
--print-ac-dir
aclocal will search to
find third-party .m4 files. When this option is given, normal
processing is suppressed. This option can be used by a package to
determine where to install a macro file.
--verbose
--version
By default, aclocal searches for .m4 files in the following
directories, in this order:
.m4 macros distributed with automake itself
are stored. APIVERSION depends on the automake release used;
for automake 1.6.x, APIVERSION = 1.6.
.m4 files, and is
configured when automake itself is built. This is
@datadir@/aclocal/, which typically
expands to ${prefix}/share/aclocal/. To find the compiled-in
value of acdir, use the --print-ac-dir option
(see aclocal options).
As an example, suppose that automake-1.6.2 was configured with
--prefix=/usr/local. Then, the search path would be:
/usr/local/share/aclocal-1.6/
/usr/local/share/aclocal/
As explained in (see aclocal options), there are several options that can be used to change or extend this search path.
--acdir
The most obvious option to modify the search path is
--acdir=dir, which changes default directory and
drops the APIVERSION directory. For example, if one specifies
--acdir=/opt/private/, then the search path becomes:
/opt/private/
Note that this option, --acdir, is intended for use
by the internal automake test suite only; it is not ordinarily
needed by end-users.
-I dirAny extra directories specified using -I options
(see aclocal options) are prepended to this search list. Thus,
aclocal -I /foo -I /bar results in the following search path:
/foo
/bar
dirlist
There is a third mechanism for customizing the search path. If a
dirlist file exists in acdir, then that file is assumed to
contain a list of directories, one per line, to be added to the search
list. These directories are searched after all other
directories.
For example, suppose
acdir/dirlist contains the following:
/test1
/test2
and that aclocal was called with the -I /foo -I /bar options.
Then, the search path would be
/foo
/bar
/test1
/test2
If the --acdir=dir option is used, then aclocal
will search for the dirlist file in dir. In the
--acdir=/opt/private/ example above, aclocal would look
for /opt/private/dirlist. Again, however, the --acdir
option is intended for use by the internal automake test suite only;
--acdir is not ordinarily needed by end-users.
dirlist is useful in the following situation: suppose that
automake version 1.6.2 is installed with
$prefix=/usr by the system vendor. Thus, the default search
directories are
/usr/share/aclocal-1.6/
/usr/share/aclocal/
However, suppose further that many packages have been manually
installed on the system, with $prefix=/usr/local, as is typical.
In that case, many of these "extra" .m4 files are in
/usr/local/share/aclocal. The only way to force
/usr/bin/aclocal to find these "extra" .m4 files
is to always call aclocal -I /usr/local/share/aclocal.
This is inconvenient. With dirlist, one may create the file
/usr/share/aclocal/dirlist
which contains only the single line
/usr/local/share/aclocal
Now, the "default" search path on the affected system is
/usr/share/aclocal-1.6/
/usr/share/aclocal/
/usr/local/share/aclocal/
without the need for -I options; -I options can be reserved
for project-specific needs (my-source-dir/m4/), rather than
using it to work around local system-dependent tool installation
directories.
Similarly, dirlist can be handy if you have installed a local
copy Automake on your account and want aclocal to look for
macros installed at other places on the system.
Automake ships with several Autoconf macros that you can use from your
configure.ac. When you use one of them it will be included by
aclocal in aclocal.m4.
AM_CONFIG_HEADER
AC_CONFIG_HEADERS
today (see Optional).
AM_ENABLE_MULTILIB
Makefile being generated; it
defaults to Makefile. The second option argument is used to find
the top source directory; it defaults to the empty string (generally
this should not be used unless you are familiar with the internals).
See Multilibs.
AM_C_PROTOTYPES
PROTOTYPES and set the output variables U and
ANSI2KNR to the empty string. Otherwise, set U to
_ and ANSI2KNR to ./ansi2knr. Automake uses these
values to implement automatic de-ANSI-fication.
AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
TIOCGWINSZ requires <sys/ioctl.h>, then
define GWINSZ_IN_SYS_IOCTL. Otherwise TIOCGWINSZ can be
found in <termios.h>. This macro is obsolete, you should
use Autoconf's AC_HEADER_TIOCGWINSZ instead.
AM_INIT_AUTOMAKE([OPTIONS])
AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])
This macro has two forms, the first of which is preferred.
In this form, AM_INIT_AUTOMAKE is called with a
single argument -- a space-separated list of Automake options which should
be applied to every Makefile.am in the tree. The effect is as if
each option were listed in AUTOMAKE_OPTIONS (see Options).
The second, deprecated, form of AM_INIT_AUTOMAKE has two required
arguments: the package and the version number. This form is
obsolete because the package and version can be obtained
from Autoconf's AC_INIT macro (which itself has an old and a new
form).
If your configure.ac has:
AC_INIT(src/foo.c)
AM_INIT_AUTOMAKE(mumble, 1.5)
you can modernize it as follows:
AC_INIT(mumble, 1.5)
AC_CONFIG_SRCDIR(src/foo.c)
AM_INIT_AUTOMAKE
Note that if you're upgrading your configure.ac from an earlier
version of Automake, it is not always correct to simply move the package
and version arguments from AM_INIT_AUTOMAKE directly to
AC_INIT, as in the example above. The first argument to
AC_INIT should be the name of your package (e.g. GNU Automake),
not the tarball name (e.g. automake) that you used to pass to
AM_INIT_AUTOMAKE. Autoconf tries to derive a tarball name from
the package name, which should work for most but not all package names.
(If it doesn't work for yours, you can use the
four-argument form of AC_INIT -- supported in Autoconf versions
greater than 2.52g -- to provide the tarball name explicitly).
By default this macro AC_DEFINE's PACKAGE and
VERSION. This can be avoided by passing the no-define
option, as in:
AM_INIT_AUTOMAKE([gnits 1.5 no-define dist-bzip2])
or by passing a third non-empty argument to the obsolete form.
AM_PATH_LISPDIR
emacs, and, if found, sets the output
variable lispdir to the full path to Emacs' site-lisp directory.
Note that this test assumes the emacs found to be a version that
supports Emacs Lisp (such as GNU Emacs or XEmacs). Other emacsen
can cause this test to hang (some, like old versions of MicroEmacs,
start up in interactive mode, requiring C-x C-c to exit, which
is hardly obvious for a non-emacs user). In most cases, however, you
should be able to use C-c to kill the test. In order to avoid
problems, you can set EMACS to "no" in the environment, or
use the --with-lispdir option to configure to
explicitly set the correct path (if you're sure you have an emacs
that supports Emacs Lisp.
AM_PROG_AS
CCAS, and will also set CCASFLAGS if required.
AM_PROG_CC_C_O
AC_PROG_CC_C_O, but it generates its results in the
manner required by automake. You must use this instead of
AC_PROG_CC_C_O when you need this functionality.
AM_PROG_LEX
AC_PROG_LEX (see Particular Program Checks), but uses the
missing script on systems that do not have lex.
HP-UX 10 is one such system.
AM_PROG_GCJ
gcj program or causes an error. It sets
GCJ and GCJFLAGS. gcj is the Java front-end to the
GNU Compiler Collection.
AM_SYS_POSIX_TERMIOS
am_cv_sys_posix_termios to
yes. If not, set the variable to no. This macro is obsolete,
you should use Autoconf's AC_SYS_POSIX_TERMIOS instead.
AM_WITH_DMALLOC
--with-dmalloc, then define
WITH_DMALLOC and add -ldmalloc to LIBS.
AM_WITH_REGEX
--with-regex to the configure command line. If
specified (the default), then the regex regular expression
library is used, regex.o is put into LIBOBJS, and
WITH_REGEX is defined. If --without-regex is given, then
the rx regular expression library is used, and rx.o is put
into LIBOBJS.
The following macros are private macros you should not call directly. They are called by the other public macros when appropriate. Do not rely on them, as they might be changed in a future version. Consider them as implementation details; or better, do not consider them at all: skip this section!
_AM_DEPENDENCIES
AM_SET_DEPDIR
AM_DEP_TRACK
AM_OUTPUT_DEPENDENCY_COMMANDS
AM_MAKE_INCLUDE
make handles
include statements. This macro is automatically invoked when
needed; there should be no need to invoke it manually.
AM_PROG_INSTALL_STRIP
install which can be used to
strip a program at installation time. This macro is
automatically included when required.
AM_SANITY_CHECK
AM_INIT_AUTOMAKE.
The aclocal program doesn't have any built-in knowledge of any
macros, so it is easy to extend it with your own macros.
This can be used by libraries which want to supply their own Autoconf
macros for use by other programs. For instance the gettext
library supplies a macro AM_GNU_GETTEXT which should be used by
any package using gettext. When the library is installed, it
installs this macro so that aclocal will find it.
A macro file's name should end in .m4. Such files should be
installed in $(datadir)/aclocal. This is as simple as writing:
aclocaldir = $(datadir)/aclocal
aclocal_DATA = mymacro.m4 myothermacro.m4
A file of macros should be a series of properly quoted
AC_DEFUN's (see Macro Definitions). The aclocal programs also understands
AC_REQUIRE (see Prerequisite Macros), so it is safe to put each macro in a separate file.
Each file should have no side effects but macro definitions.
Especially, any call to AC_PREREQ should be done inside the
defined macro, not at the beginning of the file.
Starting with Automake 1.8, aclocal will warn about all
underquoted calls to AC_DEFUN. We realize this will annoy a
lot of people, because aclocal was not so strict in the past
and many third party macros are underquoted; and we have to apologize
for this temporary inconvenience. The reason we have to be stricter
is that a future implementation of aclocal (see Future of aclocal) will have to temporary include all these third party
.m4 files, maybe several times, even those which are not
actually needed. Doing so should alleviate many problem of the
current implementation, however it requires a stricter style from the
macro authors. Hopefully it is easy to revise the existing macros.
For instance
# bad style
AC_PREREQ(2.57)
AC_DEFUN(AX_FOOBAR,
[AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
should be rewritten as
AC_DEFUN([AX_FOOBAR],
[AC_PREREQ(2.57)dnl
AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
Wrapping the AC_PREREQ call inside the macro ensures that
Autoconf 2.57 will not be required if AX_FOOBAR is not actually
used. Most importantly, quoting the first argument of AC_DEFUN
allows the macro to be redefined or included twice (otherwise this
first argument would be expansed during the second definition).
If you have been directed here by the aclocal diagnostic but
are not the maintainer of the implicated macro, you will want to
contact the maintainer of that macro. Please make sure you have the
last version of the macro and that the problem already hasn't been
reported before doing so: people tend to work faster when they aren't
flooded by mails.
Another situation where aclocal is commonly used is to
manage macros which are used locally by the package, Local Macros.
Feature tests offered by Autoconf do not cover all needs. People often have to supplement existing tests with their own macros, or with third-party macros.
There are two ways to organize custom macros in a package.
The first possibility (the historical practice) is to list all your
macros in acinclude.m4. This file will be included in
aclocal.m4 when you run aclocal, and its macro(s) will
henceforth be visible to autoconf. However if it contains
numerous macros, it will rapidly become difficult to maintain, and it
will be almost impossible to share macros between packages.
The second possibility, which we do recommend, is to write each macro
in its own file and gather all these files in a directory. This
directory is usually called m4/. To build aclocal.m4,
one should therefore instruct aclocal to scan m4/.
From the command line, this is done with aclocal -I m4. The
top-level Makefile.am should also be updated to define
ACLOCAL_AMFLAGS = -I m4
ACLOCAL_AMFLAGS contains options to pass to aclocal
when aclocal.m4 is to be rebuilt by make. This line is
also used by autoreconf (see Using autoreconf to Update configure Scripts) to run aclocal with suitable
options, or by autopoint (see Invoking the autopoint Program)
and gettextize (see Invoking the gettextize Program) to locate
the place where Gettext's macros should be installed. So even if you
do not really care about the rebuild rules, you should define
ACLOCAL_AMFLAGS.
When aclocal -I m4 is run, it will build a aclocal.m4
that m4_includes any file from m4/ that defines a
required macro. Macros not found locally will still be searched in
system-wide directories, as explained in Macro search path.
Custom macros should be distributed for the same reason that
configure.ac is: so that other people have all the sources of
your package if they want to work on it. Actually, this distribution
happens automatically because all m4_included files are
distributed.
However there is no consensus on the distribution of third-party
macros that your package may use. Many libraries install their own
macro in the system-wide aclocal directory (see Extending aclocal). For instance Guile ships with a file called
guile.m4 that contains the macro GUILE_FLAGS which can
be used to define setup compiler and linker flags appropriate for
using Guile. Using GUILE_FLAGS in configure.ac will
cause aclocal to copy guile.m4 into
aclocal.m4, but as guile.m4 is not part of the project,
it will not be distributed. Technically, that means a user which
needs to rebuild aclocal.m4 will have to install Guile first.
This is probably OK, if Guile already is a requirement to build the
package. However, if Guile is only an optional feature, or if your
package might run on architectures where Guile cannot be installed,
this requirement will hinder development. An easy solution is to copy
such third-party macros in your local m4/ directory so they get
distributed.
aclocalaclocal is expected to disappear. This feature really
should not be offered by Automake. Automake should focus on generating
Makefiles; dealing with M4 macros really is Autoconf's job.
That some people install Automake just to use aclocal, but
do not use automake otherwise is an indication of how that
feature is misplaced.
The new implementation will probably be done slightly differently.
For instance it could enforce the m4/-style layout discussed in
Local Macros, and take care of copying (and even updating)
third-party macros from /usr/share/aclocal/ into the local
m4/ directory.
We have no idea when and how this will happen. This has been discussed several times in the past, but someone still has to commit itself to that non-trivial task.
From the user point of view, aclocal's removal might turn
out to be painful. There is a simple precaution that you may take to
make that switch more seamless: never call aclocal yourself.
Keep this guy under the exclusive control of autoreconf and
Automake's rebuild rules. Hopefully you won't need to worry about
things breaking, when aclocal disappears, because everything
will have been taken care of. If otherwise you used to call
aclocal directly yourself or from some script, you will
quickly notice the change.
Many packages come with a script called bootstrap.sh or
autogen.sh, that will just call aclocal,
libtoolize, gettextize or autopoint,
autoconf, autoheader, and automake in
the right order. Actually this is precisely what autoreconf
can do for you. If your package has such a bootstrap.sh or
autogen.sh script, consider using autoreconf. That
should simplify its logic a lot (less things to maintain, yum!), it's
even likely you will not need the script anymore, and more to the point
you will not call aclocal directly anymore.
For the time being, third-party packages should continue to install
public macros into /usr/share/aclocal/. If aclocal
is replaced by another tool it might make sense to rename the
directory, but supporting /usr/share/aclocal/ for backward
compatibility should be really easy provided all macros are properly
written (see Extending aclocal).
For simple projects that distributes all files in the same directory
it is enough to have a single Makefile.am that builds
everything in place.
In larger projects it is common to organize files in different
directories, in a tree. For instance one directory per program, per
library or per module. The traditional approach is to build these
subdirectory recursively: each directory contains its Makefile
(generated from Makefile.am), and when make is run
from the top level directory it enters each subdirectory in turn to
build its contents.
In packages with subdirectories, the top level Makefile.am must
tell Automake which subdirectories are to be built. This is done via
the SUBDIRS variable.
The SUBDIRS variable holds a list of subdirectories in which
building of various sorts can occur. The rules for many targets
(e.g. all) in the generated Makefile will run commands
both locally and in all specified subdirectories. Note that the
directories listed in SUBDIRS are not required to contain
Makefile.ams; only Makefiles (after configuration).
This allows inclusion of libraries from packages which do not use
Automake (such as gettext; see also Third-Party Makefiles).
In packages that use subdirectories, the top-level Makefile.am is
often very short. For instance, here is the Makefile.am from the
GNU Hello distribution:
EXTRA_DIST = BUGS ChangeLog.O README-alpha
SUBDIRS = doc intl po src tests
When Automake invokes make in a subdirectory, it uses the value
of the MAKE variable. It passes the value of the variable
AM_MAKEFLAGS to the make invocation; this can be set in
Makefile.am if there are flags you must always pass to
make.
The directories mentioned in SUBDIRS are usually direct
children of the current directory, each subdirectory containing its
own Makefile.am with a SUBDIRS pointing to deeper
subdirectories. Automake can be used to construct packages of
arbitrary depth this way.
By default, Automake generates Makefiles which work depth-first
in postfix order: the subdirectories are built before the current
directory. However, it is possible to change this ordering. You can
do this by putting . into SUBDIRS. For instance,
putting . first will cause a prefix ordering of
directories.
Using
SUBDIRS = lib src . test
will cause lib/ to be built before src/, then the
current directory will be built, finally the test/ directory
will be built. It is customary to arrange test directories to be
built after everything else since they are meant to test what has
been constructed.
All clean rules are run in reverse order of build rules.
It is possible to define the SUBDIRS variable conditionally if,
like in the case of GNU Inetutils, you want to only build a
subset of the entire package.
To illustrate how this works, let's assume we have two directories
src/ and opt/. src/ should always be built, but we
want to decide in ./configure whether opt/ will be built
or not. (For this example we will assume that opt/ should be
built when the variable $want_opt was set to yes.)
Running make should thus recurse into src/ always, and
then maybe in opt/.
However make dist should always recurse into both src/
and opt/. Because opt/ should be distributed even if it
is not needed in the current configuration. This means
opt/Makefile should be created unconditionally.
There are two ways to setup a project like this. You can use Automake
conditionals (see Conditionals) or use Autoconf AC_SUBST
variables (see Setting Output Variables). Using Automake
conditionals is the preferred solution. Before we illustrate these
two possibility, let's introduce DIST_SUBDIRS.
SUBDIRS vs. DIST_SUBDIRS
Automake considers two sets of directories, defined by the variables
SUBDIRS and DIST_SUBDIRS.
SUBDIRS contains the subdirectories of the current directory
that must be built (see Subdirectories). It must be defined
manually; Automake will never guess a directory is to be built. As we
will see in the next two sections, it is possible to define it
conditionally so that some directory will be omitted from the build.
DIST_SUBDIRS is used in rules that need to recurse in all
directories, even those which have been conditionally left out of the
build. Recall our example where we may not want to build subdirectory
opt/, but yet we want to distribute it? This is where
DIST_SUBDIRS come into play: opt may not appear in
SUBDIRS, but it must appear in DIST_SUBDIRS.
Precisely, DIST_SUBDIRS is used by make dist, make
distclean, and make maintainer-clean. All other recursive
rules use SUBDIRS.
If SUBDIRS is defined conditionally using Automake
conditionals, Automake will define DIST_SUBDIRS automatically
from the possibles values of SUBDIRS in all conditions.
If SUBDIRS contains AC_SUBST variables,
DIST_SUBDIRS will not be defined correctly because Automake
does not know the possible values of these variables. In this case
DIST_SUBDIRS needs to be defined manually.
AM_CONDITIONAL
configure should output the Makefile for each directory
and define a condition into which opt/ should be built.
...
AM_CONDITIONAL([COND_OPT], [test "$want_opt" = yes])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
Then SUBDIRS can be defined in the top-level Makefile.am
as follows.
if COND_OPT
MAYBE_OPT = opt
endif
SUBDIRS = src $(MAYBE_OPT)
As you can see, running make will rightly recurse into
src/ and maybe opt/.
As you can't see, running make dist will recurse into both
src/ and opt/ directories because make dist, unlike
make all, doesn't use the SUBDIRS variable. It uses the
DIST_SUBDIRS variable.
In this case Automake will define DIST_SUBDIRS = src opt
automatically because it knows that MAYBE_OPT can contain
opt in some condition.
AC_SUBST
Another possibility is to define MAYBE_OPT from
./configure using AC_SUBST:
...
if test "$want_opt" = yes; then
MAYBE_OPT=opt
else
MAYBE_OPT=
fi
AC_SUBST([MAYBE_OPT])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
In this case the top-level Makefile.am should look as follows.
SUBDIRS = src $(MAYBE_OPT)
DIST_SUBDIRS = src opt
The drawback is that since Automake cannot guess what the possible
values of MAYBE_OPT are, it is necessary to define
DIST_SUBDIRS.
The semantic of DIST_SUBDIRS is often misunderstood by some
users that try to configure and build subdirectories
conditionally. Here by configuring we mean creating the
Makefile (it might also involve running a nested
configure script: this is a costly operation that explains
why people want to do it conditionally, but only the Makefile
is relevant to the discussion).
The above examples all assume that every Makefile is created,
even in directories that are not going to be built. The simple reason
is that we want make dist to distribute even the directories
that are not being built (e.g. platform-dependent code), hence
make dist must recurse into the subdirectory, hence this
directory must be configured and appear in DIST_SUBDIRS.
Building packages that do not configure every subdirectory is a tricky business, and we do not recommend it to the novice as it is easy to produce an incomplete tarball by mistake. We will not discuss this topic in depth here, yet for the adventurous here are a few rules to remember.
|
In order to prevent recursion in some non-configured directory you
must therefore ensure that this directory does not appear in
DIST_SUBDIRS (and SUBDIRS). For instance if you define
SUBDIRS conditionally using AC_SUBST and do not define
DIST_SUBDIRS explicitly, it will be default to
$(SUBDIRS); another possibility is to force DIST_SUBDIRS
= $(SUBDIRS).
Of course, directories which are omitted from DIST_SUBDIRS will
not be distributed unless you make other arrangements for this to
happen (for instance always running make dist in a
configuration where all directories are known to appear in
DIST_SUBDIRS; or writing a dist-hook target to
distribute these directories).
In few packages, non-configured directories are not even expected to
be distributed. Although these packages do not require the
aforementioned extra arrangements, there is another pitfall. If the
name of a directory appears in SUBDIRS or DIST_SUBDIRS,
automake will make sure the directory exists. Consequently
automake cannot be run on such a distribution when one
directory has been omitted. One way to avoid this check is to use the
AC_SUBST method to declare conditional directories; since
automake does not know the values of AC_SUBST
variables it cannot ensure the corresponding directory exist.
If you've ever read Peter Miller's excellent paper,
Recursive Make Considered Harmful, the preceding sections on the use of
subdirectories will probably come as unwelcome advice. For those who
haven't read the paper, Miller's main thesis is that recursive
make invocations are both slow and error-prone.
Automake provides sufficient cross-directory support 3 to enable you
to write a single Makefile.am for a complex multi-directory
package.
By default an installable file specified in a subdirectory will have its
directory name stripped before installation. For instance, in this
example, the header file will be installed as
$(includedir)/stdio.h:
include_HEADERS = inc/stdio.h
However, the nobase_ prefix can be used to circumvent this path
stripping. In this example, the header file will be installed as
$(includedir)/sys/types.h:
nobase_include_HEADERS = sys/types.h
nobase_ should be specified first when used in conjunction with
either dist_ or nodist_ (see Dist). For instance:
nobase_dist_pkgdata_DATA = images/vortex.pgm
In the GNU Build System, packages can be nested to arbitrary depth.
This means that a package can embedded other packages with their own
configure, Makefiles, etc.
These other packages should just appear as subdirectories of their
parent package. They must be listed in SUBDIRS like other
ordinary directories. However the subpackage's Makefiles
should be output by its own configure script, not by the
parent's configure. This is achieved using the
AC_CONFIG_SUBDIRS Autoconf macro (see AC_CONFIG_SUBDIRS).
Here is an example package for an arm program that links with
an hand library that is a nested package in subdirectory
hand/.
arm's configure.ac:
AC_INIT([arm], [1.0])
AC_CONFIG_AUX_DIR([.])
AM_INIT_AUTOMAKE
AC_PROG_CC
AC_CONFIG_FILES([Makefile])
# Call hand's ./configure script recursively.
AC_CONFIG_SUBDIRS([hand])
AC_OUTPUT
arm's Makefile.am:
# Build the library in the hand subdirectory first.
SUBDIRS = hand
# Include hand's header when compiling this directory.
AM_CPPFLAGS = -I$(srcdir)/hand
bin_PROGRAMS = arm
arm_SOURCES = arm.c
# link with the hand library.
arm_LDADD = hand/libhand.a
Now here is hand's hand/configure.ac:
AC_INIT([hand], [1.2])
AC_CONFIG_AUX_DIR([.])
AM_INIT_AUTOMAKE
AC_PROG_CC
AC_PROG_RANLIB
AC_CONFIG_FILES([Makefile])
AC_OUTPUT
and its hand/Makefile.am:
lib_LIBRARIES = libhand.a
libhand_a_SOURCES = hand.c
When make dist is run from the top-level directory it will
create an archive arm-1.0.tar.gz that contains the arm
code as well as the hand subdirectory. This package can be
built and installed like any ordinary package, with the usual
./configure && make && make install sequence (the hand
subpackage will be built and installed by the process).
When make dist is run from the hand directory, it will create a
self-contained hand-1.2.tar.gz archive. So although it appears
to be embedded in another package, it can still be used separately.
The purpose of the AC_CONFIG_AUX_DIR([.]) instruction is to
force Automake and Autoconf into search auxiliary script in the
current directory. For instance this means that there will be two
copies of install-sh: one in the top-level of the arm
package, and another one in the hand/ subdirectory for the
hand package.
The historical default is to search these auxiliary scripts in the
immediate parent and grand-parent directories. So if the
AC_CONFIG_AUX_DIR([.]) line was removed from
hand/configure.ac, that subpackage would share the auxiliary
script of the arm package. This may looks like a gain in size
(a few kilobytes), but it is actually a loss of modularity as the
hand subpackage is no longer self-contained (make dist
in the subdirectory will not work anymore).
Packages that do not use Automake need more work to be integrated this way. See Third-Party Makefiles.
A large part of Automake's functionality is dedicated to making it easy to build programs and libraries.
In order to build a program, you need to tell Automake which sources are part of it, and which libraries it should be linked with.
This section also covers conditional compilation of sources or programs. Most of the comments about these also apply to libraries (see A Library) and libtool libraries (see A Shared Library).
In a directory containing source that gets built into a program (as
opposed to a library or a script), the PROGRAMS primary is used.
Programs can be installed in bindir, sbindir,
libexecdir, pkglibdir, or not at all (noinst).
They can also be built only for make check, in which case the
prefix is check.
For instance:
bin_PROGRAMS = hello
In this simple case, the resulting Makefile.in will contain code
to generate a program named hello.
Associated with each program are several assisting variables which are named after the program. These variables are all optional, and have reasonable defaults. Each variable, its use, and default is spelled out below; we use the "hello" example throughout.
The variable hello_SOURCES is used to specify which source files
get built into an executable:
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
This causes each mentioned .c file to be compiled into the
corresponding .o. Then all are linked to produce hello.
If hello_SOURCES is not specified, then it defaults to the single
file hello.c (see Default _SOURCES).
Multiple programs can be built in a single directory. Multiple programs
can share a single source file, which must be listed in each
_SOURCES definition.
Header files listed in a _SOURCES definition will be included in
the distribution but otherwise ignored. In case it isn't obvious, you
should not include the header file generated by configure in a
_SOURCES variable; this file should not be distributed. Lex
(.l) and Yacc (.y) files can also be listed; see Yacc and Lex.
If you need to link against libraries that are not found by
configure, you can use LDADD to do so. This variable is
used to specify additional objects or libraries to link with; it is
inappropriate for specifying specific linker flags, you should use
AM_LDFLAGS for this purpose.
Sometimes, multiple programs are built in one directory but do not share
the same link-time requirements. In this case, you can use the
prog_LDADD variable (where prog is the name of the
program as it appears in some _PROGRAMS variable, and usually
written in lowercase) to override the global LDADD. If this
variable exists for a given program, then that program is not linked
using LDADD.
For instance, in GNU cpio, pax, cpio and mt are
linked against the library libcpio.a. However, rmt is
built in the same directory, and has no such link requirement. Also,
mt and rmt are only built on certain architectures. Here
is what cpio's src/Makefile.am looks like (abridged):
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
LDADD = ../lib/libcpio.a $(INTLLIBS)
rmt_LDADD =
cpio_SOURCES = ...
pax_SOURCES = ...
mt_SOURCES = ...
rmt_SOURCES = ...
prog_LDADD is inappropriate for passing program-specific
linker flags (except for -l, -L, -dlopen and
-dlpreopen). So, use the prog_LDFLAGS variable for
this purpose.
It is also occasionally useful to have a program depend on some other
target which is not actually part of that program. This can be done
using the prog_DEPENDENCIES variable. Each program depends
on the contents of such a variable, but no further interpretation is
done.
If prog_DEPENDENCIES is not supplied, it is computed by
Automake. The automatically-assigned value is the contents of
prog_LDADD, with most configure substitutions, -l,
-L, -dlopen and -dlpreopen options removed. The
configure substitutions that are left in are only $(LIBOBJS) and
$(ALLOCA); these are left because it is known that they will not
cause an invalid value for prog_DEPENDENCIES to be
generated.
You can't put a configure substitution (e.g., @FOO@ or
$(FOO) where FOO is defined via AC_SUBST) into a
_SOURCES variable. The reason for this is a bit hard to
explain, but suffice to say that it simply won't work. Automake will
give an error if you try to do this.
Fortunately there are two other ways to achieve the same result. One is
to use configure substitutions in _LDADD variables, the other is
to use an Automake conditional.
_LDADD substitutions
Automake must know all the source files that could possibly go into a
program, even if not all the files are built in every circumstance. Any
files which are only conditionally built should be listed in the
appropriate EXTRA_ variable. For instance, if
hello-linux.c or hello-generic.c were conditionally included
in hello, the Makefile.am would contain:
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
EXTRA_hello_SOURCES = hello-linux.c hello-generic.c
hello_LDADD = $(HELLO_SYSTEM)
hello_DEPENDENCIES = $(HELLO_SYSTEM)
You can then setup the $(HELLO_SYSTEM) substitution from
configure.ac:
...
case $host in
*linux*) HELLO_SYSTEM='hello-linux.$(OBJEXT)' ;;
*) HELLO_SYSTEM='hello-generic.$(OBJEXT)' ;;
esac
AC_SUBST([HELLO_SYSTEM])
...
In this case, HELLO_SYSTEM should be replaced by
hello-linux.o or hello-generic.o, and added to
hello_DEPENDENCIES and hello_LDADD in order to be built
and linked in.
An often simpler way to compile source files conditionally is to use
Automake conditionals. For instance, you could use this
Makefile.am construct to build the same hello example:
bin_PROGRAMS = hello
if LINUX
hello_SOURCES = hello-linux.c hello-common.c
else
hello_SOURCES = hello-generic.c hello-common.c
endif
In this case, your configure.ac should setup the LINUX
conditional using AM_CONDITIONAL (see Conditionals).
When using conditionals like this you don't need to use the
EXTRA_ variable, because Automake will examine the contents of
each variable to construct the complete list of source files.
If your program uses a lot of files, you will probably prefer a
conditional +=.
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
if LINUX
hello_SOURCES += hello-linux.c
else
hello_SOURCES += hello-generic.c
endif
Sometimes it is useful to determine the programs that are to be built
at configure time. For instance, GNU cpio only builds
mt and rmt under special circumstances. The means to
achieve conditional compilation of programs are the same you can use
to compile source files conditionally: substitutions or conditionals.
configure substitutions
In this case, you must notify Automake of all the programs that can
possibly be built, but at the same time cause the generated
Makefile.in to use the programs specified by configure.
This is done by having configure substitute values into each
_PROGRAMS definition, while listing all optionally built programs
in EXTRA_PROGRAMS.
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
As explained in EXEEXT, Automake will rewrite
bin_PROGRAMS, libexec_PROGRAMS, and
EXTRA_PROGRAMS, appending $(EXEEXT) to each binary.
Obviously it cannot rewrite values obtained at run-time through
configure substitutions, therefore you should take care of
appending $(EXEEXT) yourself, as in AC_SUBST([MT],
['mt${EXEEXT}']).
You can also use Automake conditionals (see Conditionals) to
select programs to be built. In this case you don't have to worry
about $(EXEEXT) or EXTRA_PROGRAMS.
bin_PROGRAMS = cpio pax
if WANT_MT
bin_PROGRAMS += mt
endif
if WANT_RMT
libexec_PROGRAMS = rmt
endif
Building a library is much like building a program. In this case, the
name of the primary is LIBRARIES. Libraries can be installed in
libdir or pkglibdir.
See A Shared Library, for information on how to build shared
libraries using libtool and the LTLIBRARIES primary.
Each _LIBRARIES variable is a list of the libraries to be built.
For instance to create a library named libcpio.a, but not install
it, you would write:
noinst_LIBRARIES = libcpio.a
The sources that go into a library are determined exactly as they are
for programs, via the _SOURCES variables. Note that the library
name is canonicalized (see Canonicalization), so the _SOURCES
variable corresponding to liblob.a is liblob_a_SOURCES,
not liblob.a_SOURCES.
Extra objects can be added to a library using the
library_LIBADD variable. This should be used for objects
determined by configure. Again from cpio:
libcpio_a_LIBADD = $(LIBOBJS) $(ALLOCA)
In addition, sources for extra objects that will not exist until
configure-time must be added to the BUILT_SOURCES variable
(see Sources).
Building a static library is done by compiling all object files, then
by invoking $(AR) $(ARFLAGS) followed by the name of the
library and the list of objects, and finally by calling
$(RANLIB) on that library. You should call
AC_PROG_RANLIB from your configure.ac to define
RANLIB (Automake will complain otherwise). AR and
ARFLAGS default to ar and cru respectively; you
can override these two variables my setting them in your
Makefile.am, by AC_SUBSTing them from your
configure.ac, or by defining a per-library maude_AR
variable (see Program and Library Variables).
Building shared libraries portably is a relatively complex matter. For this reason, GNU Libtool (see Introduction) was created to help build shared libraries in a platform-independent way.
Libtool abstracts shared and static libraries into a unified concept
henceforth called libtool libraries. Libtool libraries are
files using the .la suffix, and can designate a static library,
a shared library, or maybe both. Their exact nature cannot be
determined until ./configure is run: not all platforms support
all kinds of libraries, and users can explicitly select which
libraries should be built. (However the package's maintainers can
tune the default, see The AC_PROG_LIBTOOL macro.)
Because object files for shared and static libraries must be compiled
differently, libtool is also used during compilation. Object files
built by libtool are called libtool objects: these are files
using the .lo suffix. Libtool libraries are built from these
libtool objects.
You should not assume anything about the structure of .la or
.lo files and how libtool constructs them: this is libtool's
concern, and the last thing one wants is to learn about libtool's
guts. However the existence of these files matters, because they are
used as targets and dependencies in Makefiles rules when
building libtool libraries. There are situations where you may have
to refer to these, for instance when expressing dependencies for
building source files conditionally (see Conditional Libtool Sources).
People considering writing a plug-in system, with dynamically loaded
modules, should look into libltdl: libtool's dlopening library
(see Using libltdl).
This offers a portable dlopening facility to load libtool libraries
dynamically, and can also achieve static linking where unavoidable.
Before we discuss how to use libtool with Automake in details, it should be noted that the libtool manual also has a section about how to use Automake with libtool (see Using Automake with Libtool).
Automake uses libtool to build libraries declared with the
LTLIBRARIES primary. Each _LTLIBRARIES variable is a
list of libtool libraries to build. For instance, to create a libtool
library named libgettext.la, and install it in libdir,
write:
lib_LTLIBRARIES = libgettext.la
libgettext_la_SOURCES = gettext.c gettext.h ...
Automake predefines the variable pkglibdir, so you can use
pkglib_LTLIBRARIES to install libraries in
$(libdir)/@PACKAGE@/.
Like conditional programs (see Conditional Programs), there are
two main ways to build conditional libraries: using Automake
conditionals or using Autoconf AC_SUBSTitutions.
The important implementation detail you have to be aware of is that
the place where a library will be installed matters to libtool: it
needs to be indicated at link-time using the -rpath
option.
For libraries whose destination directory is known when Automake runs,
Automake will automatically supply the appropriate -rpath
option to libtool. This is the case for libraries listed explicitly in
some installable _LTLIBRARIES variables such as
lib_LTLIBRARIES.
However, for libraries determined at configure time (and thus
mentioned in EXTRA_LTLIBRARIES), Automake does not know the
final installation directory. For such libraries you must add the
-rpath option to the appropriate _LDFLAGS variable by
hand.
The examples below illustrate the differences between these two methods.
Here is an example where $(WANTEDLIBS) is an AC_SUBSTed
variable set at ./configure-time to either libfoo.la,
libbar.la, both, or none. Although $(WANTEDLIBS)
appears in the lib_LTLIBRARIES, Automake cannot guess it
relates to libfoo.la or libbar.la by the time it creates
the link rule for these two libraries. Therefore the -rpath
argument must be explicitly supplied.
EXTRA_LTLIBRARIES = libfoo.la libbar.la
lib_LTLIBRARIES = $(WANTEDLIBS)
libfoo_la_SOURCES = foo.c ...
libfoo_la_LDFLAGS = -rpath '$(libdir)'
libbar_la_SOURCES = bar.c ...
libbar_la_LDFLAGS = -rpath '$(libdir)'
Here is how the same Makefile.am would look using Automake
conditionals named WANT_LIBFOO and WANT_LIBBAR. Now
Automake is able to compute the -rpath setting itself, because
it's clear that both libraries will end up in $(libdir) if they
are installed.
lib_LTLIBRARIES =
if WANT_LIBFOO
lib_LTLIBRARIES += libfoo.la
endif
if WANT_LIBBAR
lib_LTLIBRARIES += libbar.la
endif
libfoo_la_SOURCES = foo.c ...
libbar_la_SOURCES = bar.c ...
Conditional compilation of sources in a library can be achieved in the
same way as conditional compilation of sources in a program
(see Conditional Sources). The only difference is that
_LIBADD should be used instead of _LDADD and that it
should mention libtool objects (.lo files).
So, to mimic the hello example from Conditional Sources,
we could build a libhello.la library using either
hello-linux.c or hello-generic.c with the following
Makefile.am.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
EXTRA_libhello_la_SOURCES = hello-linux.c hello-generic.c
libhello_la_LIBADD = $(HELLO_SYSTEM)
libhello_la_DEPENDENCIES = $(HELLO_SYSTEM)
And make sure $(HELLO_SYSTEM) is set to either
hello-linux.lo or hello-generic.lo in
./configure.
Or we could simply use an Automake conditional as follows.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
if LINUX
libhello_la_SOURCES += hello-linux.c
else
libhello_la_SOURCES += hello-generic.c
endif
Sometimes you want to build libtool libraries which should not be installed. These are called libtool convenience libraries and are typically used to encapsulate many sublibraries, later gathered into one big installed library.
Libtool convenience libraries are declared by
noinst_LTLIBRARIES, check_LTLIBRARIES, or even
EXTRA_LTLIBRARIES. Unlike installed libtool libraries they do
not need an -rpath flag at link time (actually this is the only
difference).
Convenience libraries listed in noinst_LTLIBRARIES are always
built. Those listed in check_LTLIBRARIES are built only upon
make check. Finally, libraries listed in
EXTRA_LTLIBRARIES are never built explicitly: Automake outputs
rules to build them, but if the library does not appear as a Makefile
dependency anywhere it won't be built (this is why
EXTRA_LTLIBRARIES is used for conditional compilation).
Here is a sample setup merging libtool convenience libraries from
subdirectories into one main libtop.la library.
# -- Top-level Makefile.am --
SUBDIRS = sub1 sub2 ...
lib_LTLIBRARIES = libtop.la
libtop_la_SOURCES =
libtop_la_LIBADD = \
sub1/libsub1.la \
sub2/libsub2.la \
...
# -- sub1/Makefile.am --
noinst_LTLIBRARIES = libsub1.la
libsub1_la_SOURCES = ...
# -- sub2/Makefile.am --
# showing nested convenience libraries
SUBDIRS = sub2.1 sub2.2 ...
noinst_LTLIBRARIES = libsub2.la
libsub2_la_SOURCES =
libsub2_la_LIBADD = \
sub21/libsub21.la \
sub22/libsub22.la \
...
When using such setup, beware that automake will assume
libtop.la is to be linked with the C linker. This is because
libtop_la_SOURCES is empty, so automake picks C as
default language. If libtop_la_SOURCES was not empty,
automake would select the linker as explained in How the Linker is Chosen.
If one of the sublibraries contains non-C source, it is important that
the appropriate linker be chosen. One way to achieve this is to
pretend that there is such a non-C file among the sources of the
library, thus forcing automake to select the appropriate
linker. Here is the top-level Makefile of our example updated
to force C++ linking.
SUBDIRS = sub1 sub2 ...
lib_LTLIBRARIES = libtop.la
libtop_la_SOURCES =
# Dummy C++ source to cause C++ linking.
nodist_EXTRA_libtop_la_SOURCES = dummy.cxx
libtop_la_LIBADD = \
sub1/libsub1.la \
sub2/libsub2.la \
...
EXTRA_*_SOURCES variables are used to keep track of source
files that might be compiled (this is mostly useful when doing
conditional compilation using AC_SUBST, see Conditional Libtool Sources), and the nodist_ prefix means the listed
sources are not to be distributed (see Program and Library Variables). In effect the file dummy.cxx does not need to
exist in the source tree. Of course if you have some real source file
to list in libtop_la_SOURCES there is no point in cheating with
nodist_EXTRA_libtop_la_SOURCES.
These are libtool libraries meant to be dlopened. They are
indicated to libtool by passing -module at link-time.
pkglib_LTLIBRARIES = mymodule.la
mymodule_la_SOURCES = doit.c
mymodule_la_LDFLAGS = -module
Ordinarily, Automake requires that a library's name starts with
lib. However, when building a dynamically loadable module you
might wish to use a "nonstandard" name. Automake will not complain
about such nonstandard name if it knows the library being built is a
libtool module, i.e., if -module explicitly appears in the
library's _LDFLAGS variable (or in the common AM_LDFLAGS
variable when no per-library _LDFLAGS variable is defined).
As always, AC_SUBST variables are black boxes to Automake since
their values are not yet known when automake is run.
Therefore if -module is set via such a variable, Automake
cannot notice it and will proceed as if the library was an ordinary
libtool library, with strict naming.
If mymodule_la_SOURCES is not specified, then it defaults to
the single file mymodule.c (see Default _SOURCES).
As shown in previous sections, the library_LIBADD
variable should be used to list extra libtool objects (.lo
files) or libtool libraries (.la) to add to library.
The library_LDFLAGS variable is the place to list
additional libtool flags, such as -version-info,
-static, and a lot more. See Link mode.
LTLIBOBJS and LTALLOCA
Where an ordinary library might include $(LIBOBJS) or
$(ALLOCA) (see LIBOBJS), a libtool library must use
$(LTLIBOBJS) or $(LTALLOCA). This is required because
the object files that libtool operates on do not necessarily end in
.o.
Nowadays, the computation of LTLIBOBJS from LIBOBJS is
performed automatically by Autoconf (see AC_LIBOBJ vs. LIBOBJS).
required file `./ltmain.sh' not found
Libtool comes with a tool called libtoolize that will
install libtool's supporting files into a package. Running this
command will install ltmain.sh. You should execute it before
aclocal and automake.
People upgrading old packages to newer autotools are likely to face
this issue because older Automake versions used to call
libtoolize. Therefore old build scripts do not call
libtoolize.
Since Automake 1.6, it has been decided that running
libtoolize was none of Automake's business. Instead, that
functionality has been moved into the autoreconf command
(see Using autoreconf). If you do not want to remember what to run and
when, just learn the autoreconf command. Hopefully,
replacing existing bootstrap.sh or autogen.sh scripts by
a call to autoreconf should also free you from any similar
incompatible change in the future.
created with both libtool and without
Sometimes, the same source file is used both to build a libtool library and to build another non-libtool target (be it a program or another library).
Let's consider the following Makefile.am.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
(In this trivial case the issue could be avoided by linking
libfoo.la with prog instead of listing foo.c in
prog_SOURCES. But let's assume we really want to keep
prog and libfoo.la separate.)
Technically, it means that we should build foo.$(OBJEXT) for
prog, and foo.lo for libfoo.la. The problem is
that in the course of creating foo.lo, libtool may erase (or
replace) foo.$(OBJEXT) - and this cannot be avoided.
Therefore, when Automake detects this situation it will complain with a message such as
object `foo.$(OBJEXT)' created both with libtool and without
A workaround for this issue is to ensure that these two objects get different basenames. As explained in renamed objects, this happens automatically when per-targets flags are used.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
prog_CFLAGS = $(AM_CFLAGS)
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
Adding prog_CFLAGS = $(AM_CFLAGS) is almost a no-op, because
when the prog_CFLAGS is defined, it is used instead of
AM_CFLAGS. However as a side effect it will cause
prog.c and foo.c to be compiled as
prog-prog.$(OBJEXT) and prog-foo.$(OBJEXT) which solves
the issue.
Associated with each program are a collection of variables which can be used to modify how that program is built. There is a similar list of such variables for each library. The canonical name of the program (or library) is used as a base for naming these variables.
In the list below, we use the name "maude" to refer to the program or
library. In your Makefile.am you would replace this with the
canonical name of your program. This list also refers to "maude" as a
program, but in general the same rules apply for both static and dynamic
libraries; the documentation below notes situations where programs and
libraries differ.
maude_SOURCES
.o file (or
.lo when using libtool). Normally these object files are named
after the source file, but other factors can change this. If a file in
the _SOURCES variable has an unrecognized extension, Automake
will do one of two things with it. If a suffix rule exists for turning
files with the unrecognized extension into .o files, then
automake will treat this file as it will any other source file
(see Support for Other Languages). Otherwise, the file will be
ignored as though it were a header file.
The prefixes dist_ and nodist_ can be used to control
whether files listed in a _SOURCES variable are distributed.
dist_ is redundant, as sources are distributed by default, but it
can be specified for clarity if desired.
It is possible to have both dist_ and nodist_ variants of
a given _SOURCES variable at once; this lets you easily
distribute some files and not others, for instance:
nodist_maude_SOURCES = nodist.c
dist_maude_SOURCES = dist-me.c
By default the output file (on Unix systems, the .o file) will be
put into the current build directory. However, if the option
subdir-objects is in effect in the current directory then the
.o file will be put into the subdirectory named after the source
file. For instance, with subdir-objects enabled,
sub/dir/file.c will be compiled to sub/dir/file.o. Some
people prefer this mode of operation. You can specify
subdir-objects in AUTOMAKE_OPTIONS (see Options).
EXTRA_maude_SOURCES
Makefile.in
requires. 4 This means that, for example, you can't put a
configure substitution like @my_sources@ into a _SOURCES
variable. If you intend to conditionally compile source files and use
configure to substitute the appropriate object names into, e.g.,
_LDADD (see below), then you should list the corresponding source
files in the EXTRA_ variable.
This variable also supports dist_ and nodist_ prefixes,
e.g., nodist_EXTRA_maude_SOURCES.
maude_AR
$(AR)
$(ARFLAGS) followed by the name of the library and then the objects
being put into the library. You can override this by setting the
_AR variable. This is usually used with C++; some C++
compilers require a special invocation in order to instantiate all the
templates which should go into a library. For instance, the SGI C++
compiler likes this variable set like so:
libmaude_a_AR = $(CXX) -ar -o
maude_LIBADD
_LIBADD
variable. For instance this should be used for objects determined by
configure (see A Library).
maude_LDADD
_LDADD variable. For instance this should be used for objects
determined by configure (see Linking).
_LDADD and _LIBADD are inappropriate for passing
program-specific linker flags (except for -l, -L,
-dlopen and -dlpreopen). Use the _LDFLAGS variable
for this purpose.
For instance, if your configure.ac uses AC_PATH_XTRA, you
could link your program against the X libraries like so:
maude_LDADD = $(X_PRE_LIBS) $(X_LIBS) $(X_EXTRA_LIBS)
maude_LDFLAGS
maude_DEPENDENCIES
_DEPENDENCIES variable. Each program depends on the
contents of such a variable, but no further interpretation is done.
If _DEPENDENCIES is not supplied, it is computed by Automake.
The automatically-assigned value is the contents of _LDADD or
_LIBADD, with most configure substitutions, -l, -L,
-dlopen and -dlpreopen options removed. The configure
substitutions that are left in are only $(LIBOBJS) and
$(ALLOCA); these are left because it is known that they will not
cause an invalid value for _DEPENDENCIES to be generated.
maude_LINK
_LINK variable must hold the name of a
command which can be passed all the .o file names as arguments.
Note that the name of the underlying program is not passed to
_LINK; typically one uses $@:
maude_LINK = $(CCLD) -magic -o $@
maude_CCASFLAGS
maude_CFLAGS
maude_CPPFLAGS
maude_CXXFLAGS
maude_FFLAGS
maude_GCJFLAGS
maude_LFLAGS
maude_OBJCFLAGS
maude_RFLAGS
maude_YFLAGS
_CCASFLAGS,
_CFLAGS,
_CPPFLAGS,
_CXXFLAGS,
_FFLAGS,
_GCJFLAGS,
_LFLAGS,
_OBJCFLAGS,
_RFLAGS, and
_YFLAGS.
When using a per-target compilation flag, Automake will choose a
different name for the intermediate object files. Ordinarily a file
like sample.c will be compiled to produce sample.o.
However, if the program's _CFLAGS variable is set, then the
object file will be named, for instance, maude-sample.o.
(See also renamed objects.)
In compilations with per-target flags, the ordinary AM_ form of
the flags variable is not automatically included in the
compilation (however, the user form of the variable is included).
So for instance, if you want the hypothetical maude compilations
to also use the value of AM_CFLAGS, you would need to write:
maude_CFLAGS = ... your flags ... $(AM_CFLAGS)
See Flag Variables Ordering, for more discussion about the
interaction between user variables, AM_ shadow variables, and
per-target variables.
maude_SHORTNAME
bin_PROGRAMS = maude
maude_CPPFLAGS = -DSOMEFLAG
maude_SHORTNAME = m
maude_SOURCES = sample.c ...
the object file would be named m-sample.o rather than
maude-sample.o.
This facility is rarely needed in practice, and we recommend avoiding it until you find it is required.
_SOURCES_SOURCES variables are used to specify source files of programs
(see A Program), libraries (see A Library), and Libtool
libraries (see A Shared Library).
When no such variable is specified for a target, Automake will define
one itself. The default is to compile a single C file whose base name
is the name of the target itself, with any extension replaced by
.c. (Defaulting to C is terrible but we are stuck with it for
historical reasons.)
For example if you have the following somewhere in your
Makefile.am with no corresponding libfoo_a_SOURCES:
lib_LIBRARIES = libfoo.a sub/libc++.a
libfoo.a will be built using a default source file named
libfoo.c, and sub/libc++.a will be built from
sub/libc++.c. (In older versions sub/libc++.a
would be built from sub_libc___a.c, i.e., the default source
was the canonized name of the target, with .c appended.
We believe the new behavior is more sensible, but for backward
compatibility automake will use the old name if a file or a rule
with that name exist.)
Default sources are mainly useful in test suites, when building many tests programs each from a single source. For instance in
check_PROGRAMS = test1 test2 test3
test1, test2, and test3 will be built
from test1.c, test2.c, and test3.c.
Another case where is this convenient is building many Libtool modules
(moduleN.la), each defined in its own file (moduleN.c).
AM_LDFLAGS = -module
lib_LTLIBRARIES = module1.la module2.la module3.la
Finally, there is one situation where this default source computation
needs to be avoided: when a target should not be built from sources.
We already saw such an example in true; this happens when all
the constituents of a target have already been compiled and need just
to be combined using a _LDADD variable. Then it is necessary
to define an empty _SOURCES variable, so that automake does not
compute a default.
bin_PROGRAMS = target
target_SOURCES =
target_LDADD = libmain.a libmisc.a
The $(LIBOBJS) and $(ALLOCA) variables list object
files that should be compiled into the project to provide an
implementation for functions that are missing or broken on the host
system. They are substituted by configure.
These variables are defined by Autoconf macros such as
AC_LIBOBJ, AC_REPLACE_FUNCS (see Generic Function Checks), or
AC_FUNC_ALLOCA (see Particular Function Checks). Many other Autoconf
macros call AC_LIBOBJ or AC_REPLACE_FUNCS to
populate $(LIBOBJS).
Using these variables is very similar to doing conditional compilation
using AC_SUBST variables, as described in Conditional Sources. That is, when building a program, $(LIBOBJS) and
$(ALLOCA) should be added to the associated *_LDADD
variable, or to the *_LIBADD variable when building a library.
However there is no need to list the corresponding sources in
EXTRA_*_SOURCES nor to define *_DEPENDENCIES. Automake
automatically adds $(LIBOBJS) and $(ALLOCA) to the
dependencies, and it will discover the list of corresponding source
files automatically (by tracing the invocations of the
AC_LIBSOURCE Autoconf macros).
These variables are usually used to build a portability library that
is linked with all the programs of the project. We now review a
sample setup. First, configure.ac contains some checks that
affect either LIBOBJS or ALLOCA.
# configure.ac
...
AC_CONFIG_LIBOBJ_DIR([lib])
...
AC_FUNC_MALLOC dnl May add malloc.$(OBJEXT) to LIBOBJS
AC_FUNC_MEMCMP dnl May add memcmp.$(OBJEXT) to LIBOBJS
AC_REPLACE_FUNCS([strdup]) dnl May add strdup.$(OBJEXT) to LIBOBJS
AC_FUNC_ALLOCA dnl May add alloca.$(OBJEXT) to ALLOCA
...
AC_CONFIG_FILES([
lib/Makefile
src/Makefile
])
AC_OUTPUT
The AC_CONFIG_LIBOBJ_DIR tells Autoconf that the source files
of these object files are to be found in the lib/ directory.
Automake does not yet use this information; it knows the source files
are expected to be in the directory where the $(LIBOBJS) and
$(ALLOCA) variables are used.
The lib/ directory should therefore contain malloc.c,
memcmp.c, strdup.c, alloca.c. Here is its
Makefile.am:
# lib/Makefile.am
noinst_LIBRARIES = libcompat.a
libcompat_a_SOURCES =
libcompat_a_LIBADD = $(LIBOBJS) $(ALLOCA)
Nothing else is required. The library can have any name, of course,
and anyway it is not going to be installed: it just holds the
replacement versions of the missing or broken functions so we can
later link them in. In many projects also include extra functions,
specific to the project, in that library: they are simply added on
the _SOURCES line.
Finally here is how this library could be used from the src/
directory.
# src/Makefile.am
# Link all programs in this directory with libcompat.a
LDADD = ../lib/libcompat.a
bin_PROGRAMS = tool1 tool2 ...
tool1_SOURCES = ...
tool2_SOURCES = ...
Please note it would be wrong to use the $(LIBOBJS) or
$(ALLOCA) in src/Makefile.am, because these variables
contains unprefixed object names, and for instance
malloc.$(OBJEXT) is not buildable in the src/ directory.
(Actually if you try using $(LIBOBJS) in src/, Automake
will require a copy of malloc.c, memcmp.c,
strdup.c, alloca.c in src/ too.)
Because $(LIBOBJS) and $(ALLOCA) contain object
filenames that end with .$(OBJEXT), they are not suitable for
Libtool libraries (where the expected object extension is .lo):
LTLIBOBJS and LTALLOCA should be used instead.
LTLIBOBJS is defined automatically by Autoconf and should not
be defined by hand (as in the past), however at the time of writing
LTALLOCA still needs to be defined from ALLOCA manually.
See AC_LIBOBJ vs. LIBOBJS.
Occasionally it is useful to know which Makefile variables
Automake uses for compilations; for instance you might need to do your
own compilation in some special cases.
Some variables are inherited from Autoconf; these are CC,
CFLAGS, CPPFLAGS, DEFS, LDFLAGS, and
LIBS.
There are some additional variables which Automake itself defines:
AM_CPPFLAGS
-I and -D options should be listed here.
Automake already provides some -I options automatically. In
particular it generates -I$(srcdir), -I., and a -I
pointing to the directory holding config.h (if you've used
AC_CONFIG_HEADERS or AM_CONFIG_HEADER). You can disable
the default -I options using the nostdinc option.
AM_CPPFLAGS is ignored in preference to a per-executable (or
per-library) _CPPFLAGS variable if it is defined.
INCLUDES
AM_CPPFLAGS (or any per-target
_CPPFLAGS variable if it is used). It is an older name for the
same functionality. This variable is deprecated; we suggest using
AM_CPPFLAGS and per-target _CPPFLAGS instead.
AM_CFLAGS
Makefile.am author can use to pass
in additional C compiler flags. It is more fully documented elsewhere.
In some situations, this is not used, in preference to the
per-executable (or per-library) _CFLAGS.
COMPILE
AM_LDFLAGS
Makefile.am author can use to pass
in additional linker flags. In some situations, this is not used, in
preference to the per-executable (or per-library) _LDFLAGS.
LINK
-o $@ and the usual variable references (for instance,
CFLAGS); it takes as "arguments" the names of the object files
and libraries to link in.
Automake has somewhat idiosyncratic support for Yacc and Lex.
Automake assumes that the .c file generated by yacc (or
lex) should be named using the basename of the input file. That
is, for a yacc source file foo.y, Automake will cause the
intermediate file to be named foo.c (as opposed to
y.tab.c, which is more traditional).
The extension of a yacc source file is used to determine the extension
of the resulting C or C++ file. Files with the extension
.y will be turned into .c files; likewise, .yy will
become .cc; .y++, c++; and .yxx,
.cxx.
Likewise, lex source files can be used to generate C or
C++; the extensions .l, .ll, .l++, and
.lxx are recognized.
You should never explicitly mention the intermediate (C or
C++) file in any SOURCES variable; only list the source
file.
The intermediate files generated by yacc (or lex) will be
included in any distribution that is made. That way the user doesn't
need to have yacc or lex.
If a yacc source file is seen, then your configure.ac must
define the variable YACC. This is most easily done by invoking
the macro AC_PROG_YACC (see Particular Program Checks).
When yacc is invoked, it is passed YFLAGS and
AM_YFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
AM_YFLAGS is usually used to pass the -d option to
yacc. Automake knows what this means and will automatically
adjust its rules to update and distribute the header file built by
yacc -d. What Automake cannot guess, though, is where this
header will be used: it is up to you to ensure the header gets built
before it is first used. Typically this is necessary in order for
dependency tracking to work when the header is included by another
file. The common solution is listing the header file in
BUILT_SOURCES (see Sources) as follows.
BUILT_SOURCES = parser.h
AM_YFLAGS = -d
bin_PROGRAMS = foo
foo_SOURCES = ... parser.y ...
If a lex source file is seen, then your configure.ac
must define the variable LEX. You can use AC_PROG_LEX
to do this (see Particular Program Checks), but using AM_PROG_LEX macro
(see Macros) is recommended.
When lex is invoked, it is passed LFLAGS and
AM_LFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
Automake makes it possible to include multiple yacc (or
lex) source files in a single program. When there is more than
one distinct yacc (or lex) source file in a directory,
Automake uses a small program called ylwrap to run yacc
(or lex) in a subdirectory. This is necessary because yacc's
output filename is fixed, and a parallel make could conceivably invoke
more than one instance of yacc simultaneously. The
ylwrap program is distributed with Automake. It should appear
in the directory specified by AC_CONFIG_AUX_DIR, or one of its
default locations (see Finding `configure' Input).
For yacc, simply managing locking is insufficient. The output of
yacc always uses the same symbol names internally, so it isn't
possible to link two yacc parsers into the same executable.
We recommend using the following renaming hack used in gdb:
#define yymaxdepth c_maxdepth
#define yyparse c_parse
#define yylex c_lex
#define yyerror c_error
#define yylval c_lval
#define yychar c_char
#define yydebug c_debug
#define yypact c_pact
#define yyr1 c_r1
#define yyr2 c_r2
#define yydef c_def
#define yychk c_chk
#define yypgo c_pgo
#define yyact c_act
#define yyexca c_exca
#define yyerrflag c_errflag
#define yynerrs c_nerrs
#define yyps c_ps
#define yypv c_pv
#define yys c_s
#define yy_yys c_yys
#define yystate c_state
#define yytmp c_tmp
#define yyv c_v
#define yy_yyv c_yyv
#define yyval c_val
#define yylloc c_lloc
#define yyreds c_reds
#define yytoks c_toks
#define yylhs c_yylhs
#define yylen c_yylen
#define yydefred c_yydefred
#define yydgoto c_yydgoto
#define yysindex c_yysindex
#define yyrindex c_yyrindex
#define yygindex c_yygindex
#define yytable c_yytable
#define yycheck c_yycheck
#define yyname c_yyname
#define yyrule c_yyrule
For each define, replace the c_ prefix with whatever you like.
These defines work for bison, byacc, and traditional
yaccs. If you find a parser generator that uses a symbol not
covered here, please report the new name so it can be added to the list.
Automake includes full support for C++.
Any package including C++ code must define the output variable
CXX in configure.ac; the simplest way to do this is to use
the AC_PROG_CXX macro (see Particular Program Checks).
A few additional variables are defined when a C++ source file is seen:
CXX
CXXFLAGS
AM_CXXFLAGS
CXXFLAGS.
CXXCOMPILE
CXXLINK
Automake includes some support for assembly code.
The variable CCAS holds the name of the compiler used to build
assembly code. This compiler must work a bit like a C compiler; in
particular it must accept -c and -o. The values of
CCASFLAGS and AM_CCASFLAGS (or its per-target
definition) are passed to the compilation.
The autoconf macro AM_PROG_AS will define CCAS and
CCASFLAGS for you (unless they are already set, it simply sets
CCAS to the C compiler and CCASFLAGS to the C compiler
flags), but you are free to define these variables by other means.
Only the suffixes .s and .S are recognized by
automake as being files containing assembly code.
Automake includes full support for Fortran 77.
Any package including Fortran 77 code must define the output variable
F77 in configure.ac; the simplest way to do this is to use
the AC_PROG_F77 macro (see Particular Program Checks).
A few additional variables are defined when a Fortran 77 source file is seen:
F77
FFLAGS
AM_FFLAGS
FFLAGS.
RFLAGS
AM_RFLAGS
RFLAGS.
F77COMPILE
FLINK
Automake can handle preprocessing Fortran 77 and Ratfor source files in addition to compiling them5. Automake also contains some support for creating programs and shared libraries that are a mixture of Fortran 77 and other languages (see Mixing Fortran 77 With C and C++).
These issues are covered in the following sections.
N.f is made automatically from N.F or N.r. This
rule runs just the preprocessor to convert a preprocessable Fortran 77
or Ratfor source file into a strict Fortran 77 source file. The precise
command used is as follows:
.F
$(F77) -F $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)
.r
$(F77) -F $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)
N.o is made automatically from N.f, N.F or
N.r by running the Fortran 77 compiler. The precise command used
is as follows:
.f
$(F77) -c $(AM_FFLAGS) $(FFLAGS)
.F
$(F77) -c $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)
.r
$(F77) -c $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)
Automake currently provides limited support for creating programs and shared libraries that are a mixture of Fortran 77 and C and/or C++. However, there are many other issues related to mixing Fortran 77 with other languages that are not (currently) handled by Automake, but that are handled by other packages6.
Automake can help in two ways:
-L and
-l) to pass to the automatically selected linker in order to link
in the appropriate Fortran 77 intrinsic and run-time libraries.
These extra Fortran 77 linker flags are supplied in the output variable
FLIBS by the AC_F77_LIBRARY_LDFLAGS Autoconf macro
supplied with newer versions of Autoconf (Autoconf version 2.13 and
later). See Fortran 77 Compiler Characteristics.
If Automake detects that a program or shared library (as mentioned in
some _PROGRAMS or _LTLIBRARIES primary) contains source
code that is a mixture of Fortran 77 and C and/or C++, then it requires
that the macro AC_F77_LIBRARY_LDFLAGS be called in
configure.ac, and that either $(FLIBS)
appear in the appropriate _LDADD (for programs) or _LIBADD
(for shared libraries) variables. It is the responsibility of the
person writing the Makefile.am to make sure that $(FLIBS)
appears in the appropriate _LDADD or
_LIBADD variable.
For example, consider the following Makefile.am:
bin_PROGRAMS = foo
foo_SOURCES = main.cc foo.f
foo_LDADD = libfoo.la $(FLIBS)
pkglib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = bar.f baz.c zardoz.cc
libfoo_la_LIBADD = $(FLIBS)
In this case, Automake will insist that AC_F77_LIBRARY_LDFLAGS
is mentioned in configure.ac. Also, if $(FLIBS) hadn't
been mentioned in foo_LDADD and libfoo_la_LIBADD, then
Automake would have issued a warning.
The following diagram demonstrates under what conditions a particular linker is chosen by Automake.
For example, if Fortran 77, C and C++ source code were to be compiled
into a program, then the C++ linker will be used. In this case, if the
C or Fortran 77 linkers required any special libraries that weren't
included by the C++ linker, then they must be manually added to an
_LDADD or _LIBADD variable by the user writing the
Makefile.am.
\ Linker
source \
code \ C C++ Fortran
----------------- +---------+---------+---------+
| | | |
C | x | | |
| | | |
+---------+---------+---------+
| | | |
C++ | | x | |
| | | |
+---------+---------+---------+
| | | |
Fortran | | | x |
| | | |
+---------+---------+---------+
| | | |
C + C++ | | x | |
| | | |
+---------+---------+---------+
| | | |
C + Fortran | | | x |
| | | |
+---------+---------+---------+
| | | |
C++ + Fortran | | x | |
| | | |
+---------+---------+---------+
| | | |
C + C++ + Fortran | | x | |
| | | |
+---------+---------+---------+
Automake includes full support for Fortran 9x.
Any package including Fortran 9x code must define the output variable
FC in configure.ac; the simplest way to do this is to use
the AC_PROG_FC macro (see Particular Program Checks).
A few additional variables are defined when a Fortran 9x source file is seen:
FC
FCFLAGS
AM_FCFLAGS
FCFLAGS.
FCCOMPILE
FCLINK
N.o is made automatically from N.f90 or N.f95
by running the Fortran 9x compiler. The precise command used
is as follows:
.f9x
$(FC) -c $(AM_FCFLAGS) $(FCFLAGS)
Automake includes support for compiled Java, using gcj, the Java
front end to the GNU Compiler Collection.
Any package including Java code to be compiled must define the output
variable GCJ in configure.ac; the variable GCJFLAGS
must also be defined somehow (either in configure.ac or
Makefile.am). The simplest way to do this is to use the
AM_PROG_GCJ macro.
By default, programs including Java source files are linked with
gcj.
As always, the contents of AM_GCJFLAGS are passed to every
compilation invoking gcj (in its role as an ahead-of-time
compiler - when invoking it to create .class files,
AM_JAVACFLAGS is used instead). If it is necessary to pass
options to gcj from Makefile.am, this variable, and not
the user variable GCJFLAGS, should be used.
gcj can be used to compile .java, .class,
.zip, or .jar files.
When linking, gcj requires that the main class be specified
using the --main= option. The easiest way to do this is to use
the _LDFLAGS variable for the program.
Automake currently only includes full support for C, C++ (see C++ Support), Fortran 77 (see Fortran 77 Support), Fortran 9x (see Fortran 9x Support), and Java (see Java Support). There is only rudimentary support for other languages, support for which will be improved based on user demand.
Some limited support for adding your own languages is available via the suffix rule handling (see Suffixes).
Although the GNU standards allow the use of ANSI C, this can have the effect of limiting portability of a package to some older compilers (notably the SunOS C compiler).
Automake allows you to work around this problem on such machines by de-ANSI-fying each source file before the actual compilation takes place.
If the Makefile.am variable AUTOMAKE_OPTIONS
(see Options) contains the option ansi2knr then code to
handle de-ANSI-fication is inserted into the generated
Makefile.in.
This causes each C source file in the directory to be treated as ANSI C.
If an ANSI C compiler is available, it is used. If no ANSI C compiler
is available, the ansi2knr program is used to convert the source
files into K&R C, which is then compiled.
The ansi2knr program is simple-minded. It assumes the source
code will be formatted in a particular way; see the ansi2knr man
page for details.
Support for de-ANSI-fication requires the source files ansi2knr.c
and ansi2knr.1 to be in the same package as the ANSI C source;
these files are distributed with Automake. Also, the package
configure.ac must call the macro AM_C_PROTOTYPES
(see Macros).
Automake also handles finding the ansi2knr support files in some
other directory in the current package. This is done by prepending the
relative path to the appropriate directory to the ansi2knr
option. For instance, suppose the package has ANSI C code in the
src and lib subdirectories. The files ansi2knr.c and
ansi2knr.1 appear in lib. Then this could appear in
src/Makefile.am:
AUTOMAKE_OPTIONS = ../lib/ansi2knr
If no directory prefix is given, the files are assumed to be in the current directory.
Note that automatic de-ANSI-fication will not work when the package is
being built for a different host architecture. That is because automake
currently has no way to build ansi2knr for the build machine.
Using LIBOBJS with source de-ANSI-fication used to require
hand-crafted code in configure to append $U to basenames
in LIBOBJS. This is no longer true today. Starting with version
2.54, Autoconf takes care of rewriting LIBOBJS and
LTLIBOBJS. (see AC_LIBOBJ vs. LIBOBJS)
As a developer it is often painful to continually update the
Makefile.in whenever the include-file dependencies change in a
project. Automake supplies a way to automatically track dependency
changes.
Automake always uses complete dependencies for a compilation, including
system headers. Automake's model is that dependency computation should
be a side effect of the build. To this end, dependencies are computed
by running all compilations through a special wrapper program called
depcomp. depcomp understands how to coax many different C
and C++ compilers into generating dependency information in the format
it requires. automake -a will install depcomp into your
source tree for you. If depcomp can't figure out how to properly
invoke your compiler, dependency tracking will simply be disabled for
your build.
Experience with earlier versions of Automake (see Dependency Tracking Evolution) taught us that it is not reliable to generate dependencies only on the maintainer's system, as configurations vary too much. So instead Automake implements dependency tracking at build time.
Automatic dependency tracking can be suppressed by putting
no-dependencies in the variable AUTOMAKE_OPTIONS, or
passing no-dependencies as an argument to AM_INIT_AUTOMAKE
(this should be the preferred way). Or, you can invoke automake
with the -i option. Dependency tracking is enabled by default.
The person building your package also can choose to disable dependency
tracking by configuring with --disable-dependency-tracking.
On some platforms, such as Windows, executables are expected to have an
extension such as .exe. On these platforms, some compilers (GCC
among them) will automatically generate foo.exe when asked to
generate foo.
Automake provides mostly-transparent support for this. Unfortunately mostly doesn't yet mean fully. Until the English dictionary is revised, you will have to assist Automake if your package must support those platforms.
One thing you must be aware of is that, internally, Automake rewrites something like this:
bin_PROGRAMS = liver
to this:
bin_PROGRAMS = liver$(EXEEXT)
The targets Automake generates are likewise given the $(EXEEXT)
extension. EXEEXT
However, Automake cannot apply this rewriting to configure
substitutions. This means that if you are conditionally building a
program using such a substitution, then your configure.ac must
take care to add $(EXEEXT) when constructing the output variable.
With Autoconf 2.13 and earlier, you must explicitly use AC_EXEEXT
to get this support. With Autoconf 2.50, AC_EXEEXT is run
automatically if you configure a compiler (say, through
AC_PROG_CC).
Sometimes maintainers like to write an explicit link rule for their
program. Without executable extension support, this is easy--you
simply write a rule whose target is the name of the program. However,
when executable extension support is enabled, you must instead add the
$(EXEEXT) suffix.
Unfortunately, due to the change in Autoconf 2.50, this means you must
always add this extension. However, this is a problem for maintainers
who know their package will never run on a platform that has
executable extensions. For those maintainers, the no-exeext
option (see Options) will disable this feature. This works in a
fairly ugly way; if no-exeext is seen, then the presence of a
rule for a target named foo in Makefile.am will override
an automake-generated rule for foo$(EXEEXT). Without
the no-exeext option, this use will give a diagnostic.
Automake can handle derived objects which are not C programs. Sometimes the support for actually building such objects must be explicitly supplied, but Automake will still automatically handle installation and distribution.
It is possible to define and install programs which are scripts. Such
programs are listed using the SCRIPTS primary name. Automake
doesn't define any dependencies for scripts; the Makefile.am
should include the appropriate rules.
Automake does not assume that scripts are derived objects; such objects must be deleted by hand (see Clean).
The automake program itself is a Perl script that is generated
from automake.in. Here is how this is handled:
bin_SCRIPTS = automake
CLEANFILES = $(bin_SCRIPTS)
do_subst = sed -e 's,[@]datadir[@],$(datadir),g' \
-e 's,[@]PERL[@],$(PERL),g' \
-e 's,[@]PACKAGE[@],$(PACKAGE),g' \
-e 's,[@]VERSION[@],$(VERSION),g' \
...
automake: automake.in Makefile
$(do_subst) < $(srcdir)/automake.in > automake
chmod +x automake
Because--as we have just seen--scripts can be built, they are not
distributed by default. Scripts that should be distributed can be
specified using a dist_ prefix as in other primaries. For
instance the following Makefile.am declares that
my_script should be distributed and installed in
$(sbindir).
dist_sbin_SCRIPTS = my_script
Script objects can be installed in bindir, sbindir,
libexecdir, or pkgdatadir.
Scripts that need not being installed can be listed in
noinst_SCRIPTS, and among them, those which are needed only by
make check should go in check_SCRIPTS.
Header files that must be installed are specified by the
HEADERS family of variables. Headers can be installed in
includedir, oldincludedir, pkgincludedir or any
other directory you may have defined (see Uniform). For instance
include_HEADERS = foo.h bar/bar.h
will install the two files as $(includedir)/foo.h and
$(includedir)/bar.h.
The nobase_ prefix is also supported,
nobase_include_HEADERS = foo.h bar/bar.h
will install the two files as $(includedir)/foo.h and
$(includedir)/bar/bar.h (see Alternative).
Usually, only header files that accompany installed libraries need to
be installed. Headers used by programs or convenience libraries are
not installed. The noinst_HEADERS variable can be used for
such headers. However when the header actually belongs to one
convenient library or program, we recommend listing it in the
program's or library's _SOURCES variable (see Program Sources) instead of in noinst_HEADERS. This is clearer for
the Makefile.am reader. noinst_HEADERS would be the
right variable to use in a directory containing only headers and no
associated library or program.
All header files must be listed somewhere; in a _SOURCES
variable or in a _HEADERS variable. Missing ones will not
appear in the distribution.
For header files that are built and must not be distributed, use the
nodist_ prefix as in nodist_include_HEADERS or
nodist_prog_SOURCES. If these generated headers are needed
during the build, you must also ensure they exist before they are
used (see Sources).
Automake supports the installation of miscellaneous data files using the
DATA family of variables.
Such data can be installed in the directories datadir,
sysconfdir, sharedstatedir, localstatedir, or
pkgdatadir.
By default, data files are not included in a distribution. Of
course, you can use the dist_ prefix to change this on a
per-variable basis.
Here is how Automake declares its auxiliary data files:
dist_pkgdata_DATA = clean-kr.am clean.am ...
Because Automake's automatic dependency tracking works as a side-effect of compilation (see Dependencies) there is a bootstrap issue: a target should not be compiled before its dependencies are made, but these dependencies are unknown until the target is first compiled.
Ordinarily this is not a problem, because dependencies are distributed
sources: they preexist and do not need to be built. Suppose that
foo.c includes foo.h. When it first compiles
foo.o, make only knows that foo.o depends on
foo.c. As a side-effect of this compilation depcomp
records the foo.h dependency so that following invocations of
make will honor it. In these conditions, it's clear there is
no problem: either foo.o doesn't exist and has to be built
(regardless of the dependencies), or accurate dependencies exist and
they can be used to decide whether foo.o should be rebuilt.
It's a different story if foo.h doesn't exist by the first
make run. For instance there might be a rule to build
foo.h. This time file.o's build will fail because the
compiler can't find foo.h. make failed to trigger the
rule to build foo.h first by lack of dependency information.
The BUILT_SOURCES variable is a workaround for this problem. A
source file listed in BUILT_SOURCES is made on make all
or make check (or even make install) before other
targets are processed. However, such a source file is not
compiled unless explicitly requested by mentioning it in some
other _SOURCES variable.
So, to conclude our introductory example, we could use
BUILT_SOURCES = foo.h to ensure foo.h gets built before
any other target (including foo.o) during make all or
make check.
BUILT_SOURCES is actually a bit of a misnomer, as any file which
must be created early in the build process can be listed in this
variable. Moreover, all built sources do not necessarily have to be
listed in BUILT_SOURCES. For instance a generated .c file
doesn't need to appear in BUILT_SOURCES (unless it is included by
another source), because it's a known dependency of the associated
object.
It might be important to emphasize that BUILT_SOURCES is
honored only by make all, make check and make
install. This means you cannot build a specific target (e.g.,
make foo) in a clean tree if it depends on a built source.
However it will succeed if you have run make all earlier,
because accurate dependencies are already available.
The next section illustrates and discusses the handling of built sources on a toy example.
Suppose that foo.c includes bindir.h, which is
installation-dependent and not distributed: it needs to be built. Here
bindir.h defines the preprocessor macro bindir to the
value of the make variable bindir (inherited from
configure).
We suggest several implementations below. It's not meant to be an exhaustive listing of all ways to handle built sources, but it will give you a few ideas if you encounter this issue.
This first implementation will illustrate the bootstrap issue mentioned in the previous section (see Sources).
Here is a tentative Makefile.am.
# This won't work.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
This setup doesn't work, because Automake doesn't know that foo.c
includes bindir.h. Remember, automatic dependency tracking works
as a side-effect of compilation, so the dependencies of foo.o will
be known only after foo.o has been compiled (see Dependencies).
The symptom is as follows.
% make
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
In this example bindir.h is not distributed, not installed, and
it is not even being built on-time. One may wonder what the
nodist_foo_SOURCES = bindir.h line has any use at all. This
line simply states that bindir.h is a source of foo, so
for instance it should be inspected while generating tags
(see Tags). In other words, it does not help our present problem,
and the build would fail identically without it.
BUILT_SOURCES
A solution is to require bindir.h to be built before anything
else. This is what BUILT_SOURCES is meant for (see Sources).
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
BUILT_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
See how bindir.h get built first:
% make
echo '#define bindir "/usr/local/bin"' >bindir.h
make all-am
make[1]: Entering directory `/home/adl/tmp'
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
gcc -g -O2 -o foo foo.o
make[1]: Leaving directory `/home/adl/tmp'
However, as said earlier, BUILT_SOURCES applies only to the
all, check, and install targets. It still fails
if you try to run make foo explicitly:
% make clean
test -z "bindir.h" || rm -f bindir.h
test -z "foo" || rm -f foo
rm -f *.o
% : > .deps/foo.Po # Suppress previously recorded dependencies
% make foo
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
Usually people are happy enough with BUILT_SOURCES because they
never build targets such as make foo before make all, as
in the previous example. However if this matters to you, you can
avoid BUILT_SOURCES and record such dependencies explicitly in
the Makefile.am.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
foo.$(OBJEXT): bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
You don't have to list all the dependencies of foo.o
explicitly, only those which might need to be built. If a dependency
already exists, it will not hinder the first compilation and will be
recorded by the normal dependency tracking code. (Note that after this
first compilation the dependency tracking code will also have recorded
the dependency between foo.o and bindir.h; so our explicit
dependency is really useful to the first build only.)
Adding explicit dependencies like this can be a bit dangerous if you are
not careful enough. This is due to the way Automake tries not to
overwrite your rules (it assumes you know better than it).
foo.$(OBJEXT): bindir.h supersedes any rule Automake may want to
output to build foo.$(OBJEXT). It happens to work in this case
because Automake doesn't have to output any foo.$(OBJEXT):
target: it relies on a suffix rule instead (i.e., .c.$(OBJEXT):).
Always check the generated Makefile.in if you do this.
bindir.h from configure
It's possible to define this preprocessor macro from configure,
either in config.h (see Defining Directories), or by processing a
bindir.h.in file using AC_CONFIG_FILES
(see Configuration Actions).
At this point it should be clear that building bindir.h from
configure work well for this example. bindir.h will exist
before you build any target, hence will not cause any dependency issue.
The Makefile can be shrunk as follows. We do not even have to mention
bindir.h.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
However, it's not always possible to build sources from
configure, especially when these sources are generated by a tool
that needs to be built first...
bindir.c, not bindir.h.
Another attractive idea is to define bindir as a variable or
function exported from bindir.o, and build bindir.c
instead of bindir.h.
noinst_PROGRAMS = foo
foo_SOURCES = foo.c bindir.h
nodist_foo_SOURCES = bindir.c
CLEANFILES = bindir.c
bindir.c: Makefile
echo 'const char bindir[] = "$(bindir)";' >$@
bindir.h contains just the variable's declaration and doesn't
need to be built, so it won't cause any trouble. bindir.o is
always dependent on bindir.c, so bindir.c will get built
first.
There is no panacea, of course. Each solution has its merits and drawbacks.
You cannot use BUILT_SOURCES if the ability to run make
foo on a clean tree is important to you.
You won't add explicit dependencies if you are leery of overriding an Automake rule by mistake.
Building files from ./configure is not always possible, neither
is converting .h files into .c files.
Since Automake is primarily intended to generate Makefile.ins for
use in GNU programs, it tries hard to interoperate with other GNU tools.
Automake provides some support for Emacs Lisp. The LISP primary
is used to hold a list of .el files. Possible prefixes for this
primary are lisp_ and noinst_. Note that if
lisp_LISP is defined, then configure.ac must run
AM_PATH_LISPDIR (see Macros).
Lisp sources are not distributed by default. You can prefix the
LISP primary with dist_, as in dist_lisp_LISP or
dist_noinst_LISP, to indicate that these files should be
distributed.
Automake will byte-compile all Emacs Lisp source files using the Emacs
found by AM_PATH_LISPDIR, if any was found.
Byte-compiled Emacs Lisp files are not portable among all versions of Emacs, so it makes sense to turn this off if you expect sites to have more than one version of Emacs installed. Furthermore, many packages don't actually benefit from byte-compilation. Still, we recommend that you byte-compile your Emacs Lisp sources. It is probably better for sites with strange setups to cope for themselves than to make the installation less nice for everybody else.
There are two ways to avoid byte-compiling. Historically, we have recommended the following construct.
lisp_LISP = file1.el file2.el
ELCFILES =
ELCFILES is an internal Automake variable that normally lists
all .elc files that must be byte-compiled. Automake defines
ELCFILES automatically from lisp_LISP. Emptying this
variable explicitly prevents byte-compilation to occur.
Since Automake 1.8, we now recommend using lisp_DATA instead. As
in
lisp_DATA = file1.el file2.el
Note that these two constructs are not equivalent. _LISP will
not install a file if Emacs is not installed, while _DATA will
always install its files.
If AM_GNU_GETTEXT is seen in configure.ac, then Automake
turns on support for GNU gettext, a message catalog system for
internationalization
(see GNU Gettext).
The gettext support in Automake requires the addition of two
subdirectories to the package, intl and po. Automake
insures that these directories exist and are mentioned in
SUBDIRS.
Automake provides support for GNU Libtool (see Introduction) with the LTLIBRARIES primary.
See A Shared Library.
Automake provides some minimal support for Java compilation with the
JAVA primary.
Any .java files listed in a _JAVA variable will be
compiled with JAVAC at build time. By default, .java
files are not included in the distribution, you should use the
dist_ prefix to distribute them.
Here is a typical setup for distributing .java files and
installing the .class files resulting from their compilation.
javadir = $(datadir)/java
dist_java_JAVA = a.java b.java ...
Currently Automake enforces the restriction that only one _JAVA
primary can be used in a given Makefile.am. The reason for this
restriction is that, in general, it isn't possible to know which
.class files were generated from which .java files - so
it would be impossible to know which files to install where. For
instance, a .java file can define multiple classes; the resulting
.class file names cannot be predicted without parsing the
.java file.
There are a few variables which are used when compiling Java sources:
JAVAC
javac.
JAVACFLAGS
AM_JAVACFLAGS
JAVACFLAGS, should be used when it is necessary to put Java
compiler flags into Makefile.am.
JAVAROOT
-d option to
javac. It defaults to $(top_builddir).
CLASSPATH_ENV
sh expression which is used to set the
CLASSPATH environment variable on the javac command line.
(In the future we will probably handle class path setting differently.)
Automake provides support for Python compilation with the PYTHON
primary.
Any files listed in a _PYTHON variable will be byte-compiled with
py-compile at install time. py-compile actually creates
both standard (.pyc) and byte-compiled (.pyo) versions of
the source files. Note that because byte-compilation occurs at install
time, any files listed in noinst_PYTHON will not be compiled.
Python source files are included in the distribution by default.
Automake ships with an Autoconf macro called AM_PATH_PYTHON which
will determine some Python-related directory variables (see below). If
you have called AM_PATH_PYTHON from configure.ac, then you
may use the following variables to list you Python source files in your
variables: python_PYTHON, pkgpython_PYTHON,
pyexecdir_PYTHON, pkgpyexecdir_PYTHON, depending where you
want your files installed.
AM_PATH_PYTHON([VERSION], [ACTION-IF-FOUND],
[ACTION-IF-NOT-FOUND]) takes three optional arguments. It will
search a Python interpreter on the system. The first argument, if
present, is the minimum version of Python required for this package:
AM_PATH_PYTHON will skip any Python interpreter which is older
than VERSION. If an interpreter is found and satisfies
VERSION, then ACTION-IF-FOUND is run. Otherwise,
ACTION-IF-NOT-FOUND is run.
If ACTION-IF-NOT-FOUND is not specified, the default is to abort
configure. This is fine when Python is an absolute requirement for the
package. Therefore if Python >= 2.2 is only optional to the
package, AM_PATH_PYTHON could be called as follows.
AM_PATH_PYTHON(2.2,, :)
AM_PATH_PYTHON creates several output variables based on the
Python installation found during configuration.
PYTHON
: if no suitable
interpreter could be found.
Assuming ACTION-IF-NOT-FOUND is used (otherwise ./configure
will abort if Python is absent), the value of PYTHON can be used
to setup a conditional in order to disable the relevant part of a build
as follows.
AM_PATH_PYTHON(,, :)
AM_CONDITIONAL([HAVE_PYTHON], [test "$PYTHON" != :])
If the ACTION-IF-NOT-FOUND
is specified
PYTHON_VERSION
1.5). This is currently the value of
sys.version[:3].
PYTHON_PREFIX
${prefix}. This term may be used in future work
which needs the contents of Python's sys.prefix, but general
consensus is to always use the value from configure.
PYTHON_EXEC_PREFIX
${exec_prefix}. This term may be used in future work
which needs the contents of Python's sys.exec_prefix, but general
consensus is to always use the value from configure.
PYTHON_PLATFORM
sys.platform. This value is sometimes needed when
building Python extensions.
pythondir
site-packages subdirectory of the
standard Python install tree.
pkgpythondir
pythondir which is named after the
package. That is, it is $(pythondir)/$(PACKAGE). It is provided
as a convenience.
pyexecdir
pkgpyexecdir
$(pyexecdir)/$(PACKAGE).
All these directory variables have values that start with either
${prefix} or ${exec_prefix} unexpanded. This works
fine in Makefiles, but it makes these variables hard to use in
configure. This is mandated by the GNU coding standards, so
that the user can run make prefix=/foo install. The Autoconf
manual has a section with more details on this topic
(see Installation Directory Variables).
Currently Automake provides support for Texinfo and man pages.
If the current directory contains Texinfo source, you must declare it
with the TEXINFOS primary. Generally Texinfo files are converted
into info, and thus the info_TEXINFOS variable is most commonly used
here. Any Texinfo source file must end in the .texi,
.txi, or .texinfo extension. We recommend .texi
for new manuals.
Automake generates rules to build .info, .dvi, .ps,
.pdf and .html files from your Texinfo sources.
The .info files are built by make all and installed
by make install (unless you use no-installinfo, see below).
The other files can be built on request by make dvi, make ps,
make pdf and make html.
If the .texi file @includes version.texi, then
that file will be automatically generated. The file version.texi
defines four Texinfo flag you can reference using
@value{EDITION}, @value{VERSION},
@value{UPDATED}, and @value{UPDATED-MONTH}.
EDITION
VERSION
UPDATED
.texi file was last modified.
UPDATED-MONTH
.texi file
was last modified.
The version.texi support requires the mdate-sh program;
this program is supplied with Automake and automatically included when
automake is invoked with the --add-missing option.
If you have multiple Texinfo files, and you want to use the
version.texi feature, then you have to have a separate version
file for each Texinfo file. Automake will treat any include in a
Texinfo file that matches vers*.texi just as an automatically
generated version file.
Sometimes an info file actually depends on more than one .texi
file. For instance, in GNU Hello, hello.texi includes the file
gpl.texi. You can tell Automake about these dependencies using
the texi_TEXINFOS variable. Here is how GNU Hello does it:
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
By default, Automake requires the file texinfo.tex to appear in
the same directory as the Texinfo source (this can be changed using the
TEXINFO_TEX variable, see below). However, if you used
AC_CONFIG_AUX_DIR in configure.ac (see Finding `configure' Input), then
texinfo.tex is looked for there. Automake supplies
texinfo.tex if --add-missing is given.
The option no-texinfo.tex can be used to eliminate the
requirement for texinfo.tex. Use of the variable
TEXINFO_TEX is preferable, however, because that allows the
dvi, ps, and pdf targets to still work.
Automake generates an install-info rule; some people apparently
use this. By default, info pages are installed by make install.
This can be prevented via the no-installinfo option.
The following variables are used by the Texinfo build rules.
MAKEINFO
.info files. This
variable is defined by Automake. If the makeinfo program is
found on the system then it will be used by default; otherwise
missing will be used instead.
MAKEINFOHTML
.html files. Automake
defines this to $(MAKEINFO) --html.
MAKEINFOFLAGS
$(MAKEINFO) and
$(MAKEINFOHTML). This user variable (see User Variables) is
not expected to be defined in any Makefile; it can be used by
users to pass extra flags to suit their needs.
AM_MAKEINFOFLAGS
AM_MAKEINFOHTMLFLAGS
makeinfo invocation. These
are maintainer variables that can be overridden in Makefile.am.
$(AM_MAKEINFOFLAGS) is passed to makeinfo when building
.info files; and $(AM_MAKEINFOHTMLFLAGS) is used when
building .html files.
For instance the following setting can be used to obtain one single
.html file per manual, without node separators.
AM_MAKEINFOHTMLFLAGS = --no-headers --no-split
By default, $(AM_MAKEINFOHTMLFLAGS) is set to
$(AM_MAKEINFOFLAGS). This means that defining
$(AM_MAKEINFOFLAGS) without defining
$(AM_MAKEINFOHTMLFLAGS) will impact builds of both .info
and .html files.
TEXI2DVI
.texi file into a
.dvi file. This defaults to texi2dvi, a script that ships
with the Texinfo package.
TEXI2PDF
.texi file into a
.pdf file. This defaults to $(TEXI2DVI) --pdf --batch.
DVIPS
.ps file out of a
.dvi file. This defaults to dvips.
TEXINFO_TEX
TEXINFO_TEX to tell Automake where to find the canonical
texinfo.tex for your package. The value of this variable should
be the relative path from the current Makefile.am to
texinfo.tex:
TEXINFO_TEX = ../doc/texinfo.tex
A package can also include man pages (but see the GNU standards on this
matter, Man Pages.) Man
pages are declared using the MANS primary. Generally the
man_MANS variable is used. Man pages are automatically installed in
the correct subdirectory of mandir, based on the file extension.
File extensions such as .1c are handled by looking for the valid
part of the extension and using that to determine the correct
subdirectory of mandir. Valid section names are the digits
0 through 9, and the letters l and n.
Sometimes developers prefer to name a man page something like
foo.man in the source, and then rename it to have the correct
suffix, e.g. foo.1, when installing the file. Automake also
supports this mode. For a valid section named SECTION, there is a
corresponding directory named manSECTIONdir, and a
corresponding _MANS variable. Files listed in such a variable
are installed in the indicated section. If the file already has a
valid suffix, then it is installed as-is; otherwise the file suffix is
changed to match the section.
For instance, consider this example:
man1_MANS = rename.man thesame.1 alsothesame.1c
In this case, rename.man will be renamed to rename.1 when
installed, but the other files will keep their names.
By default, man pages are installed by make install. However,
since the GNU project does not require man pages, many maintainers do
not expend effort to keep the man pages up to date. In these cases, the
no-installman option will prevent the man pages from being
installed by default. The user can still explicitly install them via
make install-man.
Here is how the man pages are handled in GNU cpio (which
includes both Texinfo documentation and man pages):
man_MANS = cpio.1 mt.1
EXTRA_DIST = $(man_MANS)
Man pages are not currently considered to be source, because it is not
uncommon for man pages to be automatically generated. Therefore they
are not automatically included in the distribution. However, this can
be changed by use of the dist_ prefix.
The nobase_ prefix is meaningless for man pages and is
disallowed.
Naturally, Automake handles the details of actually installing your
program once it has been built. All files named by the various
primaries are automatically installed in the appropriate places when the
user runs make install.
A file named in a primary is installed by copying the built file into the appropriate directory. The base name of the file is used when installing.
bin_PROGRAMS = hello subdir/goodbye
In this example, both hello and goodbye will be installed
in $(bindir).
Sometimes it is useful to avoid the basename step at install time. For
instance, you might have a number of header files in subdirectories of
the source tree which are laid out precisely how you want to install
them. In this situation you can use the nobase_ prefix to
suppress the base name step. For example:
nobase_include_HEADERS = stdio.h sys/types.h
Will install stdio.h in $(includedir) and types.h
in $(includedir)/sys.
Automake generates separate install-data and install-exec
rules, in case the installer is installing on multiple machines which
share directory structure--these targets allow the machine-independent
parts to be installed only once. install-exec installs
platform-dependent files, and install-data installs
platform-independent files. The install target depends on both
of these targets. While Automake tries to automatically segregate
objects into the correct category, the Makefile.am author is, in
the end, responsible for making sure this is done correctly.
Variables using the standard directory prefixes data,
info, man, include, oldinclude,
pkgdata, or pkginclude (e.g. data_DATA) are
installed by install-data.
Variables using the standard directory prefixes bin, sbin,
libexec, sysconf, localstate, lib, or
pkglib (e.g. bin_PROGRAMS) are installed by
install-exec.
Any variable using a user-defined directory prefix with exec in
the name (e.g. myexecbin_PROGRAMS) is installed by
install-exec. All other user-defined prefixes are installed by
install-data.
It is possible to extend this mechanism by defining an
install-exec-local or install-data-local rule. If these
rules exist, they will be run at make install time. These
rules can do almost anything; care is required.
Automake also supports two install hooks, install-exec-hook and
install-data-hook. These hooks are run after all other install
rules of the appropriate type, exec or data, have completed. So, for
instance, it is possible to perform post-installation modifications
using an install hook. Extending gives some examples.
Automake generates support for the DESTDIR variable in all
install rules. DESTDIR is used during the make install
step to relocate install objects into a staging area. Each object and
path is prefixed with the value of DESTDIR before being copied
into the install area. Here is an example of typical DESTDIR usage:
mkdir /tmp/staging &&
make DESTDIR=/tmp/staging install
The mkdir command avoids a security problem if the attacker
creates a symbolic link from /tmp/staging to a victim area;
then make places install objects in a directory tree built under
/tmp/staging. If /gnu/bin/foo and
/gnu/share/aclocal/foo.m4 are to be installed, the above command
would install /tmp/staging/gnu/bin/foo and
/tmp/staging/gnu/share/aclocal/foo.m4.
This feature is commonly used to build install images and packages. For more information, see Makefile Conventions.
Support for DESTDIR is implemented by coding it directly into the
install rules. If your Makefile.am uses a local install rule
(e.g., install-exec-local) or an install hook, then you must
write that code to respect DESTDIR.
Automake also generates rules for targets uninstall,
installdirs, and install-strip.
Automake supports uninstall-local and uninstall-hook.
There is no notion of separate uninstalls for "exec" and "data", as
these features would not provide additional functionality.
Note that uninstall is not meant as a replacement for a real
packaging tool.
The GNU Makefile Standards specify a number of different clean rules. See Standard Targets for Users.
Generally the files that can be cleaned are determined automatically by
Automake. Of course, Automake also recognizes some variables that can
be defined to specify additional files to clean. These variables are
MOSTLYCLEANFILES, CLEANFILES, DISTCLEANFILES, and
MAINTAINERCLEANFILES.
When cleaning involves more than deleting some hard-coded list of
files, it is also possible to supplement the cleaning rules with your
own commands. Simply define a rule for any of the
mostlyclean-local, clean-local, distclean-local,
or maintainer-clean-local targets (see Extending). A common
case is deleting a directory, for instance a directory created by the
test suite:
clean-local:
-rm -rf testSubDir
As the GNU Standards aren't always explicit as to which files should be removed by which rule, we've adopted a heuristic which we believe was first formulated by François Pinard:
make built it, and it is commonly something that one would
want to rebuild (for instance, a .o file), then
mostlyclean should delete it.
make built it, then clean should delete it.
configure built it, then distclean should delete it.
.info file), then
maintainer-clean should delete it. However
maintainer-clean should not delete anything that needs to exist
in order to run ./configure && make.
We recommend that you follow this same set of heuristics in your
Makefile.am.
The dist rule in the generated Makefile.in can be used
to generate a gzip'd tar file and other flavors of archive for
distribution. The files is named based on the PACKAGE and
VERSION variables defined by AM_INIT_AUTOMAKE
(see Macros); more precisely the gzip'd tar file is named
package-version.tar.gz.
You can use the make variable GZIP_ENV to control how gzip
is run. The default setting is --best.
For the most part, the files to distribute are automatically found by
Automake: all source files are automatically included in a distribution,
as are all Makefile.ams and Makefile.ins. Automake also
has a built-in list of commonly used files which are automatically
included if they are found in the current directory (either physically,
or as the target of a Makefile.am rule). This list is printed by
automake --help. Also, files which are read by configure
(i.e. the source files corresponding to the files specified in various
Autoconf macros such as AC_CONFIG_FILES and siblings) are
automatically distributed. Files included in Makefile.ams (using
include) or in configure.ac (using m4_include), and
helper scripts installed with automake --add-missing are also
distributed.
Still, sometimes there are files which must be distributed, but which
are not covered in the automatic rules. These files should be listed in
the EXTRA_DIST variable. You can mention files from
subdirectories in EXTRA_DIST.
You can also mention a directory in EXTRA_DIST; in this case the
entire directory will be recursively copied into the distribution.
Please note that this will also copy everything in the directory,
including CVS/RCS version control files. We recommend against using
this feature.
If you define SUBDIRS, Automake will recursively include the
subdirectories in the distribution. If SUBDIRS is defined
conditionally (see Conditionals), Automake will normally include
all directories that could possibly appear in SUBDIRS in the
distribution. If you need to specify the set of directories
conditionally, you can set the variable DIST_SUBDIRS to the
exact list of subdirectories to include in the distribution
(see Conditional Subdirectories).
Sometimes you need tighter control over what does not go into the
distribution; for instance you might have source files which are
generated and which you do not want to distribute. In this case
Automake gives fine-grained control using the dist and
nodist prefixes. Any primary or _SOURCES variable can be
prefixed with dist_ to add the listed files to the distribution.
Similarly, nodist_ can be used to omit the files from the
distribution.
As an example, here is how you would cause some data to be distributed while leaving some source code out of the distribution:
dist_data_DATA = distribute-this
bin_PROGRAMS = foo
nodist_foo_SOURCES = do-not-distribute.c
Occasionally it is useful to be able to change the distribution before
it is packaged up. If the dist-hook rule exists, it is run
after the distribution directory is filled, but before the actual tar
(or shar) file is created. One way to use this is for distributing
files in subdirectories for which a new Makefile.am is overkill:
dist-hook:
mkdir $(distdir)/random
cp -p $(srcdir)/random/a1 $(srcdir)/random/a2 $(distdir)/random
Another way to to use this is for removing unnecessary files that get recursively included by specifying a directory in EXTRA_DIST:
EXTRA_DIST = doc
dist-hook:
rm -rf `find $(distdir)/doc -name CVS`
Two variables that come handy when writing dist-hook rules are
$(distdir) and $(top_distdir).
$(distdir) points to the directory where the dist rule
will copy files from the current directory before creating the
tarball. If you are at the top-level directory, then distdir =
$(PACKAGE)-$(VERSION). When used from subdirectory named
foo/, then distdir = ../$(PACKAGE)-$(VERSION)/foo.
$(distdir) can be a relative or absolute path, do not assume
any form.
$(top_distdir) always points to the root directory of the
distributed tree. At the top-level it's equal to $(distdir).
In the foo/ subdirectory
top_distdir = ../$(PACKAGE)-$(VERSION).
$(top_distdir) too can be a relative or absolute path.
Note that when packages are nested using AC_CONFIG_SUBDIRS
(see Subpackages), then $(distdir) and
$(top_distdir) are relative to the package where make
dist was run, not to any sub-packages involved.
Automake also generates a distcheck rule which can be of help
to ensure that a given distribution will actually work.
distcheck makes a distribution, then tries to do a VPATH
build, run the test suite, and finally make another tarfile to ensure the
distribution is self-contained.
Building the package involves running ./configure. If you need
to supply additional flags to configure, define them in the
DISTCHECK_CONFIGURE_FLAGS variable, either in your top-level
Makefile.am, or on the command line when invoking make.
If the distcheck-hook rule is defined in your top-level
Makefile.am, then it will be invoked by distcheck after
the new distribution has been unpacked, but before the unpacked copy
is configured and built. Your distcheck-hook can do almost
anything, though as always caution is advised. Generally this hook is
used to check for potential distribution errors not caught by the
standard mechanism. Note that distcheck-hook as well as
DISTCHECK_CONFIGURE_FLAGS are not honored in a subpackage
Makefile.am, but the DISTCHECK_CONFIGURE_FLAGS are
passed down to the configure script of the subpackage.
Speaking about potential distribution errors, distcheck will also
ensure that the distclean rule actually removes all built
files. This is done by running make distcleancheck at the end of
the VPATH build. By default, distcleancheck will run
distclean and then make sure the build tree has been emptied by
running $(distcleancheck_listfiles). Usually this check will
find generated files that you forgot to add to the DISTCLEANFILES
variable (see Clean).
The distcleancheck behavior should be OK for most packages,
otherwise you have the possibility to override the definition of
either the distcleancheck rule, or the
$(distcleancheck_listfiles) variable. For instance to disable
distcleancheck completely, add the following rule to your
top-level Makefile.am:
distcleancheck:
@:
If you want distcleancheck to ignore built files which have not
been cleaned because they are also part of the distribution, add the
following definition instead:
distcleancheck_listfiles = \
find -type f -exec sh -c 'test -f $(srcdir)/{} || echo {}' ';'
The above definition is not the default because it's usually an error if
your Makefiles cause some distributed files to be rebuilt when the user
build the package. (Think about the user missing the tool required to
build the file; or if the required tool is built by your package,
consider the cross-compilation case where it can't be run.) There is
a FAQ entry about this (see distcleancheck), make sure you read it
before playing with distcleancheck_listfiles.
distcheck also checks that the uninstall rule works
properly, both for ordinary and DESTDIR builds. It does this
by invoking make uninstall, and then it checks the install tree
to see if any files are left over. This check will make sure that you
correctly coded your uninstall-related rules.
By default, the checking is done by the distuninstallcheck rule,
and the list of files in the install tree is generated by
$(distuninstallcheck_listfiles) (this is a variable whose value is
a shell command to run that prints the list of files to stdout).
Either of these can be overridden to modify the behavior of
distcheck. For instance, to disable this check completely, you
would write:
distuninstallcheck:
@:
Automake generates rules to provide archives of the project for distributions in various formats. Their targets are:
dist-bzip2
dist-gzip
dist-shar
dist-zip
dist-tarZ
The rule dist (and its historical synonym dist-all) will
create archives in all the enabled formats, Options. By
default, only the dist-gzip target is hooked to dist.
Automake supports two forms of test suites.
If the variable TESTS is defined, its value is taken to be a list
of programs to run in order to do the testing. The programs can either
be derived objects or source objects; the generated rule will look both
in srcdir and .. Programs needing data files should look
for them in srcdir (which is both an environment variable and a
make variable) so they work when building in a separate directory
(see Build Directories), and in particular for the distcheck rule
(see Dist).
The number of failures will be printed at the end of the run. If a given test program exits with a status of 77, then its result is ignored in the final count. This feature allows non-portable tests to be ignored in environments where they don't make sense.
The variable TESTS_ENVIRONMENT can be used to set environment
variables for the test run; the environment variable srcdir is
set in the rule. If all your test programs are scripts, you can also
set TESTS_ENVIRONMENT to an invocation of the shell (e.g.
$(SHELL) -x); this can be useful for debugging the tests.
You may define the variable XFAIL_TESTS to a list of tests
(usually a subset of TESTS) that are expected to fail. This will
reverse the result of those tests.
Automake ensures that each program listed in TESTS is built
before any tests are run; you can list both source and derived programs
in TESTS. For instance, you might want to run a C program as a
test. To do this you would list its name in TESTS and also in
check_PROGRAMS, and then specify it as you would any other
program.
If dejagnu appears in
AUTOMAKE_OPTIONS, then a dejagnu-based test suite is
assumed. The variable DEJATOOL is a list of names which are
passed, one at a time, as the --tool argument to runtest
invocations; it defaults to the name of the package.
The variable RUNTESTDEFAULTFLAGS holds the --tool and
--srcdir flags that are passed to dejagnu by default; this can be
overridden if necessary.
The variables EXPECT and RUNTEST can
also be overridden to provide project-specific values. For instance,
you will need to do this if you are testing a compiler toolchain,
because the default values do not take into account host and target
names.
The contents of the variable RUNTESTFLAGS are passed to the
runtest invocation. This is considered a "user variable"
(see User Variables). If you need to set runtest flags in
Makefile.am, you can use AM_RUNTESTFLAGS instead.
Automake will generate rules to create a local site.exp file,
defining various variables detected by ./configure. This file
is automatically read by DejaGnu. It is OK for the user of a package
to edit this file in order to tune the test suite. However this is
not the place where the test suite author should define new variables:
this should be done elsewhere in the real test suite code.
Especially, site.exp should not be distributed.
For more information regarding DejaGnu test suites, see Top.
In either case, the testing is done via make check.
The installcheck target is available to the user as a way to
run any tests after the package has been installed. You can add tests
to this by writing an installcheck-local rule.
Automake generates rules to automatically rebuild Makefiles,
configure, and other derived files like Makefile.in.
If you are using AM_MAINTAINER_MODE in configure.ac, then
these automatic rebuilding rules are only enabled in maintainer mode.
Sometimes you need to run aclocal with an argument like -I
to tell it where to find .m4 files. Since sometimes make
will automatically run aclocal, you need a way to specify these
arguments. You can do this by defining ACLOCAL_AMFLAGS; this
holds arguments which are passed verbatim to aclocal. This variable
is only useful in the top-level Makefile.am.
Sometimes it is convenient to supplement the rebuild rules for
configure or config.status with additional dependencies.
The variables CONFIGURE_DEPENDENCIES and
CONFIG_STATUS_DEPENDENCIES can be used to list these extra
dependencies. These variable should be defined in all
Makefiles of the tree (because these two rebuild rules are
output in all them), so it is safer and easier to AC_SUBST them
from configure.ac. For instance the following statement will
cause configure to be rerun each time version.sh is
changed.
AC_SUBST([CONFIG_STATUS_DEPENDENCIES], ['$(top_srcdir)/version.sh'])
Note the $(top_srcdir)/ in the filename. Since this variable
is to be used in all Makefiles, its value must be sensible at
any level in the build hierarchy.
Beware not to mistake CONFIGURE_DEPENDENCIES for
CONFIG_STATUS_DEPENDENCIES.
CONFIGURE_DEPENDENCIES adds dependencies to the
configure rule, whose effect is to run autoconf. This
variable should be seldom used, because automake already tracks
m4_included files. However it can be useful when playing
tricky games with m4_esyscmd or similar non-recommendable
macros with side effects.
CONFIG_STATUS_DEPENDENCIES adds dependencies to the
config.status rule, whose effect is to run configure.
This variable should therefore carry any non-standard source that may
be read as a side effect of running configure, like version.sh
in the example above.
Speaking of version.sh scripts, we recommend against them
today. They are mainly used when the version of a package is updated
automatically by a script (e.g., in daily builds). Here is what some
old-style configure.acs may look like:
AC_INIT
. $srcdir/version.sh
AM_INIT_AUTOMAKE([name], $VERSION_NUMBER)
...
Here, version.sh is a shell fragment that sets
VERSION_NUMBER. The problem with this example is that
automake cannot track dependencies (listing version.sh
in CONFIG_STATUS_DEPENDENCIES, and distributing this file is up
to the user), and that it uses the obsolete form of AC_INIT and
AM_INIT_AUTOMAKE. Upgrading to the new syntax is not
straightforward, because shell variables are not allowed in
AC_INIT's arguments. We recommend that version.sh be
replaced by an M4 file that is included by configure.ac:
m4_include([version.m4])
AC_INIT([name], VERSION_NUMBER)
AM_INIT_AUTOMAKE
...
Here version.m4 could contain something like
m4_define([VERSION_NUMBER], [1.2]). The advantage of this
second form is that automake will take care of the dependencies
when defining the rebuild rule, and will also distribute the file
automatically. An inconvenience is that autoconf will now be
rerun each time the version number is bumped, when only
configure had to be rerun in the previous setup.
Various features of Automake can be controlled by options in the
Makefile.am. Such options are applied on a per-Makefile
basis when listed in a special Makefile variable named
AUTOMAKE_OPTIONS. They are applied globally to all processed
Makefiles when listed in the first argument of
AM_INIT_AUTOMAKE in configure.ac. Currently understood
options are:
gnits
gnu
foreign
cygnus
Set the strictness as appropriate. The gnits option also implies
readme-alpha and check-news.
ansi2knr
/ansi2knr
Makefile.in will look in the specified
directory to find the ansi2knr program. The path should be a
relative path to another directory in the same distribution (Automake
currently does not check this).
check-news
make dist to fail unless the current version number appears
in the first few lines of the NEWS file.
dejagnu
dejagnu-specific rules to be generated. See Tests.
dist-bzip2
dist-bzip2 to dist.
dist-shar
dist-shar to dist.
dist-zip
dist-zip to dist.
dist-tarZ
dist-tarZ to dist.
filename-length-max=99
make dist. Such long filenames are generally considered not to
be portable in tarballs. See the tar-v7 and tar-ustar
options below. This option should be used in the top-level
Makefile.am or as an argument of AM_INIT_AUTOMAKE in
configure.ac, it will be ignored otherwise.
no-define
AM_INIT_AUTOMAKE. It will prevent the PACKAGE and
VERSION variables to be AC_DEFINEd.
no-dependencies
--include-deps on the command line,
but is useful for those situations where you don't have the necessary
bits to make automatic dependency tracking work
(see Dependencies). In this case the effect is to effectively
disable automatic dependency tracking.
no-dist
dist target. This is useful
when a package has its own method for making distributions.
no-dist-gzip
dist-gzip to dist.
no-exeext
Makefile.am defines a rule for target foo, it
will override a rule for a target named foo$(EXEEXT). This is
necessary when EXEEXT is found to be empty. However, by
default automake will generate an error for this use. The
no-exeext option will disable this error. This is intended for
use only where it is known in advance that the package will not be
ported to Windows, or any other operating system using extensions on
executables.
no-installinfo
Makefile.in will not cause info pages to be built
or installed by default. However, info and install-info
targets will still be available. This option is disallowed at
GNU strictness and above.
no-installman
Makefile.in will not cause man pages to be
installed by default. However, an install-man target will still
be available for optional installation. This option is disallowed at
GNU strictness and above.
nostdinc
-I options which
are ordinarily automatically provided by Automake.
no-texinfo.tex
texinfo.tex, even if there are texinfo files in
this directory.
readme-alpha
README-alpha
exists, then it will be added to the distribution. If this option is
given, version numbers are expected to follow one of two forms. The
first form is .MINOR.ALPHA.MINORstd-options
Make the installcheck rule check that installed scripts and
programs support the --help and --version options.
This also provides a basic check that the program's
run-time dependencies are satisfied after installation.
In a few situations, programs (or scripts) have to be exempted from this
test. For instance false (from GNU sh-utils) is never
successful, even for --help or --version. You can list
such programs in the variable AM_INSTALLCHECK_STD_OPTIONS_EXEMPT.
Programs (not scripts) listed in this variable should be suffixed by
$(EXEEXT) for the sake of Win32 or OS/2. For instance suppose we
build false as a program but true.sh as a script, and that
neither of them support --help or --version:
AUTOMAKE_OPTIONS = std-options
bin_PROGRAMS = false ...
bin_SCRIPTS = true.sh ...
AM_INSTALLCHECK_STD_OPTIONS_EXEMPT = false$(EXEEXT) true.sh
subdir-objects
subdir/file.cxx, then the output file would be
subdir/file.o.
tar-v7
tar-ustar
tar-pax
These three mutually exclusive options select the tar format to use
when generating tarballs with make dist. (The tar file created
is then compressed according to the set of no-dist-gzip,
dist-bzip2 and dist-tarZ options in use.)
These options must be passed as argument to AM_INIT_AUTOMAKE
(see Macros) because they can require additional configure checks.
Automake will complain if it sees such options in a
AUTOMAKE_OPTIONS variable.
tar-v7 selects the old V7 tar format. This is the historical
default. This antiquated format is understood by all tar
implementations and supports filenames with up to 99 characters. When
given longer filenames some tar implementations will diagnose the
problem while other will generate broken tarballs or use non-portable
extensions. Furthermore, the V7 format cannot store empty
directories. When using this format, consider using the
filename-length-max=99 option to catch filenames too long.
tar-ustar selects the ustar format defined by POSIX
1003.1-1988. This format is believed to be old enough to be portable.
It fully supports empty directories. It can store filenames with up
to 256 characters, provided that the filename can be split at
directory separator in two parts, first of them being at most 155
bytes long. So, in most cases the maximum file name length will be
shorter than 256 characters. However you may run against broken tar
implementations that incorrectly handle filenames longer than 99
characters (please report them to bug-automake@gnu.org so we
can document this accurately).
tar-pax selects the new pax interchange format defined by POSIX
1003.1-2001. It does not limit the length of filenames. However,
this format is very young and should probably be restricted to
packages which target only very modern platforms. There are moves to
change the pax format in an upward-compatible way, so this option may
refer to a more recent version in the future.
See Controlling the Archive Format, for further discussion about tar formats.
configure knows several ways to construct these formats. It
will not abort if it cannot find a tool up to the task (so that the
package can still be built), but make dist will fail.
0.30) can be specified. If Automake is not
newer than the version specified, creation of the Makefile.in
will be suppressed.
-Wcategory--warnings=categoryAM_INIT_AUTOMAKE([-Wall])
in your configure.ac.
Unrecognized options are diagnosed by automake.
If you want an option to apply to all the files in the tree, you can use
the AM_INIT_AUTOMAKE macro in configure.ac.
See Macros.
There are a few rules and variables that didn't fit anywhere else.
etagsAutomake will generate rules to generate TAGS files for use with
GNU Emacs under some circumstances.
If any C, C++ or Fortran 77 source code or headers are present, then
tags and TAGS rules will be generated for the directory.
All files listed using the _SOURCES, _HEADERS, and
_LISP primaries will be used to generate tags. Note that
generated source files that are not distributed must be declared in
variables like nodist_noinst_HEADERS or
nodist_prog_SOURCES or they will be ignored.
At the topmost directory of a multi-directory package, a tags
rule will be output which, when run, will generate a TAGS file
that includes by reference all TAGS files from subdirectories.
The tags rule will also be generated if the variable
ETAGS_ARGS is defined. This variable is intended for use in
directories which contain taggable source that etags does not
understand. The user can use the ETAGSFLAGS to pass additional
flags to etags; AM_ETAGSFLAGS is also available for use
in Makefile.am.
Here is how Automake generates tags for its source, and for nodes in its Texinfo file:
ETAGS_ARGS = automake.in --lang=none \
--regex='/^@node[ \t]+\([^,]+\)/\1/' automake.texi
If you add filenames to ETAGS_ARGS, you will probably also
want to set TAGS_DEPENDENCIES. The contents of this variable
are added directly to the dependencies for the tags rule.
Automake also generates a ctags rule which can be used to
build vi-style tags files. The variable CTAGS
is the name of the program to invoke (by default ctags);
CTAGSFLAGS can be used by the user to pass additional flags,
and AM_CTAGSFLAGS can be used by the Makefile.am.
Automake will also generate an ID rule which will run
mkid on the source. This is only supported on a
directory-by-directory basis.
Automake also supports the GNU Global Tags program. The GTAGS rule runs Global Tags
automatically and puts the result in the top build directory. The
variable GTAGS_ARGS holds arguments which are passed to
gtags.
It is sometimes useful to introduce a new implicit rule to handle a file type that Automake does not know about.
For instance, suppose you had a compiler which could compile .foo
files to .o files. You would simply define an suffix rule for
your language:
.foo.o:
foocc -c -o $@ $<
Then you could directly use a .foo file in a _SOURCES
variable and expect the correct results:
bin_PROGRAMS = doit
doit_SOURCES = doit.foo
This was the simpler and more common case. In other cases, you will
have to help Automake to figure which extensions you are defining your
suffix rule for. This usually happens when your extensions does not
start with a dot. Then, all you have to do is to put a list of new
suffixes in the SUFFIXES variable before you define your
implicit rule.
For instance the following definition prevents Automake to misinterpret
.idlC.cpp: as an attempt to transform .idlC into
.cpp.
SUFFIXES = .idl C.cpp
.idlC.cpp:
# whatever
As you may have noted, the SUFFIXES variable behaves like the
.SUFFIXES special target of make. You should not touch
.SUFFIXES yourself, but use SUFFIXES instead and let
Automake generate the suffix list for .SUFFIXES. Any given
SUFFIXES go at the start of the generated suffixes list, followed
by Automake generated suffixes not already in the list.
Automake has support for an obscure feature called multilibs. A multilib is a library which is built for multiple different ABIs at a single time; each time the library is built with a different target flag combination. This is only useful when the library is intended to be cross-compiled, and it is almost exclusively used for compiler support libraries.
The multilib support is still experimental. Only use it if you are familiar with multilibs and can debug problems you might encounter.
Automake supports an include directive which can be used to
include other Makefile fragments when automake is run.
Note that these fragments are read and interpreted by automake,
not by make. As with conditionals, make has no idea that
include is in use.
There are two forms of include:
include $(srcdir)/file
include $(top_srcdir)/file
Note that if a fragment is included inside a conditional, then the condition applies to the entire contents of that fragment.
Makefile fragments included this way are always distributed because
there are needed to rebuild Makefile.in.
Automake supports a simple type of conditionals.
Before using a conditional, you must define it by using
AM_CONDITIONAL in the configure.ac file (see Macros).
| AM_CONDITIONAL (conditional, condition) | Makro |
The conditional name, conditional, should be a simple string
starting with a letter and containing only letters, digits, and
underscores. It must be different from TRUE and FALSE
which are reserved by Automake.
The shell condition (suitable for use in a shell |
Conditionals typically depend upon options which the user provides to
the configure script. Here is an example of how to write a
conditional which is true if the user uses the --enable-debug
option.
AC_ARG_ENABLE(debug,
[ --enable-debug Turn on debugging],
[case "${enableval}" in
yes) debug=true ;;
no) debug=false ;;
*) AC_MSG_ERROR(bad value ${enableval} for --enable-debug) ;;
esac],[debug=false])
AM_CONDITIONAL(DEBUG, test x$debug = xtrue)
Here is an example of how to use that conditional in Makefile.am:
if DEBUG
DBG = debug
else
DBG =
endif
noinst_PROGRAMS = $(DBG)
This trivial example could also be handled using EXTRA_PROGRAMS (see Conditional Programs).
You may only test a single variable in an if statement, possibly
negated using !. The else statement may be omitted.
Conditionals may be nested to any depth. You may specify an argument to
else in which case it must be the negation of the condition used
for the current if. Similarly you may specify the condition
which is closed by an end:
if DEBUG
DBG = debug
else !DEBUG
DBG =
endif !DEBUG
Unbalanced conditions are errors.
Note that conditionals in Automake are not the same as conditionals in
GNU Make. Automake conditionals are checked at configure time by the
configure script, and affect the translation from
Makefile.in to Makefile. They are based on options passed
to configure and on results that configure has discovered
about the host system. GNU Make conditionals are checked at make
time, and are based on variables passed to the make program or defined
in the Makefile.
Automake conditionals will work with any make program.
--gnu and --gnitsThe --gnu option (or gnu in the AUTOMAKE_OPTIONS
variable) causes automake to check the following:
INSTALL, NEWS, README, AUTHORS,
and ChangeLog, plus one of COPYING.LIB, COPYING.LESSER
or COPYING, are required at the topmost directory of the package.
no-installman and no-installinfo are
prohibited.
Note that this option will be extended in the future to do even more
checking; it is advisable to be familiar with the precise requirements
of the GNU standards. Also, --gnu can require certain
non-standard GNU programs to exist for use by various maintainer-only
rules; for instance in the future pathchk might be required for
make dist.
The --gnits option does everything that --gnu does, and
checks the following as well:
make installcheck will check to make sure that the --help
and --version really print a usage message and a version string,
respectively. This is the std-options option (see Options).
make dist will check to make sure the NEWS file has been
updated to the current version.
VERSION is checked to make sure its format complies with Gnits
standards.
VERSION indicates that this is an alpha release, and the file
README-alpha appears in the topmost directory of a package, then
it is included in the distribution. This is done in --gnits
mode, and no other, because this mode is the only one where version
number formats are constrained, and hence the only mode where Automake
can automatically determine whether README-alpha should be
included.
THANKS is required.
--cygnusSome packages, notably GNU GCC and GNU gdb, have a build environment originally written at Cygnus Support (subsequently renamed Cygnus Solutions, and then later purchased by Red Hat). Packages with this ancestry are sometimes referred to as "Cygnus" trees.
A Cygnus tree has slightly different rules for how a Makefile.in
is to be constructed. Passing --cygnus to automake will
cause any generated Makefile.in to comply with Cygnus rules.
Here are the precise effects of --cygnus:
texinfo.tex is not required if a Texinfo source file is
specified. The assumption is that the file will be supplied, but in a
place that Automake cannot find. This assumption is an artifact of how
Cygnus packages are typically bundled.
make dist is not supported, and the rules for it are not
generated. Cygnus-style trees use their own distribution mechanism.
PATH. These tools are runtest, expect,
makeinfo and texi2dvi.
--foreign is implied.
no-installinfo and no-dependencies are
implied.
AM_MAINTAINER_MODE and AM_CYGWIN32 are
required.
check target doesn't depend on all.
GNU maintainers are advised to use gnu strictness in preference
to the special Cygnus mode. Some day, perhaps, the differences between
Cygnus trees and GNU trees will disappear (for instance, as GCC is made
more standards compliant). At that time the special Cygnus mode will be
removed.
In some situations, where Automake is not up to one task, one has to
resort to handwritten rules or even handwritten Makefiles.
With some minor exceptions (like _PROGRAMS variables being
rewritten to append $(EXEEXT)), the contents of a
Makefile.am is copied to Makefile.in verbatim.
These copying semantics means that many problems can be worked around
by simply adding some make variables and rules to
Makefile.am. Automake will ignore these additions.
Since a Makefile.in is built from data gathered from three
different places (Makefile.am, configure.ac, and
automake itself), it is possible to have conflicting
definitions of rules or variables. When building Makefile.in
the following priorities are respected by automake to ensure
the user always have the last word. User defined variables in
Makefile.am have priority over variables AC_SUBSTed from
configure.ac, and AC_SUBSTed variables have priority
over automake-defined variables. As far rules are
concerned, a user-defined rule overrides any
automake-defined rule for the same target.
These overriding semantics make it possible to fine tune some default
settings of Automake, or replace some of its rules. Overriding
Automake rules is often inadvisable, particularly in the topmost
directory of a package with subdirectories. The -Woverride
option (see Invoking Automake) comes handy to catch overridden
definitions.
Note that Automake does not make any difference between rules with
commands and rules that only specify dependencies. So it is not
possible to append new dependencies to an automake-defined
target without redefining the entire rule.
However, various useful targets have a -local version you can
specify in your Makefile.am. Automake will supplement the
standard target with these user-supplied targets.
The targets that support a local version are all, info,
dvi, ps, pdf, html, check,
install-data, install-exec, uninstall,
installdirs, installcheck and the various clean targets
(mostlyclean, clean, distclean, and
maintainer-clean). Note that there are no
uninstall-exec-local or uninstall-data-local targets; just
use uninstall-local. It doesn't make sense to uninstall just
data or just executables.
For instance, here is one way to install a file in /etc:
install-data-local:
$(INSTALL_DATA) $(srcdir)/afile $(DESTDIR)/etc/afile
Some rule also have a way to run another rule, called a hook,
after their work is done. The hook is named after the principal target,
with -hook appended. The targets allowing hooks are
install-data, install-exec, uninstall, dist,
and distcheck.
For instance, here is how to create a hard link to an installed program:
install-exec-hook:
ln $(DESTDIR)$(bindir)/program$(EXEEXT) \
$(DESTDIR)$(bindir)/proglink$(EXEEXT)
Although cheaper and more portable than symbolic links, hard links
will not work everywhere (for instance OS/2 does not have
ln). Ideally you should fall back to cp -p when
ln does not work. An easy way, if symbolic links are
acceptable to you, is to add AC_PROG_LN_S to
configure.ac (see Particular Program Checks) and use $(LN_S) in
Makefile.am.
For instance, here is how you could install a versioned copy of a
program using $(LN_S):
install-exec-hook:
cd $(DESTDIR)$(bindir) && \
mv -f prog$(EXEEXT) prog-$(VERSION)$(EXEEXT) && \
$(LN_S) prog-$(VERSION)$(EXEEXT) prog$(EXEEXT)
Note that we rename the program so that a new version will erase the
symbolic link, not the real binary. Also we cd into the
destination directory in order to create relative links.
When writing install-exec-hook or install-data-hook,
please bear in mind that the exec/data distinction is based on the
installation directory, not on the primary used (see Install). So
a foo_SCRIPTS will be installed by install-data, and a
barexec_SCRIPTS will be installed by install-exec. You
should define your hooks consequently.
MakefilesIn most projects all Makefiles are generated by Automake. In
some cases, however, projects need to embed subdirectories with
handwritten Makefiles. For instance one subdirectory could be
a third-party project with its own build system, not using Automake.
It is possible to list arbitrary directories in SUBDIRS or
DIST_SUBDIRS provided each of these directories has a
Makefile that recognizes all the following recursive targets.
When a user runs one of these targets, that target is run recursively
in all subdirectories. This is why it is important that even
third-party Makefiles support them.
all
Makefiles, but it does not need to be the
default in third-party Makefiles.
distdir
$(distdir), before a tarball is
constructed. Of course this target is not required if the
no-dist option (see Options) is used.
The variables $(top_distdir) and $(distdir)
(see Dist) will be passed from the outer package to the subpackage
when the distdir target is invoked. These two variables have
been adjusted for the directory which is being recursed into, so they
are ready to use.
install
install-data
install-exec
uninstall
install-info
installdirs
check
installcheck
mostlyclean
clean
distclean
maintainer-clean
dvi
pdf
ps
info
html
tags
ctags
TAGS and CTAGS (see Tags).
If you have ever used Gettext in a project, this is a good example of
how third-party Makefiles can be used with Automake. The
Makefiles gettextize puts in the po/ and
intl/ directories are handwritten Makefiles that
implement all these targets. That way they can be added to
SUBDIRS in Automake packages.
Directories which are only listed in DIST_SUBDIRS but not in
SUBDIRS need only the distclean,
maintainer-clean, and distdir rules (see Conditional Subdirectories).
Usually, many of these rules are irrelevant to the third-party
subproject, but they are required for the whole package to work. It's
OK to have a rule that does nothing, so if you are integrating a
third-party project with no documentation or tag support, you could
simply augment its Makefile as follows:
EMPTY_AUTOMAKE_TARGETS = dvi pdf ps info html tags ctags
.PHONY: $(EMPTY_AUTOMAKE_TARGETS)
$(EMPTY_AUTOMAKE_TARGETS):
Another aspect of integrating third-party build systems is whether
they support VPATH builds. Obviously if the subpackage does not
support VPATH builds the whole package will not support VPATH builds.
This in turns means that make distcheck will not work, because
it relies on VPATH builds. Some people can live without this
(actually, many Automake users have never heard of make
distcheck). Other people may prefer to revamp the existing
Makefiles to support VPATH. Doing so does not necessarily
require Automake, only Autoconf is needed (see Build Directories). The necessary
substitutions: @scrdir@, @top_srcdir@, and
@top_builddir@ are defined by configure when it
processes a Makefile (see Preset Output Variables), they are not
computed by the Makefile like the aforementioned $(distdir) and
$(top_distdir) variables..
It is sometimes inconvenient to modify a third-party Makefile
to introduce the above required targets. For instance one may want to
keep the third-party sources untouched to ease upgrades to new
versions.
Here are two other ideas. If GNU make is assumed, one possibility is
to add to that subdirectory a GNUmakefile that defines the
required targets and include the third-party Makefile. For
this to work in VPATH builds, GNUmakefile must lie in the build
directory; the easiest way to do this is to write a
GNUmakefile.in instead, and have it processed with
AC_CONFIG_FILES from the outer package. For example if we
assume Makefile defines all targets except the documentation
targets, and that the check target is actually called
test, we could write GNUmakefile (or
GNUmakefile.in) like this:
# First, include the real Makefile
include Makefile
# Then, define the other targets needed by Automake Makefiles.
.PHONY: dvi pdf ps info html check
dvi pdf ps info html:
check: test
A similar idea that does not use include is to write a proxy
Makefile that dispatches rules to the real Makefile,
either with $(MAKE) -f Makefile.real $(AM_MAKEFLAGS) target (if
it's OK to rename the original Makefile) or with cd
subdir && $(MAKE) $(AM_MAKEFLAGS) target (if it's OK to store the
subdirectory project one directory deeper). The good news is that
this proxy Makefile can be generated with Automake. All we
need are -local targets (see Extending) that perform the
dispatch. Of course the other Automake features are available, so you
could decide to let Automake perform distribution or installation.
Here is a possible Makefile.am:
all-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) all
check-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) test
clean-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) clean
# Assuming the package knows how to install itself
install-data-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-data
install-exec-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-exec
uninstall-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) uninstall
# Distribute files from here.
EXTRA_DIST = subdir/Makefile subdir/program.c ...
Pushing this idea to the extreme, it is also possible to ignore the
subproject build system and build everything from this proxy
Makefile.am. This might sounds very sensible if you need VPATH
builds but the subproject does not support them.
Makefile.insAutomake places no restrictions on the distribution of the resulting
Makefile.ins. We still encourage software authors to
distribute their work under terms like those of the GPL, but doing so
is not required to use Automake.
Some of the files that can be automatically installed via the
--add-missing switch do fall under the GPL. However, these also
have a special exception allowing you to distribute them with your
package, regardless of the licensing you choose.
New Automake releases usually include bug fixes and new features. Unfortunately they may also introduce new bugs and incompatibilities. This makes four reasons why a package may require a particular Automake version.
Things get worse when maintaining a large tree of packages, each one
requiring a different version of Automake. In the past, this meant that
any developer (and sometime users) had to install several versions of
Automake in different places, and switch $PATH appropriately for
each package.
Starting with version 1.6, Automake installs versioned binaries. This
means you can install several versions of Automake in the same
$prefix, and can select an arbitrary Automake version by running
automake-1.6 or automake-1.7 without juggling with
$PATH. Furthermore, Makefile's generated by Automake 1.6
will use automake-1.6 explicitly in their rebuild rules.
The number 1.6 in automake-1.6 is Automake's API version,
not Automake's version. If a bug fix release is made, for instance
Automake 1.6.1, the API version will remain 1.6. This means that a
package which work with Automake 1.6 should also work with 1.6.1; after
all, this is what people expect from bug fix releases.
If your package relies on a feature or a bug fix introduced in
a release, you can pass this version as an option to Automake to ensure
older releases will not be used. For instance, use this in your
configure.ac:
AM_INIT_AUTOMAKE(1.6.1) dnl Require Automake 1.6.1 or better.
or, in a particular Makefile.am:
AUTOMAKE_OPTIONS = 1.6.1 # Require Automake 1.6.1 or better.
Automake will print an error message if its version is older than the requested version.
Automake's programming interface is not easy to define. Basically it
should include at least all documented variables and targets
that a Makefile.am author can use, any behavior associated with
them (e.g. the places where -hook's are run), the command line
interface of automake and aclocal, ...
Every undocumented variable, target, or command line option, is not part of the API. You should avoid using them, as they could change from one version to the other (even in bug fix releases, if this helps to fix a bug).
If it turns out you need to use such a undocumented feature, contact automake@gnu.org and try to get it documented and exercised by the test-suite.
Automake maintains three kind of files in a package.
aclocal.m4
Makefile.ins
install-sh or py-compile
aclocal.m4 is generated by aclocal and contains some
Automake-supplied M4 macros. Auxiliary tools are installed by
automake --add-missing when needed. Makefile.ins are
built from Makefile.am by automake, and rely on the
definitions of the M4 macros put in aclocal.m4 as well as the
behavior of the auxiliary tools installed.
Because all these files are closely related, it is important to regenerate all of them when upgrading to a newer Automake release. The usual way to do that is
aclocal # with any option needed (such a -I m4)
autoconf
automake --add-missing --force-missing
or more conveniently:
autoreconf -vfi
The use of --force-missing ensures that auxiliary tools will be
overridden by new versions (see Invoking Automake).
It is important to regenerate all these files each time Automake is
upgraded, even between bug fixes releases. For instance it is not
unusual for a bug fix to involve changes to both the rules generated
in Makefile.in and the supporting M4 macros copied to
aclocal.m4.
Presently automake is able to diagnose situations where
aclocal.m4 has been generated with another version of
aclocal. However it never checks whether auxiliary scripts
are up-to-date. In other words, automake will tell you when
aclocal needs to be rerun, but it will never diagnose a
missing --force-missing.
Before upgrading to a new major release, it is a good idea to read the
file NEWS. This file lists all changes between releases: new
features, obsolete constructs, known incompatibilities, and
workarounds.
This chapter covers some questions that often come up on the mailing lists.
Packages made with Autoconf and Automake ship with some generated
files like configure or Makefile.in. These files were
generated on the developer's host and are distributed so that
end-users do not have to install the maintainer tools required to
rebuild them. Other generated files like Lex scanners, Yacc parsers,
or Info documentation, are usually distributed on similar grounds.
Automake outputs rules in Makefiles to rebuild these files. For
instance make will run autoconf to rebuild
configure whenever configure.ac is changed. This makes
development safer by ensuring a configure is never out-of-date
with respect to configure.ac.
As generated files shipped in packages are up-to-date, and because
tar preserves times-tamps, these rebuild rules are not
triggered when a user unpacks and builds a package.
Unless you use CVS keywords (in which case files must be updated at
commit time), CVS preserves timestamp during cvs commit and
cvs import -d operations.
When you check out a file using cvs checkout its timestamp is
set to that of the revision which is being checked out.
However, during cvs update, files will have the date of the
update, not the original timestamp of this revision. This is meant to
make sure that make notices sources files have been updated.
This timestamp shift is troublesome when both sources and generated
files are kept under CVS. Because CVS processes files in alphabetical
order, configure.ac will appear older than configure
after a cvs update that updates both files, even if
configure was newer than configure.ac when it was
checked in. Calling make will then trigger a spurious rebuild
of configure.
There are basically two clans amongst maintainers: those who keep all distributed files under CVS, including generated files, and those who keep generated files out of CVS.
Makefile.ins when you upgrade Automake
and make sure they look OK).
cvs update to update their copy, instead of
cvs checkout to fetch a fresh one, timestamps will be
inaccurate. Some rebuild rules will be triggered and attempt to
run developer tools such as autoconf or automake.
Actually, calls to such tools are all wrapped into a call to the
missing script discussed later (see maintainer-mode).
missing will take care of fixing the timestamps when these
tools are not installed, so that the build can continue.
configure.ac uses AM_MAINTAINER_MODE, which will
disable all these rebuild rules by default. This is further discussed
in maintainer-mode.
For instance, suppose a developer has modified Makefile.am and
rebuilt Makefile.in, and then decide to do a last-minute change
to Makefile.am right before checking in both files (without
rebuilding Makefile.in to account for the change).
This last change to Makefile.am make the copy of
Makefile.in out-of-date. Since CVS processes files
alphabetically, when another developer cvs update his or her
tree, Makefile.in will happen to be newer than
Makefile.am. This other developer will not see
Makefile.in is out-of-date.
One way to get CVS and make working peacefully is to never
store generated files in CVS, i.e., do not CVS-control files which
are Makefile targets (also called derived files).
This way developers are not annoyed by changes to generated files. It
does not matter if they all have different versions (assuming they are
compatible, of course). And finally, timestamps are not lost, changes
to sources files can't be missed as in the
Makefile.am/Makefile.in example discussed earlier.
The drawback is that the CVS repository is not an exact copy of what is distributed and that users now need to install various development tools (maybe even specific versions) before they can build a checkout. But, after all, CVS's job is versioning, not distribution.
Allowing developers to use different versions of their tools can also hide bugs during distributed development. Indeed, developers will be using (hence testing) their own generated files, instead of the generated files that will be released actually. The developer who prepares the tarball might be using a version of the tool that produces bogus output (for instance a non-portable C file), something other developers could have noticed if they weren't using their own versions of this tool.
Another class of files not discussed here (because they do not cause
timestamp issues) are files which are shipped with a package, but
maintained elsewhere. For instance tools like gettextize
and autopoint (from Gettext) or libtoolize (from
Libtool), will install or update files in your package.
These files, whether they are kept under CVS or not, raise similar concerns about version mismatch between developers' tools. The Gettext manual has a section about this, see CVS Issues.
missing and AM_MAINTAINER_MODEmissing
The missing script is a wrapper around several maintainer
tools, designed to warn users if a maintainer tool is required but
missing. Typical maintainer tools are autoconf,
automake, bison, etc. Because file generated by
these tools are shipped with the other sources of a package, these
tools shouldn't be required during a user build and they are not
checked for in configure.
However, if for some reason a rebuild rule is triggered and involves a
missing tool, missing will notice it and warn the user.
Besides the warning, when a tool is missing, missing will
attempt to fix timestamps in a way which allow the build to continue.
For instance missing will touch configure if
autoconf is not installed. When all distributed files are
kept under CVS, this feature of missing allows user
with no maintainer tools to build a package off CVS, bypassing
any timestamp inconsistency implied by cvs update.
If the required tool is installed, missing will run it and
won't attempt to continue after failures. This is correct during
development: developers love fixing failures. However, users with
wrong versions of maintainer tools may get an error when the rebuild
rule is spuriously triggered, halting the build. This failure to let
the build continue is one of the arguments of the
AM_MAINTAINER_MODE advocates.
AM_MAINTAINER_MODE
AM_MAINTAINER_MODE disables the so called "rebuild rules" by
default. If you have AM_MAINTAINER_MODE in
configure.ac, and run ./configure && make, then
make will *never* attempt to rebuilt configure,
Makefile.ins, Lex or Yacc outputs, etc. I.e., this disables
build rules for files which are usually distributed and that users
should normally not have to update.
If you run ./configure --enable-maintainer-mode, then these
rebuild rules will be active.
People use AM_MAINTAINER_MODE either because they do want their
users (or themselves) annoyed by timestamps lossage (see CVS), or
because they simply can't stand the rebuild rules and prefer running
maintainer tools explicitly.
AM_MAINTAINER_MODE also allows you to disable some custom build
rules conditionally. Some developers use this feature to disable
rules that need exotic tools that users may not have available.
Several years ago François Pinard pointed out several arguments
against AM_MAINTAINER_MODE. Most of them relate to insecurity.
By removing dependencies you get non-dependable builds: change to
sources files can have no effect on generated files and this can be
very confusing when unnoticed. He adds that security shouldn't be
reserved to maintainers (what --enable-maintainer-mode
suggests), on the contrary. If one user has to modify a
Makefile.am, then either Makefile.in should be updated
or a warning should be output (this is what Automake uses
missing for) but the last thing you want is that nothing
happens and the user doesn't notice it (this is what happens when
rebuild rules are disabled by AM_MAINTAINER_MODE).
Jim Meyering, the inventor of the AM_MAINTAINER_MODE macro was
swayed by François's arguments, and got rid of
AM_MAINTAINER_MODE in all of his packages.
Still many people continue to use AM_MAINTAINER_MODE, because
it helps them working on projects where all files are kept under CVS,
and because missing isn't enough if you have the wrong
version of the tools.
Developers are lazy. They often would like to use wildcards in
Makefile.ams, so they don't need to remember they have to
update Makefile.ams every time they add, delete, or rename a
file.
There are several objections to this:
cvs add or cvs rm anyway. Updating
Makefile.am accordingly quickly becomes a reflex.
Conversely, if your application doesn't compile
because you forgot to add a file in Makefile.am, it will help
you remember to cvs add it.
make dist will complain. Besides, you don't distribute
more than what you listed.
forget adding a file to
Makefile.am, because if you don't add it, it doesn't get
compiled nor installed, so you can't even test it.
Still, these are philosophical objections, and as such you may disagree, or find enough value in wildcards to dismiss all of them. Before you start writing a patch against Automake to teach it about wildcards, let's see the main technical issue: portability.
Although $(wildcard ...) works with GNU make, it is
not portable to other make implementations.
The only way Automake could support $(wildcard ...) is by
expending $(wildcard ...) when automake is run.
Resulting Makefile.ins would be portable since they would
list all files and not use $(wildcard ...). However that
means developers need to remember they must run automake each
time they add, delete, or rename files.
Compared to editing Makefile.am, this is really little win. Sure,
it's easier and faster to type automake; make than to type
emacs Makefile.am; make. But nobody bothered enough to write a
patch add support for this syntax. Some people use scripts to
generated file lists in Makefile.am or in separate
Makefile fragments.
Even if you don't care about portability, and are tempted to use
$(wildcard ...) anyway because you target only GNU Make, you
should know there are many places where Automake need to know exactly
which files should be processed. As Automake doesn't know how to
expand $(wildcard ...), you cannot use it in these places.
$(wildcard ...) is a black box comparable to AC_SUBSTed
variables as far Automake is concerned.
You can get warnings about $(wildcard ...) constructs using the
-Wportability flag.
This is a diagnostic you might encounter while running make
distcheck.
As explained in Dist, make distcheck attempts to build
and check your package for errors like this one.
make distcheck will perform a VPATH build of your
package, and then call make distclean. Files left in the build
directory after make distclean has run are listed after this
error.
This diagnostic really covers two kinds of errors:
The former left-over files are not distributed, so the fix is to mark them for cleaning (see Clean), this is obvious and doesn't deserve more explanations.
The latter bug is not always easy to understand and fix, so let's
proceed with an example. Suppose our package contains a program for
which we want to build a man page using help2man. GNU
help2man produces simple manual pages from the --help
and --version output of other commands (see Overview). Because we don't to force want our
users to install help2man, we decide to distribute the
generated man page using the following setup.
# This Makefile.am is bogus.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This will effectively distribute the man page. However,
make distcheck will fail with:
ERROR: files left in build directory after distclean:
./foo.1
Why was foo.1 rebuilt? Because although distributed,
foo.1 depends on a non-distributed built file:
foo$(EXEEXT). foo$(EXEEXT) is built by the user, so it
will always appear to be newer than the distributed foo.1.
make distcheck caught an inconsistency in our package. Our
intent was to distribute foo.1 so users do not need installing
help2man, however since this our rule causes this file to be
always rebuilt, users do need help2man. Either we
should ensure that foo.1 is not rebuilt by users, or there is
no point in distributing foo.1.
More generally, the rule is that distributed files should never depend on non-distributed built files. If you distribute something generated, distribute its sources.
One way to fix the above example, while still distributing
foo.1 is to not depend on foo$(EXEEXT). For instance,
assuming foo --version and foo --help do not
change unless foo.c or configure.ac change, we could
write the following Makefile.am:
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo.c $(top_srcdir)/configure.ac
$(MAKE) $(AM_MAKEFLAGS) foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This way, foo.1 will not get rebuilt every time
foo$(EXEEXT) changes. The make call makes sure
foo$(EXEEXT) is up-to-date before help2man. Another
way to ensure this would be to use separate directories for binaries
and man pages, and set SUBDIRS so that binaries are built
before man pages.
We could also decide not to distribute foo.1. In
this case it's fine to have foo.1 dependent upon
foo$(EXEEXT), since both will have to be rebuilt.
However it would be impossible to build the package in a
cross-compilation, because building foo.1 involves
an execution of foo$(EXEEXT).
Another context where such errors are common is when distributed files are built by tools which are built by the package. The pattern is similar:
distributed-file: built-tools distributed-sources
build-command
should be changed to
distributed-file: distributed-sources
$(MAKE) $(AM_MAKEFLAGS) built-tools
build-command
or you could choose not to distribute distributed-file, if
cross-compilation does not matter.
The points made through these examples are worth a summary:
|
For desperate cases, it's always possible to disable this check by
setting distcleancheck_listfiles as documented in Dist.
Make sure you do understand the reason why make distcheck
complains before you do this. distcleancheck_listfiles is a
way to hide errors, not to fix them. You can always do better.
What is the difference betweenAM_CFLAGS,CFLAGS, andmumble_CFLAGS?
Why doesautomakeoutputCPPFLAGSafterAM_CPPFLAGSon compile lines? Shouldn't it be the converse?
Myconfigureadds some warning flags intoCXXFLAGS. In oneMakefile.amI would like to append a new flag, however if I put the flag intoAM_CXXFLAGSit is prepended to the other flags, not appended.
This section attempts to answer all the above questions. We will
mostly discuss CPPFLAGS in our examples, but actually the
answer holds for all the compile flags used in Automake:
CCASFLAGS, CFLAGS, CPPFLAGS, CXXFLAGS,
FCFLAGS, FFLAGS, GCJFLAGS, LDFLAGS,
LFLAGS, OBJCFLAGS, RFLAGS, and YFLAGS.
CPPFLAGS, AM_CPPFLAGS, and mumble_CPPFLAGS are
three variables that can be used to pass flags to the C preprocessor
(actually these variables are also used for other languages like C++
or preprocessed Fortran). CPPFLAGS is the user variable
(see User Variables), AM_CPPFLAGS is the Automake variable,
and mumble_CPPFLAGS is the variable specific to the
mumble target (we call this a per-target variable,
see Program and Library Variables).
Automake always uses two of these variables when compiling C sources
files. When compiling an object file for the mumble target,
the first variable will be mumble_CPPFLAGS if it is defined, or
AM_CPPFLAGS otherwise. The second variable is always
CPPFLAGS.
In the following example,
bin_PROGRAMS = foo bar
foo_SOURCES = xyz.c
bar_SOURCES = main.c
foo_CPPFLAGS = -DFOO
AM_CPPFLAGS = -DBAZ
xyz.o will be compiled with $(foo_CPPFLAGS) $(CPPFLAGS),
(because xyz.o is part of the foo target), while
main.o will be compiled with $(AM_CPPFLAGS) $(CPPFLAGS)
(because there is no per-target variable for target bar).
The difference between mumble_CPPFLAGS and AM_CPPFLAGS
being clear enough, let's focus on CPPFLAGS. CPPFLAGS
is a user variable, i.e., a variable that users are entitled to modify
in order to compile the package. This variable, like many others,
is documented at the end of the output of configure --help.
For instance, someone who needs to add /home/my/usr/include to
the C compiler's search path would configure a package with
./configure CPPFLAGS='-I /home/my/usr/include'
and this flag would be propagated to the compile rules of all
Makefiles.
It is also not uncommon to override a user variable at
make-time. Many installers do this with prefix, but
this can be useful with compiler flags too. For instance if, while
debugging a C++ project, you need to disable optimization in one
specific object file, you can run something like
rm file.o
make CXXFLAGS=-O0 file.o
make
The reason $(CPPFLAGS) appears after $(AM_CPPFLAGS) or
$(mumble_CPPFLAGS) in the compile command is that users
should always have the last say. It probably makes more sense if you
think about it while looking at the CXXFLAGS=-O0 above, which
should supersede any other switch from AM_CXXFLAGS or
mumble_CXXFLAGS (and this of course replaces the previous value
of CXXFLAGS).
You should never redefine a user variable such as CPPFLAGS in
Makefile.am. Use automake -Woverride to diagnose such
mistakes. Even something like
CPPFLAGS = -DDATADIR=\"$(datadir)\" @CPPFLAGS@
is erroneous. Although this preserves configure's value of
CPPFLAGS, the definition of DATADIR will disappear if a
user attempts to override CPPFLAGS from the make
command line.
AM_CPPFLAGS = -DDATADIR=\"$(datadir)\"
is all what is needed here if no per-target flags are used.
You should not add options to these variables from inside
configure either, for the same reason. Occasionally you need
to modify these variables to perform a test, but you should reset
their value afterwards.
What we recommend is that you define extra flags in separate
variables. For instance you may write an Autoconf macro that computes
a set of warning options for the C compiler, and AC_SUBST them
in WARNINGCFLAGS; you may also have an Autoconf macro that
determines which compiler and which linker flags should be used to
link with library libfoo, and AC_SUBST these in
LIBFOOCFLAGS and LIBFOOLDFLAGS. Then, a
Makefile.am could use these variables as follows:
AM_CFLAGS = $(WARNINGCFLAGS)
bin_PROGRAMS = prog1 prog2
prog1_SOURCES = ...
prog2_SOURCES = ...
prog2_CFLAGS = $(LIBFOOCFLAGS) $(AM_CFLAGS)
prog2_LDFLAGS = $(LIBFOOLDFLAGS)
In this example both programs will be compiled with the flags
substituted into $(WARNINGCFLAGS), and prog2 will
additionally be compiled with the flags required to link with
libfoo.
Note that listing AM_CFLAGS in a per-target CFLAGS
variable is a common idiom to ensure that AM_CFLAGS applies to
every target in a Makefile.in.
Using variables like this gives you full control over the ordering of
the flags. For instance if there is a flag in $(WARNINGCFLAGS) that
you want to negate for a particular target, you can use something like
prog1_CFLAGS = $(AM_CFLAGS) -no-flag. If all these flags had
been forcefully appended to CFLAGS, there would be no way to
disable one flag. Yet another reason to leave user variables to
users.
Finally, we have avoided naming the variable of the example
LIBFOO_LDFLAGS (with an underscore) because that would cause
Automake to think that this is actually a per-target variable (like
mumble_LDFLAGS) for some non-declared LIBFOO target.
There are other variables in Automake that follow similar principles
to allow user options. For instance Texinfo rules (see Texinfo)
uses MAKEINFOFLAGS and AM_MAKEINFOFLAGS. Similarly,
DejaGnu tests (see Tests) use RUNTESTDEFAULTFLAGS and
AM_RUNTESTDEFAULTFLAGS. The tags and ctags rules
(see Tags) use ETAGSFLAGS, AM_ETAGSFLAGS,
CTAGSFLAGS, and AM_CTAGSFLAGS. Java rules
(see Java) use JAVACFLAGS and AM_JAVACFLAGS. None
of these rules do support per-target flags (yet).
To some extent, even AM_MAKEFLAGS (see Subdirectories)
obeys this naming scheme. The slight difference is that
MAKEFLAGS is passed to sub-makes implicitly by
make itself.
However you should not think that all variables ending with
FLAGS follow this convention. For instance
DISTCHECK_CONFIGURE_FLAGS (see Dist),
ACLOCAL_AMFLAGS (see Rebuilding and Local Macros),
are two variables that are only useful to the maintainer and have no
user counterpart.
ARFLAGS (see A Library) is usually defined by Automake and
has neither AM_ nor per-target cousin.
Finally you should not think either that the existence of a per-target
variable implies that of an AM_ variable or that of a user
variable. For instance the mumble_LDADD per-target variable
overrides the global LDADD variable (which is not a user
variable), and mumble_LIBADD exists only as a per-target
variable. See Program and Library Variables.
This happens when per-target compilation flags are used. Object files need to be renamed just in case they would clash with object files compiled from the same sources, but with different flags. Consider the following example.
bin_PROGRAMS = true false
true_SOURCES = generic.c
true_CPPFLAGS = -DEXIT_CODE=0
false_SOURCES = generic.c
false_CPPFLAGS = -DEXIT_CODE=1
Obviously the two programs are built from the same source, but it
would be bad if they shared the same object, because generic.o
cannot be built with both -DEXIT_CODE=0 and
-DEXIT_CODE=1. Therefore automake outputs rules to
build two different objects: true-generic.o and
false-generic.o.
automake doesn't actually look whether source files are
shared to decide if it must rename objects. It will just rename all
objects of a target as soon as it sees per-target compilation flags
are used.
It's OK to share object files when per-target compilation flags are not
used. For instance true and false will both use
version.o in the following example.
AM_CPPFLAGS = -DVERSION=1.0
bin_PROGRAMS = true false
true_SOURCES = true.c version.c
false_SOURCES = false.c version.c
Note that the renaming of objects is also affected by the
_SHORTNAME variable (see Program and Library Variables).
One of my source files needs to be compiled with different flags. How
do I do?
Automake supports per-program and per-library compilation flags (see Program and Library Variables and Flag Variables Ordering). With this you can define compilation flags that apply to all files compiled for a target. For instance in
bin_PROGRAMS = foo
foo_SOURCES = foo.c foo.h bar.c bar.h main.c
foo_CFLAGS = -some -flags
foo-foo.o, foo-bar.o, and foo-main.o will all be
compiled with -some -flags. (If you wonder about the names of
these object files, see renamed objects.) Note that
foo_CFLAGS gives the flags to use when compiling all the C
sources of the program foo, it has nothing to do with
foo.c or foo-foo.o specifically.
What if foo.c needs to be compiled into foo.o using some
specific flags, that none of the other files require? Obviously
per-program flags are not directly applicable here. Something like
per-object flags are expected, i.e., flags that would be used only
when creating foo-foo.o. Automake does not support that,
however this is easy to simulate using a library that contains only
that object, and compiling this library with per-library flags.
bin_PROGRAMS = foo
foo_SOURCES = bar.c bar.h main.c
foo_CFLAGS = -some -flags
foo_LDADD = libfoo.a
noinst_LIBRARIES = libfoo.a
libfoo_a_SOURCES = foo.c foo.h
libfoo_a_CFLAGS = -some -other -flags
Here foo-bar.o and foo-main.o will all be
compiled with -some -flags, while libfoo_a-foo.o will
be compiled using -some -other -flags. Eventually, all
three objects will be linked to form foo.
This trick can also be achieved using Libtool convenience libraries,
i.e., noinst_LTLIBRARIES = libfoo.la (see Libtool Convenience Libraries).
Another tempting idea to implement per-object flags is to override the
compile rules automake would output for these files.
Automake will not define a rule for a target you have defined, so you
could think about defining the foo-foo.o: foo.c rule yourself.
We recommend against this, because this is error prone. For instance
if you add such a rule to the first example, it will break the day you
decide to remove foo_CFLAGS (because foo.c will then be
compiled as foo.o instead of foo-foo.o, see renamed objects). Also in order to support dependency tracking, the two
.o/.obj extensions, and all the other flags variables
involved in a compilation, you will end up modifying a copy of the
rule previously output by automake for this file. If a new
release of Automake generates a different rule, your copy will need to
be updated by hand.
This section describes a make idiom that can be used when a
tool produces multiple output files. It is not specific to Automake
and can be used in ordinary Makefiles.
Suppose we have a program called foo that will read one file
called data.foo and produce two files named data.c and
data.h. We want to write a Makefile rule that captures
this one-to-two dependency.
The naive rule is incorrect:
# This is incorrect.
data.c data.h: data.foo
foo data.foo
What the above rule really says is that data.c and
data.h each depend on data.foo, and can each be built by
running foo data.foo. In other words it is equivalent to:
# We do not want this.
data.c: data.foo
foo data.foo
data.h: data.foo
foo data.foo
which means that foo can be run twice. Usually it will not
be run twice, because make implementations are smart enough
to check for the existence of the second file after the first one has
been built; they will therefore detect that it already exists.
However there are a few situations where it can run twice anyway:
make. If
data.c and data.h are built in parallel, two foo
data.foo commands will run concurrently. This is harmful.
data.foo) is
(or depends upon) a phony target.
A solution that works with parallel make but not with
phony dependencies is the following:
data.c data.h: data.foo
foo data.foo
data.h: data.c
The above rules are equivalent to
data.c: data.foo
foo data.foo
data.h: data.foo data.c
foo data.foo
therefore a parallel make will have to serialize the builds
of data.c and data.h, and will detect that the second is
no longer needed once the first is over.
Using this pattern is probably enough for most cases. However it does not scale easily to more output files (in this scheme all output files must be totally ordered by the dependency relation), so we will explore a more complicated solution.
Another idea is to write the following:
# There is still a problem with this one.
data.c: data.foo
foo data.foo
data.h: data.c
The idea is that foo data.foo is run only when data.c
needs to be updated, but we further state that data.h depends
upon data.c. That way, if data.h is required and
data.foo is out of date, the dependency on data.c will
trigger the build.
This is almost perfect, but suppose we have built data.h and
data.c, and then we erase data.h. Then, running
make data.h will not rebuild data.h. The above rules
just state that data.c must be up-to-date with respect to
data.foo, and this is already the case.
What we need is a rule that forces a rebuild when data.h is
missing. Here it is:
data.c: data.foo
foo data.foo
data.h: data.c
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
The above scales easily to more outputs and more inputs. One of the
output is picked up to serve as a witness of the run of the command,
it depends upon all inputs, and all other outputs depend upon it. For
instance if foo should additionally read data.bar and
also produce data.w and data.x, we would write:
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
There is still a minor problem with this setup. foo outputs
four files, but we do not know in which order these files are created.
Suppose that data.h is created before data.c. Then we
have a weird situation. The next time make is run,
data.h will appear older than data.c, the second rule
will be triggered, a shell will be started to execute the
if...fi command, but actually it will just execute the
then branch, that is: nothing. In other words, because the
witness we selected is not the first file created by foo,
make will start a shell to do nothing each time it is run.
A simple riposte is to fix the timestamps when this happens.
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
@if test -f $@; then \
touch $@; \
else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
Another solution, not incompatible with the previous one, is to use a
different and dedicated file as witness, rather than using any of
foo's outputs.
data.stamp: data.foo data.bar
@rm -f data.tmp
@touch data.tmp
foo data.foo data.bar
@mv -f data.tmp $@
data.c data.h data.w data.x: data.stamp
@if test -f $@; then \
touch $@; \
else \
rm -f data.stamp; \
$(MAKE) $(AM_MAKEFLAGS) data.stamp; \
fi
data.tmp is created before foo is run, so it has a
timestamp older than output files output by foo. It is then
renamed to data.stamp after foo has run, because we
do not want to update data.stamp if foo fails.
Using a dedicated witness like this is very handy when the list of
output files is not known beforehand. As an illustration, consider
the following rules to compile many *.el files into
*.elc files in a single command. It does not matter how
ELFILES is defined (as long as it is not empty: empty targets
are not accepted by POSIX).
ELFILES = one.el two.el three.el ...
ELCFILES = $(ELFILES:=c)
elc-stamp: $(ELFILES)
@rm -f elc-temp
@touch elc-temp
$(elisp_comp) $(ELFILES)
@mv -f elc-temp $@
$(ELCFILES): elc-stamp
@if test -f $@; then \
touch $@; \
else \
rm -f elc-stamp; \
$(MAKE) $(AM_MAKEFLAGS) elc-stamp; \
fi
For completeness it should be noted that GNU make is able to
express rules with multiple output files using pattern rules
(see Pattern Rule Examples). We do not discuss pattern rules here because they are not
portable, but they can be convenient in packages that assume GNU
make.
This chapter presents various aspects of the history of Automake. The exhausted reader can safely skip it; this will be more of interest to nostalgic people, or to those curious to learn about the evolution of Automake.
The first version of the automake script looks as follows.
#!/bin/sh
status=0
for makefile
do
if test ! -f ${makefile}.am; then
echo "automake: ${makefile}.am: No such honkin' file"
status=1
continue
fi
exec 4> ${makefile}.in
done
From this you can already see that Automake will be about reading
*.am file and producing *.in files. You cannot see
anything else, but if you also know that David is the one who created
Autoconf two years before you can guess the rest.
Several commits follow, and by the end of the day Automake is reported to work for GNU fileutils and GNU m4.
The modus operandi is the one that is still used today: variables
assignments in Makefile.am files trigger injections of
precanned Makefile fragments into the generated
Makefile.in. The use of Makefile fragments was inspired
by the 4.4BSD make and include files, however Automake aims
to be portable and to conform to the GNU standards for Makefile
variables and targets.
At this point, the most recent release of Autoconf is version 1.11,
and David is preparing to release Autoconf 2.0 in late October. As a
matter of fact, he will barely touch Automake after September.
Makefile fragments. In the README, David
states his ambivalence between "portable shell" and "more
appropriate language":
I wrote it keeping in mind the possibility of it becoming an Autoconf macro, so it would run at configure-time. That would slow configuration down a bit, but allow users to modify the Makefile.am without needing to fetch the AutoMake package. And, the Makefile.in files wouldn't need to be distributed. But all of AutoMake would. So I might reimplement AutoMake in Perl, m4, or some other more appropriate language.
Automake is described as "an experimental Makefile generator". There is no documentation. Adventurous users are referred to the examples and patches needed to use Automake with GNU m4 1.3, fileutils 3.9, time 1.6, and development versions of find and indent.
These examples seem to have been lost. However at the time of writing
(10 years later in September, 2004) the FSF still distributes a
package that uses this version of Automake: check out GNU termutils
2.0.
Makefile.in up to GNU standards. This
was hard, and one day he saw Automake on <ftp://alpha.gnu.org/>,
grabbed it and tried it out.
Tom didn't talk to djm about it until later, just to make sure he didn't mind if he made a release. He did a bunch of early releases to the Gnits folks.
Gnits was (and still is) totally informal, just a few GNU friends who
François Pinard knew, who were all interested in making a common
infrastructure for GNU projects, and shared a similar outlook on how
to do it. So they were able to make some progress. It came along
with Autoconf and extensions thereof, and then Automake from David and
Tom (who were both gnitsians). One of their ideas was to write a
document paralleling the GNU standards, that was more strict in some
ways and more detailed. They never finished the GNITS standards, but
the ideas mostly made their way into Automake.
At this time aclocal and AM_INIT_AUTOMAKE did not
exist, so many things had to be done by hand. For instance here is
what a configure.in (this is the former name of the
configure.ac we use today) must contain in order to use
Automake 0.20:
PACKAGE=cpio
VERSION=2.3.911
AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE")
AC_DEFINE_UNQUOTED(VERSION, "$VERSION")
AC_SUBST(PACKAGE)
AC_SUBST(VERSION)
AC_ARG_PROGRAM
AC_PROG_INSTALL
(Today all of the above is achieved by AC_INIT and
AM_INIT_AUTOMAKE.)
Here is how programs are specified in Makefile.am:
PROGRAMS = hello
hello_SOURCES = hello.c
This looks pretty much like what we do today, except the
PROGRAMS variable has no directory prefix specifying where
hello should be installed: all programs are installed in
$(bindir). LIBPROGRAMS can be used to specify programs
that must be built but not installed (it is called
noinst_PROGRAMS nowadays).
Programs can be built conditionally using AC_SUBSTitutions:
PROGRAMS = @progs@
AM_PROGRAMS = foo bar baz
(AM_PROGRAMS has since then been renamed to
EXTRA_PROGRAMS.)
Similarly scripts, static libraries, and data can built and installed
using the LIBRARIES, SCRIPTS, and DATA variables.
However LIBRARIES were treated a bit specially in that Automake
did automatically supply the lib and .a prefixes.
Therefore to build libcpio.a, one had to write
LIBRARIES = cpio
cpio_SOURCES = ...
Extra files to distribute must be listed in DIST_OTHER (the
ancestor of EXTRA_DIST). Also extra directories that are to be
distributed should appear in DIST_SUBDIRS, but the manual
describes this as a temporary ugly hack (today extra directories should
also be listed in EXTRA_DIST, and DIST_SUBDIRS is used
for another purpose, see Conditional Subdirectories).
If you never used Perl 4, imagine Perl 5 without objects, without
my variables (only dynamically scoped local variables),
without function prototypes, with function calls that needs to be
prefixed with &, etc. Traces of this old style can still be
found in today's automake.
bin_PROGRAMS instead of PROGRAMS,
noinst_LIBRARIES instead of LIBLIBRARIES, etc. (However
EXTRA_PROGRAMS does not exist yet, AM_PROGRAMS is still
in use; and TEXINFOS and MANS still have no directory
prefixes.) Adding support for prefixes like that was one of the major
ideas in automake; it has lasted pretty well.
AutoMake is renamed to Automake (Tom seems to recall it was François Pinard's doing).
0.25 fixes a Perl 4 portability bug.
Gordon Matzigkeit and Jim Meyering are two other early contributors that have been sending fixes.
0.27 fixes yet another Perl 4 portability bug.
configure.in for LIBOBJS
support. This is an important step because until this version
Automake did only know about the Makefile.ams it processed.
configure.in was Autoconf's world and the link between Autoconf
and Automake had to be done by the Makefile.am author. For
instance if config.h was generated by configure, it was the
package maintainer's responsibility to define the CONFIG_HEADER
variable in each Makefile.am.
Succeeding releases will rely more and more on scanning
configure.in to better automate the Autoconf integration.
0.28 also introduces the AUTOMAKE_OPTIONS variable and the
--gnu and --gnits options, the latter being stricter.
configure.in scanning, CONFIG_HEADER is gone,
and rebuild rules for configure-generated file are
automatically output.
TEXINFOS and MANS converted to the uniform naming
scheme.
EXTRA_PROGRAMS finally replaces AM_PROGRAMS.
All the third-party Autoconf macros, written mostly by François
Pinard (and later Jim Meyering), are distributed in Automake's
hand-written aclocal.m4 file. Package maintainers are expected
to extract the necessary macros from this file. (In previous version
you had to copy and paste them from the manual...)
check-local rule. Upon
Ulrich Drepper's suggestion, 0.31 makes it an Automake rule output
whenever the TESTS variable is defined.
DIST_OTHER is renamed to EXTRA_DIST, and the check_
prefix is introduced. The syntax is now the same as today.
-hook targets are introduced; an idea from Dieter Baron.
*.info files, which were output in the build directory are
now built in the source directory, because they are distributed. It
seems these files like to move back and forth as that will happen
again in future versions.
Although they were very basic at this point, these are probably among the top features for Automake today.
Jim Meyering also provides the infamous jm_MAINTAINER_MODE,
since then renamed to AM_MAINTAINER_MODE and abandoned by its
author (see maintainer-mode).
Makefile fragments. The
package has 30 pages of documentation, and 38 test cases.
aclocal.m4 contains 4 macros.
From now on and until version 1.4, new releases will occur at a rate
of about one a year. 1.1 did not exist, actually 1.1b to 1.1p have
been the name of beta releases for 1.2. This is the first time
Automake uses suffix letters to designate beta releases, an habit that
lasts.
ChangeLog for 1997 lists only 7 commits.
I've created the "automake" mailing list. It is
"automake@gnu.ai.mit.edu". Administrivia, as always, to
automake-request@gnu.ai.mit.edu.
The charter of this list is discussion of automake, autoconf, and
other configuration/portability tools (eg libtool). It is expected
that discussion will range from pleas for help all the way up to
patches.
This list is archived on the FSF machines. Offhand I don't know if
you can get the archive without an account there.
This list is open to anybody who wants to join. Tell all your
friends!
-- Tom Tromey
Before that people were discussing Automake privately, on the Gnits
mailing list (which is not public either), and less frequently on
gnu.misc.discuss.
gnu.ai.mit.edu is now gnu.org, in case you never
noticed. The archives of the early years of the
automake@gnu.org list have been lost, so today it is almost
impossible to find traces of discussions that occurred before 1999.
This has been annoying more than once, as such discussions can be
useful to understand the rationale behind a piece of uncommented code
that was introduced back then.
aclocal.m4 and requiring
people to browse this file to extract the relevant macros becomes
uncomfortable. Ideally, some of them should be contributed to
Autoconf so that they can be used directly, however Autoconf is
currently inactive. Automake 1.2 consequently introduces
aclocal (aclocal was actually started on
1996-07-28), a tool that automatically constructs an aclocal.m4
file from a repository of third-party macros. Because Autoconf has
stalled, Automake also becomes a kind of repository for such
third-party macros, even macros completely unrelated to Automake (for
instance macros that fixes broken Autoconf macros).
The 1.2 release contains 20 macros, among which the
AM_INIT_AUTOMAKE macro that simplifies the creation of
configure.in.
Libtool is fully supported using *_LTLIBRARIES.
The missing script is introduced by François Pinard; it is meant to be
a better solution than AM_MAINTAINER_MODE
(see maintainer-mode).
Conditionals support was implemented by Ian Lance Taylor. At the
time, Tom and Ian were working on an internal project at Cygnus. They
were using ILU, which is pretty similar to CORBA. They wanted to
integrate ILU into their build, which was all configure-based,
and Ian thought that adding conditionals to automake was
simpler than doing all the work in configure (which was the
standard at the time). So this was actually funded by Cygnus.
This very useful but tricky feature will take a lot of time to stabilize. (At the time this text is written, there are still primaries that have not been updated to support conditional definitions in Automake 1.9.)
The automake script has almost doubled: 6089 lines of Perl,
plus 1294 lines of Makefile fragments.
Perl 5.004_04 is out, but fixes to support Perl 4 are still
regularly submitted whenever Automake breaks it.
sourceware.cygnus.com is on-line.
sourceware.cygnus.com
sourceware.cygnus.com announces it hosts Automake
sourceware.cygnus.com. It has a
publicly accessible CVS repository. This CVS repository is a copy of
the one Tom was using on his machine, which in turn is based on
a copy of the CVS repository of David MacKenzie. This is why we still
have to full source history. (Automake is still on Sourceware today,
but the host has been renamed to sources.redhat.com.)
The oldest file in the administrative directory of the CVS repository
that was created on Sourceware is dated 1998-09-19, while the
announcement that automake and autoconf had joined
sourceware was made on 1998-10-26. They were among the first
projects to be hosted there.
The heedful reader will have noticed Automake was exactly 4-year-old
on 1998-09-19.
include
statement. Also, += assignments are introduced, but it is
still quite easy to fool Automake when mixing this with conditionals.
These two releases, Automake 1.4 and Autoconf 2.13 makes a duo that will be used together for years.
automake is 7228 lines, plus 1591 lines of Makefile
fragment, 20 macros (some 1.3 macros were finally contributed back to
Autoconf), 197 test cases, and 51 pages of documentation.
user-dep-branch is created on the CVS repository.
make). In addition,
the new scheme should be more reliable than the old one, as
dependencies are generated on the end user's machine. Alexandre Oliva
creates depcomp for this purpose.
See Dependency Tracking Evolution, for more details about the
evolution of automatic dependency tracking in Automake.
user-dep-branch is merged into the main trunk.
I think the next release should be called "3.0".
Let's face it: you've basically rewritten autoconf.
Every weekend there are 30 new patches.
I don't see how we could call this "2.15" with a straight face.
- Tom Tromey on autoconf@gnu.org
Actually Akim works like a submarine: he will pile up patches while he
works off-line during the weekend, and flush them in batch when he
resurfaces on Monday.
Aiieeee! I was dreading the day that the Demaillator turned his sights on automake... and now it has arrived! - Tom Tromey
It's only the beginning: in two months he will send 192 patches. Then he would slow down so Tom can catch up and review all this. Initially Tom actually read all these patches, then he probably trustingly answered OK to most of them, and finally gave up and let Akim apply whatever he wanted. There was no way to keep up with that patch rate.
Anyway the patch below won't apply since it predates Akim's sourcequake; I have yet to figure where the relevant passage has been moved :) - Alexandre Duret-Lutz
All these patches were sent to and discussed on automake@gnu.org, so subscribed users were literally drown in technical mails. Eventually, the automake-patches@gnu.org mailing list was created in May.
Year after year, Automake had drifted away from its initial design:
construct Makefile.in by assembling various Makefile
fragments. In 1.4, lots of Makefile rules are being emitted at
various places in the automake script itself; this does not
help ensuring a consistent treatment of these rules (for instance
making sure that user-defined rules override Automake's own rules).
One of Akim's goal was moving all these hard-coded rules to separate
Makefile fragments, so the logic could be centralized in a
Makefile fragment processor.
Another significant contribution of Akim is the interface with the
"trace" feature of Autoconf. The way to scan configure.in at
this time was to read the file and grep the various macro of interest
to Automake. Doing so could break in many unexpected ways; automake
could miss some definition (for instance AC_SUBST([$1], [$2])
where the arguments are known only when M4 is run), or conversely it
could detect some macro that was not expanded (because it is called
conditionally). In the CVS version of Autoconf, Akim had implemented
the --trace option, which provides accurate information about
where macros are actually called and with what arguments. Akim will
equip Automake with a second configure.in scanner that uses
this --trace interface. Since it was not sensible to drop the
Autoconf 2.13 compatibility yet, this experimental scanner was only
used when an environment variable was set, the traditional
grep-scanner being still the default.
The main purpose of this release is to have a stable automake which is compatible with the latest stable libtool.
The release also contains obvious fixes for bugs in Automake 1.4,
some of which were reported almost monthly.
configure.ac over configure.in, and it introduces a new
syntax for AC_OUTPUTing files.
depcomp.
Aside from the improvement on the dependency tracking itself
(see Dependency Tracking Evolution), this also streamlines the use
of automake generated Makefile.ins as the Makefile.ins
used during development are now the same as those used in
distributions. Before that the Makefile.ins generated for
maintainers required GNU make and GCC, they were different
from the portable Makefile generated for distribution; this was
causing some confusion.
Makefile.am variables.
dist_, nodist_, and nobase_
prefixes.
1.5 did broke several packages that worked with 1.4. Enough so that
Linux distributions could not easily install the new Automake version
without breaking many of the packages for which they had to run
automake.
Some of these breakages were effectively bugs that would eventually be
fixed in the next release. However, a lot of damage was caused by
some changes made deliberately to render Automake stricter on some
setup we did consider bogus. For instance make distcheck was
improved to check that make uninstall did remove all the files
make install installed, that make distclean did not omit
some file, and that a VPATH build would work even if the source
directory was read-only. Similarly, Automake now rejects multiple
definitions of the same variable (because that would mix very badly
with conditionals), and += assignments with no previous
definition. Because these changes all occurred suddenly after 1.4 had
been established for more that two years, it hurt users.
To make matter worse, meanwhile Autoconf (now at version 2.52) was
facing similar troubles, for similar reasons.
The idea was to call this version automake-1.6, call all its
bug-fix versions identically, and switch to automake-1.7 for
the next release that adds new features or changes some rules. This
scheme implies maintaining a bug-fix branch in addition to the
development trunk, which means more work from the maintainer, but
providing regular bug-fix releases proved to be really worthwhile.
Like 1.5, 1.6 also introduced a bunch of incompatibilities, meant or not. Perhaps the more annoying was the dependence on the newly released Autoconf 2.53. Autoconf seemed to have stabilized enough since its explosive 2.50 release, and included changes required to fix some bugs in Automake. In order to upgrade to Automake 1.6, people now had to upgrade Autoconf too; for some packages it was no picnic.
While versioned installation helped people to upgrade, it also
unfortunately allowed people not to upgrade. At the time of writing,
some Linux distributions are shipping packages for Automake 1.4, 1.5,
1.6, 1.7, 1.8, and 1.9. Most of these still install 1.4 by default.
Some distribution also call 1.4 the "stable" version, and present
"1.9" as the development version; this does not really makes sense
since 1.9 is way more solid than 1.4. All this does not help the
newcomer.
gcj.
Alexandre has been using Automake since 2000, and started to
contribute mostly on Akim's incitement (Akim and Alexandre have been
working in the same room from 1999 to 2002). In 2001 and 2002 he had
a lot of free time to enjoy hacking Automake.
Tom Tromey backported the versioned installation mechanism on the 1.4
branch, so that Automake 1.6.x and Automake 1.4-p6 could be installed
side by side. Another request from the GNOME folks.
configure.ac scanner Akim
was experimenting in 1.5.
Marshall, one of the character, is working on a computer virus that he
has to modify before it gets into the wrong hands or something like
that. The screenshots you see do not show any program code, they show
a Makefile.in generated by automake...
aclocal.
aclocal now uses m4_include in the produced
aclocal.m4 when the included macros are already distributed
with the package (an idiom used in many packages), which reduces code
duplication. Many people liked that, but in fact this change was
really introduced to fix a bug in rebuild rules: Makefile.in
must be rebuilt whenever a dependency of configure changes, but
all the m4 files included in aclocal.m4 where unknown
from automake. Now automake can just trace the
m4_includes to discover the dependencies.
aclocal also starts using the --trace Autoconf option
in order to discover used macros more accurately. This will turn out
to be very tricky (later releases will improve this) as people had
devised many ways to cope with the limitation of previous
aclocal versions, notably using handwritten
m4_includes: aclocal must make sure not to redefine a
rule which is already included by such statement.
Automake also has seen its guts rewritten. Although this rewriting took a lot of efforts, it is only apparent to the users in that some constructions previously disallowed by the implementation now work nicely. Conditionals, Locations, Variable and Rule definitions, Options: these items on which Automake works have been rewritten as separate Perl modules, and documented.
Makefile.in generated with
Automake 1.4 and custom build rules (1.4 did not support compiled
Java) is 250KB. The one generated by 1.8 was over 9MB! 1.9 gets it
down to 1.2MB.
Aside from this it contains mainly minor changes and bug-fixes.
Over the years Automake has deployed three different dependency tracking methods. Each method, including the current one, has had flaws of various sorts. Here we lay out the different dependency tracking methods, their flaws, and their fixes. We conclude with recommendations for tool writers, and by indicating future directions for dependency tracking work in Automake.
Our first attempt at automatic dependency tracking was based on the
method recommended by GNU make. (see Generating Prerequisites Automatically)
This version worked by precomputing dependencies ahead of time. For
each source file, it had a special .P file which held the
dependencies. There was a rule to generate a .P file by
invoking the compiler appropriately. All such .P files were
included by the Makefile, thus implicitly becoming dependencies
of Makefile.
This approach had several critical bugs.
.P file relied on gcc.
(A limitation, not technically a bug.)
make.
(A limitation, not technically a bug.)
.P file was a dependency of Makefile, this
meant that dependency tracking was done eagerly by make.
For instance, make clean would cause all the dependency files
to be updated, and then immediately removed. This eagerness also
caused problems with some configurations; if a certain source file
could not be compiled on a given architecture for some reason,
dependency tracking would fail, aborting the entire build.
make dist re-ran automake to generate a
Makefile which did not have automatic dependency tracking (and
which was thus portable to any version of make). In order to
do this portably, Automake had to scan the dependency files and remove
any reference which was to a source file not in the distribution.
This process was error-prone. Also, if make dist was run in an
environment where some object file had a dependency on a source file
which was only conditionally created, Automake would generate a
Makefile which referred to a file which might not appear in the
end user's build. A special, hacky mechanism was required to work
around this.
The code generated by Automake is often inspired by the
Makefile style of a particular author. In the case of the first
implementation of dependency tracking, I believe the impetus and
inspiration was Jim Meyering. (I could be mistaken. If you know
otherwise feel free to correct me.)
The next refinement of Automake's automatic dependency tracking scheme was to implement dependencies as side effects of the compilation. This was aimed at solving the most commonly reported problems with the first approach. In particular we were most concerned with eliminating the weird rebuilding effect associated with make clean.
In this approach, the .P files were included using the
-include command, which let us create these files lazily. This
avoided the make clean problem.
We only computed dependencies when a file was actually compiled. This avoided the performance penalty associated with scanning each file twice. It also let us avoid the other problems associated with the first, eager, implementation. For instance, dependencies would never be generated for a source file which was not compilable on a given architecture (because it in fact would never be compiled).
gcc and GNU
make. (A limitation, not technically a bug.)
make dist were still in effect.
.P file includes a dependency on a
given header file, like this:
maude.o: maude.c something.h
Now suppose that the developer removes something.h and updates
maude.c so that this include is no longer needed. If he runs
make, he will get an error because there is no way to create
something.h.
We fixed this problem in a later release by further massaging the
output of gcc to include a dummy dependency for each header
file.
The bugs associated with make dist, over time, became a real
problem. Packages using Automake were being built on a large number
of platforms, and were becoming increasingly complex. Broken
dependencies were distributed in "portable" Makefile.ins,
leading to user complaints. Also, the requirement for gcc
and GNU make was a constant source of bug reports. The next
implementation of dependency tracking aimed to remove these problems.
We realized that the only truly reliable way to automatically track dependencies was to do it when the package itself was built. This meant discovering a method portable to any version of make and any compiler. Also, we wanted to preserve what we saw as the best point of the second implementation: dependency computation as a side effect of compilation.
In the end we found that most modern make implementations support some
form of include directive. Also, we wrote a wrapper script which let
us abstract away differences between dependency tracking methods for
compilers. For instance, some compilers cannot generate dependencies
as a side effect of compilation. In this case we simply have the
script run the compiler twice. Currently our wrapper script
(depcomp) knows about twelve different compilers (including
a "compiler" which simply invokes makedepend and then the
real compiler, which is assumed to be a standard Unix-like C compiler
with no way to do dependency tracking).
This bug occurs because dependency tracking tools, such as the compiler, only generate dependencies on the successful opening of a file, and not on every probe.
Suppose for instance that the compiler searches three directories for a given header, and that the header is found in the third directory. If the programmer erroneously adds a header file with the same name to the first directory, then a clean rebuild from scratch could fail (suppose the new header file is buggy), whereas an incremental rebuild will succeed.
What has happened here is that people have a misunderstanding of what a dependency is. Tool writers think a dependency encodes information about which files were read by the compiler. However, a dependency must actually encode information about what the compiler tried to do.
This problem is not serious in practice. Programmers typically do not use the same name for a header file twice in a given project. (At least, not in C or C++. This problem may be more troublesome in Java.) This problem is easy to fix, by modifying dependency generators to record every probe, instead of every successful open.
This was also a problem in the previous dependency tracking implementation.
The current fix is to use BUILT_SOURCES to list built headers
(see Sources). This causes them to be built before any other
other build rules are run. This is unsatisfactory as a general
solution, however in practice it seems sufficient for most actual
programs.
This code is used since Automake 1.5.
In GCC 3.0, we managed to convince the maintainers to add special
command-line options to help Automake more efficiently do its job. We
hoped this would let us avoid the use of a wrapper script when
Automake's automatic dependency tracking was used with gcc.
Unfortunately, this code doesn't quite do what we want. In particular, it removes the dependency file if the compilation fails; we'd prefer that it instead only touch the file in any way if the compilation succeeds.
Nevertheless, since Automake 1.7, when a recent gcc is
detected at configure time, we inline the
dependency-generation code and do not use the depcomp
wrapper script. This makes compilations faster for those using this
compiler (probably our primary user base). The counterpart is that
because we have to encode two compilation rules in Makefile
(with or without depcomp), the produced Makefiles are
larger.
There are actually several ways for a build tool like Automake to cause tools to generate dependencies.
makedepend
makedepend ere
not completely precise; ordinarily they were conservative and
discovered too many dependencies.
clearmake does this. This is a very powerful
technique, as it doesn't require cooperation from the
tool. Unfortunately it is also very difficult to implement and also
not practical in the general case.
LD_PRELOAD
open and other syscalls. This technique is also quite
powerful, but unfortunately it is not portable enough for use in
automake.
We think that every compilation tool ought to be able to generate
dependencies as a side effect of compilation. Furthermore, at least
while make-based tools are nearly universally in use (at
least in the free software community), the tool itself should generate
dummy dependencies for header files, to avoid the deleted header file
bug. Finally, the tool should generate a dependency for each probe,
instead of each successful file open, in order to avoid the duplicated
new header bug.
Currently, only languages and compilers understood by Automake can have dependency tracking enabled. We would like to see if it is practical (and worthwhile) to let this support be extended by the user to languages unknown to Automake.
The following table (inspired by perlhist(1)) quantifies the
evolution of Automake using these metrics:
automake script.
aclocal script.
Perl supporting modules.
*.am
Makefile fragments. The number in parenthesis
is the number of files.
| Rel | am | acl | pm | *.am | m4 | doc | t | |
| 1994-09-19 | CVS | 141 | 299 (24) |
| ||||
| 1994-11-05 | CVS | 208 | 332 (28) |
| ||||
| 1995-11-23 | 0.20 | 533 | 458 (35) | 9 |
| |||
| 1995-11-26 | 0.21 | 613 | 480 (36) | 11 |
| |||
| 1995-11-28 | 0.22 | 1116 | 539 (38) | 12 |
| |||
| 1995-11-29 | 0.23 | 1240 | 541 (38) | 12 |
| |||
| 1995-12-08 | 0.24 | 1462 | 504 (33) | 14 |
| |||
| 1995-12-10 | 0.25 | 1513 | 511 (37) | 15 |
| |||
| 1996-01-03 | 0.26 | 1706 | 438 (36) | 16 |
| |||
| 1996-01-03 | 0.27 | 1706 | 438 (36) | 16 |
| |||
| 1996-01-13 | 0.28 | 1964 | 934 (33) | 16 |
| |||
| 1996-02-07 | 0.29 | 2299 | 936 (33) | 17 |
| |||
| 1996-02-24 | 0.30 | 2544 | 919 (32) | 85 (1) | 20 | 9
| ||
| 1996-03-11 | 0.31 | 2877 | 919 (32) | 85 (1) | 29 | 17
| ||
| 1996-04-27 | 0.32 | 3058 | 921 (31) | 85 (1) | 30 | 26
| ||
| 1996-05-18 | 0.33 | 3110 | 926 (31) | 105 (1) | 30 | 35
| ||
| 1996-05-28 | 1.0 | 3134 | 973 (32) | 105 (1) | 30 | 38
| ||
| 1997-06-22 | 1.2 | 6089 | 385 | 1294 (36) | 592 (23) | 37 | 126
| |
| 1998-04-05 | 1.3 | 6415 | 422 | 1470 (39) | 741 (26) | 39 | 156
| |
| 1999-01-14 | 1.4 | 7240 | 426 | 1591 (40) | 734 (23) | 51 | 197
| |
| 2001-05-08 | 1.4-p1 | 7251 | 426 | 1591 (40) | 734 (23) | 51 | 197
| |
| 2001-05-24 | 1.4-p2 | 7268 | 439 | 1591 (40) | 734 (23) | 49 | 197
| |
| 2001-06-07 | 1.4-p3 | 7312 | 439 | 1591 (40) | 734 (23) | 49 | 197
| |
| 2001-06-10 | 1.4-p4 | 7321 | 439 | 1591 (40) | 734 (23) | 49 | 198
| |
| 2001-07-15 | 1.4-p5 | 7228 | 426 | 1596 (40) | 734 (23) | 51 | 198
| |
| 2001-08-23 | 1.5 | 8016 | 475 | 600 | 2654 (39) | 1166 (32) | 63 | 327
|
| 2002-03-05 | 1.6 | 8465 | 475 | 1136 | 2732 (39) | 1603 (31) | 66 | 365
|
| 2002-04-11 | 1.6.1 | 8544 | 475 | 1136 | 2741 (39) | 1603 (31) | 66 | 372
|
| 2002-06-14 | 1.6.2 | 8575 | 475 | 1136 | 2800 (39) | 1609 (31) | 67 | 386
|
| 2002-07-28 | 1.6.3 | 8600 | 475 | 1153 | 2809 (39) | 1609 (31) | 67 | 391
|
| 2002-07-28 | 1.4-p6 | 7332 | 455 | 1596 (40) | 735 (24) | 49 | 197
| |
| 2002-09-25 | 1.7 | 9189 | 471 | 1790 | 2965 (39) | 1606 (33) | 73 | 430
|
| 2002-10-16 | 1.7.1 | 9229 | 475 | 1790 | 2977 (39) | 1606 (33) | 73 | 437
|
| 2002-12-06 | 1.7.2 | 9334 | 475 | 1790 | 2988 (39) | 1606 (33) | 77 | 445
|
| 2003-02-20 | 1.7.3 | 9389 | 475 | 1790 | 3023 (39) | 1651 (34) | 84 | 448
|
| 2003-04-23 | 1.7.4 | 9429 | 475 | 1790 | 3031 (39) | 1644 (34) | 85 | 458
|
| 2003-05-18 | 1.7.5 | 9429 | 475 | 1790 | 3033 (39) | 1645 (34) | 85 | 459
|
| 2003-07-10 | 1.7.6 | 9442 | 475 | 1790 | 3033 (39) | 1660 (34) | 85 | 461
|
| 2003-09-07 | 1.7.7 | 9443 | 475 | 1790 | 3041 (39) | 1660 (34) | 90 | 467
|
| 2003-10-07 | 1.7.8 | 9444 | 475 | 1790 | 3041 (39) | 1660 (34) | 90 | 468
|
| 2003-11-09 | 1.7.9 | 9444 | 475 | 1790 | 3048 (39) | 1660 (34) | 90 | 468
|
| 2003-12-10 | 1.8 | 7171 | 585 | 7730 | 3236 (39) | 1666 (36) | 104 | 521
|
| 2004-01-11 | 1.8.1 | 7217 | 663 | 7726 | 3287 (39) | 1686 (36) | 104 | 525
|
| 2004-01-12 | 1.8.2 | 7217 | 663 | 7726 | 3288 (39) | 1686 (36) | 104 | 526
|
| 2004-03-07 | 1.8.3 | 7214 | 686 | 7735 | 3303 (39) | 1695 (36) | 111 | 530
|
| 2004-04-25 | 1.8.4 | 7214 | 686 | 7736 | 3310 (39) | 1701 (36) | 112 | 531
|
| 2004-05-16 | 1.8.5 | 7240 | 686 | 7736 | 3299 (39) | 1701 (36) | 112 | 533
|
| 2004-07-28 | 1.9 | 7508 | 715 | 7794 | 3352 (40) | 1812 (37) | 115 | 551
|
| 2004-08-11 | 1.9.1 | 7512 | 715 | 7794 | 3354 (40) | 1812 (37) | 115 | 552
|
| 2004-09-19 | 1.9.2 | 7512 | 715 | 7794 | 3354 (40) | 1812 (37) | 132 | 554
|
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If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.
_AM_DEPENDENCIES: Private macros
AC_CANONICAL_BUILD: Optional
AC_CANONICAL_HOST: Optional
AC_CANONICAL_TARGET: Optional
AC_CONFIG_AUX_DIR: Subpackages, Optional
AC_CONFIG_FILES: Requirements
AC_CONFIG_HEADERS: Optional
AC_CONFIG_LIBOBJ_DIR: LIBOBJS
AC_CONFIG_LINKS: Optional
AC_CONFIG_SUBDIRS: Subpackages
AC_DEFUN: Extending aclocal
AC_F77_LIBRARY_LDFLAGS: Optional
AC_INIT: Public macros
AC_LIBOBJ: LIBOBJS, LTLIBOBJS, Optional
AC_LIBSOURCE: LIBOBJS, Optional
AC_LIBSOURCES: Optional
AC_OUTPUT: Requirements
AC_PREREQ: Extending aclocal
AC_PROG_CC_C_O: Public macros
AC_PROG_CXX: Optional
AC_PROG_F77: Optional
AC_PROG_FC: Optional
AC_PROG_LEX: Public macros, Optional
AC_PROG_LIBTOOL: Optional
AC_PROG_RANLIB: Optional
AC_PROG_YACC: Optional
AC_SUBST: Optional
AM_C_PROTOTYPES: ANSI, Public macros, Optional
AM_CONDITIONAL: Conditionals
AM_CONFIG_HEADER: Public macros
AM_DEP_TRACK: Private macros
AM_ENABLE_MULTILIB: Public macros
AM_GNU_GETTEXT: Optional
AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL: Public macros
AM_INIT_AUTOMAKE: Public macros, Requirements
AM_MAINTAINER_MODE: maintainer-mode, Rebuilding, Optional
AM_MAKE_INCLUDE: Private macros
AM_OUTPUT_DEPENDENCY_COMMANDS: Private macros
AM_PATH_LISPDIR: Public macros
AM_PROG_AS: Public macros
AM_PROG_CC_C_O: Public macros
AM_PROG_GCJ: Public macros
AM_PROG_INSTALL_STRIP: Private macros
AM_PROG_LEX: Public macros
AM_SANITY_CHECK: Private macros
AM_SET_DEPDIR: Private macros
AM_SYS_POSIX_TERMIOS: Public macros
AM_WITH_DMALLOC: Public macros
AM_WITH_REGEX: Public macros
m4_include: Dist, Optional
_DATA: Data
_HEADERS: Headers
_LIBRARIES: A Library
_LISP: Emacs Lisp
_LTLIBRARIES: Libtool Libraries
_MANS: Man pages
_PROGRAMS: Program Sources, Uniform
_PYTHON: Python
_SCRIPTS: Scripts
_SOURCES: Default _SOURCES, Program Sources
_TEXINFOS: Texinfo
ACLOCAL_AMFLAGS: Rebuilding, Local Macros
ALLOCA: LIBOBJS, LTLIBOBJS
AM_CCASFLAGS: Assembly Support
AM_CFLAGS: Program variables
AM_CPPFLAGS: Program variables
AM_CXXFLAGS: C++ Support
AM_ETAGSFLAGS: Tags
AM_FCFLAGS: Fortran 9x Support
AM_FFLAGS: Fortran 77 Support
AM_GCJFLAGS: Java Support
AM_INSTALLCHECK_STD_OPTIONS_EXEMPT: Options
AM_JAVACFLAGS: Java
AM_LDFLAGS: Program variables, Linking
AM_LFLAGS: Yacc and Lex
AM_MAKEFLAGS: Subdirectories
AM_MAKEINFOFLAGS: Texinfo
AM_MAKEINFOHTMLFLAGS: Texinfo
AM_RFLAGS: Fortran 77 Support
AM_RUNTESTFLAGS: Tests
AM_YFLAGS: Yacc and Lex
ANSI2KNR: Public macros
AUTOCONF: Invoking Automake
AUTOM4TE: Invoking aclocal
AUTOMAKE_OPTIONS: Options, Dependencies, ANSI, Public macros
bin_PROGRAMS: Program Sources
bin_SCRIPTS: Scripts
build_triplet: Optional
BUILT_SOURCES: Sources
CC: Program variables
CCAS: Assembly Support, Public macros
CCASFLAGS: Assembly Support, Public macros
CFLAGS: Program variables
check_: Uniform
check_LTLIBRARIES: Libtool Convenience Libraries
check_PROGRAMS: Default _SOURCES, Program Sources
check_SCRIPTS: Scripts
CLASSPATH_ENV: Java
CLEANFILES: Clean
COMPILE: Program variables
CONFIG_STATUS_DEPENDENCIES: Rebuilding
CONFIGURE_DEPENDENCIES: Rebuilding
CPPFLAGS: Program variables
CXX: C++ Support
CXXCOMPILE: C++ Support
CXXFLAGS: C++ Support
CXXLINK: C++ Support
DATA: Data, Uniform
data_DATA: Data
DEFS: Program variables
DEJATOOL: Tests
DESTDIR: Install
dist_: Dist, Alternative
dist_lisp_LISP: Emacs Lisp
dist_noinst_LISP: Emacs Lisp
DIST_SUBDIRS: Dist, Conditional Subdirectories
DISTCHECK_CONFIGURE_FLAGS: Dist
distcleancheck_listfiles: distcleancheck, Dist
DISTCLEANFILES: Dist, Clean
distdir: Third-Party Makefiles, Dist
distuninstallcheck_listfiles: Dist
DVIPS: Texinfo
EMACS: Public macros
ETAGS_ARGS: Tags
ETAGSFLAGS: Tags
EXPECT: Tests
EXTRA_DIST: Dist
EXTRA_maude_SOURCES: Program and Library Variables
EXTRA_PROGRAMS: Conditional Programs
F77: Fortran 77 Support
F77COMPILE: Fortran 77 Support
FC: Fortran 9x Support
FCCOMPILE: Fortran 9x Support
FCFLAGS: Fortran 9x Support
FCLINK: Fortran 9x Support
FFLAGS: Fortran 77 Support
FLIBS: Mixing Fortran 77 With C and C++
FLINK: Fortran 77 Support
GCJ: Public macros
GCJFLAGS: Java Support, Public macros
GTAGS_ARGS: Tags
GZIP_ENV: Dist
HEADERS: Uniform
host_triplet: Optional
include_HEADERS: Headers
INCLUDES: Program variables, Hello
info_TEXINFOS: Texinfo
JAVA: Uniform
JAVAC: Java
JAVACFLAGS: Java
JAVAROOT: Java
LDADD: Linking
LDFLAGS: Program variables
LFLAGS: Yacc and Lex
lib_LIBRARIES: A Library
lib_LTLIBRARIES: Libtool Libraries
libexec_PROGRAMS: Program Sources
libexec_SCRIPTS: Scripts
LIBOBJS: LIBOBJS, LTLIBOBJS, Optional
LIBRARIES: Uniform
LIBS: Program variables
LINK: Program variables
LISP: Uniform
lisp_LISP: Emacs Lisp
lispdir: Public macros
localstate_DATA: Data
LTALLOCA: LIBOBJS, LTLIBOBJS
LTLIBOBJS: LIBOBJS, LTLIBOBJS
MAINTAINERCLEANFILES: Clean
MAKE: Subdirectories
MAKEINFO: Texinfo
MAKEINFOFLAGS: Texinfo
MAKEINFOHTML: Texinfo
man_MANS: Man pages
MANS: Uniform
maude_AR: Program and Library Variables
maude_CCASFLAGS: Program and Library Variables
maude_CFLAGS: Program and Library Variables
maude_CPPFLAGS: Program and Library Variables
maude_CXXFLAGS: Program and Library Variables
maude_DEPENDENCIES: Program and Library Variables, Linking
maude_FFLAGS: Program and Library Variables
maude_GCJFLAGS: Program and Library Variables
maude_LDADD: Program and Library Variables, Linking
maude_LDFLAGS: Program and Library Variables, Linking
maude_LFLAGS: Program and Library Variables
maude_LIBADD: Program and Library Variables, A Library
maude_LINK: Program and Library Variables
maude_OBJCFLAGS: Program and Library Variables
maude_RFLAGS: Program and Library Variables
maude_SHORTNAME: Program and Library Variables
maude_SOURCES: Program and Library Variables
maude_YFLAGS: Program and Library Variables
MOSTLYCLEANFILES: Clean
nobase_: Alternative
nodist_: Dist, Alternative
noinst_: Uniform
noinst_HEADERS: Headers
noinst_LIBRARIES: A Library
noinst_LISP: Emacs Lisp
noinst_LTLIBRARIES: Libtool Convenience Libraries
noinst_PROGRAMS: Program Sources
noinst_SCRIPTS: Scripts
oldinclude_HEADERS: Headers
PACKAGE: Dist
pkgdata_DATA: Data
pkgdata_SCRIPTS: Scripts
pkgdatadir: Uniform
pkginclude_HEADERS: Headers
pkgincludedir: Uniform
pkglib_LIBRARIES: A Library
pkglib_LTLIBRARIES: Libtool Libraries
pkglib_PROGRAMS: Program Sources
pkglibdir: Uniform
pkgpyexecdir: Python
pkgpythondir: Python
PROGRAMS: Uniform
pyexecdir: Python
PYTHON: Python, Uniform
PYTHON_EXEC_PREFIX: Python
PYTHON_PLATFORM: Python
PYTHON_PREFIX: Python
PYTHON_VERSION: Python
pythondir: Python
RFLAGS: Fortran 77 Support
RUNTEST: Tests
RUNTESTDEFAULTFLAGS: Tests
RUNTESTFLAGS: Tests
sbin_PROGRAMS: Program Sources
sbin_SCRIPTS: Scripts
SCRIPTS: Scripts, Uniform
sharedstate_DATA: Data
SOURCES: Default _SOURCES, Program Sources
SUBDIRS: Dist, Subdirectories
SUFFIXES: Suffixes
sysconf_DATA: Data
TAGS_DEPENDENCIES: Tags
target_triplet: Optional
TESTS: Tests
TESTS_ENVIRONMENT: Tests
TEXI2DVI: Texinfo
TEXI2PDF: Texinfo
TEXINFO_TEX: Texinfo
TEXINFOS: Texinfo, Uniform
top_distdir: Third-Party Makefiles, Dist
U: Public macros
VERSION: Dist
WARNINGS: Invoking Automake
WITH_DMALLOC: Public macros
WITH_REGEX: Public macros
XFAIL_TESTS: Tests
YACC: Optional
YFLAGS: Yacc and Lex
## (special Automake comment): General Operation
+=: General Operation
--acdir: aclocal options
--add-missing: Invoking Automake
--copy: Invoking Automake
--cygnus: Invoking Automake
--enable-debug, example: Conditionals
--enable-maintainer-mode: Optional
--force: aclocal options
--force-missing: Invoking Automake
--foreign: Invoking Automake
--gnits: Invoking Automake
--gnits, complete description: Gnits
--gnu: Invoking Automake
--gnu, complete description: Gnits
--gnu, required files: Gnits
--help: aclocal options, Invoking Automake
--help check: Options
--include-deps: Invoking Automake
--libdir: Invoking Automake
--no-force: Invoking Automake
--output: aclocal options
--output-dir: Invoking Automake
--print-ac-dir: aclocal options
--verbose: aclocal options, Invoking Automake
--version: aclocal options, Invoking Automake
--version check: Options
--warnings: Invoking Automake
--with-dmalloc: Public macros
--with-regex: Public macros
-a: Invoking Automake
-c: Invoking Automake
-f: Invoking Automake
-hook targets: Extending
-I: aclocal options
-i: Invoking Automake
-local targets: Extending
-module, libtool: Libtool Modules
-o: Invoking Automake
-v: Invoking Automake
-W: Invoking Automake
.la suffix, defined: Libtool Concept
_DATA primary, defined: Data
_DEPENDENCIES, defined: Linking
_HEADERS primary, defined: Headers
_JAVA primary, defined: Java
_LDFLAGS, defined: Linking
_LDFLAGS, libtool: Libtool Flags
_LIBADD, libtool: Libtool Flags
_LIBRARIES primary, defined: A Library
_LISP primary, defined: Emacs Lisp
_LTLIBRARIES primary, defined: Libtool Libraries
_MANS primary, defined: Man pages
_PROGRAMS primary variable: Uniform
_PYTHON primary, defined: Python
_SCRIPTS primary, defined: Scripts
_SOURCES and header files: Program Sources
_SOURCES primary, defined: Program Sources
_SOURCES, default: Default _SOURCES
_SOURCES, empty: Default _SOURCES
_TEXINFOS primary, defined: Texinfo
AC_SUBST and SUBDIRS: Conditional Subdirectories
acinclude.m4, defined: Complete
aclocal program, introduction: Complete
aclocal search path: Macro search path
aclocal's scheduled death: Future of aclocal
aclocal, extending: Extending aclocal
aclocal, Invoking: Invoking aclocal
aclocal, Options: aclocal options
aclocal.m4, preexisting: Complete
SUFFIXES: Suffixes
all: Extending
all-local: Extending
ALLOCA, and Libtool: LTLIBOBJS
ALLOCA, example: LIBOBJS
ALLOCA, special handling: LIBOBJS
AM_CCASFLAGS and CCASFLAGS: Flag Variables Ordering
AM_CFLAGS and CFLAGS: Flag Variables Ordering
AM_CONDITIONAL and SUBDIRS: Conditional Subdirectories
AM_CPPFLAGS and CPPFLAGS: Flag Variables Ordering
AM_CXXFLAGS and CXXFLAGS: Flag Variables Ordering
AM_FCFLAGS and FCFLAGS: Flag Variables Ordering
AM_FFLAGS and FFLAGS: Flag Variables Ordering
AM_GCJFLAGS and GCJFLAGS: Flag Variables Ordering
AM_INIT_AUTOMAKE, example use: Complete
AM_LDFLAGS and LDFLAGS: Flag Variables Ordering
AM_LFLAGS and LFLAGS: Flag Variables Ordering
AM_MAINTAINER_MODE, purpose: maintainer-mode
AM_OBJCFLAGS and OBJCFLAGS: Flag Variables Ordering
AM_RFLAGS and RFLAGS: Flag Variables Ordering
AM_YFLAGS and YFLAGS: Flag Variables Ordering
ansi2knr: Options, ANSI
ansi2knr and LIBOBJS: ANSI
ansi2knr and LTLIBOBJS: ANSI
autogen.sh and autoreconf: Libtool Issues
automake options: Invoking Automake
automake, invoking: Invoking Automake
autoreconf and libtoolize: Libtool Issues
bootstrap.sh and autoreconf: Libtool Issues
BUILT_SOURCES, defined: Sources
CCASFLAGS and AM_CCASFLAGS: Flag Variables Ordering
CFLAGS and AM_CFLAGS: Flag Variables Ordering
check: Extending, Tests
check-local: Extending
check-news: Options
check_ primary prefix, definition: Uniform
check_PROGRAMS example: Default _SOURCES
clean: Extending
clean-local: Extending, Clean
--enable-debug: Conditionals
SUBDIRS: Conditional Subdirectories
config.guess: Invoking Automake
configure.ac, from GNU Hello: Hello
configure.ac, scanning: configure
cpio example: Uniform
CPPFLAGS and AM_CPPFLAGS: Flag Variables Ordering
cvs-dist: General Operation
cvs-dist, non-standard example: General Operation
CXXFLAGS and AM_CXXFLAGS: Flag Variables Ordering
cygnus: Options
cygnus strictness: Cygnus
DATA primary, defined: Data
_SOURCES: Default _SOURCES
dejagnu: Options, Tests
depcomp: Dependencies
dirlist: Macro search path
dist: Dist
dist-bzip2: Options, Dist
dist-gzip: Dist
dist-hook: Extending, Dist
dist-shar: Options, Dist
dist-tarZ: Options, Dist
dist-zip: Options, Dist
dist_ and nobase_: Alternative
DIST_SUBDIRS, explained: Conditional Subdirectories
distcheck: Dist
distcheck-hook: Dist
distclean: distcleancheck, Extending
distclean, diagnostic: distcleancheck
distclean-local: Extending, Clean
distcleancheck: distcleancheck, Dist
distdir: Third-Party Makefiles
dmalloc, support for: Public macros
dvi: Extending
dvi-local: Extending
EDITION Texinfo flag: Texinfo
else: Conditionals
_SOURCES: Default _SOURCES
endif: Conditionals
--enable-debug: Conditionals
EXTRA_PROGRAMS: Uniform
false and true: true
aclocal: Extending aclocal
EXTRA_, prepending: Uniform
EXTRA_prog_SOURCES, defined: Conditional Sources
EXTRA_PROGRAMS, defined: Conditional Programs, Uniform
false Example: true
FCFLAGS and AM_FCFLAGS: Flag Variables Ordering
FFLAGS and AM_FFLAGS: Flag Variables Ordering
filename-length-max=99: Options
FLIBS, defined: Mixing Fortran 77 With C and C++
foreign: Options
foreign strictness: Strictness
GCJFLAGS and AM_GCJFLAGS: Flag Variables Ordering
gnits: Options
gnits strictness: Strictness
gnu: Options
configure.ac: Hello
gnu strictness: Strictness
GNUmakefile including Makefile: Third-Party Makefiles
_SOURCES: Program Sources
HEADERS primary, defined: Headers
HEADERS, installation directories: Headers
configure.ac: Hello
lex problems: Public macros
html: Extending
html-local: Extending
id: Tags
if: Conditionals
include: Include, Dist
include, distribution: Dist
INCLUDES, example usage: Hello
Makefile fragment: Include
info: Extending, Options
info-local: Extending
install: Extending, Install
install-data: Install
install-data-hook: Extending
install-data-local: Extending, Install
install-exec: Extending, Install
install-exec-hook: Extending
install-exec-local: Extending, Install
install-info: Options, Texinfo
install-info target: Texinfo
install-man: Options, Man pages
install-man target: Man pages
install-strip: Install
installcheck: Extending
installcheck-local: Extending
installdirs: Extending, Install
installdirs-local: Extending
aclocal: Invoking aclocal
automake: Invoking Automake
JAVA primary, defined: Java
JAVA restrictions: Java
LDFLAGS and AM_LDFLAGS: Flag Variables Ordering
lex problems with HP-UX 10: Public macros
lex, multiple lexers: Yacc and Lex
LFLAGS and AM_LFLAGS: Flag Variables Ordering
libltdl, introduction: Libtool Concept
LIBOBJS and ansi2knr: ANSI
LIBOBJS, and Libtool: LTLIBOBJS
LIBOBJS, example: LIBOBJS
LIBOBJS, special handling: LIBOBJS
LIBRARIES primary, defined: A Library
libtool, introduction: Libtool Concept
libtoolize and autoreconf: Libtool Issues
libtoolize, no longer run by automake: Libtool Issues
LISP primary, defined: Emacs Lisp
LN_S example: Extending
LTALLOCA, special handling: LTLIBOBJS
LTLIBOBJS and ansi2knr: ANSI
LTLIBOBJS, special handling: LTLIBOBJS
LTLIBRARIES primary, defined: Libtool Libraries
ltmain.sh not found: Libtool Issues
m4_include, distribution: Dist
maintainer-clean-local: Clean
make check: Tests
make clean support: Clean
make dist: Dist
make distcheck: Dist
make distclean, diagnostic: distcleancheck
make distcleancheck: Dist
make distuninstallcheck: Dist
make install support: Install
make installcheck, testing --help and --version: Options
Makefile fragment, including: Include
MANS primary, defined: Man pages
mdate-sh: Texinfo
missing, purpose: maintainer-mode
mostlyclean: Extending
mostlyclean-local: Extending, Clean
configure.ac files: Invoking Automake
lex lexers: Yacc and Lex
yacc parsers: Yacc and Lex
no-define: Options, Public macros
no-dependencies: Options, Dependencies
no-dist: Options
no-dist-gzip: Options
no-exeext: Options
no-installinfo: Options, Texinfo
no-installman: Options, Man pages
no-texinfo.tex: Options, Texinfo
nobase_ and dist_ or nodist_: Alternative
nobase_ prefix: Alternative
nodist_ and nobase_: Alternative
noinst_ primary prefix, definition: Uniform
noinstall-info option: Texinfo
noinstall-man option: Man pages
nostdinc: Options
OBJCFLAGS and AM_OBJCFLAGS: Flag Variables Ordering
--warnings=category-Wcategoryansi2knr: Options
check-news: Options
cygnus: Options
dejagnu: Options
dist-bzip2: Options
dist-shar: Options
dist-tarZ: Options
dist-zip: Options
filename-length-max=99: Options
foreign: Options
gnits: Options
gnu: Options
no-define: Options
no-dependencies: Options
no-dist: Options
no-dist-gzip: Options
no-exeext: Options
no-installinfo: Options
no-installman: Options
no-texinfo.tex: Options
noinstall-info: Texinfo
noinstall-man: Man pages
nostdinc: Options
readme-alpha: Options
tar-pax: Options
tar-ustar: Options
tar-v7: Options
aclocal: aclocal options
automake: Invoking Automake
std-options: Options
subdir-objects: Options
PACKAGE, directory: Uniform
PACKAGE, prevent definition: Public macros
pdf: Extending
pdf-local: Extending
pkgdatadir, defined: Uniform
pkgincludedir, defined: Uniform
pkglibdir, defined: Uniform
DATA: Data
HEADERS: Headers
JAVA: Java
LIBRARIES: A Library
LISP: Emacs Lisp
LTLIBRARIES: Libtool Libraries
MANS: Man pages
PROGRAMS: Uniform
PYTHON: Python
SCRIPTS: Scripts
SOURCES: Program Sources
TEXINFOS: Texinfo
prog_LDADD, defined: Linking
PROGRAMS primary variable: Uniform
PROGRAMS, bindir: Program Sources
Makefile for third-party packages: Third-Party Makefiles
ps: Extending
ps-local: Extending
PYTHON primary, defined: Python
README-alpha: Gnits
readme-alpha: Options
Makefiles: Third-Party Makefiles
JAVA: Java
RFLAGS and AM_RFLAGS: Flag Variables Ordering
configure.ac: configure
SCRIPTS primary, defined: Scripts
SCRIPTS, installation directories: Scripts
site.exp: Tests
SOURCES primary, defined: Program Sources
std-options: Options
foreign: Strictness
gnits: Strictness
gnu: Strictness
subdir-objects: Options
SUBDIRS and AC_SUBST: Conditional Subdirectories
SUBDIRS and AM_CONDITIONAL: Conditional Subdirectories
SUBDIRS, conditional: Conditional Subdirectories
SUBDIRS, explained: Subdirectories
.la, defined: Libtool Concept
.lo, defined: Libtool Concept
SUFFIXES, adding: Suffixes
tags: Tags
TAGS support: Tags
tar formats: Options
tar-pax: Options
tar-ustar: Options
tar-v7: Options
install-info: Texinfo
install-man: Man pages
EDITION: Texinfo
UPDATED: Texinfo
UPDATED-MONTH: Texinfo
VERSION: Texinfo
texinfo.tex: Texinfo
TEXINFOS primary, defined: Texinfo
true Example: true
AC_DEFUN: Extending aclocal
uninstall: Extending, Install
uninstall-hook: Extending
uninstall-local: Extending
UPDATED Texinfo flag: Texinfo
UPDATED-MONTH Texinfo flag: Texinfo
tar format: Options
VERSION Texinfo flag: Texinfo
VERSION, prevent definition: Public macros
version.m4, example: Rebuilding
version.sh, example: Rebuilding
yacc, multiple parsers: Yacc and Lex
YFLAGS and AM_YFLAGS: Flag Variables Ordering
ylwrap: Yacc and Lex
zardoz example: Complete
Makefile.in
configure.ac
LTLIBOBJS and LTALLOCA
_SOURCES
--gnu and --gnits
--cygnus
Makefile.ins
missing and AM_MAINTAINER_MODE
These variables are also called make macros in Make terminology, however in this manual we reserve the term macro for Autoconf's macros.
Older Autoconf versions used
configure.in. Autoconf 2.50 and greater promotes
configure.ac over configure.in. The rest of this
documentation will refer to configure.ac, but Automake also
supports configure.in for backward compatibility.
We believe. This work is new and there are probably warts. See Introduction, for information on reporting bugs.
There are other, more obscure reasons for this limitation as well.
Much, if not most, of the information in the following sections pertaining to preprocessing Fortran 77 programs was taken almost verbatim from Catalogue of Rules.
For example,
the cfortran package
addresses all of these inter-language issues, and runs under nearly all
Fortran 77, C and C++ compilers on nearly all platforms. However,
cfortran is not yet Free Software, but it will be in the next
major release.