GAMMA(3)              libc math functions              GAMMA(3)





NAME
       gamma,  gammaf,  gammal - (logarithm of the) gamma func-
       tion

SYNOPSIS
       #include <math.h>

       double gamma(double x);

       float gammaf(float x);

       long double gammal(long double x);


DESCRIPTION
       For the definition of the Gamma function, see tgamma(3).


   *BSD version
       4.4BSD  and  FreeBSD  libm  have a gamma() function that
       computes the Gamma function, as one would expect.

   glibc version
       Glibc has a  gamma()  function  that  is  equivalent  to
       lgamma() and computes the natural logarithm of the Gamma
       function.  (This  is  for  compatibility  reasons  only.
       Don't use this function.)

HISTORY
       4.2BSD  had  a  gamma()  that computed ln(|Gamma(|x|)|),
       leaving the sign of Gamma(|x|) in the  external  integer
       signgam.   In  4.3BSD  the name was changed to lgamma(),
       and the man page promises

          "At some time in the future the name  gamma  will  be
          rehabilitated and used for the Gamma function"

       This did indeed happen in 4.4BSD, where gamma() computes
       the Gamma function (with no effect  on  signgam).   How-
       ever,  this came too late, and we now have tgamma(), the
       "true gamma" function.

CONFORMING TO
       4.2BSD. Compatible with previous mistakes.

SEE ALSO
       lgamma(3), signgam(3), tgamma(3)



GNU                        2002-08-10                  GAMMA(3)
