# stream_socket_recvfrom

(PHP 5, PHP 7)

stream_socket_recvfrom — Receives data from a socket, connected or not

### 说明

stream_socket_recvfrom ( resource `$socket` , int `$length` [, int `$flags` = 0 [, string `&$address` ]] ) : string

stream_socket_recvfrom() accepts data from a remote socket up to `length` bytes.

### 参数

`socket`

  The remote socket.

`length`

  The number of bytes to receive from the `socket`.

`flags`

  The value of `flags` can be any combination of the following:

  Possible values for `flags`
  `STREAM_OOB` | Process OOB (out-of-band) data.
  `STREAM_PEEK` | Retrieve data from the socket, but do not consume the buffer. Subsequent calls to fread() or stream_socket_recvfrom() will see the same data.

`address`

  If `address` is provided it will be populated with the address of the remote socket.

### 返回值

Returns the read data, as a string

### 范例

Example #1 stream_socket_recvfrom() example

    <?php
    /* Open a server socket to port 1234 on localhost */
    $server = stream_socket_server('tcp://127.0.0.1:1234');

    /* Accept a connection */
    $socket = stream_socket_accept($server);

    /* Grab a packet (1500 is a typical MTU size) of OOB data */
    echo "Received Out-Of-Band: '" . stream_socket_recvfrom($socket, 1500, STREAM_OOB) . "'\n";

    /* Take a peek at the normal in-band data, but don't consume it. */
    echo "Data: '" . stream_socket_recvfrom($socket, 1500, STREAM_PEEK) . "'\n";

    /* Get the exact same packet again, but remove it from the buffer this time. */
    echo "Data: '" . stream_socket_recvfrom($socket, 1500) . "'\n";

    /* Close it up */
    fclose($socket);
    fclose($server);
    ?>

### 注释

> Note:

> If a message received is longer than the `length` parameter, excess bytes may be discarded depending on the type of socket the message is received from (such as UDP).

> Note:

> Calls to stream_socket_recvfrom() on socket-based streams, after calls to buffer-based stream functions (like fread() or stream_get_line()) read data directly from the socket and bypass the stream buffer.

### 参见

- stream_socket_sendto() - Sends a message to a socket, whether it is connected or not
- stream_socket_client() - Open Internet or Unix domain socket connection
- stream_socket_server() - Create an Internet or Unix domain server socket