stream_socket_pair

Creates a pair of connected, indistinguishable socket streams

&reftitle.description; ``array``false```stream_socket_pair` `int` `domain` `int` `type` `int` `protocol`

`stream_socket_pair` creates a pair of connected, indistinguishable socket streams. This function is commonly used in IPC (Inter-Process Communication).

&reftitle.parameters;

`domain`

- The protocol family to be used: `STREAM_PF_INET`, `STREAM_PF_INET6` or `STREAM_PF_UNIX`

`type`

- The type of communication to be used: `STREAM_SOCK_DGRAM`, `STREAM_SOCK_RAW`, `STREAM_SOCK_RDM`, `STREAM_SOCK_SEQPACKET` or `STREAM_SOCK_STREAM`

`protocol`

- The protocol to be used: `STREAM_IPPROTO_ICMP`, `STREAM_IPPROTO_IP`, `STREAM_IPPROTO_RAW`, `STREAM_IPPROTO_TCP` or `STREAM_IPPROTO_UDP`

Please consult the Streams constant list for further details on each constant.

&reftitle.returnvalues;

Returns an `array` with the two socket resources on success, or &false; on failure.

&reftitle.examples;

### A `stream_socket_pair` example

This example shows the basic usage of `stream_socket_pair` in Inter-Process Communication.

    <?php

    $sockets = stream_socket_pair(STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
    $pid     = pcntl_fork();

    if ($pid == -1) {
         die('could not fork');

    } else if ($pid) {
         /* parent */
        fclose($sockets[0]);

        fwrite($sockets[1], "child PID: $pid\n");
        echo fgets($sockets[1]);

        fclose($sockets[1]);

    } else {
        /* child */
        fclose($sockets[1]);

        fwrite($sockets[0], "message from child\n");
        echo fgets($sockets[0]);

        fclose($sockets[0]);
    }

    ?>

&example.outputs.similar;

    child PID: 1378
    message from child