php_unix_domain_socket_unnamed.php

<?php
$sockets = stream_socket_pair(STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
$pid = pcntl_fork();
const EXIT_CODE = "-1\n";

if ($pid == -1) {
    die('フォークできません');
} else if ($pid) {
    echo "@start parent\n";
    while (($buffer = fgets($sockets[0], 4096)) !== false) {
        if ($buffer === EXIT_CODE) {
            break;
        }
        echo $buffer;
    }
    fclose($sockets[1]);
    echo "@end parent\n";
} else {
    echo "@start child\n";
    for ($i = 1; $i <= 10; $i++) {
        fwrite($sockets[1], "${i}回目\n");
        sleep(1);
    }
    fwrite($sockets[1], EXIT_CODE);
    fclose($sockets[0]);
    echo "@end child\n";
}