/** * this is a demo for php fork and pipe usage. fork use * to create child process and pipe is used to sychoroize * the child process and its main process. * @author bourneli * @date: 2012-7-6 */ define("PC", 10); // 进程个数define("TO", 4); // 超时define("TS", 4); // 事件跨度，用于模拟任务延时 if (!function_exists(‘pcntl_fork‘)) {    die("pcntl_fork not existing");} // 创建管道$sPipePath = "my_pipe.".posix_getpid();if (!posix_mkfifo($sPipePath, 0666)) {    die("create pipe {$sPipePath} error");} // 模拟任务并发for ($i = 0; $i < PC; ++$i ) {    $nPID = pcntl_fork(); // 创建子进程    if ($nPID == 0) {        // 子进程过程        sleep(rand(1,TS)); // 模拟延时        $oW = fopen($sPipePath, ‘w‘);        fwrite($oW, $i."\n"); // 当前任务处理完比，在管道中写入数据        fclose($oW);        exit(0); // 执行完后退出    }} // 父进程$oR = fopen($sPipePath, ‘r‘);stream_set_blocking($oR, FALSE); // 将管道设置为非堵塞，用于适应超时机制$sData = ‘‘; // 存放管道中的数据$nLine = 0;$nStart = time();while ($nLine < PC && (time() - $nStart) < TO) {    $sLine = fread($oR, 1024);    if (empty($sLine)) {        continue;      }           echo "current line: {$sLine}\n";    // 用于分析多少任务处理完毕，通过‘\n’标识    foreach(str_split($sLine) as $c) {        if ("\n" == $c) {            ++$nLine;        }    }    $sData .= $sLine;}echo "Final line count:$nLine\n";fclose($oR);unlink($sPipePath); // 删除管道，已经没有作用了 // 等待子进程执行完毕，避免僵尸进程$n = 0;while ($n < PC) {    $nStatus = -1;    $nPID = pcntl_wait($nStatus, WNOHANG);    if ($nPID > 0) {        echo "{$nPID} exit\n";        ++$n;    }} // 验证结果，主要查看结果中是否每个任务都完成了$arr2 = array();foreach(explode("\n", $sData) as $i) {// trim all    if (is_numeric(trim($i))) {        array_push($arr2, $i);     }}$arr2 = array_unique($arr2);if ( count($arr2) == PC) {     echo ‘ok‘;} else {    echo  "error count " . count($arr2) . "\n";    var_dump($arr2);}