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/**
* 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);
}
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