msg_receive ( resource $queue , int $desiredmsgtype , int &$msgtype , int $maxsize , mixed &$message [, bool $unserialize [, int $flags [, int &$errorcode ]]] )
msg_receive用于读取消息队列中的数据。
msg_remove_queue ( resource $queue )
msg_remove_queue用于销毁一个队列。
示例代码_1只是展示了PHP操作消息队列函数的应用。下面的代码具体描述了进程间通信的场景
<?php
$message_queue_key = ftok(__FILE__, 'a');
$message_queue = msg_get_queue($message_queue_key, 0666);
$pids = array();
for ($i = 0; $i < 5; $i++) {
//创建子进程
$pids[$i] = pcntl_fork();
if ($pids[$i]) {
echo "No.$i child process was created, the pid is $pids[$i]rn";
} elseif ($pids[$i] == 0) {
$pid = posix_getpid();
echo "process.$pid is writing nowrn";
msg_send($message_queue, 1, "this is process.$pid's datarn");
posix_kill($pid, SIGTERM);
}
}
do {
msg_receive($message_queue, 0, $message_type, 1024, $message, true, MSG_IPC_NOWAIT);
echo $message;
//需要判断队列是否为空，如果为空就退出
//break;
} while(true)
?>
运行结果为：
No.0 child process was created, the pid is 5249
No.1 child process was created, the pid is 5250
No.2 child process was created, the pid is 5251
No.3 child process was created, the pid is 5252
No.4 child process was created, the pid is 5253
process.5251 is writing now
this is process.5251's data
process.5253 is writing now
process.5252 is writing now
process.5250 is writing now
this is process.5253's data
this is process.5252's data
this is process.5250's data
process.5249 is writing now
this is process.5249's data
这段程序每次的运行结果都会不同，这正说明了多进程的异步性。从结果也能看出消息队列FIFO特性。
以上便是我研究的一点心得。接下来将会继续研究PHP利用信号、socket等进行进程间通信的方法。
