Is php multi-process?

When running scripts on the server, some time-consuming tasks cannot be avoided, and the use of multiple processes is essential. After PHP5.5, PHP began to add multi-process elements to meet development needs.

Note

Extensions that need to be enabled to implement multiple processes: pcntl, posix. (Recommended learning: PHP video tutorial)

Multi-process programming of PHP is not supported in the Windows environment. This article is mainly developed and tested in the Linux environment

A simple structure diagram

##Main functions##pcntl_fork: Create multiple processes, two items will be returned after calling The pid of the process, 0 is the child process, greater than 0 is the parent process (the parent process gets the id of the child process, so it is greater than 0), -1 means the creation failed

$pid = $pcntlInstall ? pcntl_fork() : 0;if ($pid == -1) {
    //fork失败
 } elseif ($pid > 0) {
    //父进程
    ......
 } elseif ($pid == 0) {
    //子进程
    ......
 }

pcntl_signal: Register a signal processing callback function, you can Capture the signal sent when the child process ends

/配合pcntl_signal使用
declare (ticks = 1);

//当子进程退出时，会触发该函数,当前子进程数-1
pcntl_signal(SIGCHLD, function ($signo) {
    switch ($signo) {
        case SIGCHLD:
            echo $curChildPro . 'SIGCHLD', PHP_EOL;
            $curChildPro--;
            break;
    }
});

pcntl_wait: used to pause the parent process and wait for the child process to exit

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