php mkfifo

<?php
$fifoPath ='/tmp/testfifo';

function writedata($data)
{
    printf("this is child start");
    file_put_contents("/tmp/testdata",FILE_APPEND);
    printf("this is  child end");
}


while(1)
{
    if($argv[1]==1)
    {
        printf("this is cycle task\r\n");
        sleep(60);
        continue;
    }

    // immediate

    $fd  = fopen($fifoPath, 'r');
    // 定義爲非阻塞模式.
    stream_set_blocking($fd,false);
    $readers = array($fd);
    $bytes = 4;

    $write  = NULL;
    $except = NULL;

    // 需要區分類型的.
    while(stream_select($readers, $write, $except, 0, 15) == 1) {
        $data = fread($fd, $bytes);
        if($data)
        {
            printf("recv data:%d\r\n",$data);
            $pid = pcntl_fork();
            //父進程和子進程都會執行下面代碼
            if ($pid == -1) {
                //錯誤處理：創建子進程失敗時返回-1.
                printf('could not fork\r\n');
            } else if ($pid) {
                //父進程會得到子進程號，所以這裏是父進程執行的邏輯
                printf("this is  parent process\r\n");
                pcntl_wait($status); //等待子進程中斷，防止子進程成爲殭屍進程。
            } else {
                //子進程得到的$pid爲0, 所以這裏是子進程執行的邏輯。
                printf("this is child process\r\n");
                writedata($data);
                exit(0);
            }
            sleep(1);
        }else{
            printf("this is read  0 bytes\r\n");
            sleep(1);
            continue;
        }
    }
}