Question

我有一个php脚本，分叉和父调用pnctl_wait（）。根据php手册，pcntl_wait（）应暂停执行当前进程，直到子进程退出。但这不会发生。父进程根本不会等待，并立即执行下一行。

我试图在下面的小样本脚本中复制该问题

<?php
$parentpid=getmypid();
declare(ticks=1);
$apid = pcntl_fork();
if ($apid == -1) {
  die('could not fork for client '.$client);
 } else if ($apid) {     //parent                                                                                                              


pcntl_wait($status,WNOHANG); //Protect against Zombie children                                                                     
/* Parent does not wait here */ 

  print "PARENT $parentpid has forked $apid \n";   

  sleep(100);
 } else { // child                                                                                                                             
  $pid = getmypid();
  print "CHILD $pid  is sleeping\n";
  sleep(40);
 }


?>

Answer 1

您不希望在此处选择WNOHANG。只需使用：

pcntl_wait($status);

如果您通过WNOHANG pcntl_wait()，则不会等待孩子返回。它仅报告已被终止的孩子。

整个示例应如下所示：

$parentpid = getmypid();
$apid = pcntl_fork();

if ($apid == -1) {
  die('could not fork for client '.$client);
} else if ($apid) {
    // Parent process
    print "PARENT $parentpid has forked $apid \n";

    // Wait for children to return. Otherwise they 
    // would turn into "Zombie" processes
    pcntl_wait($status);
} else {
  // Child process
  $pid = getmypid();
  print "CHILD $pid  is sleeping\n";
  sleep(40);
}

PHP pcntl_wait（）不等待子退出

1 个答案: