php教程之多进程实例(2)

<?php 
// 多进程实例
date_default_timezone_set( 'Asia/Chongqing'); 
declare (ticks = 1); 
pcntl_signal(SIGCHLD, "garbage" ); 
echo "parent start, pid ", getmypid(), "\n" ; 
beep(); 
for ($i=0; $i<3; ++$i){ 
      $pid = pcntl_fork(); 
       if ($pid == -1){ 
             die ("cannot fork" ); 
      } else if ($pid > 0){ 
             echo "parent continue \n"; 
             for ($k=0; $k<2; ++$k){ 
                  beep(); 
            } 
      } else if ($pid == 0){ 
             echo "child start, pid ", getmypid(), "\n" ; 
             for ($j=0; $j<5; ++$j){ 
                  beep(); 
            } 
             exit (0); 
      } 
} 
// parent 
while (1){ 
       // do something else 
      sleep(5); 
} 
// www.jbxue.com
function garbage($signal){ 
       echo "signel $signal received\n" ; 
       
       while (($pid = pcntl_waitpid(-1, $status, WNOHANG))> 0){ 
             echo "\t child end pid $pid , status $status\n" ; 
      } 
} 
function beep(){ 
       echo getmypid(), "\t" , date( 'Y-m-d H:i:s', time()), "\n" ; 
      sleep(1); 
} 
?>