PHP pthreads与线程号异步卡住

Question

I'm trying to achive a script that start threads async with a limit(5) and does wait if all threads are busy. If the threads are busy my script has to wait untill one is free and it should start another one but for some reasons does get stuck. Yesterday I discovered pthreads and after a few hours today this is all I came with:

EDIT: There are examples with 500 threads for example but in my case I need to parse large files(a few MBs) of targets and I need to make it to work async.

<?php
class My extends Thread {
  public function run() {
    echo $this->getThreadId() . "\n";
    sleep(rand(1, 3)); // Simulate some work...
    global $active_threads;
    $active_threads = $active_threads - 1; // It should decrese the number of active threads. Here could be the problem?
  }
}

$active_threads = 0;
$maximum_threads = 5;

while(true) {
  if($active_threads == $maximum_threads) {
    echo 'Too many threads, just wait for a moment untill some threads are free.' . "\n";
    sleep(3);
    continue;
  }

  $threads = array();
  for($i = $active_threads; $i < $maximum_threads; $i++) {
    $active_threads = $active_threads + 1;
    $threads[] = new My();
  }

  foreach($threads as $thread) {
    $thread->start();
  }
}
?>

Output:

[root@localhost tests]# zts-php test
140517320455936
140517237061376
140517228668672
140517220275968
140517207701248
Too many threads, just wait for a moment.
Too many threads, just wait for a moment.
Too many threads, just wait for a moment.
Too many threads, just wait for a moment.

I know is pretty primitive but I'm totally new to pthreads and all the examples are without async threads number limit. There is for sure something wrong in my code but I have no ideea where.

Answer 1

The problem as stated in another post is that the global memory is not shared. So your $active_thread will not decrement even if you use global .

See post: How to share global variable across thread in php?