即使在Windows上的后台运行命令，PHP脚本仍停留在exec上

我想要一个php脚本，我可以从中执行一个程序，并终止它，如果它不能在2秒钟内完成执行。我正在使用Windows。我尝试了以下代码：

exec("start /B program.exe");
sleep(2);
exec('taskkill /F /IM "program.exe"');

这似乎不起作用，因为只要

program.exe

未完成执行，脚本就卡在第一个

exec

语句上。我不知道如何解决此问题。

对，

exec（）

将阻止执行，直到执行完成。对于如何在超时的情况下执行

exec（）

，有很好的答案。我想这可能对你最合适。为了完整起见，我将在这里发布代码（但我不能接受任何信用！）

编辑

proc\u open（）

的“exec”部分可能在Windows上不起作用，但它可能是不必要的。

exec（）

手册页面的部分显示了一个非常简单的示例。

您是在使用它吗？打开一个窗口。
不要因为等待程序而被阻止

php myscript.php

也可以将exec start放入单独的脚本中，并使用

exec

/**
 * Execute a command and return it's output. Either wait until the command exits or the timeout has expired.
 *
 * @param string $cmd     Command to execute.
 * @param number $timeout Timeout in seconds.
 * @return string Output of the command.
 * @throws \Exception
 */
function exec_timeout($cmd, $timeout) {
  // File descriptors passed to the process.
  $descriptors = array(
    0 => array('pipe', 'r'),  // stdin
    1 => array('pipe', 'w'),  // stdout
    2 => array('pipe', 'w')   // stderr
  );

  // Start the process.
  $process = proc_open('exec ' . $cmd, $descriptors, $pipes);

  if (!is_resource($process)) {
    throw new \Exception('Could not execute process');
  }

  // Set the stdout stream to none-blocking.
  stream_set_blocking($pipes[1], 0);

  // Turn the timeout into microseconds.
  $timeout = $timeout * 1000000;

  // Output buffer.
  $buffer = '';

  // While we have time to wait.
  while ($timeout > 0) {
    $start = microtime(true);

    // Wait until we have output or the timer expired.
    $read  = array($pipes[1]);
    $other = array();
    stream_select($read, $other, $other, 0, $timeout);

    // Get the status of the process.
    // Do this before we read from the stream,
    // this way we can't lose the last bit of output if the process dies between these     functions.
    $status = proc_get_status($process);

    // Read the contents from the buffer.
    // This function will always return immediately as the stream is none-blocking.
    $buffer .= stream_get_contents($pipes[1]);

    if (!$status['running']) {
      // Break from this loop if the process exited before the timeout.
      break;
    }

    // Subtract the number of microseconds that we waited.
    $timeout -= (microtime(true) - $start) * 1000000;
  }

  // Check if there were any errors.
  $errors = stream_get_contents($pipes[2]);

  if (!empty($errors)) {
    throw new \Exception($errors);
  }

  // Kill the process in case the timeout expired and it's still running.
  // If the process already exited this won't do anything.
  proc_terminate($process, 9);

  // Close all streams.
  fclose($pipes[0]);
  fclose($pipes[1]);
  fclose($pipes[2]);

  proc_close($process);

  return $buffer;
}

pclose(popen("start /B program.exe", "r"));
sleep(2);
exec('taskkill /F /IM program.exe');
exit(0);