我正在调用proc_open()，但无法捕获写入stderr的进程输出:$curFolder=getcwd();$procDescriptor=array(2=>array("pipe","w"));$cmd="MyApp.exe-foptimization.csv";$process=proc_open($cmd,$procDescriptor,$pipes,$curFolder);if(is_resource($process)==true){$procStatus=proc_get_status($process);while($procStatus['running']===t