Why timeout is not working - php

Question

sorry for stupid question, but
Im trying to set the timeout for program called cirsym. Because sometimes Im facing with infinity process and I have to cancel the operation using ssh...
Would be really thankfull if someone help...
<?
/**
* 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;
}
// 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 $buffer;
}
This is the function
private function Exec(){
if(shell_exec($this->canonical_path."cirsym_v2.1.bin") != NULL)
{
return true;
}else{
return false;
}
}