Internal Server Error due to set_time_limit in PHP -

i'm trying run following php script on shared hosting make run forever:

<?php ignore_user_abort(true); set_time_limit(0);  include_once("function.php");  while (true) {   if (file_exists("stop_test.txt")) {     echo "break file exists!";       break;   }   // something, commenting section, face internal server error too!   sleep(30); }  exit(); ?> 

but face "internal server error" after 1 minute. contacted hosting provider , asked them problem , have told me there no problem on server side , these kind of cron-like scripts allowed on shared hosting , suggested me review code.

i couldn't figure out why script results in internal server error, problem script?

i facing same issue, directly setting ini using ini_set() seems have corrected issue:

ini_set('max_execution_time', 0); 

however, suggested in comments, it's best practice set sane limit (30 seconds or so).