Question

I wanted to execute a bunch of code for 5 seconds and if it has not finished executing within the specificed time frame I need to execute another piece of code..

Whether it’s possible?

Ex..
There are two functions A and B

If A takes more than 30 seconds to execute the control should pass on to B

Answer 1

http://php.net/manual/en/features.connection-handling.php

Set a time limit and a shutdown function, which checks if the status is 2 (timeout) and does your stuff if so.
One thing to note is that the time limit set this way only counts actual php processing time. Time spent with php waiting for another process or a database or http connection, etc, will not count and your time limit will not be considered reached.

If you need to count actual time that passed, even if it was not php processing time, you’re going to have to go with the above suggested answer. Manually inserting that time check in places where it makes sense is the best, i.e. inside loops that you know may run too long, maybe even not on every iteration but on every N iterations, etc. Alternatively a more general approach is to use register_tick_function(), but that might lead to a noticeable performance hit with a low tick count, and you must take care to unregister it or use appropriate flags so you don’t end up infinitely starting more and more calls to your timeout handling code once the timeout has happened.

Other approaches are also possible, you can register a handler for some signal using pcntl_signal() and have it sent to your process when the time limit is reached by an outside program (‘man timeout’ if you are on a linux box) or by a fork()-ed instance of your own php script, etc.