Synchronized functions using PHP

Question

How to make functions in PHP synchronized so that same function won't be executed concurrently ? 2nd user must wait till 1st user is done with the function. Then 2nd user can execute the function.

Thanks

Answer 1

You are looking for a Semaphore

Bear in mind that using a semaphore (or any other blocking mechanism) can have serious peformance issues, as the requests can not be handled while the semaphore is up.