Difference among sleep() and usleep() in PHP

Question

Can any body explain me what is the difference among sleep() and usleep() in PHP.

I have directed to use following scripts to do chat appli

Answer 1

The argument to sleep is seconds, the argument to usleep is microseconds. Other than that, I think they're identical.

sleep($n) == usleep($n * 1000000)

usleep(25000) only sleeps for 0.025 seconds.

Answer 2

sleep() allows your code to sleep in seconds.

• sleep(5); // sleeps for 5 seconds

usleep() allows your code with respect to microseconds.

• usleep(2500000); // sleeps for 2.5 seconds

Answer 3

One other difference is sleep returns 0 on success, false on error. usleep doesn't return anything.

Answer 4

usleep() is used to delay execution in "microseconds" while sleep() is used to delay execution in seconds. So usleep(25000) is 0.025 seconds.

Is there any difference between the two?

Answer 5

Simply

usleep uses CPU Cycles while sleep does not.

sleep takes seconds as argument

while usleep takes microseconds as argument