Shat is the difference among sleep() , usleep() & [NSThread sleepForTimeInterval:]?

sleep_in_ios.md

#iOSBySheldon #objective-c #swift #unitTest #uiTest #sleep

This notes is written by Sheldon. You can find me with #iOSBySheldon in Github, Youtube, Facebook, etc.

The only reason that I wrote this short quick note is that, the answers on the internet is somewhat misleading.

If we are running sleep() usleep() or [NSThread sleepForTimeInterval:] in your main app, there should not be any difference. Because the first two functions are just functions that from c and the third one is from objective-c.

However,

• You probably should NOT call them in your main app, because for delay operations you should more use (in Swift) swift DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(4), execute: { // Put your code which should be executed with a delay here })
• If you are using these functions in tests (Unit test & UI automation Test), they are slightly different. In my observation, calling sleep() will pause the operation (tap, swipe), [NSThread sleepForTimeInterval:] will likely pause the app execution.

Summary

Trying all of the three in your code, specially in testing classes, if one is not working. They are not quite same.

gde otveeet