What is the best way to exit out of a loop after an elapsed time of 30ms in C++

Question

What is the best way to exit out of a loop as close to 30ms as possible in C++. Polling boost:microsec_clock ? Polling QTime ? Something else?

Something like:

Answer 1

If you need to do work until a certain time has elapsed, then docflabby's answer is spot-on. However, if you just need to wait, doing nothing, until a specified time has elapsed, then you should use usleep()