Sleep and Wait

One important feature that multithreading components such as threads, locks, condition variables, and futures have in common is the notion of time.

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Conventions

The methods for handling time in multithreading programs follow a simple convention: Methods ending with _for have to be parametrized by a time duration; methods ending with _until by a time point. Here is a concise overview of the methods that deal with sleeping, blocking, and waiting:

Multithreading Component	_until	_for
std::thread th	th.sleep_until(in2min)	th.sleep_for(2s)
std::unique_lock lk	lk.try_lock_until(in2min)	lk.try_lock(2s)
std::condition_variable cv	cv.wait_until(in2min)	cv.wait_for(2s)
std::future fu	fu.wait_until(in2min)	fu.wait_for(2s)
std::shared_future shFu	shFu.wait(in2min)	shFu.wait_for(2s)

in2min stands for a time 2 minutes in the future; 2s is a time duration of 2 seconds. Although I use auto in the initialization of the time point in2min, the following is still verbose: