usleep

Sleep for the specified duration (in microseconds). GHC Note: threadDelay is a better choice. Without the -threaded option, usleep will block all other user threads. Even with the -threaded option, usleep requires a full OS thread to itself. threadDelay has neither of these shortcomings.

Pauses the current thread for the given number of microseconds. There are 1 million microseconds per second (represented by the USEC_PER_SEC macro). usleep may have limited precision, depending on hardware and operating system; don't rely on the exact length of the sleep.