Defined in File time.h
Returns the number of nanoseconds from when when the calling thread was started in CPU time.
This uses CLOCK_THREAD_CPUTIME_ID. This time only increments when the processor is working on the calling thread and not when the thread is sleeping. This is usually for timing how long blocks of user-code take to execute. This function itself takes about 2100ns to complete on a beaglebone at 1ghz under ideal circumstances.
nanoseconds of CPU time since thread started