Yield processor.
Standard Library (libc.a)
#include <sched.h>
int sched_yield (void) ;
The sched_yield function forces the running thread to relinquish the processor until it again becomes the head of its thread list. It takes no arguments.
The sched_yield function returns 0 if it completes successfully, or it returns a value of -1 and sets errno to indicate the error.