| YIELD(3) | YIELD(3) | 
#include <mpcxx.h>
void yield(void);
yield() function yields the current thread.  This means that
the current thread is temporarily suspended and the next eligible-to-run
thread in a scheduling queue will be scheduled. If there is no
eligible-to-run thread then this function has no effect. 
When a thread calls yield(), the communication network 
is polled, and if there are one or more messages, then the received 
message(s) are processed. Thus, yield() must be
called in a busy loop waiting for some particular message(s).