The SwitchToThread function causes the calling thread to yield execution to another thread that is ready to run on the current processor. The operating system selects the thread to yield to.
BOOL SwitchToThread(VOID)
This function has no parameters.
If calling the SwitchToThread function causes the operating system to switch execution to another thread, the return value is nonzero.
If there are no other threads ready to execute, the operating system does not switch execution to another thread, and the return value is zero.
The yield of execution is in effect for up to one thread-scheduling time slice. After that, the operating system reschedules execution for the yielding thread. The rescheduling is determined by the priority of the yielding thread and the status of other threads that are available to run.
Note that the yield of execution is limited to the processor of the calling thread. The operating system will not switch execution to another processor, even if that processor is idle or is running a thread of lower priority.