If your QuickWin program runs concurrently with other Windows applications, it should yield processing time to the other applications so they can service their message queues. QuickWin attempts to yield to other applications at appropriate times, but there may be cases where your program should make additional calls to the _wyield function.
Summary: QuickWin takes care of Windows message processing for you.
If Windows appears sluggish when your program runs, insert additional _wyield calls. In particular, you may want to make _wyield calls during lengthy processing loops. This allows the user to select menu commands or switch to another application without having to wait for your program to finish processing.
Note:
QuickWin programs do not require the standard Windows message loop.
The _wyield function returns void.