OL_AutoYield()
 Automaticly return times slices back to the OS.
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 Syntax

       OL_AutoYield( [<lOn>] ) --> lOld

 Arguments

      <lOn> is an optional logical variable that tells the function if
      it should turn the yielding on or off. If not supplied the function
      just returns the current setting.

 Returns

      The current/old setting.

 Description

      OL_AutoYield() can be used to yield time slices back to the
      operating system in those situations where you don't have access
      to or control over the code that is causing the slice hogging.
      For example, if you were to use Clipper's "Menu To" command you
      would not be able to make use of the OL_Yield() function so
      turning on OL_AutoYield() will allow the yielding of times slices.

 Examples

      // Turn on auto yielding.

      OL_AutoYield( TRUE )

 Source: AUTYIELD.C

 Author: Dave Pearson, heavily stolen from Ted Means