WACLOSE()
 Closes all windows
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 Syntax

     WACLOSE() --> nError

 Returns

     WACLOSE() returns 0 when successful or -1 if an error occurs.

 Description

     This function closes all windows in a work session.  If no windows were
     opened with WOPEN(), then WACLOSE() returns a value of -1.  If windows
     were opened with WOPEN(), then WACLOSE() returns a value of 0.

 Example

     WOPEN( ... )            // Many windows will be opened
     WOPEN( ... )
     WOPEN( ... )

     WACLOSE()               // Close all windows!