Allows one thread within a process to cancel a VioSavRedrawWait issued by another thread within the same process.

#define INCL_VIO
#include <os2.h>

ULONG     OwnerIndic;  /*  Ownership indicator */
ULONG     KillIndic;   /*  Terminate indicator */
HVIO      VioHandle;   /*  Reserved.  Must be 0. */
APIRET    rc;          /*  Return code. */

rc = VioSavRedrawUndo(OwnerIndic, KillIndic,
       VioHandle);