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

#define INCL_VIO
#include <os2.h>

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

rc = VioModeUndo(OwnerIndic, KillIndic, Reserved);