Updates the physical display buffer with the logical video buffer (LVB).

#define INCL_VIO
#include <os2.h>

ULONG     OffSet;     /*  Offset into the LVB. */
ULONG     Length;
HVIO      VioHandle;  /*  VIO presentation-space handle. */
APIRET    rc;         /*  Return code */

rc = VioShowBuf(OffSet, Length, VioHandle);