This example uses the WinSubstractRect call to subtract two rectangles.

#define INCL_WINRECTANGLES
#include <OS2.H>
HAB hab;
RECTL resultrcl;   /* result. */
RECTL rclminuend={25, /* x coordinate of left-hand edge of */
                      /* rectangle. */
                  25, /* y coordinate of bottom edge of    */
                      /* rectangle. */
                  425,/* x coordinate of right-hand edge of */
                      /* rectangle. */
                  425};/* y coordinate of top edge of rectangle. */

RECTL rclsubtrahend={15, /* x coordinate of left-hand edge of */
                      /* rectangle. */
                  15, /* y coordinate of bottom edge of    */
                      /* rectangle. */
                  125,/* x coordinate of right-hand edge of */
                      /* rectangle. */
                  125};/* y coordinate of top edge of rectangle.*/


WinSubtractRect(hab,
                &resultrcl,
                &rclminuend,
                &rclsubtrahend);