This example converts a client window's boundaries into screen coordinates and calls WinCalcFrameRect to calculate an equivalent frame rectangle size.

#define INCL_WINFRAMEMGR        /* Window Frame Functions       */
#define INCL_WINWINDOWMGR       /* Window Manager Functions     */
#include <os2.h>

BOOL  fSuccess;         /* Success indicator                    */
HWND  hwndClient;       /* client window                        */
HWND  hwndFrame;        /* frame window                         */
RECTL  rclBoundary;     /* Boundary rectangle                   */

/* convert client boundary coordinates to screen coordinates */
WinMapWindowPoints(hwndClient, HWND_DESKTOP, (PPOINTL)&rclBoundary,
                   2);

/* calculate equivalent frame boundary from boundary data */
fSuccess = WinCalcFrameRect(hwndFrame, &rclBoundary, FALSE);