This function returns a window rectangle.

#define INCL_WINWINDOWMGR /* Or use INCL_WIN, INCL_PM, Also in COMMON section */
#include <os2.h>

HWND      hwnd;      /*  Window handle whose rectangle is retrieved. */
PRECTL    prclDest;  /*  Window rectangle. */
BOOL      rc;        /*  Rectangle-returned indicator. */

rc = WinQueryWindowRect(hwnd, prclDest);