This example broadcasts a WM_CLOSE message to all descendants of the specified window.

#define INCL_WINMESSAGEMGR      /* Window Message Functions     */
#include <os2.h>

BOOL  fSuccess;         /* Success indicator                    */
HWND  hwndParent;       /* parent window handle                 */
ULONG   ulMsgId;        /* Message identifier                   */
MPARAM  mpParam1;       /* Parameter 1                          */
MPARAM  mpParam2;       /* Parameter 2                          */
ULONG   flCmd;          /* message command                      */

/* set msg to close window, parameters to NULL */
ulMsgId = WM_CLOSE;
mpParam1 = MPVOID;
mpParam2 = MPVOID;

/* broadcast to all descendants */
flCmd = BMSG_DESCENDANTS;

fSuccess = WinBroadcastMsg(hwndParent, ulMsgId, mpParam1,
                            mpParam2, flCmd);