WM CLOSE

This message is sent to a frame window to indicate that the window is being closed by the user.

Syntax

param1
    ULONG   ulReserved; /* Reserved value, should be 0. */

param2
    ULONG   ulReserved; /* Reserved value, should be 0. */

Parameters

ulReserved (ULONG) - input: Reserved value, should be 0.
ulReserved (ULONG) - input: Reserved value, should be 0.

Returns

ulReserved (ULONG) - returns: Reserved value, should be 0.

Remarks

This message is sent by the frame to itself as a result of receiving a WM_SYSCOMMAND message with SC_CLOSE code set. If this message is passed to WinDefDlgProc, this function calls WinDismissDlg and passes the DID_CANCEL result code to it.

in Frame Controls

Frame control sends this message to the client window (FID_CLIENT) if it exists, otherwise it calls the WinDefWindowProc function.

Default Processing

The default window procedure posts a WM_QUIT message to the appropriate queue and sets ulReserved to 0.

in Default Dialogs

The default dialog procedure responds to this message by dismissing the dialog by issuing the WinDismissDlg function with its parameter set to DID_CANCEL.

in Frame Controls

The default window procedure posts a WM_QUIT message to the appropriate queue and sets ulReserved to 0.

Example Code

This example checks the `fChanges` variable. If it is TRUE, the user is asked if he wants to exit without saving any changes. If the user responds by choosing the No button, zero is returned and the application does not exit. If the user responds by choosing the Yes button, a WM_QUIT message is posted and the application terminates.

case WM_CLOSE:
    if (fChanges) {
        if (WinMessageBox(HWND_DESKTOP, hwndClient,
                        "Do you want to exit without saving your changes?",
                        "", 0, MB_NOICON | MB_YESNO) == MBID_NO)
            return (0L);
    }
    WinPostMsg(hwnd, WM_QUIT, 0L, 0L);
    return (0L);

Related Messages

WM_CLOSE (Default Dialogs)
WM_CLOSE (in Frame Controls)