WM_CLOSE message

Sent as a signal that a window or an application should terminate.

A window receives this message through its WindowProc function.

#define WM_CLOSE                        0x0010

Parameters

wParam

This parameter is not used.

lParam

This parameter is not used.

Return value

Type: LRESULT

If an application processes this message, it should return zero.

Example

LRESULT CALLBACK WindowProc(
    __in HWND hWindow,
    __in UINT uMsg,
    __in WPARAM wParam,
    __in LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_CLOSE:
        DestroyWindow(hWindow);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWindow, uMsg, wParam, lParam);
    }

    return 0;
}

Example from Windows Classic Samples on GitHub.

Remarks

An application can prompt the user for confirmation, prior to destroying a window, by processing the WM_CLOSE message and calling the DestroyWindow function only if the user confirms the choice.

By default, the DefWindowProc function calls the DestroyWindow function to destroy the window.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Winuser.h (include Windows.h)

See also

Reference

DefWindowProc

DestroyWindow

Conceptual

Windows