WINAPI postquitmessage leaves window hanging - c++

Question

i'm using a Dialog to ask the user for some input, but my window 'hangs' after the user is done (controls don't respond anymore, but it's still visible) and disappears only when the application quits.
Here's my code:
LRESULT CALLBACK Level2Auth(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
switch (Message)
{
case WM_CREATE:
{
{... do stuff ...}
CreateWindow(L"BUTTON", L"Connect",
WS_VISIBLE | WS_CHILD | WS_BORDER,
370, 10, 70, 20,
hwnd, (HMENU)1, NULL, NULL);
break;
}
case WM_COMMAND:
{
switch (LOWORD(wParam))
{
case 1:
{
{... retrieve input ...}
Level2Auth(NULL, WM_DESTROY, NULL, NULL);
break;
}
default:
{
break;
}
}
break;
}
case WM_DESTROY:
{
PostQuitMessage(0);
break;
}
default:
return DefWindowProc(hwnd, Message, wParam, lParam);
}
return 0;
}
And the message loop:
INT WINAPI launchLevel2Auth()
{
MSG Msg; HWND hwnd;
hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, L"Level2AuthPopUp", L"Remote PKCS#11 PIN entry", WS_VISIBLE | WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
640,
100,
NULL, NULL, hInstance, NULL);
if (hwnd == NULL) {
return 0;
}
while (GetMessage(&Msg, NULL, 0, 0) > 0) {
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
My intention was to retrieve some data in a text field as the "Connect" button was clicked, and then to close the window.
Thanks a lot for your answers.

Answer 1

When you are calling your own message handler with WM_DESTROY message directly, you are bypassing any cleanup, that needs to be done by WINAPI framework. Instead, use DestroyWindow:
...
switch (LOWORD(wParam))
{
case 1:
{
{... retrieve input ...}
DestroyWindow (hwnd);
// Level2Auth(NULL, WM_DESTROY, NULL, NULL);
break;
}
...
Article for further reading: Destroying Windows in WINAPI.