PowerToys/src/common/window_helpers.cpp

#include "window_helpers.h"
#include "pch.h"

HWND CreateMsgWindow(_In_ HINSTANCE hInst, _In_ WNDPROC pfnWndProc, _In_ void* p)
{
    WNDCLASS wc = { 0 };
    
    PCWSTR wndClassName = L"MsgWindow";

    wc.lpfnWndProc = DefWindowProc;
    wc.cbWndExtra = sizeof(void*);
    wc.hInstance = hInst;
    wc.hbrBackground = (HBRUSH)(COLOR_BTNFACE + 1);
    wc.lpszClassName = wndClassName;

    RegisterClass(&wc);

    HWND hwnd = CreateWindowEx(
        0, wndClassName, nullptr, 0, 0, 0, 0, 0, HWND_MESSAGE, 0, hInst, nullptr);
    if (hwnd)
    {
        SetWindowLongPtr(hwnd, 0, (LONG_PTR)p);
        if (pfnWndProc)
        {
            SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)pfnWndProc);
        }
    }

    return hwnd;
}