cos-public

#include <Windows.h>
#include <cstdint>

template <typename WindowT, typename CtorArgs>
inline LRESULT CALLBACK window_proc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
	if (message == WM_CREATE) {
		::OutputDebugStringW(L"WM_CREATE\n");
		auto cp = reinterpret_cast<LPCREATESTRUCTW>(lParam);
		void * create_params = cp->lpCreateParams;
		auto * args_tuple = reinterpret_cast<CtorArgs *>(cp->lpCreateParams); /// last parameter passed to ::CreateWindow()

cos-public

#include <Windows.h>
#include <cstdint>

inline LRESULT CALLBACK main_window_proc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
	if (message == WM_CREATE) {
		::OutputDebugStringW(L"WM_CREATE\n");
	}

	if (message == WM_PAINT) {
		::OutputDebugStringW(L"WM_PAINT\n");