Keyboard hook for preventing SublimeText from focusing menu when pressing ALT on windows.

st-alt-hook.c

// gcc -DHOOKDLL -shared -o bin/st-alt-hook.dll st-alt-hook.c
// gcc bin/st-alt-hook.dll -mwindows st-alt-hook.c -o bin/st-alt-hook.exe

#include <windows.h>

#ifdef HOOKDLL

// *************** DLL ***************

static HHOOK hKeyboardHook = 0;

LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
	if ((nCode >= 0) && (wParam == VK_MENU) &&
		(HIWORD(lParam) & KF_REPEAT) == 0 &&
		(HIWORD(lParam) & KF_UP) == 0)
	{
		char classname[256];
		GetClassName(GetForegroundWindow(), classname, sizeof(classname));
		
		if (strcmp(classname, "PX_WINDOW_CLASS") == 0)
			return 1;
	}

	return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
}

BOOL __declspec(dllexport) RegisterHook(HMODULE hLib)
{
	if (hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD, (HOOKPROC)KeyboardProc, hLib, 0))
		return TRUE;
	else
		return FALSE;
}

void __declspec(dllexport) UnRegisterHook()
{
	if (hKeyboardHook)
		UnhookWindowsHookEx(hKeyboardHook);
}

#else

// *************** EXE ***************

#define NAME "st-alt-hook"

BOOL __declspec(dllimport) RegisterHook(HMODULE);
void __declspec(dllimport) UnRegisterHook();
LRESULT CALLBACK HookWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);

static HMODULE hLib = 0;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int iCmdShow)
{
	WNDCLASS wc;
	MSG msg;
	HWND hWnd = FindWindow(NAME, NAME);

	if (hWnd)
	{
		if (strstr(szCmdLine, "--exit"))
			SendMessage(hWnd, WM_CLOSE, 0, 0);
		else
			MessageBox(NULL, NAME " is already running.", NAME, MB_OK | MB_ICONINFORMATION);

		return 0;
	}

	if (!(hLib = LoadLibrary(NAME ".dll")))
	{
		MessageBox(NULL, "Error loading " NAME ".dll.", NAME, MB_OK | MB_ICONERROR);
		return 0;
	}

	if (!RegisterHook(hLib))
	{
		MessageBox(NULL, "Error setting hook procedure.", NAME, MB_OK | MB_ICONERROR);
		return 0;
	}

	wc.style         = 0;
	wc.lpfnWndProc   = HookWndProc;
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = hInstance;
	wc.hIcon         = NULL;
	wc.hCursor       = NULL;
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
	wc.lpszMenuName  = NULL;
	wc.lpszClassName = NAME;

	if (!RegisterClass(&wc))
	{
		MessageBox(NULL, "Error creating window class", NAME, MB_OK | MB_ICONERROR);
		return 0;
	}

	if (!(hWnd = CreateWindow(NAME, NAME, WS_OVERLAPPED, 0, 0, 0, 0, 0, 0, hInstance, 0)))
	{
		MessageBox(NULL, "Error creating window", NAME, MB_OK | MB_ICONERROR);
		return 0;
	}

	while (IsWindow(hWnd) && GetMessage(&msg, hWnd, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return 0;
}

LRESULT CALLBACK HookWndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	if (msg == WM_DESTROY)
	{
		UnRegisterHook();
		FreeLibrary(hLib);
		PostQuitMessage(0);
	}

	return DefWindowProc(hWnd, msg, wParam, lParam);
}

#endif