Function LoadKeyboardLayoutModule

source/keyboard_mouse.cpp:3775–3803

HMODULE LoadKeyboardLayoutModule(HKL aLayout)
// Loads a keyboard layout DLL and returns its handle.
// Activates the layout as a side-effect, but reverts it if !aSideEffectsOK.
{
	HMODULE hmod = NULL;
	// Unfortunately activating the layout seems to be the only way to retrieve it's name.
	// This may have side-effects in general (such as the language selector flickering),
	// but shouldn't have any in our case since we're only changing layouts for our thread,
	// and only if some other window is active (because if our window was active, aLayout
	// is already the current layout).
	if (HKL old_layout = ActivateKeyboardLayout(aLayout, 0))
	{
		#define KEYBOARD_LAYOUTS_REG_KEY _T("SYSTEM\\CurrentControlSet\\Control\\Keyboard Layouts\\")
		const size_t prefix_length = _countof(KEYBOARD_LAYOUTS_REG_KEY) - 1;
		TCHAR keyname[prefix_length + KL_NAMELENGTH];
		_tcscpy(keyname, KEYBOARD_LAYOUTS_REG_KEY);
		if (GetKeyboardLayoutName(keyname + prefix_length))
		{
			TCHAR layout_file[MAX_PATH]; // It's probably much smaller (like "KBDUSX.dll"), but who knows what whacky custom layouts exist?
			if (ReadRegString(HKEY_LOCAL_MACHINE, keyname, _T("Layout File"), layout_file, _countof(layout_file)))
			{
				hmod = LoadLibrary(layout_file);
			}
		}
		if (aLayout != old_layout)
			ActivateKeyboardLayout(old_layout, 0); // Nothing we can do if it fails.
	}
	return hmod;
}