Windows 10 系統 註冊表讀寫

// 返回 ERROR_FILE_NOT_FOUND 表示沒有，返回 ERROR_SUCCESS 表示成功
static LONG OpenKey(HKEY hRootKey, wchar_t* strKey, HKEY &hKey)
{
	LONG nError = RegOpenKeyEx(hRootKey, strKey, NULL, KEY_ALL_ACCESS, &hKey);
	return nError;
}

// 創建之後已經打開，直接使用 hKey
static bool CreateKey(HKEY hRootKey, wchar_t* strKey, HKEY& hKey)
{
	LONG nError = RegCreateKeyEx(hRootKey, strKey, NULL, NULL, REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, NULL, &hKey, NULL);
	if (nError == ERROR_SUCCESS)
	{
		return true;
	}
	return false;
}

static bool SetVal(HKEY hKey, LPCTSTR lpValue, DWORD data)
{
	LONG nError = RegSetValueEx(hKey, lpValue, NULL, REG_DWORD, (LPBYTE)& data, sizeof(DWORD));

	if (nError == ERROR_SUCCESS)
		return true;
	return false;
}

// 返回 ERROR_FILE_NOT_FOUND 表示沒有，返回 ERROR_SUCCESS 表示成功
static LONG GetVal(HKEY hKey, LPCTSTR lpValue, DWORD &data)
{     
	DWORD size = sizeof(data);    
	DWORD type = REG_DWORD;
	LONG nError = RegQueryValueEx(hKey, lpValue, NULL, &type, (LPBYTE)& data, &size);
	return nError;
}

static void CloseKey(HKEY &hKey)
{
	RegCloseKey(hKey);
}

使用

    HKEY hRetKeyTmp;
	LPCWSTR tmp= L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\App Paths\\tmp";
	LONG lRet = OpenKey(HKEY_LOCAL_MACHINE, (wchar_t *)tmp, hRetKeyTmp);
	if (lRet == ERROR_FILE_NOT_FOUND)
	{
		width = 1024;
		if (CreateKey(HKEY_LOCAL_MACHINE, (wchar_t*)tmp, hRetKeyTmp))
		{
			SetVal(hRetKeyTmp, L"Width", width);
		}
	}