class mutex {
    protected:
        bool locked;
        HANDLE mutexHandle;
    public:
        mutex(): locked(false){
            mutexHandle = CreateMutex(NULL, FALSE, NULL);
            if(!mutexHandle)
                error("failed to retrieve mutex");
        }

        void lock(){
            switch(WaitForSingleObject(mutexHandle, 2000)){
                case WAIT_TIMEOUT:
                    error("mutex did not get lock in time (2 seconds maximum)");
                case WAIT_ABANDONED:
                    error("mutex owner thread quit without unlocking.");
                case WAIT_FAILED:
                    error("mutex failed with error " + GetLastError());
            }
            locked = true;
        }

        void unlock(){
            locked = false;
            ReleaseMutex(mutexHandle);
        }

};