//! Returns metadb_handle object referencing specified location (attempts to find existing one, creates new one if doesn't exist).
   //! @param p_out Receives metadb_handle pointer.
   //! @param p_location Location to create metadb_handle for.
   //! @returns true on success, false on failure (rare).
   virtual void handle_create(metadb_handle_ptr & p_out,const playable_location & p_location)=0;

    //! Returns true when signaled, false on timeout
    static bool g_wait_for(HANDLE p_event,double p_timeout_seconds) {
        SetLastError(NO_ERROR);
        DWORD status = WaitForSingleObject(p_event,g_calculate_wait_time(p_timeout_seconds));
        switch(status) {
        case WAIT_FAILED:
            throw exception_win32(GetLastError());
        default:
            throw pfc::exception_bug_check();
        case WAIT_OBJECT_0:
            return false;
        case WAIT_TIMEOUT:
            return true;
        }
    }

So there is no chance of failure now?

The latter is fixed in current SDK.