library_singleton.py 文件源码

def get():
    '''get

    Returns the library.Library singleton for nidcpower.
    '''
    global _instance
    global _instance_lock

    with _instance_lock:
        if _instance is None:
            try:
                library_type = _get_library_type()
                if library_type == 'windll':
                    ctypes_library = ctypes.WinDLL(_get_library_name())
                else:
                    assert library_type == 'cdll'
                    ctypes_library = ctypes.CDLL(_get_library_name())
            except OSError:
                raise errors.DriverNotInstalledError()
            _instance = library.Library(ctypes_library)
        return _instance