def recvfds(sock, size):
        ‘‘‘Receive an array of fds over an AF_UNIX socket.‘‘‘
        a = array.array(‘i‘)                                                           #聲明一個整型數組，itemsize
        bytes_size = a.itemsize * size                                                 #數組容量設置
        msg, ancdata, flags, addr 
 
= sock.recvmsg(1, socket.CMSG_LEN(bytes_size))       #從套接字中讀取數據到msg，ancdata,recvmsg函數是標準posix函數，可以參閱：http://pubs.opengroup.org/onlinepubs/009695399/functions/recvmsg.html
        if not msg and not ancdata:
            raise EOFError
        try:
            if len(ancdata) != 1:                                                      #對於接收到的附加數據，長度不為1個元組的情況下退出
                
 
raise RuntimeError(‘received %d items of ancdata‘ %
                                   len(ancdata))
            cmsg_level, cmsg_type, cmsg_data = ancdata[0]                              #從附加數據中提取（cmsg_level, cmsg_type, cmsg_data）元組
            if (cmsg_level == socket.SOL_SOCKET and
                cmsg_type 
 
== socket.SCM_RIGHTS):
                if len(cmsg_data) % a.itemsize != 0:
                    raise ValueError
                a.frombytes(cmsg_data)                                                 #從cmsg_data中提取fd到數組a
                assert len(a) % 256 == msg[0]
                return list(a)
        except (ValueError, IndexError):
            pass
        raise RuntimeError(‘Invalid data received‘)

yocto-sumo源碼解析（十一）: recvfds