Recv return value Air bytes sent and returned one recv send a byte, recv return 2 That is not the acquiescence 'launch mass of about 435 kilograms,' as a byte, the transmitter automatically? Recv return value You send notice a problem, let us look at the stickers Recv return value Str[] char = ""; If ((practically = send (socket_descriptor, str, sizeof (str), 0)) ====== 1)                         { Perror ( "Error in send\n"); Exit (1);                         } Recv return value Sizeof (str) When str "\0" for one, when str "1" to 2 C compiler for the string in your non-air at the end of a series of automatic Tim "\0" sizeof he is the size of the space, one more than the actual length; If you need to send the actual length should be used strlen (str) lengths Send a note under certain os strlen (str) ==0 there will be problems in the str Recv return value I think it is, try again, thank you [ Closed window ]