Question

I’m using non-blocking sockets with winsock and I wonder that if I can partially receive data ?

My packet contains a “length” WORD and I must first read it then read whole packet according to the “length”.

Actually this question is like “how does recv() work and end ?”, Can i use recv() until I got all the data ?

Answer 1

It depends on the type of the socket. If it’s a datagram socket, recv will read exactly one entire datagram. If it’s a TCP socket:

• recv will read at least one byte before returning
• recv can read more than one complete message

If you’re using TCP, you’ll probably want to do something like this:

• Read at least the bytes comprising the length
• Read length bytes
• You now have a complete message
• Rinse, repeat

You could start with the readn function.