recvfrom( ) returns NULL pointers

Networking and Multiplayer Programming

Started by 3DNeophyte March 20, 2004 08:37 AM

2 comments, last by 3DNeophyte 20 years, 1 month ago

122

Author

March 20, 2004 08:37 AM

In my UDP server code, I make a call to recvfrom(udp_sock, ibuffer, MAX_MSGSIZE, 0, (sockaddr*)client, clientlen), where ''client'' is a pointer to a sockaddr structure and ''clientlen'' is an int* . This works fine in that I am able to receive messages from the client. However, sending back to the client crashes because recvfrom() returned NULL for the ''client'' and ''clientlen'' pointers. Anyone know why this is happening?

3DNeophyte

122

Author

March 20, 2004 11:23 AM

Ok, problem solved. ''client'' and ''clientlen'' must be non-NULL when passed into recvfrom(). Go figure... why the docs didn''t mention this, I have not clue. All is well now...

Shadowdancer

319

March 20, 2004 11:36 AM

taken from the recvfrom manpage:

quote:
If from is not NULL, and the underlying protocol provides the source address, this source address is filled in. The argument fromlen is a value‐result parameter, initialized to the size of the buffer associated with from, and modified on return to indicate the actual size of the address stored there.