Sending structs through Unix domain sockets

Question

I am using Unix domain sockets to do some interprocess communication in Linux. Upon connection, the client sends a struct using send to the server. This struct contains some information about the client including an identifier string at the end. The server receives the info just find and sends another struct back. The client blocks with recv, but never gets anything. The server completes the send call without any errors and moves on.

Is there something fundamental that I am missing here? When I send strings across the socket both sides send and receive just fine. Does the data have to have a terminating NULL? That does not seem right...

Your question implies that this only happens with structs. Does everything work fine with ints or chars? — Mike DeSimone, Sep 13 '10 at 22:32
This sounds like the kind of thing that would be explained in a man page for one of the relevant function calls. Not that it's a bad question for SO, I just would advise you to have a careful look at the documentation while you're waiting for answers. — David Z, Sep 13 '10 at 22:49
What you've described should work fine. Perhaps try and isolate the problem to a small code sample? — caf, Sep 14 '10 at 00:09
@ David: The man pages are the first place that I checked and I didn't find anything relevant. — waffleman, Sep 14 '10 at 12:29

score 1 · Accepted Answer · answered Nov 09 '10 at 18:27

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When I came in the next day, I could not reproduce the error again.

answered Nov 09 '10 at 18:27

waffleman

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score 0 · Answer 2 · answered Sep 13 '10 at 23:34

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Try flushing the socket on the server.

answered Sep 13 '10 at 23:34

Steve Emmerson

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I don't see anything besides **close** that could flush a socket. – waffleman Sep 14 '10 at 12:26
Try setting the `flags` argument of the `send()` function to `MSG_EOR`. – Steve Emmerson Sep 14 '10 at 19:01

Sending structs through Unix domain sockets

2 Answers2