NetNews Usenet Archive 1992 #19/NN_1992_19.iso/spool/comp/unix/programm/4507

Text File | 1992-08-31 | 1.7 KB | 42 lines

Newsgroups: comp.unix.programmer
Path: sparky!uunet!cs.utexas.edu!csc.ti.com!tilde.csc.ti.com!fstop.csc.ti.com!pioneer!fcw
From: [e-mail] (Fred Wedemeier)
Subject: Sending "datagrams" on a connected socket.
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Organization: TI Telecom Systems, Dallas
Date: Tue, 1 Sep 1992 06:19:51 GMT
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I've RTFM'd sections (2) and (4) of the UNIX manual, hammered out some
test code, and still can't figure out how to do the following:

I need two processes to talk to each other in a "reliable,
flow-controlled, in-order, two-way" manner, quoting tcp(4). These
processes need to exchange discrete messages rather than boundary-less
streams of bytes.

I've tried a number of things with SOCK_STREAMs and send()/recv(), all
of which which concatenate messages if the receiving process isn't
waiting when each message arrives. For example, if I send() a message
"hello" followed by a message "goodbye" and then recv() at the other
end, what I get is "hellogoodbye" rather than a "hello" and a
"goodbye."

It appears that features of both SOCK_STREAMs and SOCK_DGRAMs are
needed. Or more likely a SOCK_SEQPACKET, which according to socket(2)
is "presently not implemented for any protocol family."

I can add a layer onto a stream or datagram socket, but it would be
nice if some incantation of socket library calls can do it instead.
Email or net help would be appreciated... Either suggestions how to do
it or a knowledgeable statement that it ain't possible.

thx.
---
Fred Wedemeier    pho: 214-997-3213     fax: [phone]
                timsg: fcw             inet: [e-mail]