Path: utzoo!attcan!uunet!bloom-beacon!bu-cs!madd
From: madd@bu-cs.BU.EDU (Jim Frost)
Newsgroups: comp.unix.wizards
Subject: Re: socket communication problems
Message-ID: <38713@bu-cs.BU.EDU>
Date: 22 Sep 89 20:05:18 GMT
References: <16453@watdragon.waterloo.edu>
Reply-To: madd@std.com
Followup-To: comp.unix.wizards
Distribution: na
Organization: Boston University Distributed Systems Group
Lines: 26

In article <16453@watdragon.waterloo.edu> sekoppenhoef@rose.waterloo.edu writes:
|Shouldn't I be able to read and write on
|BOTH ends of a socket connection? [...]
|What am i doing wrong?
[...]
|**These two commands are what I'm using to write and read... the 'write' works
|**on the client end but not the read, and vice versa for the server end
|the server end uses an ACCEPT to get the scket name for communication of course.	
|	write(sock, buf, n) 
|	read(sock,buf,sizeof(buf) ) 

This will fix your problem:

	for (i= 0; i < sizeof(buf);)
	  i += read(sock, buf + i, sizeof(buf) - i);

How fondly I remember having this same problem, asking Barry Shein
about it, and hearing "did you check the return value from read?" and
feeling very silly.  You'll find that socket reads don't read the
whole thing much of the time.

Note that you should really do error checking in that loop, too.

jim frost
software tool & die
madd@std.com