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Sockets

Peter Hansen peter at engcorp.com
Wed Oct 10 22:47:47 EDT 2001 
Hugo Martires wrote:
> 
> My server need to send 2 strings separeted:
>  s1= 'xxx'
>  s2= 'yyy'
> 
> My client must received like this:
>  rec1= 'xxx'
>  rec2= 'yyy'
> 
> The problem is that the Client received s1 and s2 in one only string.
> 
> How can i received in 2 separeted variables ?

I note the other answers, and still feel the need to point out two
things.

1. When asking questions of this sort, it is *always* advisable
   to post sample code showing what you are trying to do. 
   If you don't, the answers are just guesses (maybe educated ones,
   but still guesses).

2. Assuming you are opening a socket between the two programs, 
   my (educated :-) guess is that you are doing a pair of socket.send()
   calls with the two strings, and expecting these two be 
   received *separately* with two recv() calls on the other end.
   If this is so, you misunderstand how sockets and TCP/IP and
   such work.  Nowhere in the documentation will you find any
   guarantee that the data from two consecutive send() calls
   matches up with the two recv() calls.  They might be lumped
   together so that you get 'xxxyyy' after the first recv().
   You might have to use four recv() calls and get 'x', 'x',
   'xxy' and finally 'yy'.  No guarantees.  Don't ever assume
   you have all the data just because recv() returns.

   And that's the reason behind John's suggestion of disabling
   the Nagel algorithm, since it *might* appear to solve the
   problem.  Don't be fooled: it's a very fragile, hackish
   way of "fixing" the problem, and not suitable for "real"
   programs in most cases.  (Standard anti-flame disclaimers
   apply...)

-- 
----------------------
Peter Hansen, P.Eng.
peter at engcorp.com
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