[Haskell-cafe] Re: Coming up with a better API for
Brandon S. Allbery KF8NH
allbery at ece.cmu.edu
Sat Feb 28 15:55:29 EST 2009
On 2009 Feb 27, at 4:25, Colin Paul Adams wrote:
>> Anyway, the POSIX spec indicates the EOF condition as return -1
>> with errno
>> == ECONNRESET; this should not be taken as anything but the limited
>> expressiveness of a C-based API. We should map this return to
> Johan> I'm not sure I agree. I think using exceptions in this case
> is fine as
> Johan> loosing the connection is indeed an exceptional condition and
> the best
> Johan> thing a program can do in this case is probably to abort
> processing of
> Johan> the disconnected client.
> I guess this depends upon how exceptional you want an exception to be.
> To my mind, a lost connection is a fairly normal condition (FAR to
> normal for my teleworking situation :-( ). That is, I would expect
> the exception to occur rather than not, during one run of a
> program. On that basis, I would suggest Nothing is better than an
Actually, thinking about this, ECONNRESET can be a normal end-of-
connection for TCP, but for UDP should never happen (on recv(); on
send() it is surely an exception). But at the same time, if you're
using recv() with TCP you are probably not working with a higher level
protocol that simply shuts down the connection when it's done: it's
more of a stream-oriented behavior, and the stream-oriented read()
handles it as such.
That said I have heard of cases where recv() is used for stream
protocols for efficiency reasons. I don't know if the efficiency
argument relates to anything newer than a PDP11 or VAX 750, though....
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university KF8NH
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