On 2009 Feb 26, at 23:41, Achim Schneider wrote:
"Brandon S. Allbery KF8NH" <allb...@ece.cmu.edu> wrote:On 2009 Feb 26, at 16:45, Johan Tibell wrote:definition of `recv` would look like. My current thinking is that it would mimic what C/Python/Java does and return a zero length ByteString when EOF is reached.Ew. Isn't this what Maybe is for? Anyway, the reason recv doesn't return 0 is that if you have a datagram socket, a zero-length recv is valid and doesn't mean EOF.My man page says a retval of 0 means that "the peer has performed an orderly shutdown", which, in the UDP case, means that it has send a complete datagram... no mention of EOF. A true EOF in the sense of "no more data will be received" would mean unbinding the socket.
Right. Just have to realize that a zero-length datagram packet is possible and even meaningful, so 0 isn't available as an EOF flag.
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 Nothing.
-- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH
PGP.sig
Description: This is a digitally signed message part
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
