Re: recv() clarification in SCTP sockets API draft

["Brian F. G. Bidulock" <[e-mail]>]

Michael,

Michael Tuexen wrote:                       (Thu, 05 Aug 2010 22:03:58)
> On Aug 5, 2010, at 9:03 PM, Brian F. G. Bidulock wrote:
> > SOCK_SEQPACKET is clearly "reliable".  What do you mean by
> How can I receive "using one or more input operations". I can't
> do that with recv(), recvfrom() or recvmsg(). They drop the
> bytes of the record which do not fit into the buffer. This
> makes it "unreliable". As a receiver I have no idea how big
> the largest message would be. For SCTP we do no want to loose
> parts of the messages.

Both recvmsg() and recv() offer MSG_PEEK.  If the application is
worried about it, it can always peek the message size and provide
a suitably sized buffer before calling recvmsg() or recv() without
MSG_PEEK.  This is one or more input operations.

If the application is not worried about it, it provides a buffer
large enough for the largest valid message, and simply calls
recv().

This does not make recvmsg() nor recv() unreliable for
SOCK_SEQPACKET: it allows the user to specify whether they care
about bytes beyond a maximum message size: which I believe
was the original point in this thread.

--brian

-- 
Brian F. G. Bidulock
[e-mail]
http://www.openss7.org/