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From: sjw <simon.j.wright@mac.com>
Newsgroups: comp.lang.ada
Subject: Re: API design problem - buffer scatter I/O
Date: Sat, 22 Nov 2008 08:54:47 -0800 (PST)
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Date: 2008-11-22T08:54:47-08:00
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On Nov 22, 4:05=A0pm, Maciej Sobczak <see.my.homep...@gmail.com> wrote:
> I have a problem finding the best, from the Ada point of view,
> interface for the scatter I/O API.

There is a binding in GCC 4.3.0 - Receive_Vector and Send_Vector. Not
sure when this was introduced - wasn't in GNAT 3.16.

I don't know how scatter-gather is canonically intended to be used,
but one way that it would have been nice to use were we not stuck on a
historic version of the compiler would be to cope with application-
specific message headers - these are all 20 bytes, so we could have
had a 20-byte header buffer and a channel-specific message buffer to
great advantage. As it is, on TCP_NODELAY & UDP sockets, we have to:
(a) prepare the message
(b) prepare the header (including fields depending on the message)
(c) concatenate the header and the message
(d) send the message.
Not cool.