Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!mimsy!eneevax!umd5!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Complex type ?
Message-ID: <5838@brl-smoke.ARPA>
Date: Thu, 7-May-87 00:53:17 EDT
Article-I.D.: brl-smok.5838
Posted: Thu May  7 00:53:17 1987
Date-Received: Sat, 9-May-87 02:03:13 EDT
References: <7264@brl-adm.ARPA>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 43

Complex numbers, in-line functions, and several other possibly
worthy extensions to C have indeed been discussed before and
considered by X3J11 for the Draft Proposed Standard.  Most of
these extensions were NOT put in the standard, out of a desire
to keep the language and its implementation relatively small.
(Complex numbers are often requested by Fortran folk; at the
last X3J11 meeting a nice proposal (by Tom ? of Cray? -- my
notes aren't at hand) for them was defeated; as I recall, it
actually gathered a simple majority, but since the Draft went
out for public review it now takes a 2/3 majority to make
substantive changes.)  Since several vendors feel the
necessity to supply some of these extensions for their
customers, it would be nice if implementors would agree on the
syntax and semantics of such extensions.  To this end, Rex
Jaeschke (of the C Journal) organized a BOF session at the
last X3J11 meeting.  We drew up a list of proposed extensions
(I forget how many, but I think over 30) and took a poll to
determine interest in each one.  For those extensions having
the most interest, "points of contact" were established; their
voluntary r^ole is to co"ordinate interested parties and
mediate ensuing discussions.  The idea is to try to develop
consensus for the form of the extensions, to "publish" to
other interested parties results of experiments with them, and
generally to garner experience with the extensions.  It is
felt that any extension that has developed widespread vendor
and customer experience and support by the time of the NEXT C
standards committee (something like 5-10 years hence) will
stand an excellent chance of being incorporated into the
revised standard.

I don't have a list of all the extensions and POCs; I'm POC
for three topics (which I would have to look up, except I
remember that one of them was 0-sized data objects; so far
nobody who had said they were interested in my topics has
contacted me, probably because we're all too busy trying to
get the first standard out).  I think Rex was going to
publish the list in the C Journal.

While you're waiting for your compiler vendor to get together
with Tom or whoever the POC is and implement complex data
types, you'll have to use the struct & library-routine
approach for complex arithmetic.  I have an implementation
you can build on; I'll try to package it up for mod.sources.