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From: kwh@bentley.UUCP (KW Heuer)
Newsgroups: net.lang.c
Subject: Re: Float Double Parameters; extern/static scope
Message-ID: <713@bentley.UUCP>
Date: Wed, 16-Apr-86 10:30:50 EST
Article-I.D.: bentley.713
Posted: Wed Apr 16 10:30:50 1986
Date-Received: Fri, 18-Apr-86 06:02:43 EST
References: <1377@lll-crg.ARpA>
Organization: AT&T Bell Laboratories, Liberty Corner
Lines: 30

In article <1377@lll-crg.ARpA> brooks@lll-crg.ARpA (Eugene D. Brooks III) writes:
>The reason for keeping the conversion in is purely historical.
>Its called those old dusty decks (sorry, files).  The way that
>the proposed ANSI standard deals with the problem, introduce
>function prototypes, seems like a reasonable way to provide
>efficiency for those who need it while at the same time not
>breaking old code.

I haven't seen the proposed standard, but from the conversation so far I
gather that "f(x) float x; { ... }" will involve widening whereas the new
syntax "f(float x) { ... }" will not.  (And likewise "extern f(float)" is
the signal to the compiler that the caller should not widen the argument.)
Hmm, I'd say things are going to be a bit confusing for a while, but it's
not easy to phase in a new idea.  (I presume the old syntax will be dropped
eventually, like the "=+" anachronisms.)

What's the word on extern vs. static scope for external identifiers?  Last
I heard, there was some talk about changing the default from extern to
static, but I think it got dropped for compatibility reasons.  (Also, C++
was supposed to have static as a default, but Bjarne had to revert back to
extern to maintain peaceful coexistence with C.)  I think this modification
should be phased in, too; the first step would be to issue a warning on an
external definition like "int i = 4;" and "void f() {...}" (warning: extern
scope assumed) and force the user to specify either "static int i = 4;" and
"static void f() {...}", or "extern int i; int i = 4;" and "extern void f();
void f() {...}", whichever was intended.  Then the default could be changed
(warning: static scope assumed) and finally the warning could be dropped.
I'd like to see this introduced with the ANSI standard.

Karl W. Z. Heuer (ihnp4!bentley!kwh), The Walking Lint