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Date:      Tue, 4 Jul 2006 03:25:12 +0300
From:      Giorgos Keramidas <keramida@ceid.upatras.gr>
To:        Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org>
Cc:        James Bailie <jimmy@jamesbailie.com>, freebsd-hackers@freebsd.org, Randall Hyde <randyhyde@earthlink.net>
Subject:   Re: getc in BSD (was FLEX issues)
Message-ID:  <20060704002512.GA91588@gothmog.pc>
In-Reply-To: <17577.45340.818482.432245@bhuda.mired.org>
References:  <16887068.1151618963387.JavaMail.root@elwamui-cypress.atl.sa.earthlink.net> <20060630081019.GB734@turion.vk2pj.dyndns.org> <002501c69ecf$5967c6b0$6302a8c0@pentiv> <44A9AC43.3090606@jamesbailie.com> <17577.45340.818482.432245@bhuda.mired.org>

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On 2006-07-03 20:06, Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org> wrote:
> In <44A9AC43.3090606@jamesbailie.com>, James Bailie <jimmy@jamesbailie.com> typed:
> > Randall Hyde wrote:
> >  > This kind of gives me the impression that "getc" is defined a bit
> >  > differently under FreeBSD than other environments?  Any ideas?
> > Yes.  It's defined as a macro.
>
> Linux says that getc "may be implemented as a macro". Anything that
> needs a function should be using fgetc, not getc. But

The C99 standard (actually the latest public draft[1]) allows
getc() to be a macro:

[1] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf
    from http://www.open-std.org/jtc1/sc22/wg14/www/standards

|     §7.19.7.5 The getc function
|   
|     Synopsis
|   
|   1         #include <stdio.h>
|             int getc(FILE *stream);
|   
|     Description
|   
|   2 The getc function is equivalent to fgetc, except that if it is
|     implemented as a macro, it may evaluate stream more than once,
|     so the argument should never be an expression with side
|     effects.

This means one shouldn't depend on getc() being a function.




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