From: Alexey Salmin <alexey.salmin@gmail.com>
To: gcc-help@gcc.gnu.org
Cc: "John (Eljay) Love-Jensen" <eljay@adobe.com>,
dclarke@blastwave.org, aph@redhat.com, david.kirkby@onetel.net,
ams@gnu.org
Subject: Re: Why is gcc going to default to "GNU dialect of ISO C99?"
Date: Thu, 11 Feb 2010 13:48:00 -0000 [thread overview]
Message-ID: <87a8dc11002110544q2531b46x8344c74f70b1b556@mail.gmail.com> (raw)
In-Reply-To: <C79952E6.1947E%eljay@adobe.com>
On Thu, Feb 11, 2010 at 6:23 PM, John (Eljay) Love-Jensen
<eljay@adobe.com> wrote:
> Hi Alexey,
>
>> It all reminds me a story when I won a bottle of beer from my
>> scientific adviser back in 2005. We had a bet: will gcc compile this
>> code:
>> #include <stdio.h>
>> int main() {
>> printf("a");
>> int a;
>> printf("b");
>> return 0;
>> }
>> He was so sure that gcc won't allow it that didn't ever tried :) Thus,
>> I think gnu extensions by default are not so bad :)
>
> Why wouldn't GCC compile that code?
>
> It is ISO 9899:1999 compliant. Even compiles with the -pedantic flag. (Or
> am I missing something?)
>
> Mmmmmm, beer. :-)
>
> Sincerely,
> --Eljay
>
It's not ANSI C compliant. And since GNU89 is default for C code it's
reasonable (in some way) for this not to work.
Fortunately I wasn't very familiar with different standarts and stuff
that time, I just knew that it works with GCC :)
This code actually gives a warning with -pedantic and error (your C.O.
:P ) with -pedantic-errors.
salmin@salmin:~/test$ gcc -o test test.c
salmin@salmin:~/test$ gcc -std=gnu89 -o test test.c
salmin@salmin:~/test$ gcc -std=c89 -o test test.c
salmin@salmin:~/test$ gcc -pedantic -o test test.c
test.c: In function ‘main’:
test.c:5: warning: ISO C90 forbids mixed declarations and code
salmin@salmin:~/test$ gcc -pedantic-errors -o test test.c
test.c: In function ‘main’:
test.c:5: error: ISO C90 forbids mixed declarations and code
salmin@salmin:~/test$ gcc -std=c89 -pedantic-errors -o test test.c
test.c: In function ‘main’:
test.c:5: error: ISO C90 forbids mixed declarations and code
salmin@salmin:~/test$ gcc -std=gnu89 -pedantic-errors -o test test.c
test.c: In function ‘main’:
test.c:5: error: ISO C90 forbids mixed declarations and code
salmin@salmin:~/test$ gcc -std=c99 -pedantic-errors -o test test.c
salmin@salmin:~/test$ gcc -std=gnu99 -pedantic-errors -o test test.c
salmin@salmin:~/test$ cat test.c
#include <stdio.h>
int main() {
printf("a");
int a;
printf("b");
return 0;
}
Alexey
next prev parent reply other threads:[~2010-02-11 13:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-11 2:40 Dennis Clarke
2010-02-11 9:43 ` Alfred M. Szmidt
2010-02-11 12:00 ` Alexey Salmin
[not found] ` <C79952E6.1947E%eljay@adobe.com>
2010-02-11 13:48 ` Alexey Salmin [this message]
[not found] ` <C79973C1.194A3%eljay@adobe.com>
2010-02-11 14:58 ` Alexey Salmin
2010-02-11 15:11 ` John (Eljay) Love-Jensen
2010-02-12 5:32 ` Patrick Horgan
-- strict thread matches above, loose matches on Subject: below --
2010-02-11 17:14 Dennis Clarke
2010-02-11 14:50 Dennis Clarke
2010-02-11 14:14 Dennis Clarke
2010-02-11 14:42 ` Alexey Salmin
2010-02-11 13:44 Dennis Clarke
2010-02-11 14:00 ` Alexey Salmin
2010-02-10 17:00 Dr. David Kirkby
2010-02-10 17:26 ` Andrew Haley
2010-02-10 17:45 ` Dr. David Kirkby
2010-02-10 18:07 ` Alfred M. Szmidt
2010-02-10 19:25 ` Dr. David Kirkby
2010-02-10 20:59 ` Kevin P. Fleming
2010-02-10 18:39 ` Andrew Haley
2010-02-11 2:46 ` Ian Lance Taylor
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