Date: Thu, 02 Dec 2004 16:12:53 +0900 From: Rob <spamrefuse@yahoo.com> To: FreeBSD <freebsd-questions@freebsd.org> Subject: gcc violates const-ness of variable? Message-ID: <41AEC075.50207@yahoo.com>
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Hi,
This should probably be discussed in the GNU gcc mailinglist.
But I'm more familiar here, and I first want to share it here
with other FreeBSD users.
I'm surprised about this piece of code:
#include<stdio.h>
int main()
{
const int n = 0;
scanf("%d", &n);
printf("%d\n", n);
return 0;
}
With gcc compiler, the constant variable 'n' will be overwritten
by the scanf statement. With g++ it (silently) is not.
So, I get following:
$ gcc -W -Wall code.c
code.c: In function `main':
code.c:5: warning: writing into constant object (arg 2)
$ ./a.out
9
9
$ g++ -W -Wall code.c
code.c: In function `int main()':
code.c:5: warning: writing into constant object (arg 2)
$ ./a.out
9
0
Is this a bug in gcc, or a feature?
Rob.
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