From: Alejandro Colomar <alx.manpages@gmail.com>
To: gcc@gcc.gnu.org
Subject: [BUG] missing warning for pointer arithmetic out of bounds
Date: Tue, 13 Dec 2022 20:08:20 +0100 [thread overview]
Message-ID: <e4e4281f-c837-8427-9843-2a28336fee86@gmail.com> (raw)
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Hi!
For the following program:
$ cat buf.c
#include <stdio.h>
int main(void)
{
char *p, buf[5];
p = buf + 6;
printf("%p\n", p);
}
There are no warnings in gcc, as I would expect:
$ gcc -Wall -Wextra buf.c -O0
Clang does warn, however:
$ clang -Weverything -Wall -Wextra buf.c -O0
buf.c:8:17: warning: format specifies type 'void *' but the argument has
type 'char *' [-Wformat-pedantic]
printf("%p\n", p);
~~ ^
%s
buf.c:7:6: warning: the pointer incremented by 6 refers past the end of the
array (that contains 5 elements) [-Warray-bounds-pointer-arithmetic]
p = buf + 6;
^ ~
buf.c:5:2: note: array 'buf' declared here
char *p, buf[5];
^
2 warnings generated.
Cheers,
Alex
--
<http://www.alejandro-colomar.es/>
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next reply other threads:[~2022-12-13 19:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-13 19:08 Alejandro Colomar [this message]
2022-12-13 19:15 ` Alejandro Colomar
2022-12-13 19:18 ` Andrew Pinski
2022-12-18 12:48 ` Optimization levels for getting all warnings (was: [BUG] missing warning for pointer arithmetic out of bounds) Alejandro Colomar
2022-12-13 19:22 ` [BUG] missing warning for pointer arithmetic out of bounds David Malcolm
2022-12-13 19:22 ` Paul Koning
2022-12-13 19:24 ` Alejandro Colomar
2022-12-13 20:45 ` Jonathan Wakely
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