> On Dec 13, 2022, at 2:08 PM, Alejandro Colomar via Gcc <gcc@gcc.gnu.org>
> wrote:
>
> 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;
> ^ ~
I thought void * is a generic pointer that accepts any pointer argument. So a
warning about char* being passed in seems to be flat out wrong.
> buf.c:5:2: note: array 'buf' declared here
> char *p, buf[5];
> ^
> 2 warnings generated.
That was discussed just days ago: C says that a pointer one past the end of the
array is legal. So here too it looks like Clang is wrong and GCC is right.
paul
