Implicition declarations of functions and bugs

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Hi,

In buildd logs, I could find several
test.c:3: warning: implicit declaration of function 'f'
warnings

This can be very problematic on 64bits architectures such as AMD64:

test.c:
#include <stdio.h>
int main(void) {
        printf("%p\n",f(-1));
        return 0;
}

test2.c:
#include <stdio.h>
void *f(long a) {
	char c;
        printf("%ld %p\n",a,&c);
        return &c;
}

result:
4294967295 0x7ffffffc725f
0xfffc725f

instead of
-1 0x7ffffffc725f
0x7ffffffc725f

, which can of course entail a lot of bugs...

Maybe the debian policy should require
-Werror-implicit-function-declaration in CFLAGS so as to avoid such
issue?

Regards,
Samuel