I'm curious if this is a gcc bug or not. The warning I get is trying to
highlight a real problem, but it's referring to a string literal as a
directive, which I thought was just for the %XX printf commands. Given the
following:
#include <stdio.h>
void f() {
char x[4];
char y[5];
sprintf(x, "%s_%s", y, y);
}
$ gcc a.c -c -Wall
a.c: In function 'f':
a.c:6:16: warning: '_' directive writing 1 byte into a region of size
between 0 and 4 [-Wformat-overflow=]
6 | sprintf(x, "%s_%s", y, y);
| ^
a.c:6:2: note: 'sprintf' output between 2 and 10 bytes into a destination
of size 4
6 | sprintf(x, "%s_%s", y, y);
| ^~~~~~~~~~~~~~~~~~~~~~~~~
I hope the fixed width display shows this correctly. The point is that the
^ points to the underscore, which is right, but the message calls the
underscore a printf directive.
Maybe I'm splitting hairs, but this confused me for a good half hour before
I realized what was wrong.
