https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102936
Bug ID: 102936
Summary: Excessive warnings about passing NULL for an "%s"
specifier
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: eyalroz1 at gmx dot com
Target Milestone: ---
Consider the following program:
#include <stddef.h>
__attribute__((format(__printf__, 2, 3)))
int sprintf_(char* buffer, const char* format, ...)
{
(void) buffer;
(void) format;
return 0;
}
int main() {
char buffer[100];
return sprintf_(buffer, "%s", NULL);
}
when compiled with `-W -Wall`, we get two warnings:
a.c:15:28: warning: format ‘%s’ expects argument of type ‘char *’, but
argument 3 has type ‘void *’ [-Wformat=]
a.c:15:9: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
The second warning seems legit. However - I don't think I should be getting the
first warning. If I can write:
char* ptr = NULL;
and not get a type warning, I don't see why I should get one for passing NULL
to the function.
