http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58959
Bug ID: 58959
Summary: Add warning when format specifiers refers to wrong
signess
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: lotharlutz at gmx dot de
When using a format specifier that refers to a different sign (signed vs
unsigned) as to corresponding variable has, a warning should be emitted.
Version:
gcc version 4.8.2 20131017 (Red Hat 4.8.2-1) (GCC)
Example:
-----
#include <stdio.h>
int main()
{
short i = -1;
//correct usage
printf("%hd\n",i);
//should yield a warning, but does not
printf("%hu\n",i);
//correctly yields a warning
printf("%ld\n",i);
return 0;
}
----
gcc -Wall -Wextra test.c
test.c: In function ‘main’:
test.c:14:5: warning: format ‘%ld’ expects argument of type ‘long int’, but
argument 2 has type ‘int’ [-Wformat=]
printf("%ld\n",i);
gcc warns when the variable has the wrong size (line 14), but not on the wrong
size (line 11)
