Open Radar

 
Summary:
GCC and Clang as installed with Xcode 4.1 both give duplicate warnings for the -Wformat flag when using printf with the wrong format specifiers.

Steps to Reproduce:

$ cat test.c 
#include <stdio.h>
int main (int argc, char const *argv[])
{
    printf("%i\n", 0l);
    return 0;
}
$ gcc -Wall -o /dev/null test.c 

Expected Results:

test.c: In function ‘main’:
test.c:5: warning: format ‘%i’ expects type ‘int’, but argument 2 has type ‘long int’

Actual Results:

test.c: In function ‘main’:
test.c:5: warning: format ‘%i’ expects type ‘int’, but argument 2 has type ‘long int’
test.c:5: warning: format ‘%i’ expects type ‘int’, but argument 2 has type ‘long int’

Regression:

Notes:

It appears this is because in Apple's stdio.h, the printf() declaration has an unnecessary GCC format attribute attached to it. See the accepted answer to this Stack Overflow question:

http://stackoverflow.com/questions/7380880/why-does-gcc-show-duplicate-warnings-for-bad-printf-format-specifier



27-Jan-2012 10:28 PM Oscar Hernandez :
Engineering has provided the following feedback regarding this issue:

We have no plans to fix this in GCC, only in Clang.

We consider this issue resolved.