// clang -Wall format-args-bug.c
#include <stdio.h>
#include <libgen.h>  // basename()

// Same signature of basename()
extern char* foo(char* arg) __attribute__ ((__nothrow__));

int main(int argc, char** argv) {
    // Fails to emit -Wformat-extra-args diagnostic
    printf("too %s", "many", basename(argv[0]));

    // Works as expected
    printf("too %s", "many", foo(argv[0]));
}