https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110322
Bug ID: 110322 Summary: Be more helpful when a varargs function is called in a wrong way Product: gcc Version: 12.0 Status: UNCONFIRMED Keywords: diagnostic Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: roland.illig at gmx dot de Target Milestone: --- ~~~c #include <stdarg.h> #include <stdio.h> static void __attribute__((__format__(__printf__, 1, 2))) my_printf(const char *fmt, ...) { va_list ap; va_start(ap, fmt); fprintf(stderr, fmt, ap); va_end(ap); } int main(int argc, char **argv) { my_printf("%d", 4); my_printf("%.*s\n", 5, "hello, world"); return 0; } ~~~ In the above program, I am accidentally trying to call fprintf with a va_list, instead of the correct vfprintf. GCC warns: sl.c:10:2: error: format not a string literal, argument types not checked [-Werror=format-nonliteral] 10 | fprintf(stderr, fmt, ap); | ^~~~~~~ In this situation, where my only mistake was to forget the 'v' from the function name, GCC should not complain that the format string is not a string literal, but rather that I'm calling the wrong function.