Is GCC mishandling a pointer to a va_list passed to a function?

Question

The question \'Pass va_list or pointer to va_list?\' has an answer which quotes the standard (ISO/IEC 9899:1999 - §7.15 \'Variable arguments , f

Answer 1

As others have noted, this issue manifests itself when va_list is an array type. This is allowed by the standard, which only says that va_list must be an "object type".

You can fix the test_val() function like so:

static void test_val(const char *fmt, va_list args)
{
    va_list args_copy;

    /* Note: This seemingly unnecessary copy is required in case va_list
     * is an array type. */
    va_copy(args_copy, args);
    test_ptr(fmt, &args_copy);
    va_end(args_copy);
}