Avoiding "ISO C99 requires rest arguments to be used"

Question

With gcc 4.6.3 (with -ansi -pedantic), I've got the following code:

// Argument counting macro
#define NARGS(...) NARGS_(__VA_ARGS__, 5, 4, 3, 2, 1)
#define NARGS_(_1, _2, _3, _4, _5, _, ...) _

static inline void fi_init_(size_t nargs, fileinfo_t *finfo, ...) {
    // Default fmt/type values
    char* fmt  = "CD";
    int   type = 1000;

    if (nargs == 2) {
        va_list  ap;
        va_start(ap, hdr);
        fmt  = va_arg(ap, char*);
        type = va_arg(ap, int);
        va_end(ap);
    } 

    // Do some junk with it
}

#define fi_init(...) fi_init_(NARGS(__VA_ARGS__)-1, __VA_ARGS__)

When called as:

fileinfo_t out; fi_init(&out);

I get a warning:

warning: ISO C99 requires rest arguments to be used

When called as:

fileinfo_t out; fi_init(&out, "CF", 2222);

I don't. How can I suppress this?

I thought I understood why these occurred, but clearly I don't. I'd like to fix what I'm doing wrong if possible. — gct, Jul 24 '12 at 03:36
By the way, this might be a duplicate of http://stackoverflow.com/questions/4100746/suppressing-iso-c99-requires-rest-arguments-to-be-used?rq=1 — LastStar007, Jul 24 '12 at 03:37
I saw that question, but I've got all my arguments folded into my ellipses, so I wasn't sure if I was seeing the same thing. — gct, Jul 24 '12 at 03:39

score 5 · Accepted Answer · answered Jul 24 '12 at 04:27

I think my problem was here:

#define NARGS(...) NARGS_(__VA_ARGS__, 5, 4, 3, 2, 1)
#define NARGS_(_1, _2, _3, _4, _5, _, ...) _

Changing that to:

#define NARGS(...) NARGS_(__VA_ARGS__, 5, 4, 3, 2, 1, 0)
#define NARGS_(_1, _2, _3, _4, _5, _, ...) _

Seems to have fixed it

Avoiding "ISO C99 requires rest arguments to be used"

1 Answers1