va_args going unused ok?

[Michael B Allen]

Is it legit to not use arguments of a variable argument function? For
example consider that printf here does not use arg if fi = 1.

void
foo(int fi, const char *arg)
{
const char *fmts = { "%s", "" };
printf(fmts[fi], arg);
}

Thanks,
Mike

 

[Krishanu Debnath]

Is it legit to not use arguments of a variable argument function? For
example consider that printf here does not use arg if fi = 1.

void
foo(int fi, const char *arg)
{
const char *fmts = { "%s", "" };

typo I guess, you meant ..
const char *fmts[] = { "%s", "" };

printf(fmts[fi], arg);
}

Thanks,
Mike

Yes, it is legitimate. c99 Sec 7.19.6.1 para 2 says ..
"If the format is exhausted while arguments remain, the excess arguments
are evaluated (as always) but are otherwise ignored."

Krishanu