If this is really what you want, you could use the unused attribute (gcc only), something like:
void foo(int __attribute__((__unused__)) bar) {
...
}
Not just for function parameters, of course, but that's the most common use case, since it might be a callback function for an API where you don't actually need all the input.
Additionally, GLib has a G_GNUC_UNUSED macro which I believe expands to that attribute.
