SIGNATURE_CHECK (if_freenameindex, void, (struct if_nameindex *));
SIGNATURE_CHECK (if_indextoname, char *, (unsigned int, char *));
SIGNATURE_CHECK (if_nameindex, struct if_nameindex *, (void));
SIGNATURE_CHECK (if_nametoindex, unsigned int, (const char *));
SIGNATURE_CHECK (if_freenameindex, void, (struct if_nameindex *));
SIGNATURE_CHECK (if_indextoname, char *, (unsigned int, char *));
SIGNATURE_CHECK (if_nameindex, struct if_nameindex *, (void));
SIGNATURE_CHECK (if_nametoindex, unsigned int, (const char *));