extern (C) @nogc nothrow nothrow @nogc
struct nn_optset_vfptr {
extern (C)
void function(nn_optset* self) destroy;
extern (C)
int function(nn_optset* self, int option, const(void)* optval, size_t optvallen) setopt;
extern (C)
int function(nn_optset* self, int option, void* optval, size_t* optvallen) getopt;
}