stat

static VALUE
gc_stat(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    VALUE hash;

    if (rb_scan_args(argc, argv, "01", &hash) == 1) {
        if (TYPE(hash) != T_HASH)
            rb_raise(rb_eTypeError, "non-hash given");
    }

    if (hash == Qnil) {
        hash = rb_hash_new();
    }

    rest_sweep(objspace);

    rb_hash_aset(hash, ID2SYM(rb_intern("count")), SIZET2NUM(objspace->count));

    /* implementation dependent counters */
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_used")), SIZET2NUM(objspace->heap.used));
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_length")), SIZET2NUM(objspace->heap.length));
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_increment")), SIZET2NUM(objspace->heap.increment));
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_live_num")), SIZET2NUM(objspace->heap.live_num));
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_free_num")), SIZET2NUM(objspace->heap.free_num));
    rb_hash_aset(hash, ID2SYM(rb_intern("heap_final_num")), SIZET2NUM(objspace->heap.final_num));
    return hash;
}