test.c

/*
 * cc -g $(pkg-config --cflags ruby-2.3 glib-2.0 gtk+-3.0) test.c $(pkg-config --libs ruby-2.3 glib-2.0 gtk+-3.0)
 */

#include <ruby/ruby.h>

#include <gtk/gtk.h>
#include <glib-object.h>

const char script[] = "                                                           \n"
"require 'rubygems'                                                               \n"
"require 'gir_ffi'                                                                \n"
"                                                                                 \n"
"class ExtensionRbFFI < GObject::Object                                           \n"
"                                                                                 \n"
"    GirFFI.define_type(ExtensionRbFFI) do |info|                                 \n"
"        info.g_name = 'ExtensionRbFFI'                                           \n"
"        bits = GObject::ParamFlags[:readable] |                                  \n"
"                GObject::ParamFlags[:writable]                                   \n"
"        info.install_property GObject.param_spec_object('object',                \n"
"                                                        'object',                \n"
"                                                        'object',                \n"
"                                                        GObject::Object.gtype,   \n"
"                                                        bits)                    \n"
"    end                                                                          \n"
"                                                                                 \n"
"    def initialize                                                               \n"
"        super                                                                    \n"
"    end                                                                          \n"
"end                                                                              \n"
"                                                                                 \n"
"ExtensionRbFFI.gtype.to_i";

int main(int argc, char *argv[])
{
    VALUE ret;
    GType t;
    GObject *prop, *obj;
    int ex_state;

    gtk_init(&argc, &argv);

    ruby_init();
    ruby_init_loadpath();

    ret = rb_eval_string_protect(script, &ex_state);
    g_assert(ex_state == 0);

    t = NUM2LONG(ret);
    prop = G_OBJECT(gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0));
    g_object_ref_sink(prop);

    g_assert(prop->ref_count == 1);
    obj = g_object_new(t, "object", prop, NULL);

    /* I would expect 2 */
    g_assert(prop->ref_count == 3);

    g_object_unref(obj);
    /* Calling rb_gc() or not doesn't make a difference */
    rb_gc();
    /* ERROR */
    g_assert(prop->ref_count == 1);

    g_object_unref(prop);
}