Not understanding the g_type_from_name() behaviour

[Marc Balmer <marc msys ch>]

I have a (hopefully) basic question.  g_type_from_name() does not behave
as I would it expect to behave:

When I call it with e.g. "GtkButton", I get GTK_TYPE_BUTTON.  But when I
call it with "GtkFrame", it returns 0 (no such type found).

To add to my confusion, when I call "printf("%s\n",
g_type_name(GTK_TYPE_FRAME)" before calling g_type_from_name(), it
returns "GtkFrame" (as expected) and the following call to
g_type_from_name() succeeds as well.

I am obviously missing sth here, or making a stupid mistake, so any
pointers would be greatly appreciated.

- mb


#include <gtk/gtk.h>

int
main(int argc, char *argv[])
{
        gtk_init(&argc, &argv);
        g_type_init();

        /* Uncomment the following line, GtkFrame will be found */
        /* printf("%s\n", g_type_name(GTK_TYPE_FRAME)); */
        if (g_type_from_name("GtkFrame") == 0)
                printf("no GtkFrame\n");
        else
                printf("GtkFrame exists\n");
        if (g_type_from_name("GtkButton") == 0)
                printf("no GtkButton\n");
        else
                printf("GtkButton exists\n");
        gtk_main();
        return 0;
}