variable.c:211
void
rb_set_class_path(klass, under, name)
    VALUE klass, under;
    const char *name;
{
    VALUE str;

    if (under == rb_cObject) {
	str = rb_str_new2(name);
    }
    else {
	str = rb_str_dup(rb_class_path(under));
	rb_str_cat2(str, "::");
	rb_str_cat2(str, name);
    }
    rb_ivar_set(klass, classpath, str);
}
