[Vala] DBus GValue trouble

[Sebastian Spaeth <sebastian sspaeth de>]

I call a DBus Method "GetValue" which has a return signature of 'v'
(variant) (which in this special case contains a string). However, I
can't get the return value due to errors:

GLib-GObject-WARNING **: gvalue.c:185: cannot initialize GValue with
type `gchararray', the value has already been initialized as `(null)'

It seems the GValue (I also tried 'Value?') is wrongly initialized or
something. I am a bit at a loss, being somewhat of a GLib newbie.

See the couple of lines that do the call in Vala and translated to C.
THanks for any pointer.
spaetz
-------------------------------------------------------------------
VALA CODE

dynamic DBus.Object dbus_pro_set
dbus_profile = dbus.get_object ("org.freesmartphone.opreferencesd",
                                 "/org/freesmartphone/Preferences",
                                 "org.freesmartphone.Preferences");
Value val = dbus_pro_set.GetValue (str);
debug(val.type().name());
debug("str: %s", val.get_string());

-----------------------------------------------------------------
C CODE WHICH RETURNS THE ERROR:
GValue _dynamic_GetValue17 (DBusGProxy* self, const char* param1,
GError** error) {
        GValue result;
        dbus_g_proxy_call (self, "GetValue", error, G_TYPE_STRING, param1,
G_TYPE_INVALID, G_TYPE_VALUE, &result, G_TYPE_INVALID);
        if (*error) {
                return;
        }
        return result;
}