Pidgin.

static void call_user(PurpleBlistNode *node) {

    PurpleAccount *acc                  = NULL;
    PurpleConnection *gc                = NULL;
    PurplePlugin *prpl                  = NULL;
    PurplePluginProtocolInfo *prpl_info = NULL;
    PurpleNotifyUiOps *ops;

    purple_debug_warning("plugin-call-a-buddy", "Variablen wurden initialisiert.\n");

    const char *name = NULL;

    PurpleBuddy *buddy  = (PurpleBuddy*) node;
    acc = purple_buddy_get_account(buddy);

    purple_debug_warning("plugin-call-a-buddy", "Node Konvertiert und Acc geholt.\n");

    gc = acc->gc;
    purple_debug_warning("plugin-call-a-buddy", "GC wird geholt.\n");
    if(!gc) {
        return;
    }

    prpl = purple_connection_get_prpl(gc);
    purple_debug_warning("plugin-call-a-buddy", "Hole Protocol.\n");

    if(!prpl) {
        return;
    }

    prpl_info = PURPLE_PLUGIN_PROTOCOL_INFO(prpl);
    purple_debug_warning("plugin-call-a-buddy", "Plugin_Protocol_INFO wird geholt. \n");
    if(!prpl_info || !prpl_info->get_info) {
        return;
    }

    prpl_info->get_info(gc, name);
    purple_debug_warning("plugin-call-a-buddy", "Entsprechende Infos werden ermittelt \n");

    ops = purple_notify_get_ui_ops();
    purple_debug_warning("plugin-call-a-buddy", "Notify_Get_UI_Ops \n");

    notify_userinfo_ori = ops->notify_userinfo;
    purple_debug_warning("plugin-call-a-buddy", (char*)notify_userinfo_ori);

    ops->notify_userinfo = birthday_reminder_notify_userinfo;
    purple_debug_warning("plugin-call-a-buddy", "Birthday_Reminder_Notify_Userinfo \n");

    if(!PURPLE_BLIST_NODE_IS_BUDDY(node)) {
        purple_debug_fatal("plugin-call-a-buddy", "Es wird versucht einen Nicht-User anzurufen.\n");
        return;
    }
    test();

//  const char *userInfo;

    free(acc);
    free(gc);
    free(prpl);
    free(prpl_info);
    free(ops);
    free(buddy);

//  PurpleBuddy *buddy  = (PurpleBuddy*) node;
//  PurpleAccount *p    = purple_buddy_get_account(buddy);

//  const char *name = purple_buddy_get_name(buddy);

}