while (true)
{
lock (groupslocker)
{
if (groups.Count == 0)
break;
else
gr = groups.Dequeue();
}
string url = rand_url();
int h = od_group_join(gr, url);
if (h == -1)
{
// How to return to this line string url = rand_url(); ???
}
else
.........
}
if (h == -1)
から行に戻る方法string url = rand_url();
???