What's the meaning of this comma?

[Iver.Leung]

I am reading the source code of tfn2k,
in function "tfntransmit" within file "tribe.c",
there is a defination saying that:
int tot_len = sizeof (struct ip), ssock;
and ssock becomes a struct ip.
I wanna know why, thanks

 

[Iver.Leung]

I found out it's the problem of source insight...