What does mean [@0] file descriptor?

Anybody knows what does mean “@0” file descriptor shown by “sin fd”?
Something like this:

5 -//1 [@0]
6 -//1 [@0]

These were TCP sockets, but after closing they remain like this.

TIA,
Grzegorz Wrobel


wrobel@no-spam.zdania.com.pl Experimental Department of Scientific
phone: (+48 12) 617-2883 Equipment and Automation
fax: (+48 12) 634-2205 30-059 Krakow, al.Mickiewicza 30, Poland