Re: [RTnet-users] question about rt_socket->fd

[Jan K. <jan...@we...>]

Hans-Peter Bock schrieb:

> Hello,
> 
> what does "bit 8-30: instance id" as comment in the definition of "fd" mean?
> 

Convenience bits. :)

If task A closes a file descriptor, the structure returns to the global 
pool of used sockets. If now task B creates a new socket, it may get the 
same structure (thus the same socket index), but the instance id will be 
incremented by one. This avoids that task A can mistakenly continue to 
use the old file descriptor. Well-written software will of course not - 
but in case...

Jan