Re: Bug in socket(7) man page

[CC widended]

Tobias,

On 7 August 2017 at 13:53, Tobias Klausmann [off-list ref] wrote:

Hi!

This bug pertains to the manpage as visible on man7.org right
now.

The socket(7) man page has this paragraph:

       SO_RXQ_OVFL (since Linux 2.6.33)
              Indicates that an unsigned 32-bit value ancillary message (cmsg) should be attached to
              received skbs indicating the number of packets dropped by the socket between the  last
              received packet and this received packet.

The second half is wrong: the counter (internally,
SOCK_SKB_CB(skb)->dropcount is *not* reset after every packet.
That is, it is a proper counter, not a gauge, in monitoring
parlance.

A better version of that paragraph:

       SO_RXQ_OVFL (since Linux 2.6.33)
              Indicates that an unsigned 32-bit value ancillary message (cmsg) should be attached to
              received skbs indicating the number of packets dropped by the socket since its
              creation.

Thanks for the report. See also my reply to Petr in just a moment.
I've taken your suggested text change.

Cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/