Exact definition of SO_SNDLOWAT and SO_RCVLOWAT

[Richard Sharpe]

Hi,

I am seeing conflicting definitions of SO_SNDLOWAT and SO_RCVLOWAT, and
would like some confirmation of these.

>From some man pages I have found, it seems that the following might be true:

On a write operation, the min of the write size and the value supplied in
any SO_SNDLOWAT will be written to the protocol later, which will then
segment this. However, SO_NODELAY will control whether that is sent as a
segment immediately, or whether or not TCP will delay a short while to see
if more data is available.

Now, if you have set TCP_NODELAY, then it seems that a good size for
SO_SNDLOWAT would be 1460. This would allow full ethernet packets ...

Comments please.


Regards
-------
Richard Sharpe, sharpe at ns.aus.com
Samba (Team member, www.samba.org), Ethereal (Team member, www.zing.org)
Co-author, SAMS Teach Yourself Samba in 24 Hours
Author: First Australian 5-day, intensive, hands-on Linux SysAdmin course
Author: First Australian 2-day, intensive, hands-on Samba course