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Date:      Mon, 26 Oct 1998 12:12:55 -0500 (EST)
From:      Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To:        "Louis A. Mamakos" <louie@TransSys.COM>
Cc:        freebsd-net@FreeBSD.ORG
Subject:   questions of taste..  mbuf header change
Message-ID:  <199810261712.MAA19008@khavrinen.lcs.mit.edu>
In-Reply-To: <199810252219.RAA10102@whizzo.transsys.com>
References:  <199810252219.RAA10102@whizzo.transsys.com>

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<<On Sun, 25 Oct 1998 17:19:56 -0500, "Louis A. Mamakos" <louie@TransSys.COM> said:

> - what, if anything, breaks if there are 8 or 10 bytes fewer space in
> the first mbuf?  There was some discussion a while ago about increasing
> MSIZE from 128 to something larger, but this didn't seem to happen.

Probably local-domain datagram sockets with long path names.  Can't
think of anything else.  I'm inclined to increase MSIZE to 256 in any
case...

> - how to minimize header file dependencies by introducing a new data type.
> Should I add a

> 	#ifndef	_SYS_TIME_H_
> 	#include <sys/time.h>
> 	#endif

> in sys/mbuf.h?

No.  What I would do instead is to declare a new structure which is an
intentional type pun for `struct timespec'.

(You have stumbled into one of the most annoying misfeatures of the C
language: there is no way to actually USE an incomplete structure that
is even marginally useful; in order to have opaque objects it is
necessary to insert a level of indirection which is less than
desirable in a low-level context such as this.)

-GAWollman

--
Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu  | O Siem / The fires of freedom 
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick

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