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From: Jeff Garzik <jeff@garzik.org>
To: "Robert P. J. Day" <rpjday@crashcourse.ca>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: what's the purpose of MAXHOSTNAMELEN?
Date: Tue, 29 Dec 2009 14:40:05 -0500	[thread overview]
Message-ID: <4B3A5B15.5060807@garzik.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0912291416230.4967@localhost>

On 12/29/2009 02:19 PM, Robert P. J. Day wrote:
>
>    in prepping for coalescing a lot of param.h files, i'm curious about
> the purpose of this macro:
>
> $ grep -rw MAXHOSTNAMELEN *
> arch/s390/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/sparc/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/alpha/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/mn10300/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/arm/include/asm/param.h:#define MAXHOSTNAMELEN  64
> arch/m32r/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/mips/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/m68k/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/xtensa/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/ia64/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/h8300/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/avr32/include/asm/param.h:#define MAXHOSTNAMELEN	64
> arch/cris/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/um/include/asm/param.h:#define MAXHOSTNAMELEN  64      /* max length of hostname */
> arch/powerpc/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/parisc/include/asm/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> arch/frv/include/asm/param.h:#define MAXHOSTNAMELEN		64	/* max length of hostname */
> include/asm-generic/param.h:#define MAXHOSTNAMELEN	64	/* max length of hostname */
> include/net/sctp/structs.h:#include<asm/param.h>		/* We get MAXHOSTNAMELEN.     */
> $
>
>    so lots of people define it but no one uses it.  it *is* exported to
> user space in /usr/include/asm/param.h, but i still have no idea what
> it's for in user space.  obsolete?

According to RFC 1034, "Each node has a label, which is zero to 63 
octets in length"

What is it used for in userspace, and why is it export from the kernel? 
  Good question...

	Jeff




  parent reply	other threads:[~2009-12-29 19:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-29 19:19 what's the purpose of MAXHOSTNAMELEN? Robert P. J. Day
2009-12-29 19:28 ` Samuel Thibault
2009-12-29 19:40 ` Jeff Garzik [this message]
2009-12-29 19:56   ` Samuel Thibault
2009-12-29 20:20     ` Jeff Garzik
2009-12-29 20:26       ` Samuel Thibault
2009-12-29 21:00       ` Vikram Dhillon
2009-12-29 20:13   ` Robert P. J. Day

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