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Date: Wed, 09 Nov 2005 00:07:01 -0800
From: Nate Lawson <nate@root.org>
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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Cc: Craig Rodrigues <rodrigc@FreeBSD.org>, cvs-src@FreeBSD.org,
	src-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/kern vfs_mount.c
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Poul-Henning Kamp wrote:
> In message <43716BD6.5050604@root.org>, Nate Lawson writes:
> 
> 
>>While I don't have ideas for a better general mechanism for this, I 
>>think it sets a bad precedent.  We can't have every complex syscall 
>>transporting its own error message strings back to the user program. 
>>And we can't expand errno to be the union of every single API-specific 
>>error either.
> 
> 
> That was one the main points of my ioctl talk at BSDcan.
> 
> One way to solve it:
> 
> Hang a sbuf pointer in each thread and APIs cound stuff their error
> message there.
> 
> Add a new syscall to return the string to userland.
> 
> Modify perror(3), err(3) and similar to pull out the "extended"
> error, if there is one.

This sounds better.  Not sure if it's fully baked, but definitely a 
better direction.

-- 
Nate