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Date: Fri, 06 Jul 2007 09:38:31 -0700
From: Julian Elischer <julian@elischer.org>
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To: Ed Schouten <ed@fxq.nl>
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Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>,
	Robert Watson <rwatson@FreeBSD.org>, d@delphij.net
Subject: Re: add closefrom() call
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Ed Schouten wrote:
> * LI Xin <delphij@delphij.net> wrote:
>> Here is my implementation for FreeBSD.  Some difference between my and
>> DragonFly's implementation:
>>
>>  - closefrom(-1) would be no-op on DragonFly, my version would close all
>> open files (From my understanding of OpenSolaris's userland
>> implementation, this is Solaris's behavior).
>>  - my version closefrom(very_big_fd) would result in EBADF.  I am not
>> very sure whether this is correct, but it does not hurt for applications
>> that thinks closefrom() would return void.
> 
> Wouldn't it be better to just implement it through fcntl() and implement
> closefrom() in libc?
> 

that's a possibility but I personally thing the huge difference in efficiency
makes it worth putting it in the kernel.
Quite a few programs I know of could really help their startup time with this as 
the first thing they do is "close the first 2000 file descriptors.