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From: Christoph Rohland <cr@sap.com>
To: Paul Menage <pmenage@ensim.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] Pollable /proc/<pid>/ - avoid SIGCHLD/poll() races
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Organisation: SAP LinuxLab
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Date: 04 Oct 2001 12:25:36 +0200
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Hi Paul,

On Thu, 04 Oct 2001, Paul Menage wrote:
>>> The only real user-space solution to this is to have the SIGCHLD
>>> handler somehow cause the select() to return immediately
>>
>>... or implement pselect:
>>http://mesh.eecs.umich.edu/cgi-bin/man2html/usr/share/man/man2/select.2.gz
> 
> Agreed, althought that's not a user-space solution. Is there any
> fundamental reason why no-one's implemented pselect()/ppoll() for
> Linux yet?

Missing knowledge and/or demand? It should be pretty easy to
implement.

>>or use sigsetjmp/siglongjmp
> 
> Yes, that would probably solve the situation in question, provided
> that siglongjmp() is portably safe. (A comment on LKML in the past
> suggested that it's not safe on cygwin, for example.)

It should be at least portable between different U*X versions. I never
used cygwin though.

Greetings
		Christoph


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