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Date: Mon, 12 Aug 2002 16:59:25 -0700 (PDT)
From: David Xu <bsddiy@yahoo.com>
Subject: Re: Thread-safe resolver [patches for review]
To: Terry Lambert <tlambert2@mindspring.com>,
	Maxim Sobolev <sobomax@FreeBSD.org>
Cc: "hackers@FreeBSD.ORG " <hackers@FreeBSD.ORG>,
	"audit@FreeBSD.ORG" <audit@FreeBSD.ORG>,
	Alexander Litvin <archer@whichever.org>,
	Andriy Gapon <agapon@excite.com>
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> 
> No.  I don't think any of the _r functions are needed, so long
> as the results are not cached by pointer instead of a copy,
> before passing them from one thread to another.  It's a risk on
> the clobber case of a call with a cached reference outstanding
> but not processed by another thread which is not an issue with
> the _r functions, which require that you pass the storage down.
> 
> Of course, if you pass down per thread storage, you could have
> the same problem if you didn't copy rather than reference the
> results before passing to another thread by address.
> 
> Given that, per thread allocations ("thread local storage")
> makes more sense than allocate/free fights between threads
> based on who's responsible for owning the memory after an
> inter-thread call.  8-).
> 
> -- Terry

localtime() etc. are candidate to make them use per thread
storage.

David Xu


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