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From: Anthony Williams (anthony.williamsNOSPAM_at_[hidden])
Date: 2002-10-17 08:20:50

David Abrahams writes:
> <anthony.williamsNOSPAM_at_[hidden]> writes:
> > David Abrahams writes:
> > > I suggest the following simple rewrite:
> > >
> > > "An object [1.8, 1.9] is accessible from multiple threads
> > > if it is of static storage duration (static, extern) [3.7.1],
> > > or if a pointer or reference to it is accessible from multiple
> > > threads."
> > >
> > > End of story.
> >
> > Except that it isn't --- the pointers and references need not
> > themselves be accessible from multiple threads for the pointed- or
> > referred-to object to be accessible from mutlple threads, if the
> > pointers or references are _copies_ of values accessible from
> > multiple threads.
> Fair enough. Yep, this wording is hard to get right. Got a suggestion?

Actually, I'm inclined to think that your wording is right after all. To get a
pointer or reference which is not itself accessible from multiple threads, but
points/refers to an object that is, you have to copy/take the address
of/dereference another pointer or reference which _is_ accessible from
multiple threads. The only exception is data which is passed into a thread by
the OS thread API, which is therefore only data from the thread object ---
everything else follows from there.

How about adding a "Note --- this includes pointers or references contained in
the boost::thread object used to start the thread and it's threadfunc"?


Anthony Williams
Senior Software Engineer, Beran Instruments Ltd.
Remove NOSPAM when replying, for timely response.

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