Re: [boost] Threads Review

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