Re: [Boost-users] is read/write mutex example correct

From: Patrick Loney (Patrick.Loney_at_[hidden])
Date: 2008-05-16 07:07:37

What you need is something that guarantees not to move its elements
rather than something that doesn't guarantee contiguous memory. I don't
know if deque does this but you could end up with code that only works
if it's built with the right compiler...

 

________________________________

From: boost-users-bounces_at_[hidden]
[mailto:boost-users-bounces_at_[hidden]] On Behalf Of Igor R.
Sent: 16 May 2008 12:04
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] is read/write mutex example correct

 

I see... Then the whole problem could be solved just by using deque
instead of vector - since deque does't guarantee contiguous memory block
for its elements, and thus it shouldn't reallocate the storage.

> >> > The problem with this code is that you are returning a reference
> to data that might be immediately invalidated. A push_back via >
another thread can cause the referenced memory to no longer be valid.
> > Does push_back() really invalidate iterators to *previous* vector
elements?!
> 
> Yes: it might have to allocate a new chunk of memory for the vector,
in which
> case it will have to move all the existing elements to the new memory,
and
> free the old one.
> 
> Anthony

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