Re: [boost] [Review] Shmem Library

From: Andrew J Bromage (ajb_at_[hidden])
Date: 2006-02-11 18:38:07

G'day.

Ion Gaztañaga <igaztanaga <at> gmail.com> writes:

> However, being from the old school, [...]

So why are you proposing a Boost library? :-)

(I hope that emoticon was big enough!)

> I don't 
> like much the mandatory use of shared_ptr in the interface (so that 
> mapped_file must be allocated only via new).

That's not true!  You can take a shared_ptr to a static or auto object
by using a custom deleter.  This approach doesn't provide any safety in
this case (since mmaped_region doesn't manage the lifetime of
mmaped_file), but it works at least.

> file_mappings could have 
> also ordering operators so that we can store them in containers.

Yes.  The application that I had in mind was an application-controlled
buffer cache, so the ability to store them in containers is certainly
a useful feature there.
 
> I think both your mapping approach and boost::shmem::mmapped_file can be 
> complementary, being boost::shmem::mmapped_file for simple uses and this 
> multi-mapping approach for advanced ones.

Yes.  In fact, the more I think about it, the more I suspect that this is
the better approach, with mmaped_file perhaps being a convenience wrapper
built on top of the other two classes.

In addition, while designing these classes, it may turn out that a more
general memory mapped file library is warranted.

So in summary: We (I include myself) should work on supporting this
functionality, but it's not a barrier to accepting Shmem into Boost.

Cheers,
Andrew Bromage