Re: [boost] [Review] Shmem Library

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2006-02-11 19:47:13

Hi Andrew,

>> However, being from the old school, [...]
> 
> So why are you proposing a Boost library? :-)

Good point! Maybe because I felt old-school resources (IPC, shared 
memory, etc...) are not present in Boost ;-)

>> 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.

Right.

>> 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.

The buffer cache is definitely a good tool to design. Don't forget two 
present it to a Boost review!

> 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.

Yes, that would be easy.

> 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.

Thanks. I think that multi-mapping functionality has many possibilities, 
so is definitely a good project.

Cheers,

Ion