Re: [Boost-users] [interprocess] access dynamically accessed shared region in another process

Subject: Re: [Boost-users] [interprocess] access dynamically accessed shared region in another process
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2009-04-01 15:13:33

> Meanwhile I suspected as much, but didn't know for sure how to interpret the 
> docs. 
> Also, this alignment check taken from the docs doesn't compile anymore with a 
> pointer type as such:
> 
> struct transfer_buffer {
>    boost::interprocess::offset_ptr<void>   buf; 
>    size_t                                  bufsize; 
> };
> ...
> ret->bufsize = SIZE;
> ret->buf = seg->allocate_aligned(ret->bufsize, Alignment);
> 
> // Check alignment
> assert((static_cast<void *>(ret->buf) - static_cast<void *>(0)) % Alignment == 
> 0);

Obviously, offset_ptr is not a pointer so it can be static_cast'ed. 
offset_ptr is a smart pointer that emulates a pointer that can be placed 
in shared memory. See offset_ptr docs and implementation for more 
details. Try

// Check alignment
assert((static_cast<void *>(ret->buf.get()) - static_cast<void *>(0)) % 
Alignment ==
 > 0);

Regards,

Ion