Re: [boost] [Review] Shmem

From: Jeff Flinn (TriumphSprint2000_at_[hidden])
Date: 2006-02-08 10:20:05

Pavel Vozenilek wrote:
> "Jeff Flinn" wrote:
>
>> I think he's pointing out the lack of RAII. From your first example:
>>
>>
>>  named_shared_object segment;
>>
>>   if(!segment.create("/MySharedMemory",  //segment name
>>                     65536)){            //segment size in bytes
>>      return -1;
>>   }
>>
>>   void * shptr   = segment.allocate(1024/*bytes to allocate*/);
>>
>>   segment.deallocate(shptr);
>>
>> I'd rather see:
>>
>>  try
>>  {
>>     named_shared_object segment("/MySharedMemory",65536);
>>
>>     shmem::shared_ptr lPtr = segment.allocate(1024);
>>  }
>>  catch( const shmem::exception& aExc )
>>  {
>>    ...
>>  }
>>
>> Where the shared_ptr has a deleter calling
>> named_shared_object::deallocate. I'd also think that the
>> 'shared_memory' should not be destructed until the last
>> shmem::shared_ptr is released.
>
> Rather than yet another underdocumented shared pointer with
> subtly different name it should be:
>
> boost::shared_ptr<void, shmem::deleter> p = segment.allocate(1024);

Yes that was my intent.

> and
>
> void* p = segment_allocate(1024, shmem::manual_lifetime);

Did you mean for the above to be a free function? Is there really a need for 
this? Is there precedent with other boost libs dealing in unsafe raw 
pointers?

> And there could be debug mode flag that checks
> the data is deallocated in the same modeit was allocated.

By 'mode' do you mean whether the shared_ptr, or raw pointer was returned?

Thanks, Jeff