Re: [boost] Interprocess regexes

Subject: Re: [boost] Interprocess regexes
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2009-12-05 11:55:31

John Maddock" wrote:
>>> basic_string and other containers take an
>>> allocator template argument, while basic_regex does not.
>>>
>>> If basic_regex had an allocator it would reap all the same benefits that
>>> other string and container types do. In particular, it would be possible
>>> to use boost::interprocess to place them in shared memory.
>>
>> IIUC, while the custom allocators let you put std::containers in shared
>> memory they are still not very useful since they can only be used by
>> the process that put them there - other processes will (potentially)
>> see the shared memory at a different address and all the pointers will
>> be wrong.  Is this level of functionality useful to you?
>
> That would certainly be a killer blow as far as using this with regex is 
> concerned... but don't you have the option of at least trying to load shared 
> memory at a specific address?

Yes you can ask to map it at a particular address, but that can fail.

Actually there is another case that I forgot about before: if you 
create the shared memory before forking, the new process will see it at 
the same address as its parent.  So this could be useful in that 
situation.  Sorry, it's a while since I did anything with shared memory...

Phil.