Re: [Boost-users] [Boost.Interprocess] int key and flat_multimap_index

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2008-08-17 05:15:32

Robert Kubrick wrote:
> A couple of beginner questions on basic_managed_heap_memory:
> 
> 1) I want to access elements in the contiguous memory segment by using 
> an int key,  rather than a char string. Can I declare something like this:
> 
> typedef basic_managed_heap_memory < 
>    int, /* my key is an integer */ 
>    rbtree_best_fit<null_mutex_family>,
>    flat_map_index
>    >  managed_heap_memory;
> 
> I need to lookup objects using an external integer ID but the ID can 
> have any value (ie, does not match the 0-N array element order of my 
> memory segment). 

No sorry, named allocation is only availables for chars. One workaround 
thing you can do is to allocate anonymous objects in the managed segment 
and create another map-like structure pointing to those anonymous 
objects. More inefficient, I know, but I can't think another way. 
Anyway, I think you've shown me a good use case to study the possibility 
of using non-char indexes (something I suspect will require a lot of 
work, because all the code supposes string keys).

> 2) If I want to insert multiple objects with the same char* name (ala 
> multimap) can I create a flat_multimap_index?

You can't. Names must be unique because it should identify a unique 
named object. Otherwise, we wouldn't be capable to find an object correctly.

Regards,

Ion