Re: [Boost-users] multi_index_container for composite key

Subject: Re: [Boost-users] multi_index_container for composite key
From: joaquin_at_[hidden]
Date: 2010-09-09 03:00:52

Uthpal Urubail escribió:
> Joaquín M López Muñoz,
> Thanks for offering me the help.
>   

You're welcome. Please don't top-post and try to follow the
general discussion policies outlined at

http://www.boost.org/community/policy.html

> One interesting observation:
> If I use the below in finding the objects it is not retrieving properly
> 	indexed_by<
> 	    	ordered_unique<  /// INSTEAD if I use ordered_non_unique< it works fine
>       		  composite_key<
>   

If you use ordered_unique then there cannot be two elements with the same
node[0], node[1], node[2] values. I guess this is what's happening in 
your case.

> I am still not clear with my question:2
> 	Can I define the container like below?
> 	I don't want to create the temporary data structure. I will get these information from a class object. Can I use them directly??
> 	Please help me in understanding.
>
> 	typedef multi_index_container<
>     	<pointer???>, //??
>     		indexed_by<
>     			ordered_unique<
>         			composite_key<
>             			<pointer????>, //???
> 			            BookNodeExtractor<0>,
> 			            BookNodeExtractor<1>,
> 			            BookNodeExtractor<2>
>             		>
>     			>,
> 	    		ordered_unique<
>     				member<classname,size_t,&classname::id>
>     			>
>     		>
> 	> beambook;
>   

I'm not sure what your question is, but if you wonder whether you can
define a container of pointers to Books rather than Book objects proper,
the answer is: you can, but you have to modify BookNodeExtractor so
that it accepts pointers rather than Book &s.

Joaquín  M López Muñoz
Telefónica, Investigación y Desarrollo