Re: [Boost-users] [bind] Help with functional composition ofshared_ptr::use_count in std::map

From: Hughes, James (jhughes_at_[hidden])
Date: 2007-06-11 07:15:20

> -----Original Message-----
> From: boost-users-bounces_at_[hidden] 
> [mailto:boost-users-bounces_at_[hidden]] On Behalf Of 
> Hughes, James
> Sent: 11 June 2007 12:04
> To: boost-users_at_[hidden]
> Subject: [Boost-users] [bind] Help with functional 
> composition ofshared_ptr::use_count in std::map
> 
> Hello all,
> 
> I'm trying to use bind to help with removeif in a 
> std::map<string, shared_ptr<something> >. I want to remove 
> items where the shared_ptr use_count is 1.
> 
> map<string, shared_ptr<data> > Fred;
> 
> RemoveIf(Fred.begin(),
>          Fred.end(),
>          boost::bind(std::equal_to<long>(),
> 		1,
> 		boost::bind(&map<string, shared_ptr<data>
> >::value_type::second::use_count, _1)
> 	)
> 
> However, I get a compile error on ::second not being a class 
> or namespace.
> 
> Anyone know how I should do this? I'm a beginner at 
> boost::bind, so be gentle....
> 
> James

Sorry, that should read remove_if, and in fact the purpose is better
served using shared_ptr<>::unique, which should mean I can get rid of
the std:equal_to stuff

RemoveIf(Fred.begin(),
         Fred.end(),
           boost::bind(&map<string, shared_ptr<data>
>::value_type::second::unique, _1)
        )

Still get same compile fault however. 

James

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