Re: [boost] [type_erasure] any and shared_ptr

Subject: Re: [boost] [type_erasure] any and shared_ptr
From: Christophe Henry (christophe.j.henry_at_[hidden])
Date: 2012-10-16 15:31:15

>> typedef mpl::vector<
>>       pointer<>,
>>       same_type<pointer<>::element_type,_a >,
>>       relaxed_match,
>>       has_foo<void()>
>>     > PointeeConcept;
>> 
>>   // will not compile, shared_ptr<Pointee> has no foo...
>>   boost::shared_ptr<Pointee> p (new Pointee) ;
>>   any<PointeeConcept> ap (p);
>>   ap.foo();
>> 
> 
> The placeholder _self maps to shared_ptr<Pointee>
> and the placeholder _a maps to Pointee.
> has_foo<void()> is actually has_foo<void(), _self>
> because of the default argument.  This says
> that shared_ptr<Pointee> has a member called foo.
> What you really want is has_foo<void(), _a> to
> say that foo is a member of Pointee.
> 
> In Christ,
> Steven Watanabe

Ok, got it. I made a second mistake, I need (*ap).foo();

Thanks,
Christophe