Re: Problem understanding 'boost::intrusive::list_member_hook<>'

From: John Emmas (john_at_[hidden])
Date: 2021-09-09 13:21:02

Thanks Joaquin - one quick question... do I need to define 'struct 
animal_tag' and 'struct dog_tag' somewhere?

At present, your code compiles and links okay but I still see a runtime 
crash at the same line ('dogs.push_back (a2);')

This time though, it gives me a runtime error message saying:- Assertion 
failed: !safemode_or_autounlink || node_algorithms::inited(to_insert), 
file F:\+GTK-SOURCES\gnu-windows\include\boost\intrusive\list.hpp, line 271

Thanks, John

On 09/09/2021 12:16, Joaquin M López Muñoz via Boost-users wrote:
>
> if you mean for the elements to be allowed in both lists at the same 
> time, use tags:
>
>     #include <boost/intrusive/list.hpp>
>     #include <string>
>     #include <utility>
>
>     typedef 
> boost::intrusive::list_base_hook<boost::intrusive::tag<struct 
> animal_tag>> animals_hook;
>     typedef 
> boost::intrusive::list_base_hook<boost::intrusive::tag<struct 
> dog_tag>> dogs_hook;
>
>     class animal :
>       public animals_hook, public dogs_hook
>     {
>      public:
>         animal (std::string n, int l) : name{std::move(n)}, legs{l} {}
>
>         std::string name;
>         int legs;
>     };
>
>     typedef 
> boost::intrusive::list<animal,boost::intrusive::base_hook<animals_hook>> 
> Animals;
>     typedef 
> boost::intrusive::list<animal,boost::intrusive::base_hook<dogs_hook>> 
> Dogs;
>
>     int main()
>     {
>         animal a1{"labrador", 4};
>         animal a2{"bulldog", 4};
>
>         Animals animals;
>         animals.push_back (a2);  // <--- 'bulldog' works okay
>
>         Dogs dogs;
>         dogs.push_back (a1);     // <--- 'labrador' works okay
>         dogs.push_back (a2);     // <--- 'bulldog' works okay
>
>         return 0;
>     }
>
> Joaquín M López Muñoz
>
>
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