CODEWITHSUNDEEP
c++
Nikhil
Nikhil

Reputation: 2318

C++: incomplete type named in nested name specifier

I am trying to resolve a circular dependency in my c++ project and based on other answers here on StackOverflow, I followed the same methodology. However, I am still seeing an issue:

This is my code snippet below:

// In ip6.hh
namespace net
{
    class Inet4;

      /** IP6 layer */
      class IP6
      {
         using Stack = class Inet4;

         void set_packet_forwarding(Stack::Forward_delg fwd)
         { forward_packet_ = fwd; }

         Stack& stack_;
     }
}

// In Inet4.hpp
#include "ip6/ip6.hpp" 
namespace net {

  class Inet4 : public Inet<IP4>{

  IP6& ip_obj()
  { return ip6_; }

   IP6    ip6_;
  }
}

In main.cpp, I am including it as follows:

#include <net/ip6/ip6.hpp>
#include <net/inet4.hpp>

> /home/nikhil/projects/ipv6/IncludeOS/api/net/ip6/ip6.hpp:84:32: error:
> incomplete type 'net::Inet4' named in nested name specifier
>     void set_packet_forwarding(Stack::Forward_delg fwd)
>                                ^~~~~~~ /home/nikhil/projects/ipv6/IncludeOS/api/net/ip6/ip6.hpp:35:9: note:
> forward declaration of 'net::Inet4'   class Inet4;

Upvotes: 0

Views: 417

Answers (1)

code707
code707

Reputation: 1701

there is only Inet decalaration (not definition). Compiler does not know definition of Inet4 (hence Stack which is alaised to Inet4).

Upvotes: 2

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