Re: [Boost-users] shared_ptr to object in stl set container?

Subject: Re: [Boost-users] shared_ptr to object in stl set container?
From: Nathan Ridge (zeratul976_at_[hidden])
Date: 2011-12-13 05:06:10

> Your operators are likely not being called because they are of the  
> incorrect signature. The type of a member equality operator should be  
> as shown: 
> struct Foo 
> { 
>     bool operator==(const Foo& f) const; 
>  
>     // this is the incorrect equivalent of your operator 
>     // bool operator==(Foo f); 
> } 
>  
>  
> The const parameter is the correct way to do it, but it is most likely  
> the method not being const that prevents your operators from being  
> invoked. 

Actually, the reason the operator< is not being invoked is because
the way it's defined, it compares a Node object to a NodePtr:

class Node
{
  ...  
  bool operator<(NodePtr otherNode) {
    return (id < otherNode->id);
  }
};

What you want is an operator< that compares a NodePtr to a NodePtr,
because this is what set<NodePtr>::find() will call. This needs to be
defined as a non-member function:

bool operator<(NodePtr a, NodePtr b)
{
    return a->getID() < b->getID();
}

Having said that, Rob is right that using ptr_container is a better approach.

Regards,
Nate