undefined reference to..passing a stl::queue to a function

[Elliott]

Hello,

I'm trying to pass a queue to a function. My queue uses a type I've created called "node" and is defined as:

queue<node> bredthFringe;

the function I'm attempting to call is:

currentNode.addChildrenToFringe(bredthFringe);

It's definition in node.ccp is:

template<typename T> void node::addChildrenToFringe(T &fringeQueue){
//doing stuff with fringeQueue here
}

and in node.h is:

template< typename T > void node::addChildrenToFringe(T &fringeQueue);

The error I get is:

In function bredthFirstSearch:
undefined reference to `void node::addChildrenToFringe<std::queue<node, std::deque<node, std::allocator<node> > > >(std::queue<node, std::deque<node, std::allocator<node> > >&)' 

I don't understand this error enough to track down what I'm doing wrong. Does anyone have any ideas?

Thank you for your time,
Elliott

[jsmith]

Template functions must be implemented in the header file.

[Elliott]

Really, that's it?!

I guess in the examples I saw they just had a forward declaration and then the implementation below in one .cpp file - so I assumed the dec. would go in the header and the implementation in the .cpp. Guess I was wrong!

Thank you!

[Disch]

I guess in the examples I saw they just had a forward declaration and then the implementation below in one .cpp file - so I assumed the dec. would go in the header and the implementation in the .cpp. Guess I was wrong!

That's exactly what you do except for templates.

For non-template functions, you had the right idea. Templates are just weird.