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dave

How do i deal with this link error?

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Hey all, I have this link error i dont know how to deal with. Error: ain.obj : error LNK2001: unresolved external symbol "public: virtual __thiscall sList<float>::~sList<float>(void)" (??1?$sList@M@@UAE@XZ) main.obj : error LNK2001: unresolved external symbol "public: __thiscall sList<float>::sList<float>(void)" (??0?$sList@M@@QAE@XZ) main.cpp
#include "file.h"
#include "linked_list.h"

struct RECT
{
	int x, y, right, left;
};

int main (void)
{
	file newFile("C:\\Documents and Settings\\Dave\\Desktop\\star.bmp", "rb+");


	sList<RECT> recList;
	return 0;
}

list.h
#ifndef	_S_LINKED_LIST_
#define	_S_LINKED_LIST_

template <class TYPE>
class sList
{
public:
	sList();
	virtual ~sList();

private:

	// MEMBER DATA
	struct SLIST
	{
		TYPE structOfType;


		SLIST* next;
	} start, *node;

	// MEMBER METHODS
	inline void InitLinkedList();

};

#endif	_S_LINK

list.c
#include "linked_list.h"

template <class TYPE>
sList<TYPE>::sList()
{
	InitLinkedList();
}

template <class TYPE>
sList<TYPE>::~sList()
{
}

template <class TYPE>
void sList<TYPE>::InitLinkedList()
{
	start.next = NULL;
	node = &start;
}

Thanx for any help ace

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Unless your compiler supports the export keyword, and seeing as that looks like a MSVC error code, I'm willing to bet that yours doesn't, then you can't put the definition of a template in a separate source file without explicit instantiation for specific types. Without explicit instantiation, the complete definition of the template needs to be available at point of instantiation, which means, in effect, that the definition needs to go into the header. (Or an inline file of some sort, etc.)

For more details see these articles: "Export" Restrictions, Part 1 and "Export" Restrictions, Part 2.

And before petewood gets to this thread, I suppose I'll post this link for him. It's an article entitled "Instantiator: A (Mostly) Portable Framework for Separate Compilation of Templates"

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Template member functions need to be available inline at the point of usage; putting them in a separately compiled .cpp file doesn't work unless your compiler has template repository support (which neither MSVC nor GCC has).

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Quote:
Original post by SiCrane
And before petewood gets to this thread, I suppose I'll post this link for him. It's an article entitled "Instantiator: A (Mostly) Portable Framework for Separate Compilation of Templates"


Thanks (c:

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Yeah, that part of my stock answer used to read
Quote:

And since petewood no longer posts on the boards, I suppose I should post this link for him. It's an article entitled "Instantiator: A (Mostly) Portable Framework for Separate Compilation of Templates"


But now that you're back, maybe I should just take out that line and let you post it yourself. :P

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It's nice to be refered to. Makes me feel special. Thanks SiCrane.

I've been busy with my new 3 month old baby boy and also my dad died a month ago so things have been all over the place for me.

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