Link error for user defined class type template parameter
- by isurulucky
Hi,
I implemented a Simple STL map in C++. Factored out the comparison as a type as I was instructed to, then implemented the comparison as shown below:
template <typename T> int KeyCompare<T>::operator () (T tKey1, T tKey2)
{
if(tKey1 < tKey2)
return -1;
else if(tKey1 > tKey2)
return 1;
else
return 0;
}
here, tKey1 and tKet2 are the two keys I'm comparing. This worked well for all the basic data types and string. I added a template specialization to compare keys of a user defined type named Test and added a specialization as follows:
int KeyCompare<Test>::operator () (Test tKey1, Test tKey2)
{
if(tKey1.a < tKey2.a)
return -1;
else if(tKey1.a > tKey2.a)
return 1;
else
return 0;
}
when I run this, I get a linking error saying
SimpleMap.obj : error LNK2005: "public: int __thiscall KeyCompare::operator()(class Test,class Test)" (??R?$KeyCompare@VTest@@@@QAEHVTest@@0@Z) already defined in MapTest.obj
SimpleMap.obj : error LNK2005: "public: __thiscall KeyCompare::~KeyCompare(void)" (??1?$KeyCompare@VTest@@@@QAE@XZ) already defined in MapTest.obj
SimpleMap.obj : error LNK2005: "public: __thiscall KeyCompare::KeyCompare(void)" (??0?$KeyCompare@VTester@@@@QAE@XZ) already defined in MapTest.obj
MapTest.cpp is the test harness class in which I wrote the test case. I have used include guards as well, to stop multiple inclusions.
Any idea what the matter is??
Thank you very much!!
