How to separate the implementation and definition for template function in c++

When I use template function in my class TestClass. The complier will throw out a Link Error below.

TestClass.h 

template<class T>    

T foo(T a, T b);

TestClass.cpp 
   

template<class T>    

T TestClass::foo(T a, T b) 

{
return a;

}

Client.cpp 

TestClass testClass;

testClass.foo(0, 1); 

Link Error 

Error    1    error LNK2019: unresolved external symbol "public: int __cdecl TestClass::foo<int>(int,int)" (??$foo@H@TestClass@@QAAHHH@Z) referenced in function "private: bool __cdecl Client::TestFunction()" (?TestFunction@Client@@@Z)    Client.obj    

There are some approach we can use to fix this issue. I prefer to use the implementation header to fix that issue. 
Add a new file called TestClass_impl.h and move all the template functions from TestClass.cpp to TestClass_impl.h

Include TestClass_impl.h into TestClass.h

TestClass.h 

class TestClass

{
template<class T>    

T foo(T a, T b);

};
#include "TestClass_impl.h" 

All done.

    本文转自Jake Lin博客园博客，原文链接：http://www.cnblogs.com/procoder/archive/2010/06/29/How-to-Separate-the-Implementation-and-Definition-of-Template-Function-in-CPP.html，如需转载请自行联系原作者