VC2005 Breaking Change: typename’ needed for dependent name to be treated as a type

re: VC2005 Breaking Change: typename’ needed for dependent name to be treated as a type

ikk — Thu, 07 Jun 2007 11:05:18 GMT

It's nice to see the conformance improvements made to VC++. Congratulations!

re: VC2005 Breaking Change: typename’ needed for dependent name to be treated as a type

Michael Gourlay — Mon, 25 Jun 2007 00:45:46 GMT

template <class ItemT> class Container

{

public:

class Iterator

{

} ;

template <class ItemT> class ContainerAdapter : private Container<ItemT>

{ // MSVC compiles this, no problem. GCC does not.

Container<ItemT>::Iterator mIter ;

} ;

// How do you get this to compile in Microsoft Visual Studio or GCC?

// BTW, GCC does not like "typename".

template <class ItemT> class ContainerContainer

{

Container<typename ItemT> mContainer;

Container<typename ItemT>::Iterator mIter ;

} ;

re: VC2005 Breaking Change: typename’ needed for dependent name to be treated as a type

mijagourlay — Mon, 25 Jun 2007 08:51:58 GMT

I figured it out.

Putting "typename" before "Container" in the last line allows it to compile.

The "typename" inside the angle brackets is not necessary.

This works in GCC also.

vs 2005 error LNK2019: unresolved external symbol

Richard — Sat, 21 Feb 2009 11:14:27 GMT

I'm getting a linker error LNK2019 on vs2005 that I dont understand. Any advice to figured it out are appreicated.

Original Code:

#include "stdafx.h"

template<class T,int BIT>

class Test

{

public:

typedef struct

{

T a;

} _BUF;

template<typename T>friend Test<T,BIT>operator+(Test<T,BIT>&, Test<T,BIT>&);

friend Test<T,BIT>BufRestore(_BUF& buf, int exp, int sign );

};

template<typename T,int BIT>

Test<T,BIT> operator+(Test<T,BIT>& ss, Test<T,BIT>& tt)

{

return ss;

}

template<class T,int BIT>

Test<T,BIT> BufRestore( typename Test<T,BIT>::_BUF& buf, int exp, int sign )

{

typename Test<T,BIT>::_BUF& b1;

Test<T,BIT> rv;

return rv;

}

int _tmain(int argc, _TCHAR* argv[])

{

Test<int,8> t,t1,t2;

Test<int,8>::_BUF b1;

t = t1+t2;

t2 = BufRestore( b1, 10, 0);

return 0;

}

Errors VC2005 issue:

Compiling...

Test.cpp

Compiling manifest to resources...

Linking...

Test.obj : error LNK2019: unresolved external symbol "class Test<int,8> __cdecl BufRestore(struct Test<int,8>::_BUF &,int,int)" (?BufRestore@@YA?AV?$Test@H$07@@AAU_BUF@1@HH@Z) referenced in function _wmain

C:\Documents and Settings\Richard\My Documents\Visual Studio 2005\Projects\Test\Debug\Test.exe : fatal error LNK1120: 1 unresolved externals

Build log was saved at "file://c:\Documents and Settings\Richard\My Documents\Visual Studio 2005\Projects\Test\Debug\BuildLog.htm"

Test - 2 error(s), 0 warning(s)