missing ; before identifier while compiling VC6 code in VC9

Question

The following code compiles fine in VC6 but when I compile the same project in VS2008 it gives the following error error C2146: syntax error : missing ';' before identifier 'm_pItr'

template <class pKey, class Data, class pCompare, 
       class hKey = int, class hCompare = less<hKey>,
       class sKey = int, class sCompare = less<sKey>,
       class tKey = int, class tCompare = less<tKey>,
       class cKey = int, class cCompare = less<cKey>>

class  GCache
{
    private:

     typedef map<pKey, Data, pCompare> PRIMARY_MAP;
     PRIMARY_MAP pMap;

     PRIMARY_MAP::iterator m_pItr; //error here

//Code truncated
}

Any ideas of what is wrong here? Someone with experience in migrating C++ code from VC6 to VC2005/2008 might be able to help.

Answer 1

You may be falling victim to a common template problem:

class cKey = int, class cCompare = less<cKey>>

should be:

class cKey = int, class cCompare = less<cKey> >

Note the space between the llast two angle brackets.

Answer 2

You may need to insert 'typename', to tell the compiler PRIMARY_MAP::iterator is, in all cases, a type.

e.g.

class  GCache
{
    private:

        typedef map<pKey, Data, pCompare> PRIMARY_MAP;
        PRIMARY_MAP pMap;

        typename PRIMARY_MAP::iterator m_pItr;

//Code truncated
}

Answer 3

It should be typename PRIMARY_MAP::iterator m_pItr; . Otherwise compiler thinks that PRIMARY_MAP::iterator is a static object and will not be able to recognize it as a type. So you have to give an hint to the compiler indicating that it is a type and not a static object.