too few template-parameter-lists with nested template

Michael Gourlay mgourlay@fiea.ucf.edu
Thu Mar 16 21:32:00 GMT 2006


I've seen other posts asking a similar question, but the solution continues to evade me.

I have a line of code that compiles and runs as designed with MSVC but not under g++ 3.4.2 (mingw-special):

HashTable<Factory<AbstractProductUnitTest>::FactoryEntry> Factory<AbstractProductUnitTest>::sFactoryTable ;

The following lines do compile (but see caveat below):

template <class EntryT> class HashTable<Factory<AbstractProductUnitTest>::FactoryEntry> Factory<AbstractProductUnitTest>::sFactoryTable ;

...or...

template <> class HashTable<Factory<AbstractProductUnitTest>::FactoryEntry> Factory<AbstractProductUnitTest>::sFactoryTable ;


The resulting code, however, seems not to have called the constructor on sFactoryTable by the time it gets used, which is well after "main" starts - i.e. this is not a problem with order of execution of static constructors.


Here is some context for the code above:

template <class EntryT> class HashTable
{
      ...
    protected:
        LinkedList<EntryT> * mLists ;
      ...
} ;

template <class AbstractProductT> class Factory : public HashEntry
{
      ...
    protected:
        struct FactoryEntry : public HashEntry
        {   // struct to associate a factory with a hash table key.
            Factory<AbstractProductT> * mFactory ;
        } ;
        static HashTable<FactoryEntry> sFactoryTable ;  // singleton list of concrete factories associated with this abstract factory
} ;

I searched http://gcc.gnu.org/ and found several simpler variations where people complained about initialization of static templated class members, the solution to which was to prefix the class name with "template <>", but I found no mention of a situation like that above, which involves nested templated classes.

I apologize if this reflects my ignorance rather than a bug in the GNU C compiler, and would appreciate having somebody explain how to make this work.

Thanks.

                                                            
Michael J. Gourlay



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