Template question

From:
Adrian <nntp@bluedreamer.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 2 Dec 2009 08:00:43 -0800 (PST)
Message-ID:
<4789f593-4d25-4b8d-9f2b-241c164fc862@d10g2000yqh.googlegroups.com>
Hi All,

Is the output from the following code correct? Is the result
undefined? I am not quite sure what I expected from this :-). Should
both the time_t and DateTime creation call the specialized class or
should only the time_t. Both results would make sense to me.

Does it say this anywhere in the standard at all?

TIA

Adrian

------------------------------------
#include <iostream>
#include <ctime>

typedef time_t DateTime;

class BoringBase
{
   public:
      virtual ~BoringBase() {}
};

template<typename T>
class Foo : public BoringBase
{
   public:
      Foo() { std::cout << "Constructing run-of-the-mill Foo\n"; }
};

template<>
class Foo<time_t> : public BoringBase
{
   public:
      Foo() { std::cout << "Special time_t Foo\n"; }
};

int main(int /* argc */, char /* *argv[] */)
{
   BoringBase *a,*b,*c;

   a=new Foo<int>();
   b=new Foo<time_t>();
   c=new Foo<DateTime>();

   return 0;
}

// Outputs:
// [adrianc@mlx32dev:~]$g++ -Wall -ansi -pedantic -Wextra -Weffc++
foo.cc
// [adrianc@mlx32dev:~]$a.out
// Constructing run-of-the-mill Foo
// Special time_t Foo
// Special time_t Foo

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