Re: template template argument in C++

From:
SG <s.gesemann@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Mon, 25 May 2009 04:42:48 -0700 (PDT)
Message-ID:
<74c1e796-57e5-4568-824a-558ac02c3b68@z5g2000yqn.googlegroups.com>
On 25 Mai, 11:40, nishit.gu...@nsitlounge.in wrote:

Can somebody please send me some good documentation / links explaining
template template arguments in C++, i.e.


I have no links handy. Probably the best source would be a good text
book about C++.

 template <int T> struct A
 {
 };

 template <> struct A<32>
 {
    typedef int B;
 };

 template <> struct A<64>
 {
    typedef char B;
 };


A template template argument is a template argument that is a class
template. I don't see those in your example. You just declared a class
template which takes a non-type as parameter and provided two
specializations. But you could use this class template as argument for
another template:

  template< int I, template<int> class TT >
  class foo {
  public:
    typedef TT<I> tti;
    typedef typename tti::B bar;
    ...
  };

Unfortunately, without class template aliases (which will be
introduced in C++0x) those template template arguments are of limited
use.

Cheers!
SG

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