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Re: what may cause compile error (expected nested-name-specifier before 'Policy-T')?

From "Bo Persson" <bop@gmb.dk>
Newsgroups comp.lang.c++
Subject Re: what may cause compile error (expected nested-name-specifier before 'Policy-T')?
Date 2011-07-11 22:42 +0200
Message-ID <9815h1F7tlU1@mid.individual.net> (permalink)
References <64a52045-54be-4994-a805-72aab256b2b2@j14g2000prn.googlegroups.com>

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eric wrote:
> Dear advanced c/g++ programers:
>
>   I tried to test a piece code about Defining constrained Value
> Types
> --------------------------------------------------------------------------------------------------------
> // Example 5-10 constrained_value.hpp
> #ifndef CINSTRAINED_VALUE_HPP
> #define CONSTRAINED_VALUE_HPP
>
> #include <cstdlib>
> #include <iostream>
>
> using namespace std;
>
> template<class Policy_T>
> struct ConstrainedValue
> {
>   public:
>   // public typedefs
>   typedef typename Policy_T policy_type;

Here "typename" is not required, so it is not allowed. Hard rules!

>   typedef typename Policy_T::value_type value_type;

Here "typename" indicates that the nested name is a type, so it is 
required.


Bo Persson


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Thread

what may cause compile error (expected nested-name-specifier before 'Policy-T')? eric <cneric12lin0@gmail.com> - 2011-07-11 11:59 -0700
  Re: what may cause compile error (expected nested-name-specifier before 'Policy-T')? "Bo Persson" <bop@gmb.dk> - 2011-07-11 22:42 +0200
  Re: what may cause compile error (expected nested-name-specifier before 'Policy-T')? Qi <no@no.no> - 2011-07-12 10:14 +0800

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