预期的嵌套名称说明符- gcc

expected nested name specifier - gcc

本文关键字：说明符 gcc 嵌套      更新时间：2023-10-16

在此代码中:

Int.h: 

#include <type_traits>

#include "Best_Fit.h"
template<class Int_T, typename Best_Fit<Int_T>::type Min_Range,typename Best_Fit<Int_T>::type Max_Range>
class Int_Core
{//If I move this class to a separate header I'm getting aforementioned error
};
template<class Int_T, typename Best_Fit<Int_T>::type Min_Range, typename Best_Fit<Int_T>::type Max_Range>
class Int : private Int_Core<Int_T,Min_Range,Max_Range>
{
};

Best_Fit.h: 

struct Signed_Type
{
    typedef long long type;
};
struct Unsigned_Type
{
    typedef unsigned long long type;
};
template<bool Cond, class First, class Second>
struct if_
{
    typedef typename First::type type;
};
template<class First, class Second>
struct if_<false,First,Second>
{
    typedef typename Second::type type;
};
template<class Int_T>
struct Best_Fit
{
    typedef typename if_<std::is_signed<Int_T>::value,Signed_Type,Unsigned_Type>::type type;
};

main.cpp: 

#include <iostream>
using namespace std;
#include "Int.h"
int main(int argc, char* argv[])
{
    return 0;
}
错误:

error: expected nested-name-specifier before 'Best_Fit'|

我正在用gcc 4.6.1编译它
有什么原因不能把Int_Core在单独的头?

这可能一点帮助都没有，但我正在使用以下版本的g++编译此代码:

g++ --version 
g++ (Ubuntu 4.4.3-4ubuntu5) 4.4.3
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

使用以下命令:

g++ main.cpp -std=c++0x -o main

如果没有-std=c++0x，我会得到错误"expected nested-name-specifier"

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