嵌套名称说明符 [英] nested-name-specifier

问题描述

我有一个类似的代码:

namespace mymap {
    template <class Key,template <typename T > class Allocator> myownmap {
        typedef pair<const unsigned int, Key> typename _myPair;
        typedef multimap<unsigned int, Key,less<Key> ,Allocator<_myPair> > typename _entriesType;
    }
}

它可以在MSVC下成功编译(并且可以工作)，但是gcc抱怨语法无效:

It compiles successfully (and works) under MSVC, but gcc is complaining about invalid syntax:

.hpp:20: error: expected nested-name-specifier before ‘_myPair’
.hpp:20: error: two or more data types in declaration of ‘_myPair’

我做错了什么?

推荐答案

此处不需要typename，因此不允许使用.

The typename is not needed there, and is therefore not allowed.

MSVC在实际使用模板之前无法正确解析模板，因此直到稍后才发现一些错误.

MSVC do not parse templates properly until they are actually used, so some errors are not found until later.

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