如何扩展std :: tr1 :: hash自定义类型？ [英] How to extend std::tr1::hash for custom types?

问题描述

如何允许STL实现提取我的自定义类型？在MSVC上，有一个类 std :: tr1 :: hash ，我可以使用

How do I allow the STL implementation to pick up my custom types? On MSVC, there is a class std::tr1::hash, which I can partially specialize by using

namespace std 
{
    namespace tr1 
    { 
        template <> 
        struct hash<MyType> 
        { ... };
    } 
}

但这是推荐的方法吗？此外，这是否与GCC的实现一起使用？对于 boost :: hash ，足以提供一个自由函数 size_t hash_value（const MyType&）类似的TR1实现？

but is this the recommended way? Moreover, does this work with GCC's implementation as well? For boost::hash, it's enough to provide a free function size_t hash_value (const MyType&), is there something similar for the TR1 implementation?

推荐答案

是的，这也将适用于GCC。我在一个更大的项目中使用它，它的工作没有问题。你也可以为TR1容器提供你自己的自定义哈希类，但是它指定std :: tr1 :: hash<>是默认的哈希类。专门用于自定义类型似乎是扩展标准哈希函数的自然方式。

Yes, this will also work for GCC. I'm using it in a bigger project and it works without problems. You could also provide your own custom hashing class for the TR1 containers, but it is specified that std::tr1::hash<> is the default hashing class. Specializing it for custom types seems like the natural way to extend the standard hashing functionality.

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