# std::hash<std::thread::id>

< cpp‎ | thread‎ | thread‎ | id

定义于头文件 `<thread>` |  |
template<> struct hash<std::thread::id>; |  | (C++11 起)

std::hash 对 std::thread::id 类的模板特化允许用户获得线程标识符的哈希。

### 示例

| 本节未完成 原因：有意义地使用哈希的示例

    #include <iostream>
    #include <thread>
    #include <chrono>
    #include <vector>
    using namespace std::chrono_literals;
    void foo()
    {
        std::this_thread::sleep_for(10ms);
    }

    int main()
    {
        std::vector<std::thread> v;
        for(int n = 0; n < 4; ++n)
            v.emplace_back(foo);

        std::hash<std::thread::id> hasher;
        for(auto& t : v) {
            std::cout << "thread " << t.get_id() << " hashes to " << hasher(t.get_id()) << '\n';
            t.join();
        }
    }

可能的输出：

    thread 139786440144640 hashes to 8905351942358389397
    thread 139786431751936 hashes to 9222844670065909738
    thread 139786423359232 hashes to 18199000599186780501
    thread 139786414966528 hashes to 15386662774029264672

### 参阅

hash (C++11) | 散列函数对象 (类模板)