# std::jthread::hardware_concurrency

< cpp‎ | thread‎ | jthread

[[nodiscard]] static unsigned int hardware_concurrency() noexcept; |  | (C++20 起)

返回实现支持的并发线程数。应该只把该值当做提示。

### 参数

（无）

### 返回值

支持的并发线程数。若该值非良定义或不可计算，则返回 ​0​ 。

### 示例

    #include <iostream>
    #include <thread>

    int main() {
        unsigned int n = std::jthread::hardware_concurrency();
        std::cout << n << " concurrent threads are supported.\n";
    }

可能的输出：

    4 concurrent threads are supported.

### 参阅

hardware_destructive_interference_size hardware_constructive_interference_size (C++17) | 避免假共享的最小偏移 促使真共享的最大偏移 (常量)