std::thread::joinable
来自cppreference.com
bool joinable() const noexcept; |
(C++11 起) | |
检查 std::thread
对象是否标识活跃的执行线程。具体而言,若 get_id() != std::thread::id() 则返回 true 。故默认构造的 thread 不可结合。
结束执行代码,但仍未结合的线程仍被当作活跃的执行线程,从而可结合。
参数
(无)
返回值
若 thread 对象标识活跃的执行线程则为 true ,否则为 false 。
示例
运行此代码
#include <iostream> #include <thread> #include <chrono> void foo() { std::this_thread::sleep_for(std::chrono::seconds(1)); } int main() { std::thread t; std::cout << "before starting, joinable: " << std::boolalpha << t.joinable() << '\n'; t = std::thread(foo); std::cout << "after starting, joinable: " << t.joinable() << '\n'; t.join(); std::cout << "after joining, joinable: " << t.joinable() << '\n'; }
输出:
before starting, joinable: false after starting, joinable: true after joining, joinable: false
引用
- C++20 standard (ISO/IEC 14882:2020):
- 32.4.2.5 Members [thread.thread.member]
- C++17 standard (ISO/IEC 14882:2017):
- 33.3.2.5 thread members [thread.thread.member]
- C++14 standard (ISO/IEC 14882:2014):
- 30.3.1.5 thread members [thread.thread.member]
- C++11 standard (ISO/IEC 14882:2011):
- 30.3.1.5 thread members [thread.thread.member]
参阅
返回线程的 id (公开成员函数) | |
等待线程完成其执行 (公开成员函数) | |
容许线程从线程句柄独立开来执行 (公开成员函数) |