std::thread::joinable
bool joinable() const noexcept; |
(since C++11) | |
Checks if the thread object identifies an active thread of execution. Specifically, returns true if get_id() != std::thread::id(). So a default constructed thread is not joinable.
A thread that has finished executing code, but has not yet been joined is still considered an active thread of execution and is therefore joinable.
Parameters
(none)
Return value
true if the thread object identifies an active thread of execution, false otherwise
Example
Run this code
#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'; }
Output:
before starting, joinable: false after starting, joinable: true after joining, joinable: false
See also
returns the id of the thread (public member function) | |
waits for a thread to finish its execution (public member function) | |
permits the thread to execute independently from the thread handle (public member function) |
References
- C++11 standard (ISO/IEC 14882:2011):
- 30.3.1.5 thread members [thread.thread.member]