bool joinable() const; | (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.
Exceptions
noexcept
specification: noexcept
Example
#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: " << 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: 0 after starting, joinable: 1 after joining, joinable: 0
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]
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