cpp / latest / thread / jthread / detach.html /

std::jthread::detach

void detach();
(since C++20)

Separates the thread of execution from the jthread object, allowing execution to continue independently. Any allocated resources will be freed once the thread exits.

After calling detach *this no longer owns any thread.

Parameters

(none).

Return value

(none).

Postconditions

joinable is false.

Exceptions

std::system_error if joinable() == false or an error occurs.

Example

#include <iostream>
#include <chrono>
#include <thread>
 
void independentThread() 
{
    std::cout << "Starting concurrent thread.\n";
    std::this_thread::sleep_for(std::chrono::seconds(2));
    std::cout << "Exiting concurrent thread.\n";
}
 
void threadCaller() 
{
    std::cout << "Starting thread caller.\n";
    std::jthread t(independentThread);
    t.detach();
    std::this_thread::sleep_for(std::chrono::seconds(1));
    std::cout << "Exiting thread caller.\n";
}
 
int main() 
{
    threadCaller();
    std::this_thread::sleep_for(std::chrono::seconds(5));
}

Possible output:

Starting thread caller.
Starting concurrent thread.
Exiting thread caller.
Exiting concurrent thread.

References

  • C++20 standard (ISO/IEC 14882:2020):
    • 32.4.3.2 Members [thread.jthread.mem]

See also

waits for the thread to finish its execution
(public member function)
checks whether the thread is joinable, i.e. potentially running in parallel context
(public member function)
C documentation for thrd_detach

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/thread/jthread/detach