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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++23 standard (ISO/IEC 14882:2023):

33.4.4.3 Members [thread.jthread.mem]

C++20 standard (ISO/IEC 14882:2020):

32.4.3.2 Members [thread.jthread.mem]

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