Do C++11 threads provide a way for detached threads to continue after the main thread exits?

Question

Normally, when main() exits, all threads are killed. pthread_exit(3) says

To allow other threads to continue execution, the main thread should terminate by calling pthread_exit() rather than exit(3).

Is there an equivalent C++11 API call? Something like std::this_thread::exit(0) ?

Answer 1

Historically, the main() function has been special - it represents the lifetime of the application. C++11 does not change this.

When the main function returns, the program cleans up and terminates. That's hard-coded into the C runtime.

Anything that will prevent main from retuning normally will work (but there is no portable way to terminate a thread).

A workaround in your case might be just to block the main thread forever, or re-use it to do some monitoring/housekeeping.

Answer 2

Page 1121 of the Working Draft, Standard for Programming Language C++ from 2012-01-16 seems to state that once the main thread exits, its detached threads will be cleaned up as well (unless I'm misinterpreting it):

void detach();

Requires: joinable() is true.

Effects: The thread represented by *this continues execution without the calling thread blocking. When detach() returns, *this no longer represents the possibly continuing thread of execution. When the thread previously represented by *this ends execution, the implementation shall release any owned resources.

Postcondition: get_id() == id().

Throws: system_error when an exception is required (30.2.2).

Error conditions:

— no_such_process — if the thread is not valid.

— invalid_argument — if the thread is not joinable.