c++ 中的线程取消点

Question

Is there a concept of thread cancellation points in c++ just like in POSIX. I personally felt it's very handful feature especially when terminating threads that got blocked when a blocking function is called(eg. socket recvfrom function).

Answer 1

No, there is no direct equivalent.

The closest thing is std::jthread 's std::stop_token since C++20 which is a voluntary mechanism with which you can define points in the thread function at which the thread can be requested to terminate. You can wrap standard library or platform-specific functions in that, but it won't help you to cancel a thread that is stuck in a blocking library/system call.

There is no standard mechanism to cancel a blocking thread or cancel a thread involuntary. But you can access .native_handle() of a std::thread or std::jthread to get a handle to the underlying platform-specific thread implementation and then use platform-specific features from that (although you probably need to check that they don't interfere with the std::thread / std::jthread implementation; all of this will be implementation-defined).