c++ - 为什么 boost this_thread::interrupt 可以在没有 try-catch 的情况下工作？

Question

我用这段代码进行了测试。两个线程，thread_1 每 200 毫秒打印一个字符串，thread_2 在 3 秒内终止 thread_1。

int main() {
    boost::thread t1([&]() {
        while(1) {
            boost::this_thread::interruption_point();
            cout << "t1 running" << endl;
            Sleep(200);
        }
        cout << "it never goes here" << endl;
    });
    boost::thread t2([&]() {
        Sleep(3000); // wait 3 seconds to terminate thread 1
        cout << "interrupt t1" << endl;
        t1.interrupt(); // thread 1 should raise a thread_interrupted exception ?
    });

    t1.join();
    t2.join();
    Sleep(5000); // sleep 5 seconds waiting for the crash
}

我预计代码会崩溃，但事实并非如此。然后我猜想有来自 boost::thread 的 try-catch，我在所有“thread.hpp”和“thread_data.hpp”中搜索关键字 catch 但一无所获.

它是如何工作的？谢谢。

Answer 1

库实现(源文件，而不是头文件)包含处理错误的代理函数。

正如您在 phtreads 变体中看到的那样，它还执行一些其他内务处理:http://www.boost.org/doc/libs/1_56_0/libs/thread/src/pthread/thread.cpp

    namespace
    {
        extern "C"
        {
            static void* thread_proxy(void* param)
            {
                boost::detail::thread_data_ptr thread_info = static_cast<boost::detail::thread_data_base*>(param)->self;
                thread_info->self.reset();
                detail::set_current_thread_data(thread_info.get());
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS
                BOOST_TRY
                {
#endif
                    thread_info->run();
#if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS

                }
                BOOST_CATCH (thread_interrupted const&)
                {
                }
// Removed as it stops the debugger identifying the cause of the exception
// Unhandled exceptions still cause the application to terminate
//                 BOOST_CATCH(...)
//                 {
//                   throw;
//
//                     std::terminate();
//                 }
                BOOST_CATCH_END
#endif
                detail::tls_destructor(thread_info.get());
                detail::set_current_thread_data(0);
                boost::lock_guard<boost::mutex> lock(thread_info->data_mutex);
                thread_info->done=true;
                thread_info->done_condition.notify_all();

                return 0;
            }
        }
    }