我目前正在编写一个使用 boost 线程的 DLL。我在使用 boost::thread::interrupt() 和捕获 thread_interrupted 异常时遇到了问题。对于一些中断点，中断被抛出并在线程中被捕获，而对于其他点，中断被抛出到调用 thread.interrupt() 的地方。为什么会这样？我已经写了一个基本的例子来说明我的观点，它在这篇文章的底部
程序启动一个线程，该线程使用其中一个辅助函数，每个辅助函数中都有不同的中断点。当用户按下回车键时，线程被中断并且程序关闭。在打印每个语句之前，线程 ID 被打印出来，以便我们可以看到发生了什么。
我期待这样的事情:
13c4 main thread
790 worker thread
790 thread iteration 1 Press Enter to stop
790 thread iteration 2 Press Enter to stop
790 thread iteration 3 Press Enter to stop
790 Thread is stopped in ThreadFunction
13c4 main: thread ended
Process returned 0 (0x0) execution time : 0.200 s
Press any key to continue.
主线程运行的地方，与工作线程并行。当用户按下回车键时，中断在主线程中被调用，但在工作线程中被捕获。然后线程被销毁。然后主线程继续，程序退出。
在我尝试过的所有中断点(interruptation_point() 除外)中，我看到的是中断在主线程中被捕获，似乎是工作线程继续执行主线程.像这样:
1364 main thread
964 worker thread
964 thread iteration 1 Press Enter to stop
964 thread iteration 2 Press Enter to stop
964 thread iteration 3 Press Enter to stop
964 Thread is joined
964 main: thread ended
Process returned 0 (0x0) execution time : 1.510 s
Press any key to continue.
这是什么原因造成的？例如，当使用条件变量时，如何在工作函数中捕获中断？我是不是哪里弄错了？
我的代码:
#define BOOST_THREAD_USE_LIB 1
#define BOOST_SYSTEM_NO_DEPRECATED 1
#define _WIN32_WINNT 0x0501
#define WINVER 0x0501
#include <boost/thread.hpp>
#include <iostream>
using namespace std;
void ThreadFunctionSleep()
{
cout << boost::this_thread::get_id() << " worker thread " << endl;
int counter = 0;
while(1)
{
cout << boost::this_thread::get_id() << " thread iteration " << ++counter << " Press Enter to stop" << endl;
try
{
boost::this_thread::sleep(boost::posix_time::milliseconds(5000));
}
catch(boost::thread_interrupted&)
{
cout << boost::this_thread::get_id() << " Thread is stopped in ThreadFunction " << endl;
return;
}
}
}
void ThreadFunctionSleep2()
{
cout << boost::this_thread::get_id() << " worker thread " << endl;
int counter = 0;
try
{
cout << boost::this_thread::get_id() << " thread iteration " << ++counter << " Press Enter to stop" << endl;
while(1)
{
boost::this_thread::sleep(boost::posix_time::milliseconds(5000));
}
}
catch(boost::thread_interrupted&)
{
cout << boost::this_thread::get_id() << " Thread is stopped in ThreadFunction " << endl;
return;
}
}
void ThreadFunctionInterruptionPoint()
{
cout << boost::this_thread::get_id() << " worker thread " << endl;
int counter = 0;
while(1)
{
cout << boost::this_thread::get_id() << " thread iteration " << ++counter << " Press Enter to stop" << endl;
try
{
boost::this_thread::interruption_point();
}
catch(boost::thread_interrupted&)
{
cout << boost::this_thread::get_id() << " Thread is stopped in ThreadFunction " << endl;
return;
}
}
}
bool myPredicate()
{
return false;
}
boost::condition_variable full;
boost::condition_variable empty;
boost::mutex fullMut;
boost::mutex emptyMut;
void waitedConditionVariable()
{
try
{
while(1)
{
boost::system_time const timeout=boost::get_system_time()+ boost::posix_time::milliseconds(1000);
boost::unique_lock<boost::mutex> lock(fullMut);
std::cout << boost::this_thread::get_id()<< " waiting for condition variable or for timeout" << std::endl;
if (full.timed_wait(lock, timeout, myPredicate))
{
std::cout << boost::this_thread::get_id()<< " condition variable signalled " << std::endl;
}
else
{
std::cout << boost::this_thread::get_id()<< " condition variable timeout. " << std::endl;
}
}
}
catch(boost::thread_interrupted & )
{
std::cout<< boost::this_thread::get_id() << " waitedConditionVariable thread_interrupted " << std::endl;
return;
}
catch (std::exception& e)
{
std::cerr << boost::this_thread::get_id()<< " waitedConditionVariable Thread "
<< " caught std::exception" << e.what() << std::endl;
return;
}
catch(...)
{
std::cout<< boost::this_thread::get_id() << " waitedConditionVariable other" << std::endl;
return;
}
}
void waitedConditionVariable2()
{
while(1)
{
try
{
boost::system_time const timeout=boost::get_system_time()+ boost::posix_time::milliseconds(1000);
boost::unique_lock<boost::mutex> lock(fullMut);
std::cout << boost::this_thread::get_id()<< " waiting for condition variable or for timeout" << std::endl;
if (full.timed_wait(lock, timeout, myPredicate))
{
std::cout << boost::this_thread::get_id()<< " condition variable signalled " << std::endl;
}
else
{
std::cout << boost::this_thread::get_id()<< " condition variable timeout. " << std::endl;
}
}
catch(boost::thread_interrupted & )
{
std::cout<< boost::this_thread::get_id() << " waitedConditionVariable thread_interrupted " << std::endl;
return;
}
catch (std::exception& e)
{
std::cerr << boost::this_thread::get_id()<< " waitedConditionVariable Thread "
<< " caught std::exception" << e.what() << std::endl;
return;
}
catch(...)
{
std::cout<< boost::this_thread::get_id() << " waitedConditionVariable other" << std::endl;
return;
}
}
}
void normalConditionVariable()
{
try
{
boost::unique_lock<boost::mutex> lock(fullMut);
while(1)
{
std::cout << boost::this_thread::get_id()<< " waiting for condition variable " << std::endl;
full.wait(lock);
std::cout << boost::this_thread::get_id()<< " wait done " << std::endl;
}
}
catch(boost::thread_interrupted & )
{
std::cout<< boost::this_thread::get_id() << " normalConditionVariable thread_interrupted " << std::endl;
return;
}
catch (std::exception& e)
{
std::cerr << boost::this_thread::get_id()<< " normalConditionVariable Thread "
<< " caught std::exception" << e.what() << std::endl;
return;
}
catch(...)
{
std::cout<< boost::this_thread::get_id() << " normalConditionVariable other" << std::endl;
return;
}
}
void normalConditionVariable2()
{
while(1)
{
boost::unique_lock<boost::mutex> lock(fullMut);
try
{
std::cout << boost::this_thread::get_id()<< " waiting for condition variable " << std::endl;
full.wait(lock);
std::cout << boost::this_thread::get_id()<< " wait done " << std::endl;
}
catch(boost::thread_interrupted & )
{
std::cout<< boost::this_thread::get_id() << " normalConditionVariable thread_interrupted " << std::endl;
return;
}
catch (std::exception& e)
{
std::cerr << boost::this_thread::get_id()<< " normalConditionVariable Thread "
<< " caught std::exception" << e.what() << std::endl;
return;
}
catch(...)
{
std::cout<< boost::this_thread::get_id() << " normalConditionVariable other" << std::endl;
return;
}
}
}
int main()
{
cout << boost::this_thread::get_id() << " main thread " << endl;
// Start thread
//use thes functions:
// ThreadFunctionSleep
// ThreadFunctionSleep2
//ThreadFunctionInterruptionPoint
//ThreadFunctionInterruptionPoint2
// waitedConditionVariable
// waitedConditionVariable2
// normalConditionVariable
// normalConditionVariable2
boost::thread t(&waitedConditionVariable2);
// Wait for Enter
char ch;
cin.get(ch);
// Ask thread to stop
try
{
t.interrupt();
}
catch(boost::thread_interrupted&)
{
cout << boost::this_thread::get_id() << " Thread is stopped" << endl;
}
// Join - wait when thread actually exits
try
{
t.join();
}
catch(boost::thread_interrupted&)
{
cout << boost::this_thread::get_id() << " Thread is joined" << endl;
}
catch(...){
cout << boost::this_thread::get_id() << " other exception" << endl;
}
cout << boost::this_thread::get_id() << " main: thread ended" << endl;
return 0;
}
我使用的是 boost 1.53.0 和 MinGW 4.4.1。我正在为 boost::thread 和 boost::system 使用 runtime-link-static 多线程库
谢谢你的帮助
最佳答案
应该重新抛出异常，否则 boost::thread 不会真正中断。
试试下面的代码。您可以尝试不同的 join() 位置来查看显示线程状态的不同输出。
#include <iostream>
#include <boost/thread.hpp>
void foo()
{
while(true) try
{
boost::this_thread::sleep_for(boost::chrono::milliseconds(1000));
std::cout << "Thread is running..." << std::endl;
}
catch (boost::thread_interrupted&)
{
std::cout << "The thread is interrupted" << std::endl;
throw boost::thread_interrupted();
}
}
int main(int argc, char *argv[])
{
boost::thread t(foo);
std::cout << "Press Enter to quit..." << std::endl;
std::cin.get();
t.interrupt();
//t.join();
if (!t.try_join_for(boost::chrono::milliseconds(1)))
{
std::cout << "Thread is running." << std::endl;
}
else
{
std::cout << "Thread is not running." << std::endl;
}
//t.join();
boost::this_thread::sleep_for(boost::chrono::milliseconds(1000));
// The out put should be "Thread is running.", because thread is not joinalb, the test function itself is wrong.
if (!t.try_join_for(boost::chrono::milliseconds(1)))
{
std::cout << "Thread is running." << std::endl;
}
else
{
std::cout << "Thread is not running." << std::endl;
}
}
关于c++ - Boost::thread::interrupt() 对于不同的中断点表现不同。为什么？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19221523/