我正在使用C++ Rest SDK ("Casablanca")从Websocket服务器接收提要。当前，我使用websocket_callback_client class到同时运行的三个不同服务器具有三个不同的连接。
程序运行了不确定的时间，然后突然收到SIGTRAP, Trace/ Breakpoint trap。这是GDB的输出：
#0 0x00007ffff5abec37 in __GI_raise (sig=5) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x000000000047bb8e in pplx::details::_ExceptionHolder::~_ExceptionHolder() ()
#2 0x000000000044be29 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() ()
#3 0x000000000047fa39 in pplx::details::_Task_impl<unsigned char>::~_Task_impl() ()
#4 0x000000000044be29 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() ()
#5 0x00007ffff6feb09f in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x7fffc8021420, __in_chrg=<optimized out>) at /usr/include/c++/4.8/bits/shared_ptr_base.h:546
#6 0x00007ffff6fffa38 in std::__shared_ptr<pplx::details::_Task_impl<unsigned char>, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x7fffc8021418, __in_chrg=<optimized out>) at /usr/include/c++/4.8/bits/shared_ptr_base.h:781
#7 0x00007ffff6fffa52 in std::shared_ptr<pplx::details::_Task_impl<unsigned char> >::~shared_ptr (this=0x7fffc8021418, __in_chrg=<optimized out>) at /usr/include/c++/4.8/bits/shared_ptr.h:93
#8 0x00007ffff710f766 in pplx::details::_PPLTaskHandle<unsigned char, pplx::task<unsigned char>::_InitialTaskHandle<void, void web::websockets::client::details::wspp_callback_client::shutdown_wspp_impl<websocketpp::config::asio_tls_client>(std::weak_ptr<void> const&, bool)::{lambda()#1}, pplx::details::_TypeSelectorNoAsync>, pplx::details::_TaskProcHandle>::~_PPLTaskHandle() (this=0x7fffc8021410, __in_chrg=<optimized out>)
at /home/cpprestsdk/Release/include/pplx/pplxtasks.h:1631
#9 0x00007ffff716e6f2 in pplx::task<unsigned char>::_InitialTaskHandle<void, void web::websockets::client::details::wspp_callback_client::shutdown_wspp_impl<websocketpp::config::asio_tls_client>(std::weak_ptr<void> const&, bool)::{lambda()#1}, pplx::details::_TypeSelectorNoAsync>::~_InitialTaskHandle() (this=0x7fffc8021410, __in_chrg=<optimized out>) at /home/cpprestsdk/Release/include/pplx/pplxtasks.h:3710
#10 0x00007ffff716e722 in pplx::task<unsigned char>::_InitialTaskHandle<void, void web::websockets::client::details::wspp_callback_client::shutdown_wspp_impl<websocketpp::config::asio_tls_client>(std::weak_ptr<void> const&, bool)::{lambda()#1}, pplx::details::_TypeSelectorNoAsync>::~_InitialTaskHandle() (this=0x7fffc8021410, __in_chrg=<optimized out>) at /home/cpprestsdk/Release/include/pplx/pplxtasks.h:3710
#11 0x00007ffff71f9cdd in boost::_bi::list1<boost::_bi::value<void*> >::operator()<void (*)(void*), boost::_bi::list0> (this=0x7fffdc7d7d28, f=@0x7fffdc7d7d20: 0x479180 <pplx::details::_TaskProcHandle::_RunChoreBridge(void*)>, a=...)
at /usr/local/include/boost/bind/bind.hpp:259
#12 0x00007ffff71f9c8f in boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > >::operator() (this=0x7fffdc7d7d20) at /usr/local/include/boost/bind/bind.hpp:1222
#13 0x00007ffff71f9c54 in boost::asio::asio_handler_invoke<boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > > > (function=...) at /usr/local/include/boost/asio/handler_invoke_hook.hpp:69
#14 0x00007ffff71f9bea in boost_asio_handler_invoke_helpers::invoke<boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > >, boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > > > (function=..., context=...) at /usr/local/include/boost/asio/detail/handler_invoke_helpers.hpp:37
#15 0x00007ffff71f9b2e in boost::asio::detail::completion_handler<boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > > >::do_complete (owner=0x7488d0, base=0x7fffc801ecd0)
at /usr/local/include/boost/asio/detail/completion_handler.hpp:68
#16 0x00000000004c34c1 in boost::asio::detail::task_io_service::run(boost::system::error_code&) ()
#17 0x00007ffff709fb27 in boost::asio::io_service::run (this=0x7ffff759ab78 <crossplat::threadpool::shared_instance()::s_shared+24>) at /usr/local/include/boost/asio/impl/io_service.ipp:59
#18 0x00007ffff7185a81 in crossplat::threadpool::thread_start (arg=0x7ffff759ab60 <crossplat::threadpool::shared_instance()::s_shared>) at /home/cpprestsdk/Release/include/pplx/threadpool.h:133
#19 0x00007ffff566e184 in start_thread (arg=0x7fffdc7d8700) at pthread_create.c:312
#20 0x00007ffff5b8237d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
在第18行，给出了资源/pplx/threadpool.h:133。
这是围绕这些行的源代码：
123 static void* thread_start(void *arg)
124 {
125 #if (defined(ANDROID) || defined(__ANDROID__))
126 // Calling get_jvm_env() here forces the thread to be attached.
127 get_jvm_env();
128 pthread_cleanup_push(detach_from_java, nullptr);
129 #endif
130 threadpool* _this = reinterpret_cast<threadpool*>(arg);
131 try
132 {
133 _this->m_service.run();
134 }
135 catch (const _cancel_thread&)
136 {
137 // thread was cancelled
138 }
139 catch (...)
140 {
141 // Something bad happened
142 #if (defined(ANDROID) || defined(__ANDROID__))
143 // Reach into the depths of the 'droid!
144 // NOTE: Uses internals of the bionic library
145 // Written against android ndk r9d, 7/26/2014
146 __pthread_cleanup_pop(&__cleanup, true);
147 throw;
148 #endif
149 }
150 #if (defined(ANDROID) || defined(__ANDROID__))
151 pthread_cleanup_pop(true);
152 #endif
153 return arg;
154 }
为了澄清起见，
m_service是boost::asio::io_service。在我看来，＃133行引发异常，它在＃139行被捕获，然后重新抛出。在这一点上，我必须亲自处理它，因为如果我不这样做，并且
pplx-对象因未捕获的异常而被破坏，它将引发SIGTRAP。这就是我的研究成果。问题是我不知道这是哪里发生的。我已经用
websocket_callback_client包围了从try {} catch(...){}发送数据或从接收数据的每个位置，并且仍在发生。也许以前使用过该库的人可以帮助我。
最佳答案
以我的经验，这是由于一个单独的问题而发生的。
当websocket_callback_client的关闭处理程序被调用时，大多数人会尝试删除websocket_callback_client。这在内部调用close函数。
发生这种情况时，websocket_callback_client将等待关闭完成。如果另一个线程意识到连接已死，并尝试清理，您将在2个不同的位置删除同一对象，这将导致严重问题。
Howto reconnect to a server which does not answer to close()对cpprestsdk调用关闭时发生的情况进行了相当全面的审查。
希望这可以帮助 ：）
编辑：
事实证明（我在链接的问题中给出的响应具有此含义），如果您尝试从关闭处理程序中关闭或删除websocket_callback_client，它将自己调用关闭处理程序，该操作将锁定线程。
我发现最适合我的解决方案是在关闭处理程序中设置一个标志，并在主线程或至少一个备用线程中处理清除。
关于c++ - C++ Rest SDK卡萨布兰卡Sigtrap，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/38552098/