[C++知识库]C++打印堆栈

今日发现http_msg_server异常，遂查看日志，发现了这么一坨东西：

2021-08-24 20:13:20.102 [ERROR] [0x7f7fe5a80820] [IM] - <HttpConn.cpp>|<178>|<Close>,erase handle:99 ,./http_msg_server(_Z13GetTraceStackv+0x2f) [0x4f766f]
./http_msg_server(_ZN9CHttpConn5CloseEv+0x36) [0x4da342]
./http_msg_server(_ZN9CHttpConn15OnWriteCompleteEv+0x18) [0x4dab76]
./http_msg_server(_ZN9CHttpConn4SendEPvi+0xc6) [0x4da306]
./http_msg_server(_ZN9CHttpConn12SendAndCloseEiPKc+0xad) [0x4e099d]
./http_msg_server(_ZN9CHttpConn24onHandleNginxHealthCheckERKSsS1_+0x8d) [0x4dda83]
./http_msg_server(_ZNKSt7_Mem_fnIM9CHttpConnFvRKSsS2_EEclIIS2_S2_EvEEvPS0_DpOT_+0x91) [0x4e9c97]
./http_msg_server(_ZNSt5_BindIFSt7_Mem_fnIM9CHttpConnFvRKSsS3_EEPS1_St12_PlaceholderILi1EES8_ILi2EEEE6__callIvJS3_S3_EJLm0ELm1ELm2EEEET_OSt5tupleIJDpT0_EESt12_Index_tupleIJXspT1_EEE+0xa0) [0x4e8c1c]
./http_msg_server(_ZNSt5_BindIFSt7_Mem_fnIM9CHttpConnFvRKSsS3_EEPS1_St12_PlaceholderILi1EES8_ILi2EEEEclIJS3_S3_EvEET0_DpOT_+0x5e) [0x4e6f0a]
./http_msg_server(_ZNSt17_Function_handlerIFvRKSsS1_ESt5_BindIFSt7_Mem_fnIM9CHttpConnFvS1_S1_EEPS5_St12_PlaceholderILi1EESA_ILi2EEEEE9_M_invokeERKSt9_Any_dataS1_S1_+0x4f) [0x4e5455]
./http_msg_server(_ZNKSt8functionIFvRKSsS1_EEclES1_S1_+0x61) [0x4e2749]
./http_msg_server(_ZN9CHttpConn6OnReadEv+0x38c) [0x4da8e2]

给我整懵了，这是崩溃了？

还是咋回事？

于是看了下代码：

void CHttpConn::Close() {
    if (m_state != CONN_STATE_CLOSED) {
        m_state = CONN_STATE_CLOSED;

        loge("erase handle:%d ,%s", m_conn_handle, GetTraceStack().c_str());

        g_http_conn_map.erase(m_conn_handle);
        netlib_close(m_sock_handle);
        handle_map_.clear();

        ReleaseRef();
    }
}

这个GetTraceStack() 看起来是打印堆栈的意思

std::string GetTraceStack()
{
   static const int MAX_STACK_FRAMES = 12;
   void *pStack[MAX_STACK_FRAMES];

   char ** pStackList = NULL;
   int frames = backtrace(pStack, MAX_STACK_FRAMES);
   pStackList = backtrace_symbols(pStack, frames);
   if (NULL == pStackList)
      return "" ;

   std::string szStackInfo;
   for (int i = 0; i < frames; ++i)
   {
      if (NULL == pStackList[i])
         break;

      szStackInfo += pStackList[i];
      szStackInfo += "\n";
   }

   return szStackInfo;    
}

原理是正常的，然后通过对堆栈一分析，应该是健康检查导致http链接关闭，所以频繁的会打印这个错误。