开始简单的几行如下：

boost::mutex::scoped_lock lock(g_start_mutex);
  if (g_started)	//如果节点已经运行，返回
  {
    return;
  }

  g_shutdown_requested = false;
  g_shutting_down = false;
  g_started = true;
  g_ok = true;

  bool enable_debug = false;
  std::string enable_debug_env;
  // 获得环境变量，是否DEBUG
  if ( get_environment_variable(enable_debug_env,"ROSCPP_ENABLE_DEBUG") )
  {
    try
    {
      enable_debug = boost::lexical_cast<bool>(enable_debug_env.c_str());
    }
    catch (boost::bad_lexical_cast&)
    {
    }
  }

下面是重要的一句：XMLRPCManager::instance()->bind("shutdown", shutdownCallback);

bool XMLRPCManager::bind(const std::string& function_name, const XMLRPCFunc& cb)
{
  boost::mutex::scoped_lock lock(functions_mutex_);
  if (functions_.find(function_name) != functions_.end())
  {
    return false;
  }

  FunctionInfo info;
  info.name = function_name;
  info.function = cb;
  info.wrapper.reset(new XMLRPCCallWrapper(function_name, cb, &server_));
  functions_[function_name] = info;

  return true;
}

几个变量的定义：

typedef boost::shared_ptr<XMLRPCCallWrapper> XMLRPCCallWrapperPtr;
struct FunctionInfo
{
	std::string name;
	XMLRPCFunc function;
	XMLRPCCallWrapperPtr wrapper;
};
typedef std::map<std::string, FunctionInfo> M_StringToFuncInfo;
boost::mutex functions_mutex_;
M_StringToFuncInfo functions_;

关键的XMLRPCCallWrapper其实是XML-RPC服务端的子类：

class XMLRPCCallWrapper : public XmlRpcServerMethod
{
public:
  XMLRPCCallWrapper(const std::string& function_name, const XMLRPCFunc& cb, XmlRpcServer *s)
  : XmlRpcServerMethod(function_name, s)
  , name_(function_name)
  , func_(cb)
  { }

  void execute(XmlRpcValue &params, XmlRpcValue &result)
  {
    func_(params, result);
  }

private:
  std::string name_;
  XMLRPCFunc func_;
};