迭代器不会遍历整个地图

Question

我有以下功能:

   void send_sequence_to_device( std::map<const string_t,device_t*> &msg2device_p, std::vector<response_t>& result_list, ushort num_attempts)
    {
        cout<<"sarit enter to send_seq_device"<<endl;
        std::map<const string_t, device_t*>::iterator msg_itf;
        for( msg_itf=msg2device_p.begin(); msg_itf!=msg2device_p.end(); msg_itf++ )
        {
            cout<<"sarit enter to seq "<<msg_itf->first<<endl;
        }
    }

我通过另一个函数调用此函数:

 void node_layer_manager_t::calc_ts_job_function()
    {
        vector<response_t> res;
        map<const string_t, device_t*> getRegMsg={{"get_node_ts_est",&tx},{"get_node_ts_est",&rx},{"get_tx_num_clk_ts",&tx}};
        cout<< "sarit ts clk function nlm first"<<endl;
        send_sequence_to_device(getRegMsg,res);
    }

我可以看到循环只迭代2而不是3.输出是:

sarit enter to seq get_node_ts_est

sarit enter to get_tx_num_clk_ts

虽然我期望:

sarit enter to seq get_node_ts_est

sarit enter to seq get_node_ts_est

sarit enter to get_tx_num_clk_ts

Answer 1

A std::map不允许重复键.

您的两个值具有相同的键,因此其中只有一个将进入地图.

如果您需要重复键,请使用std::multimap而不是std::map.