使用gtkmm3的套接字服务器

Question

我正在尝试制作一个GUI，当用户按下按钮时，它将连接到网络。我在尝试编译gui_ex.cpp文件时遇到编译错误。

gui_ex.cpp: In member function ‘void Gui_Ex::on_connect()’:
gui_ex.cpp:110:19: error: no matching function for call to ‘Gui_Ex::close(int&)’
         close(sock);
                   ^
gui_ex.cpp:110:19: note: candidate is:
In file included from /usr/include/gtkmm-3.0/gtkmm/dialog.h:30:0,
                 from /usr/include/gtkmm-3.0/gtkmm/aboutdialog.h:33,
                 from /usr/include/gtkmm-3.0/gtkmm.h:99,
                 from gui_ex.h:4,
                 from gui_ex.cpp:1:
/usr/include/gtkmm-3.0/gtkmm/window.h:2026:8: note: void Gtk::Window::close()
   void close();
        ^
/usr/include/gtkmm-3.0/gtkmm/window.h:2026:8: note:   candidate expects 0 arguments, 1 provided
gui_ex.cpp:117:19: error: no matching function for call to ‘Gui_Ex::close(int&)’
         close(sock);
                   ^
gui_ex.cpp:117:19: note: candidate is:
In file included from /usr/include/gtkmm-3.0/gtkmm/dialog.h:30:0,
                 from /usr/include/gtkmm-3.0/gtkmm/aboutdialog.h:33,
                 from /usr/include/gtkmm-3.0/gtkmm.h:99,
                 from gui_ex.h:4,
                 from gui_ex.cpp:1:
/usr/include/gtkmm-3.0/gtkmm/window.h:2026:8: note: void Gtk::Window::close()
   void close();
        ^
/usr/include/gtkmm-3.0/gtkmm/window.h:2026:8: note:   candidate expects 0 arguments, 1 provided

看起来程序把套接字的close命令和Gtk::Window的close命令搞混了。有没有可能调整代码，以便编译器能够区分这两个？

下面是我的代码: gui_ex.h文件

#ifndef GTKMM_EX_GUI_H
#define GTKMM_EX_GUI_H

#include <gtkmm.h>

class Gui_Ex : public Gtk::Window
{
public:
    Gui_Ex();
    virtual ~Gui_Ex();

protected:
    // Signal handlers:
    // new button
    void on_connect();
  void on_spin();

  //void on_spinbutton_digits_changed();

    //child widgets
  //Gtk::Frame m_Frame_Init, m_Frame_Control;
  Glib::RefPtr<Gtk::Adjustment> m_adjustment;
  Gtk::Label m_label;
  Gtk::Grid m_grid;

  Gtk::SpinButton m_spin;
    Gtk::Button m_button2, m_button3; //m_connect;



};

#endif // GTKMM_EX_GUI_H

gui_ex.cpp

#include "gui_ex.h"
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <cstring>
#include <string.h> // memset
#include <pthread.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>
#include <netdb.h>
#include <vector>
#include <string>
using namespace std;

#define PORT "8888"
//#define BACKLOG 2
#define IP_ADDR "192.168.137.99"
#define MAXLEN 1024

int BACKLOG =0;
static unsigned int cli_count = 0;
static int uid = 20;
vector<int> cliarray;

Gui_Ex::Gui_Ex()
:
  // m_button1("Button 1"),
   m_adjustment( Gtk::Adjustment::create(1.0, 1.0, 5.0, 1.0, 5.0, 0.0) ),
   m_button2("Enter"),
   m_button3("Connect"),
   m_spin(m_adjustment),
   m_label("Choose # clients")


{
    set_title("Grid");
  set_border_width(12);


  m_grid.attach(m_label, 0,0,1,1); //column, row, width (# col span), height (# row span)
  m_grid.attach(m_spin, 1,0,1,1);
  m_spin.set_wrap();
  m_spin.set_numeric(true);

  m_grid.attach(m_button2, 2,0,1,1);

  m_grid.attach(m_button3, 0,1,3,1);
  m_button3.set_sensitive(false);

  m_button2.signal_clicked().connect(sigc::mem_fun(*this, &Gui_Ex::on_spin));
  m_button3.signal_clicked().connect(sigc::mem_fun(*this, &Gui_Ex::on_connect));
  //m_button3.signal_clicked().connect(sigc::bind<int>(sigc::mem_fun(*this, &Gui_Ex::on_connect), m_spin.get_value_as_int()));  

  add(m_grid);
  m_grid.show_all();
  //show_all_children();

}

Gui_Ex::~Gui_Ex()
{
}


void Gui_Ex::on_spin()
{
  cout<<"Spin value =: " << m_spin.get_value_as_int() << endl;
  BACKLOG = m_spin.get_value_as_int();
  m_spin.set_sensitive(false);
  m_button2.set_sensitive(false);
  m_button3.set_sensitive(true);

}

void Gui_Ex::on_connect()
{
    int connfd =0, n = 0;
    int *new_sock, sock;

    cout << BACKLOG << endl;
    pthread_t thread;
    struct addrinfo hints, *res;
    int reuseaddr = 1; // True 

    // Get the address info 
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    if (getaddrinfo(IP_ADDR, PORT, &hints, &res) != 0) {
        perror("getaddrinfo");
        //return 1;
    }

    // Create the socket 
    sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    if (sock == -1) {
        perror("socket");
       // return 1;
    }

    // Enable the socket to reuse the address 
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(int)) == -1) {
        perror("setsockopt");
        close(sock);
       // return 1;
    }

    // Bind to the address 
    if (bind(sock, res->ai_addr, res->ai_addrlen) == -1) {
        perror("bind");
        close(sock);
        //return 0;
    }

    freeaddrinfo(res);

    // Listen 
    if (listen(sock, BACKLOG) == -1) {
        perror("listen");
       // return 0;
    }
    cout << "listening for connections" << endl;
    // Main loop 
    bool running = true;
    // Initialize clients 
    while (running)
    {  
      size_t size = sizeof(struct sockaddr_in);
      struct sockaddr_in their_addr;
      int clilen = sizeof(their_addr);
      int newsock = accept(sock, (struct sockaddr*)&their_addr, &size);
      if (newsock == -1) 
      {
        perror("accept");
       // return -1;
      }
      cli_count++;
      printf("Got a connection from %s on port %d\n", inet_ntoa(their_addr.sin_addr), htons(their_addr.sin_port));
      cliarray.push_back(newsock);
      if (cli_count == BACKLOG)
      {
         cout << "Max clients reached" << endl;
        running = false;
        break;
      }
    }
}

Answer 1

您只需要在这里显式地调用全局名称空间。也就是说，当尝试调用libc中的close函数而不是基类的close方法时，应该预先考虑全局名称空间指示符：

::close(sock);

基本上，对象命名空间中的close方法隐藏了同名的全局符号。有关更完整的解释，请参阅第一个答案：Global scope vs global namespace