qt winsocket网络编程-udp

深藏阁楼爱情的钟 2022-12-19 09:13 190阅读 0赞

网络编程不仅可以用于网络间通信还可以用于进程间通信，一般是server和client的模式

*相较于百兆的VC++ 6.0（优势是编译出来的程序很小，由于系统原生支持，也不需要太多的lib，但编辑界面不太友好），Qt Creator的编辑器比较好用，而且整个Qt安装只需要要小几个GB空间，较VS小很多，还有跨平台优势（导致编译后的程序需要打包后才可以在其它机器上使用）。*

environment:

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70][]

![20201114115141628.png][]

udp client send example:

#include <QCoreApplication>
    //
    #include "math.h"
    #include <winsock2.h>
    #include <ws2tcpip.h>
    #include <stdio.h>
    #include <windows.h>
    //#pragma comment(lib,"WS2_32.lib")
    
    /*
    关于WSAStartup方法和WSACleanup方法引用出错的解决:
        错误：
        编译的时候出现
        undefined reference to `__imp_WSAStartup'
        undefined reference to `__imp_WSACleanup'
        在一般编译器中不会直接连接编译wsock动态库，需要手动添加库
        首先可以尝试代码中直接引入动态库，#pragam comment(lib,"ws2_32");
        如果不行再手动添加库
        在vc中，点项目(project-->project option)在makefile中输入-L"ws2_32"
        在dvc C++中点击工具(Tool)-->编译选项（Compile Option)在编译命令框中输入-lwsokt32
        Qt中：pro文件最后添加
        LIBS += -lWs2_32
    */
    
    
    SOCKET s;
    sockaddr_in serAddr;
    #define SERVER_PORT_NUM   5002
    char ip_addr[16];
    #define  MAXSLEN 128
    char chars[MAXSLEN]="\0";
    char space_s[] = " ";
    
    int udp_send(char* str_t,unsigned int len)
    {
    
        //初始化WS2_32.dll
        WSADATA wsaData;
        WORD sockVersion = MAKEWORD(2, 0);
        ::WSAStartup(sockVersion, &wsaData);
        s=0;
        //---
        //创建套字节
        //SOCKET s = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);//TCP
        //SOCKET
        s = ::socket(AF_INET, SOCK_DGRAM, 0);//UDP
        if (s == INVALID_SOCKET)
        {
            printf("Failed socket()\n");
            ::WSACleanup();
            return 0;//a.exec();
        }
        //也可以在这里调用bind()函数绑定一个地址，否则系统将会自动安排填写远程地址信息
        serAddr.sin_family = AF_INET;
        serAddr.sin_port = htons(SERVER_PORT_NUM);
        //注意：这里要填写服务器程序所在机器的IP地址
        //如果计算机没有联网，直接使用127.0.0.1即可
        serAddr.sin_addr.S_un.S_addr = inet_addr(ip_addr);
        //if (::connect(s, (sockaddr*)&serAddr, sizeof(serAddr)) == -1)
        //{
        //	printf("Failed connect()\n");
        //	::WSACleanup();
        //	return;
        //}
        //
    
        //printf("hello\r\n");
        //scanf("%[^\n]",chars);
        //fflush(stdin);
        sendto(s, str_t,len,0, (sockaddr*)&serAddr,sizeof(sockaddr_in));
        printf("end\r\n");
        //--
        ::closesocket(s);    //关闭套字节
    
    }
    //
    int main(int argc, char *argv[])
    {
        //QCoreApplication a(argc, argv);
        //-----------------------------------
        FILE* fp = fopen("EX.cfg", "r");//只读方式打开，不存在则为NULL
        if (fp != NULL)
        {
            char DataLineT[128];
            memset(DataLineT,0,128);
            if (fgets(DataLineT, 128, fp))
            {
                unsigned int l = strlen(DataLineT);
                strncpy(ip_addr, DataLineT, l - 1);
            }
            //
            fclose(fp);
        }
        else
        {
            strcpy(ip_addr, "127.0.0.1");
    
    
        }
        printf("target ip:%s\n",ip_addr);
    
        //
        if(argc>0)
        {
         if(argc == 1)
         // printf("a1:%s\r\n",argv[0]);
         ;
         else if(argc == 2)
         {
             printf("a2:%s\r\n",argv[1]);
             strcpy(chars,argv[1]);
             printf("chars:%s\r\n",chars);
             udp_send(chars,32);
             return 0;
         }
         else if(argc == 3)
         {
             printf("a2:%s\r\n",argv[1]);
             printf("a3:%s\r\n",argv[2]);
             strcpy(chars,argv[1]);
             strcat(chars,space_s);
             strcat(chars,argv[2]);
             printf("chars:%s\r\n",chars);
             udp_send(chars,64);
             return 0;
         }
         else if(argc == 4)
         {
             printf("a2:%s\r\n",argv[1]);
             printf("a3:%s\r\n",argv[2]);
             printf("a4:%s\r\n",argv[3]);
             strcpy(chars,argv[1]);
             strcat(chars,space_s);
             strcat(chars,argv[2]);
             strcat(chars,space_s);
             strcat(chars,argv[3]);
             printf("chars:%s\r\n",chars);
             udp_send(chars,96);
             return 0;
          }
        }
        //
        return 0;//a.exec();
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 1][]

udp server receive example:

#include <stdio.h>
    #include <math.h>
    #include <stdlib.h>
    #include <string.h>
    #include <time.h>
    #include <winsock2.h>
    #include <stdio.h>
    #include <windows.h>
    //#pragma comment(lib,"WS2_32.lib")  //告诉连接器与WS2_32库连接
    
    int sFd;
    char g_buf[8192];
    int sockAddrSize;
    struct sockaddr_in clientAddr;
    unsigned char  udpServer(void)
    {
        struct sockaddr_in serverAddr;
    
        struct request clientRequest;
    
        char inetAddr[16];
        //
        //初始化WS2_32.dll
        WSADATA wsaData;
        WORD sockVersion = MAKEWORD(2, 0);
        ::WSAStartup(sockVersion, &wsaData);
    
        //
        sockAddrSize = sizeof(struct sockaddr_in);
        memset((char*)&serverAddr,0,sockAddrSize);
        serverAddr.sin_family = AF_INET;
        serverAddr.sin_port = htons(SERVER_PORT_NUM);
        serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    
        if ((sFd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)) == -1)//
        {
            perror("socket");
            return 0;
        }
        //
        int iMode = 1; //0：阻塞
        ioctlsocket(sFd,FIONBIO, (u_long FAR*) &iMode);//非阻塞设置
    
    //     int flag = fcntl(sFd, F_GETFL, 0);
    //        if (flag < 0) {
    //            perror("fcntl F_GETFL fail");
    //            return 0;
    //        }
    //        if (fcntl(sFd, F_SETFL, flag | O_NONBLOCK) < 0) {
    //            perror("fcntl F_SETFL fail");
    //        }
    
        //
        if (bind(sFd, (struct sockaddr*)&serverAddr, sockAddrSize) == -1)
        {
            perror("socket");
            return (-1);
    
        }
        return 0;
        while (1)
        {
            //成功则返回接收到的字符数,失败返回-1.
            //MSG_DONTWAIT：操作不会被阻塞。
            int t =recvfrom(sFd, (char*)g_buf, 8192, 0, (struct sockaddr*)&clientAddr, &sockAddrSize);
    //        if (t == -1)
    //        {
    //            perror("socket");
    //            return (-1);
    //        }
            /*if(clientRequest.display)*/
            if(t>0)
            {
                /*convert an network address to dot notation, store it in a buffer*/
                printf("%s %d %s", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), g_buf);
                if (strncmp(g_buf, "exit", 4) == 0)
                {
                    break;
                }
                else if (strncmp(g_buf, "start", 5) == 0)
                {
                    if (Samp_Mark == 0)
                    {
                        Samp_Mark = 1;
                        //taskSpawn("udpClient", 200, 0, 1000, (FUNCPTR)udpClient, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
                    }
                }
                else if (strncmp(g_buf, "stop", 4) == 0)
                {
                    Samp_Mark = 0;
                }
    
    
            }
        }
        /* return OK;*/
    
    }
    
    
    int main(int argc, char *argv[])
    {
        //QCoreApplication a(argc, argv);
        printf("hello\r\n");
        #define  MAXSLEN 255
        char chars[MAXSLEN]="\0";
        char space_s[] = " ";
        //support tcl:
    
        if(argc>0)
        {
          if(argc == 1)
          //printf("a1:%s\r\n",argv[0]);
          ;
          else if(argc == 2){
             printf("a2:%s\r\n",argv[1]);
             strcpy(chars,argv[1]);
             printf("chars:%s\r\n",chars);
             MProcess(argv[1],1);
             return 0;
          }
          else if(argc == 3)
          {
             printf("a2:%s\r\n",argv[1]);
             printf("a3:%s\r\n",argv[2]);
             strcpy(chars,argv[1]);
             strcat(chars,space_s);
             strcat(chars,argv[2]);
             printf("chars:%s\r\n",chars);
             MProcess(chars,1);
             return 0;
          }
    
          else if(argc == 4)
          {
             printf("a2:%s\r\n",argv[1]);
             printf("a3:%s\r\n",argv[2]);
             printf("a4:%s\r\n",argv[3]);
             strcpy(chars,argv[1]);
             strcat(chars,space_s);
             strcat(chars,argv[2]);
             strcat(chars,space_s);
             strcat(chars,argv[3]);
             printf("chars:%s\r\n",chars);
             MProcess(chars,1);
             return 0;
          }
          else if(argc == 5)//server model
          {
             udpServer();
             while(1)
             {
    
               //printf("easy_xdc:");
               //scanf("%[^\n]",chars);
               //fflush(stdin);
               int t =recvfrom(sFd, (char*)g_buf, 8192, 0, (struct sockaddr*)&clientAddr, &sockAddrSize);
               if(t>0){
                   printf("%s %d %s\r\n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), g_buf);
    
                   //
                   strcpy(chars,g_buf);
                   MProcess(chars,1);
               }
             }
          }
        }
    
    //--------------------------------
    
       while(1)
       {
         printf("easy_xdc:");
         scanf("%[^\n]",chars);
         fflush(stdin);
         MProcess(chars,1);
         memset(chars,0,255);
       }
    
    //----------------------------------
       printf("end\r\n");
       //
       return 0;//a.exec();
    }

需要注意设置recvfrom函数的非阻塞模式的方法：

![20201114114303773.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 2][]

网上也有下面的设置方式，但实际尝试没有效果，供参考吧：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 3][]

Qt打包后会多出一些运行需要的lib:

![20201114114842339.png][]

参考：

[https://www.man7.org/linux/man-pages/man2/socket.2.html][https_www.man7.org_linux_man-pages_man2_socket.2.html]

[https://blog.csdn.net/kai8wei/article/details/77479240][https_blog.csdn.net_kai8wei_article_details_77479240]

[https://www.cnblogs.com/ahuo/archive/2008/01/09/1031638.html][https_www.cnblogs.com_ahuo_archive_2008_01_09_1031638.html]

[http://blog.chinaunix.net/uid-22964557-id-4824283.html][http_blog.chinaunix.net_uid-22964557-id-4824283.html]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70]: /images/20221120/870ef3e3f20c469e8fa098cca8ea736b.png
[20201114115141628.png]: /images/20221120/ca998a849bf846dbad99ed29eaac249a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20201114112039320.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[20201114114303773.png]: https://img-blog.csdnimg.cn/20201114114303773.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20201114114632779.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20201114114450673.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[20201114114842339.png]: https://img-blog.csdnimg.cn/20201114114842339.png
[https_www.man7.org_linux_man-pages_man2_socket.2.html]: https://www.man7.org/linux/man-pages/man2/socket.2.html
[https_blog.csdn.net_kai8wei_article_details_77479240]: https://blog.csdn.net/kai8wei/article/details/77479240
[https_www.cnblogs.com_ahuo_archive_2008_01_09_1031638.html]: https://www.cnblogs.com/ahuo/archive/2008/01/09/1031638.html
[http_blog.chinaunix.net_uid-22964557-id-4824283.html]: http://blog.chinaunix.net/uid-22964557-id-4824283.html