参考链接

• send函数和recv函数 – gudako's memo

注意事项

• 代码很low，主要看封装的Send函数所体现的切片思想即可

server代码

//udp服务端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>
#include <string>
#include <iostream>#define SLICE_SIZE 5bool Send(int sock_fd, char* buffer, int length)
{int once;            //一次发送的返回值int total = 0;        //目前发送了多少数据int thislen = 0;    //本次要发送的数据长度do{if (length - total > SLICE_SIZE)thislen = SLICE_SIZE;elsethislen = length - total;once = send(sock_fd, buffer + total, thislen, 0);if (once <= 0)                        //如果once < 0则表示发送失败，用break跳出循环，返回FALSE{break;}total += once;} while (total < length);                //如果total < length说明数据还未完全发送，继续循环if (total == length)                    //当total == length时，说明已完全发送，返回TRUEreturn true;return false;
}int main(int argc, char const *argv[])
{//1.创建socketint cfd = socket(AF_INET,SOCK_DGRAM,0);if(cfd<0){perror("socket error");return -1;}//绑定struct sockaddr_in serv;struct sockaddr_in client;bzero(&serv,sizeof(serv));serv.sin_family = AF_INET;serv.sin_port = htons(7777);serv.sin_addr.s_addr = htonl(INADDR_ANY);bind(cfd,(struct sockaddr *)&serv,sizeof(serv));//3.循环读取读取客户端消息和给客户端回复消息int i;int n;socklen_t len;char buf[1024];std::string merge;while(1){//4.读取数据memset(buf,0x00,sizeof(buf));len = sizeof(client);n = recvfrom(cfd,buf,sizeof(buf),0,(struct sockaddr*)&client,&len);merge += buf;printf("serv端口号=[%d]:本次发送字节数=[%d],buf=[%s]\n",ntohs(client.sin_port),n,buf);//        printf("serv端口号=[%d]:本次发送字节数=[%d],bufer=[%s]\n",ntohs(serv.sin_port),once,tmp);std::cout << "merge= " << merge << ";" << "merge size is " << merge.size() <<  std::endl;//5.给客户端回复消息sendto(cfd,buf,n,0,(struct sockaddr*)&client,len);}//关闭套接字close(cfd);return 0;
}

client代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>#define SLICE_SIZE 5char* buffer = {"Helloworld\n"};
char* tmp[1024] ={0};
struct sockaddr_in serv;
bool Send(int sock_fd, char* buffer, int length)
{int once;            //一次发送的返回值int total = 0;        //目前发送了多少数据int thislen = 0;    //本次要发送的数据长度do{if (length - total > SLICE_SIZE)thislen = SLICE_SIZE;elsethislen = length - total;once = send(sock_fd, buffer + total, thislen, 0);
//        printf("serv端口号=[%d]:本次发送字节数=[%d],bufer=[%s]\n",ntohs(serv.sin_port),once,tmp);//        sendto(cfd,buf,n,0,(struct sockaddr*)&serv,sizeof(serv));if (once <= 0)                        //如果once < 0则表示发送失败，用break跳出循环，返回FALSE{break;}total += once;} while (total < length);                //如果total < length说明数据还未完全发送，继续循环if (total == length)                    //当total == length时，说明已完全发送，返回TRUEreturn true;return false;
}int main(){//1.创建socketint cfd = socket(AF_INET,SOCK_DGRAM,0);if(cfd<0){perror("socket error");return -1;}int n ;serv.sin_family = AF_INET;serv.sin_port = htons(7777);inet_pton(AF_INET,"127.0.0.1",&serv.sin_addr.s_addr);struct sockaddr_in client;client.sin_family = AF_INET;client.sin_port = htons(3333);bind(cfd, (struct sockaddr*)&client, sizeof(client));connect(cfd, (struct sockaddr*)&serv, sizeof(serv));char buf[1024] = {'\0'};
//    while(1){//读取标准输入数据
//        memset(buf,0x00,sizeof(buf));
//        n = read(STDIN_FILENO,buf, sizeof(buf));
//        buf[n-1] = 0x00;
//        n -= 1;Send(cfd,buffer, strlen(buffer));//发送数据
//        sendto(cfd,buf,n,0,(struct sockaddr*)&serv,sizeof(serv));//读取数据memset(buf,0x00,sizeof(buf));n = recvfrom(cfd,buf,sizeof(buf),0,NULL,NULL);
//        printf("[%d]:n=[%d],buf=[%s]\n",ntohs(serv.sin_port),n,buf);
//    }//关闭套接字close(cfd);return 0;
}