UDP编程模型如下： UDP编程示例代码：
udp_server.c：
//服务器端代码 server.c #include <stdio.h> #include <string.h> #include <sys/socket.h> #include <netinet/in.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <arpa/inet.h> int main(int argc, char **argv) { int ret; struct sockaddr_in servaddr; char recvline[1024]; //SOCK_STREAM int sockfd = socket(PF_INET, SOCK_DGRAM, 0); //服务器 ip port bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = htonl(INADDR_ANY); servaddr.sin_port = htons(50001); //fcntl(sockfd, F_SETFL,O_NONBLOCK);//设置为非阻塞，根据具体需要决定是否需要非阻塞模式 bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)); while(1) { struct sockaddr_in addrClient; int sizeClientAddr = sizeof(struct sockaddr_in); ret = recvfrom(sockfd, recvline, 1024, 0, (struct sockaddr*)&addrClient,(socklen_t*)&sizeClientAddr); char *pClientIP =inet_ntoa(addrClient.sin_addr); printf("%s-%d(%d) says:%s\n",pClientIP,ntohs(addrClient.sin_port),addrClient.sin_port, recvline); sendto(sockfd, recvline, ret, 0, (struct sockaddr *)&addrClient, sizeClientAddr); } close(sockfd); }udp_client.c：
//客户端代码 client.c #include <stdio.h> #include <string.h> #include <sys/socket.h> #include <netinet/in.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <arpa/inet.h> int main(int argc,char **argv) { int ret; char recvline[1024]; int sockfd = socket(PF_INET, SOCK_DGRAM, 0); //server ip port struct sockaddr_in servaddr; struct sockaddr_in client_addr; char sendline[100] = "hello world!"; bzero(&servaddr,sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = htons(50001); servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); //my ip port (bind),也可以不绑定本地port，那么本地发送的port就是随机的。 bzero(&client_addr,sizeof(client_addr)); client_addr.sin_family = AF_INET; client_addr.sin_port = htons(40001); client_addr.sin_addr.s_addr = htonl(INADDR_ANY); //client发出的udp包就是从这个port发出 if(bind(sockfd, (struct sockaddr *)&client_addr,sizeof(client_addr))<0) { printf("video rtcp bind ret < 0\n"); } sendto(sockfd, sendline, strlen(sendline) + 1, 0, (struct sockaddr *)&servaddr,sizeof(servaddr)); while(1) { struct sockaddr_in addrClient; int sizeClientAddr = sizeof(struct sockaddr_in); ret = recvfrom(sockfd, recvline, 1024, 0, (struct sockaddr*)&addrClient,(socklen_t*)&sizeClientAddr); char *pClientIP =inet_ntoa(addrClient.sin_addr); printf("%s-%d(%d) says:%s\n",pClientIP,ntohs(addrClient.sin_port),addrClient.sin_port, recvline); sendto(sockfd, recvline, ret, 0, (struct sockaddr *)&addrClient, sizeClientAddr); } close(sockfd); return 1; }参考资料：
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