針對UDP套接字調用connect函數不會與對方UDP套接字創建鏈接,只是向UDP套接字註冊目標IP和端口信息。c++
服務器代碼不須要修改,只需修改客戶端代碼。調用connect函數以後,能夠調用write函數和read函數來發送、接收數據,而不須要調用sendto函數和recvfrom函數。git
include <cstdio> #include <cstdlib> #include <cstring> #include <unistd.h> #include <arpa/inet.h> #include <sys/socket.h> const int BUF_SIZE = 30; void error_handling(const char *message); // 接收兩個參數,argv[1]爲IP地址,argv[2]爲端口號 int main(int argc, char *argv[]) { int sock; char message[BUF_SIZE]; ssize_t str_len; struct sockaddr_in server_addr; if (argc != 3) { printf("Usage : %s <IP> <port>\n", argv[0]); exit(1); } sock = socket(PF_INET, SOCK_DGRAM, 0); if (sock == -1) { error_handling("socket() error"); } // 地址信息初始化 memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; // IPV4 地址族 server_addr.sin_addr.s_addr = inet_addr(argv[1]); // 服務器IP地址 server_addr.sin_port = htons(atoi(argv[2])); // 服務器端口號 while (1) { fputs("Insert message(q or Q to quit): ", stdout); fgets(message, BUF_SIZE, stdin); // 若是輸入q或者Q,則退出 if (!strcmp(message, "q\n") || !strcmp(message, "Q\n")) { break; } write(sock, message, strlen(message)); str_len = read(sock, message, sizeof(message) - 1); message[str_len] = 0; printf("Message from server: %s", message); } close(sock); return 0; }
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