[問題] UDP發送接收

看板C_and_CPP (C/C++)作者s890269 (賽)時間9年前 (2016/11/08 23:15)推噓1(1推 0噓 2→)

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開發平台(Platform): (Ex: Win10, Linux, ...) Win7 編譯器(Ex: GCC, clang, VC++...)+目標環境(跟開發平台不同的話需列出) Microsoft Visual Studio C++ 問題(Question)：我最一開始有撰寫UDP Server以及UDP Client,UDP開著,client發送封包給server, server接收到後,會發送回給client,所以client可以發送跟接收但我最近在改寫時就發現server跟client連不到,這次的寫法是 server發送封包給client接收但就接收不到了,應該說根本沒有連上但我不太覺得程式碼有錯誤,因為我是參考之前成功的範例去改的所以不知道是有程式碼以外的問題嗎? 預期的正確結果(Expected Output)： server發送的封包client可以接收成功出現的error都是在接收發送那裏接下來進入的if bind或者初始的設定沒跑出error 程式碼(Code)：(請善用置底文網頁, 記得排版) Server端 #include "stdafx.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <winsock2.h> #include <iostream> #include <sys/types.h> using namespace std; #pragma comment(lib,"ws2_32.lib") //Winsock Library #define SERVER_PORT1 8889 #define BUFLEN 1024 int _tmain(int argc, _TCHAR* argv[]){ struct sockaddr_in addrsend; SOCKET s1; int length_addrsend; char buf[BUFLEN]; int sendbol; int receivebol; double cur_ang[3]; WSADATA wsa; printf("\nInitializing Winsock..."); if (WSAStartup(MAKEWORD(2,2),&wsa) != 0){ printf("Failed. Error Code : %d",WSAGetLastError()); } printf("Initialized.\n"); if ((s1= socket(AF_INET, SOCK_DGRAM, 0)) <0){ perror ("socket s1 failed"); } memset(&addrsend,'\0',sizeof(addrsend)); addrsend.sin_family = AF_INET; addrsend.sin_addr.s_addr = htonl(INADDR_ANY); addrsend.sin_port = htons(SERVER_PORT1); if (bind(s1,(struct sockaddr*)&addrsend,sizeof(addrsend)) <0) { perror ("bind s1 failed\n"); } printf("bind done"); length_addrsend=sizeof(addrsend); printf("Server is ready to receive !!\n"); printf("Can strike Cntrl-c to stop Server >>\n"); memset(buf,'\0', BUFLEN); cur_ang[0]=0.5678; cur_ang[1]=0.51278; cur_ang[2]=0.589678; while(1){ sprintf(buf,"%f %f %f ",cur_ang[0],cur_ang[1],cur_ang[2]); sendbol=sendto(s1,buf,BUFLEN,0,(struct sockaddr*)&addrsend,length_addrsend); if (sendbol<0){ perror("Could not send datagram!!\n"); continue; } memset(buf,'\0',BUFLEN); } closesocket(s1); WSACleanup(); system("pause"); return 0; } Client端 #include "stdafx.h" #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <winsock2.h> #include <fcntl.h> #include <string.h> #include <iostream> #include <cstdio> #include <cassert> #include <cmath> #include <math.h> #include <time.h> #pragma comment(lib,"ws2_32.lib") using namespace std; #define SERV_PORT 8889 //receive from server #define BUFLEN 1024 #define SERVER "127.0.0.1" int main(int argc, char **argv){ struct sockaddr_in server;//one port struct hostent *hp; /* holds IP address of server */ SOCKET s; int size_server; char data; char buf[BUFLEN]={0}; char buf1[BUFLEN]={0}; int sendbol, receivebol; WSADATA wsa; //Initialise winsock printf("\nInitializing Winsock..."); if (WSAStartup(MAKEWORD(2,2),&wsa) != 0){ printf("Failed. Error Code : %d",WSAGetLastError()); } printf("Initialized.\n"); //create socket if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == SOCKET_ERROR){ printf("socket() failed with error code : %d" , WSAGetLastError()); } server.sin_family = AF_INET; server.sin_addr.s_addr = htonl(INADDR_ANY); server.sin_addr.s_addr=inet_addr(SERVER); server.sin_port = htons(SERV_PORT); size_server=sizeof(server); while(1){ receivebol=recvfrom(s,buf,BUFLEN,0,(struct sockaddr*)&server,&size_server); if (receivebol< 0) { printf("receive failed: %d\n" , WSAGetLastError()); } else{ printf("bytes have been received\n"); printf("%s\n",buf); } } closesocket(s); WSACleanup(); system("pause"); return 0; } -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 140.116.234.232 ※ 文章網址: https://www.ptt.cc/bbs/C_and_CPP/M.1478618153.A.8E6.html