如何实现组播？用mfc或者c都可以，需要在操作系统做什么设置吗？
这是我的一段代码，但是不起作用！
SOCKET s;
struct ip_mreq ipmr;
struct sockaddr_in local,from;
char recvbuf[2480];
int len=sizeof(struct sockaddr_in);
long ret;
s=socket(AF_INET,SOCK_DGRAM,0);
local.sin_family=AF_INET;
local.sin_addr.s_addr=htonl(INADDR_ANY);
local.sin_port=htons(5520);
ipmr.imr_multiaddr.s_addr=inet_addr("224.2.223.193");
ipmr.imr_interface.s_addr=htonl(INADDR_ANY);
bind(s,(SOCKADDR *)&local,sizeof(local));
if (setsockopt(s,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char *)&ipmr,sizeof(ipmr))==SOCKET_ERROR) {
TRACE("SetSocketOpt失败\n");
return;
}
else {
TRACE("设置组播成功\n");
}
while (1) {
if ((ret=recvfrom(s,recvbuf,2480,0,(struct sockaddr *)&from,&len))==SOCKET_ERROR) {
TRACE("recvfrom failed\n");
}
else {
TRACE("TestSocket---------%s,length=%d\n",inet_ntoa(from.sin_addr),ret);
}
}
问题点数：100、回复次数：3Top
1 楼xuying（）回复于 2002-06-12 10:29:42 得分 60
组播不需要什么特殊的设置。下面是的代码在win2k 局域网环境下试验通过:
//发送方程序 sender.c
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#define BUFFSIZE 2048
#define IP_ADDR "224.8.8.1"
#define DEST_PORT 8888
int main(int argc,char *argv[])
{
int sockfd;
struct sockaddr_in addr;
char szError[100];
char buf[] = "Hello, World!";
int ttl = 255 ; // Arbitrary TTL value.
WSADATA WSAData;
WORD wVersionRequested;
wVersionRequested = MAKEWORD(2, 2);
if (WSAStartup (wVersionRequested , &WSAData) != 0)
{
printf ("recver:Initialize Winsock error!");
exit(1);
}
if (LOBYTE(WSAData.wVersion) != 2 || HIBYTE(WSAData.wVersion) != 2 ) {
WSACleanup( );
printf ("setsockopt failed! Error: %d", WSAGetLastError ());
exit(1);
}
addr.sin_family = AF_INET;
addr.sin_port = htons(DEST_PORT);
addr.sin_addr.s_addr = inet_addr(IP_ADDR);
if ((sockfd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
printf("sender:new a socket error!\n");
exit(1);
}
if(setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, (char *)&ttl, sizeof(ttl))!=0)
{
printf("error setsockopt IP_MULTICAST_TTL\n");
exit(1);
}
/*
if (bind(sockfd,(struct sockaddr *)&recver_addr,sizeof(recver_addr)) < 0) {
closesocket(sockfd);
printf("recver:bind socket error!\n");
exit(1);
}
*/
if (sendto (sockfd, buf, sizeof(buf) , 0, (struct sockaddr *)&addr, sizeof(addr))
== SOCKET_ERROR)
{
wsprintf (szError, TEXT("sendto failed! Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (sockfd);
return FALSE;
}
else
{
printf("send ok\n");
}
// Close Sock.
closesocket (sockfd);
WSACleanup ();
return 0;
}
// 接收方程序 receivers.c
//#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#define BUFFSIZE 2048
#define RECV_IP_ADDR "224.8.8.1"
#define DEST_PORT 8888
int main(int argc,char *argv[])
{
int sockfd;
int sock_reuse = 1;
struct ip_mreq multicast;
struct sockaddr_in recver_addr;
char szError[100];
int index = 0, // Integer index
iRecvLen; // Length of recv_sin
char szMessageA[1024*320]; // ASCII string
TCHAR szMessageW[1024*320]; // Unicode string
WSADATA WSAData;
WORD wVersionRequested;
wVersionRequested = MAKEWORD(2, 2);
if (WSAStartup (wVersionRequested , &WSAData) != 0)
{
printf ("recver:Initialize Winsock error!");
exit(1);
}
if (LOBYTE(WSAData.wVersion) != 2 || HIBYTE(WSAData.wVersion) != 2 ) {
WSACleanup( );
printf ("setsockopt failed! Error: %d", WSAGetLastError ());
exit(1);
}
multicast.imr_multiaddr.s_addr = inet_addr(RECV_IP_ADDR);
multicast.imr_interface.s_addr = htonl(INADDR_ANY);
recver_addr.sin_family = AF_INET;
recver_addr.sin_port = htons(DEST_PORT);
recver_addr.sin_addr.s_addr = INADDR_ANY;
if ((sockfd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
printf("recver:new a socket error!\n");
exit(1);
}
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *)&sock_reuse, sizeof(sock_reuse)) < 0) {
printf("recver : socket options set error");
exit(1);
}
if (bind(sockfd,(struct sockaddr *)&recver_addr,sizeof(recver_addr)) < 0) {
closesocket(sockfd);
printf("recver:bind socket error!\n");
exit(1);
}
if (setsockopt(sockfd,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char *)&multicast,sizeof(multicast)) < 0 ) {
sprintf (szError, TEXT("setsockopt failed! Error: %d"), WSAGetLastError ());
printf("%s\n", szError);
closesocket(sockfd);
exit(1);
}
printf("Receive on %s:%d\n", RECV_IP_ADDR, DEST_PORT);
iRecvLen = sizeof (recver_addr);
memset(szMessageA, 0, sizeof(szMessageA));
// Receive data from the multicasting group server.
if (recvfrom (sockfd,
szMessageA,
sizeof(szMessageA),
0,
(struct sockaddr FAR *) &recver_addr,
&iRecvLen) == SOCKET_ERROR)
{
wsprintf (szError, TEXT("recvfrom failed! Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (sockfd);
return FALSE;
}
else
{
// Convert the ASCII string to a Unicode string.
for (index = 0; index <= sizeof (szMessageA); index++)
szMessageW[index] = szMessageA[index];
MessageBox (NULL, szMessageW, TEXT("Info"), MB_OK);
}
// Disable receiving on Sock before closing it.
shutdown (sockfd, 0x00);
// Close Sock.
closesocket (sockfd);
WSACleanup ();
return 0;
}
Top
2 楼djhdu（小火花）回复于 2002-06-12 10:45:16 得分 0
哦，是不是只要发送给这个组播地址，其它组播接收程序就都可以收到？Top
3 楼xuying（）回复于 2002-06-12 11:02:33 得分 40
发送程序很简单，只要给组播地址发就可以了。
接收的时候要先加入组播组。就是下面这一段程序:
if (setsockopt(sockfd,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char *)&multicast,sizeof(multicast)) < 0 ) {
sprintf (szError, TEXT("setsockopt failed! Error: %d"), WSAGetLastError ());
printf("%s\n", szError);
closesocket(sockfd);
exit(1);
Top
4 楼xuying（）回复于 2002-06-12 11:03:34 得分 0
发送程序很简单，只要给组播地址发就可以了。
接收的时候要先加入组播组。就是下面这一段程序:
if (setsockopt(sockfd,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char *)&multicast,sizeof(multicast)) < 0 ) {
sprintf (szError, TEXT("setsockopt failed! Error: %d"), WSAGetLastError ());
printf("%s\n", szError);
closesocket(sockfd);
exit(1);
Top
相关问题
关键词
得分解答快速导航
相关链接
广告也精彩
反馈
