在DLL中使用组播失败，高分请教高手！！！

[iamstupid]

以下为出错代码，在运行到setsockopt加入组播组时失败，但同样的代码在exe中就没有问题。

SOCKET hSock = INVALID_SOCKET;
int nTTL;

WSADATA wsaData;
if( WSAStartup( 0x101, &wsaData ) != 0 )
goto FAIL_EXIT;

//create socket
hSock = socket(AF_INET, SOCK_DGRAM, 0);
if( hSock == INVALID_SOCKET )
goto FAIL_EXIT;

//bind
sockaddr_in localAddr;
localAddr.sin_family = AF_INET;
localAddr.sin_addr.S_un.S_addr = INADDR_ANY; //inet_addr(szLocalAddr);
localAddr.sin_port = htons(wUdpPort);
if( bind(hSock, (sockaddr *)&localAddr, sizeof(localAddr))!=0 )
goto FAIL_EXIT;

//join to multicast group
ip_mreq mreq;
mreq.imr_multiaddr.S_un.S_addr = inet_addr(szMulticastAddr);
mreq.imr_interface.S_un.S_addr = INADDR_ANY; //inet_addr(szLocalAddr);
if( setsockopt(hSock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&mreq, sizeof(mreq)) == SOCKET_ERROR )
{
//此处调用失败，返回10042：不支持此功能
//但在exe中直接使用组播则没有问题
int result = WSAGetLastError();
goto FAIL_EXIT;
}

//set multicast ttl
nTTL = 255;
if( setsockopt(hSock, IPPROTO_IP, IP_MULTICAST_TTL, (char*)&nTTL, sizeof(nTTL)) == SOCKET_ERROR )
goto FAIL_EXIT;

//connect, set dest IP addr
sockaddr_in groupAddr;
groupAddr.sin_family = AF_INET;
groupAddr.sin_addr.S_un.S_addr = inet_addr(szMulticastAddr);//inet_addr("192.168.0.1");
groupAddr.sin_port = htons(wUdpPort);
if( connect(hSock, (sockaddr*)&groupAddr, sizeof(groupAddr))!=0 )
goto FAIL_EXIT;
return hSock;

FAIL_EXIT:
if( hSock != INVALID_SOCKET )
closesocket(hSock);
return INVALID_SOCKET;

[iamstupid]

up

[lwugui]

你是不是在exe时先择了对SOCKET的支持，而在DLL时没有初使化SOCKET呢？
加入Winsock的头文件并连接相应库文件，如下：
#include "winsock.h"
#pragma comment(lib,"wsock32")


在初使话函数中进行初使化：

WSADATA wsaData(2,0);
WORD version = MAKEWORD(2,0);
int ret = WSAStartup(version,&wsaData);
if(ret != 0)
TRACE("Initilize Error!\n");
试试

[iamstupid]

lwugui(乌龟):
我试了你的办法，不行

[NAICKY]

我也有一个类似的问题，搞不懂!