socket： 无论IP是多少connect()函数总返回0
我想通过connect（）函数访问一台网络设备，可是无论IP错误与否，connect总是返回0，只有在recv时接收数据超时才知道连接原来是失败的。阻塞模式和非阻塞模式我都试过了，实在不知道到底是什么原因。请高手帮忙，不甚感激！我将部分代码贴出来
WORD wVersionRequested;
WSADATA wsaData;
int err;
struct hostent *pHostEntry;
wVersionRequested = MAKEWORD( 2, 2 );
//加载套接字DLL库
err = WSAStartup( wVersionRequested, &wsaData );
if ( err != 0 ) {
return -1;
}
// map host to ip, allow ip
if ((pHostEntry = gethostbyname(hostip))) {
memcpy((char *)&addr.sin_addr, pHostEntry->h_addr,
pHostEntry->h_length);
}
else if ((addr.sin_addr.s_addr = inet_addr(hostip))==INADDR_NONE) {
DBG_LOG (("Can't resolve %s\n", hostip));
return -1;
}
// create an IP network socket
sock = socket (AF_INET, SOCK_STREAM, 0);
{
// set a read timeout
optval = READ_TIMEOUT*1000; // timeout in milliseconds
if(setsockopt (sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&optval,
sizeof (optval))==SOCKET_ERROR)
{closesocket (sock);
return -1;
}
int bfsize;
int optsize = sizeof(bfsize);
if (getsockopt (sock, SOL_SOCKET, SO_RCVBUF,
(char *)&bfsize, &optsize) != SOCKET_ERROR) {
DBG_LOG (("rcvbuf is %u\n", bfsize));
}
bfsize = SOCK_BF_LEN;
if (setsockopt (sock, SOL_SOCKET, SO_RCVBUF,
(char *)&bfsize, sizeof(bfsize)) == SOCKET_ERROR) {
DBG_LOG (("failed to set rcvbuf to %u\n", bfsize));
}
else {
DBG_LOG (("rcvbuf set to %u\n", bfsize));
}
}
addr.sin_family = AF_INET;
addr.sin_port = htons (80);
if (connect (sock, (struct sockaddr *)&addr, sizeof (addr)) == -1) {
DBG_LOG (("unable to connect\n"));
closesocket (sock);
}
[解决办法]
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