我正在尝试在 c++ 应用程序中实现 UpNp，我在 google 中找到了这段代码：
BOOL upnp_discover( upnp_device_t* Device, ushort Tries )
{
SOCKET Sock;
struct sockaddr_in Addr;
char Buffer[1450],
*Begin = NULL,
*End = NULL;
int i = 0,
t = 0,
Ret = 0,
TrueLen = sizeof(bool);
bool True = true;
ulong One = 1,
Zero = 0;
Sock = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP );
memset( &Addr, 0, sizeof(Addr) );
Addr.sin_family = AF_INET;
Addr.sin_port = htons( upnp_broadcast_port );
Addr.sin_addr.s_addr = inet_addr( upnp_broadcast_ip );
Ret = setsockopt( Sock, SOL_SOCKET, SO_BROADCAST, (char*)&True, TrueLen );
for( i = 0; i < Tries; ++i )
{
memset( &Buffer, 0, sizeof(Buffer) );
strcpy( Buffer, upnp_search_request );
sendto( Sock, Buffer, strlen(Buffer), 0, (struct sockaddr*)&Addr, sizeof(Addr) );
for( t = 0; t < 10; ++t )
{
ioctlsocket( Sock, FIONBIO, &One );
memset( &Buffer, 0, sizeof(Buffer) );
Ret = recvfrom( Sock, Buffer, (sizeof(Buffer) - 1), 0, NULL, NULL );
if( Ret == SOCKET_ERROR)
{
Sleep( 1000 );
continue;
} else {
Begin = strstr( Buffer, "http://" );
if( Begin != NULL )
{
End = strchr( Begin, '\r' );
if( End != NULL )
{
*End = '\0';
strncpy( Device->Location, Begin, (sizeof(Device->Location) - 1) );
upnp_parse_url( Device );
closesocket( Sock );
return TRUE;
}
}
}
}
ioctlsocket( Sock, FIONBIO, &Zero );
}
closesocket( Sock );
return FALSE;
}
但它总是返回 false，并且我在启用 UPnP 的路由器后面。我在 google 上找到了其他一些资源，但它们过于依赖于它们所属的应用程序的其余部分，而且由于我对 c++ 有点陌生，所以我几乎无法理解它们。
有人有在 c++ 中使用 UpNP 的简单示例吗？
编辑：
调试表明：
Ret = recvfrom( Sock, Buffer, (sizeof(Buffer) - 1), 0, NULL, NULL );
总是-1（SOCKET_ERROR），有人知道为什么会这样吗？