Establishing a tcp connection from within a DLL
- by Nicholas Hollander
I'm trying to write a piece of code that will allow me to establish a TCP connection from within a DLL file. Here's my situation: I have a ruby application that needs to be able to send and receive data over a socket, but I can not access the native ruby socket methods because of the environment in which it will be running. I can however access a DLL file and run the functions within that, so I figured I would create a wrapper for winsock. Unfortunately, attempting to take a piece of code that should connect to a TCP socket in a normal C++ application throws a slew of LNK2019 errors that I can not for the life of me resolve.
This is the method I'm using to connect:
//Socket variable
SOCKET s;
//Establishes a connection to the server
int server_connect(char* addr, int port)
{
//Start up Winsock
WSADATA wsadata;
int error = WSAStartup(0x0202, &wsadata);
//Check if something happened
if (error)
return -1;
//Verify Winock version
if (wsadata.wVersion != 0x0202)
{
//Clean up and close
WSACleanup();
return -2;
}
//Get the information needed to finalize a socket
SOCKADDR_IN target;
target.sin_family = AF_INET; //Address family internet
target.sin_port = _WINSOCKAPI_::htons(port); //Port #
target.sin_addr.s_addr = inet_addr(addr);
//Create the socket
s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s == INVALID_SOCKET)
{
return -3;
}
//Try connecting
if (connect(s, (SOCKADDR *)&target, sizeof(target)) == SOCKET_ERROR)
{
//Failed to connect
return -4;
}
else
{
//Success
return 1;
}
}
The exact errors that I'm receiving are:
Error 1 error LNK2019: unresolved external symbol _closesocket@4 referenced in function _server_disconnect [Project Path]
Error 2 error LNK2019: unresolved external symbol _connect@12 referenced in function _server_connect [Project Path]
Error 3 error LNK2019: unresolved external symbol _htons@4 referenced in function _server_connect [Project Path]
Error 4 error LNK2019: unresolved external symbol _inet_addr@4 referenced in function _server_connect [Project Path]
Error 5 error LNK2019: unresolved external symbol _socket@12 referenced in function _server_connect [Project Path]
Error 6 error LNK2019: unresolved external symbol _WSAStartup@8 referenced in function _server_connect [Project Path]
Error 7 error LNK2019: unresolved external symbol _WSACleanup@0 referenced in function _server_connect [Project Path]
Error 8 error LNK1120: 7 unresolved externals [Project Path] 1 1
Many thanks!
