tcpclient C3145 - dll

Question

I'm currently using Visual Studio C++ to generate .dll in order to transmit data between two programs: essentially, one program notifies the other when an event occurs. I'm trying to do this via a TcP client socket.
my header file goes something like this:
#include <string>
using namespace std;
extern "C"
{
__declspec (dllexport) bool trackerConnect( char* ipAddress, int port );
__declspec (dllexport) void sendEvent ( char* ev);
__declspec (dllexport) void disconnect();
}
My .cpp file looks something like this
#define WIN32_LEAN_AND_MEAN
#include "logEvents.h"
#using "system.dll"
using namespace System;
using namespace System::Net;
using namespace System::Net::Sockets;
using namespace System::Text;
TcpClient^ logClient;
NetworkStream^ logStream;
bool trackerConnect( char* ipAddress, int port )
{
/*Connects to server, gets stream, and returns whether the connection was
successful or not*/
}
void sendEvent ( char* ev )
{
/*Converts ev into a Byte array and sends it to the server to notify it
that an event has occurred*/
}
void disconnect ()
{
//closes the connection with the server
}
Given that all three functions need access to the TcPClient, I declared it as a global variable. However, when I compile, I get error C3145: global or static variable may not have managed type. If I can't declare the TcPClient as a global variable, how am I supposed to use it in the three functions?