How do I setup Using Systems::IO::Ports in DLL so that it can be called from a loadlibrary function - dll

Question

Using vc2012 express c++
I am a little confused on how a runtime library works, but I had needed to create one for a driver from some hardware I have so that it can be used in a SDK.
My source code is as follows
#include "PhantomAdapter.h"
#include <stdexcept>
int ready()
{
//return Comms::SerialPort::check();
return 1;
}
int open()
{
int flag=0;
//flag=Comms::SerialPort::openPort();
return flag;
}
int close()
{
Comms::SerialPort::closePort();
return 1;
}
int angle(double& angle)
{
angle = Comms::SerialPort::read();
return 0;
}
int torque(double torque)
{
Comms::SerialPort::send((Byte)torque);
return 1;
}
namespace Comms
{
//static p1 = gcnew System::IO::Ports::SerialPort();
int SerialPort::openPort()
{
bool check=0;
p1 = gcnew System::IO::Ports::SerialPort();
p1->BaudRate = 57600;
p1->PortName = "COM3";
if(p1->IsOpen)
return 0;
else {
p1->Open();
return 1;
}
}
int SerialPort::check()
{
array<String^>^ serialPorts = nullptr;
bool flag = true;
serialPorts = p1->GetPortNames();
for each(String^ port in serialPorts)
{
if(port=="COM3")
flag= true;
}
return flag;
}
void SerialPort::closePort()
{
p1->Close();
}
void SerialPort::send(Byte data)
{
array<unsigned char>^ buffer = gcnew array<Byte>(1);
buffer[0] = (char)data;
p1->Write(buffer,0,1);
}
double SerialPort::read()
{
double data;
data = p1->ReadByte();
return data;
}
}
header
#define PHANTOMADAPTER_API __declspec(dllexport)
#else
#define PHANTOMADAPTER_API __declspec(dllexport)
#endif
#using <mscorlib.dll>
#using <system.dll>
using namespace System;
using namespace System::IO::Ports;
using namespace System::Threading;
extern "C" {
PHANTOMADAPTER_API int ready();
PHANTOMADAPTER_API int open();
PHANTOMADAPTER_API int close();
PHANTOMADAPTER_API int angle(double& angle);
PHANTOMADAPTER_API int torque(double torque);
}
namespace Comms
{
public ref class SerialPort
{
private:
static System::IO::Ports::SerialPort^ p1;
public:
static int openPort();
static void closePort();
static double read();
static void send(Byte data);
static int check();
};
}
I am getting the following error when I call the angle DLL function or any function that requires the Comms namespace.
System.NullReferenceException: Object reference not set to an instance of an object.
at System.IO.Ports.SerialPort.get_IsOpen()
at System.IO.Ports.SerialPort.ReadByte()
at angle(Double* angle)
can someone please point me in the right direction, I feel as if the serialPort class can't be open from runtime library unless I import it somehow