native has exited with code 0(0x0)

/** Serial.cpp
 *
 *
 */

#include <iostream>
using namespace std;
#include <windows.h>
#include <tchar.h>
#include <crtdbg.h>

#include "serialtestdll.h"

int WINAPI _tWinMain
          (
           HINSTANCE /*hInst*/, 
           HINSTANCE /*hInstPrev*/, 
           LPTSTR    /*lptszCmdLine*/, 
          int       /*nCmdShow*/
          ){
}

Serial::Serial(tstring &commPortName, int baudeRate)
{
	commHandle = CreateFile(commPortName.c_str(), GENERIC_READ|GENERIC_WRITE, 0,NULL, OPEN_EXISTING, 
		0, NULL);

	if(commHandle == INVALID_HANDLE_VALUE) 
	{
		throw("ERROR: Could not open com port");
	}
	else 
	{
		// set timeouts
		COMMTIMEOUTS cto = { MAXDWORD, 0, 10,100, 500};
		DCB dcb;
		if(!SetCommTimeouts(commHandle,&cto))
		{
			Serial::~Serial();
			throw("ERROR: Could not set com port time-outs");
		}

		// set DCB
		memset(&dcb,0,sizeof(dcb));
		dcb.DCBlength = sizeof(dcb);
		dcb.BaudRate = 9600;
		dcb.fBinary = 1;
		dcb.fDtrControl = DTR_CONTROL_ENABLE;
		dcb.fRtsControl = RTS_CONTROL_ENABLE;

		dcb.Parity = NOPARITY;
		dcb.StopBits = ONESTOPBIT;
		dcb.ByteSize = 8;

		if(!SetCommState(commHandle,&dcb))
		{
			Serial::~Serial();
			throw("ERROR: Could not set com port parameters");
		}
	}
}

Serial::~Serial()
{
	CloseHandle(commHandle);
}

double Serial::write(const char *buffer)
{
	char cmd[] = "!GV\r";
	DWORD numWritten;
	WriteFile(commHandle, cmd, 5, &numWritten, NULL); 

	return numWritten;
}

int Serial::write(const char *buffer, int buffLen)
{
	char cmd[] = "!GV\r";
	DWORD numWritten;
	
	WriteFile(commHandle, cmd, 5, &numWritten, NULL); 

	return numWritten;
}

int Serial::read(char *buffer, int buffLen, bool nullTerminate)
{
	DWORD numRead;
	if(nullTerminate)
	{
	--buffLen;
	}

	BOOL ret = ReadFile(commHandle, buffer, buffLen, &numRead, NULL);

	if(!ret)
	{
		return 0;
	}

	if(nullTerminate)
	{
		buffer[numRead] = '\r';
	}

	return numRead;
}

#define FLUSH_BUFFSIZE 10

void Serial::flush()
{
	char buffer[FLUSH_BUFFSIZE];
	int numBytes = read(buffer, FLUSH_BUFFSIZE, false);
	while(numBytes != 0)
	{
		numBytes = read(buffer, FLUSH_BUFFSIZE, false);
	}
}