Serial Port Programming on Windows

Here is a sample code of serial port programming on Windows:
it compile and run at Dev C++, but you need to change CreateFile to CreateFileA on VC++ 2010 express

#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <commdlg.h>
#include <windef.h>

int nread,nwrite;

int main()
{
HANDLE hSerial;
COMMTIMEOUTS timeouts;
COMMCONFIG dcbSerialParams;
char *words, *buffRead, *buffWrite;
DWORD dwBytesWritten, dwBytesRead;
   
hSerial = CreateFile("COM1",
    GENERIC_READ | GENERIC_WRITE,
    0,
    NULL,
    OPEN_EXISTING,
    FILE_ATTRIBUTE_NORMAL,
    NULL);

if ( hSerial == INVALID_HANDLE_VALUE)
{
   if (GetLastError() == ERROR_FILE_NOT_FOUND)
   {
      printf(" serial port does not exist \n");
   }
   printf(" some other error occured. Inform user.\n");
}

//DCB dcbSerialParams ;
//GetCommState( hSerial, &dcbSerialParams.dcb);
if (!GetCommState(hSerial, &dcbSerialParams.dcb))
{
printf("error getting state \n");
}

dcbSerialParams.dcb.DCBlength = sizeof(dcbSerialParams.dcb);

dcbSerialParams.dcb.BaudRate = CBR_38400;
dcbSerialParams.dcb.ByteSize = 8;
dcbSerialParams.dcb.StopBits = TWOSTOPBITS;
dcbSerialParams.dcb.Parity = NOPARITY;

dcbSerialParams.dcb.fBinary = TRUE;
dcbSerialParams.dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcbSerialParams.dcb.fRtsControl = RTS_CONTROL_DISABLE;
dcbSerialParams.dcb.fOutxCtsFlow = FALSE;
dcbSerialParams.dcb.fOutxDsrFlow = FALSE;
dcbSerialParams.dcb.fDsrSensitivity= FALSE;
dcbSerialParams.dcb.fAbortOnError = TRUE;

if (!SetCommState(hSerial, &dcbSerialParams.dcb))
{
printf(" error setting serial port state \n");
}

GetCommTimeouts(hSerial,&timeouts);
//COMMTIMEOUTS timeouts = {0};

timeouts.ReadIntervalTimeout = 50;
timeouts.ReadTotalTimeoutConstant = 50;
timeouts.ReadTotalTimeoutMultiplier = 10;
timeouts.WriteTotalTimeoutConstant = 50;
timeouts.WriteTotalTimeoutMultiplier= 10;

if(!SetCommTimeouts(hSerial, &timeouts))
{
printf("error setting port state \n");
}

//****************Write Operation*********************//
words = "This is a string to be written to serial port COM1";
nwrite = strlen(words);

buffWrite = words;
dwBytesWritten = 0;

if (!WriteFile(hSerial, buffWrite, nwrite, &dwBytesWritten, NULL))
{
printf("error writing to output buffer \n");
}
//printf("Data written to write buffer is \n %s \n",buffWrite);

//***************Read Operation******************//
/*
buffRead = 0;
dwBytesRead = 0;
nread = strlen(words);

if (!ReadFile(hSerial, buffRead, nread, &dwBytesRead, NULL))
{
printf("error reading from input buffer \n");
}
printf("Data read from read buffer is \n %s \n",buffRead);
*/

CloseHandle(hSerial);
system("pause");
return 1;
}