uart

In windows (vc6), I believe you have to create a file with the name COM1, then you can use ReadFile and WriteFile to communicate.

extern HANDLE hcom;
extern FILE * f;
extern unsigned char page;
BOOL InitSerCom(char comport, int baudrate)
{
//    return true;
    page = 255;
    char s;
    sprintf(s,"COM%d",comport);
    if ((hcom = CreateFile(s,GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 
       FILE_ATTRIBUTE_NORMAL, NULL)) != NULL)
    {
  DCB dcb;
  sprintf(s,"baud=%d parity=O data=8 stop=1",baudrate);
  
  GetCommState(hcom, &dcb);
  
  BuildCommDCB(s, &dcb);
  SetCommState(hcom, &dcb);
  COMMTIMEOUTS comt;
  comt.ReadIntervalTimeout = 20;
  comt.ReadTotalTimeoutMultiplier = 20;
  comt.ReadTotalTimeoutConstant = 20;
  comt.WriteTotalTimeoutMultiplier = 20;
  comt.WriteTotalTimeoutConstant = 20;
      SetCommTimeouts(hcom, &comt);
  GetCommState(hcom, &dcb);
  GetCommTimeouts(hcom, &comt);
  return true;
    }
    else
  return false;
}

DWORD nrsend;
char senddata = 'q';
    
WriteFile(hcom,&senddata,1,&nrsend, NULL);
//check nrsend variable to check it was actually sent

DWORD nrrecd;
char recdata;
    
ReadFile(hcom, &recdata, 100, &nrrecd, NULL);   //100 is the buffersize!
//nrrecd will be the number of characters actually received