Serial Port with MinGW(C/C++)

Update: I uploaded a Version of my mapper to GitHub

I searched for this topic and found no real leads so i looked it up.
Opening the serial port
First point is to open a connection. Before opening any connection several informations must be acquired.

• The name of the serial port.(Usually COM1-COM6 )
• The direction of communication.
• (It is possible to set the communication to an asynchronic mode but it is far mor complex and unintuitive than the synchronic mode used here)

#include <windows.h>
LPCSTR portname = "COM6";
DWORD  accessdirection =GENERIC_READ | GENERIC_WRITE;
HANDLE hSerial = CreateFile(portname,
    accessdirection,
    0,
    0,
    OPEN_EXISTING,
    0,
    0);
if (hSerial == INVALID_HANDLE_VALUE) {
    //call GetLastError(); to gain more information
}

After opening the port further settings like Baudrate, Byte size, the number of stopbits and the Parity need to be set.

DCB dcbSerialParams = {0};
dcbSerialParams.DCBlength=sizeof(dcbSerialParams);
if (!GetCommState(hSerial, &dcbSerialParams)) {
     //could not get the state of the comport
}
dcbSerialParams.BaudRate=460800;
dcbSerialParams.ByteSize=8;
dcbSerialParams.StopBits=ONESTOPBIT;
dcbSerialParams.Parity=NOPARITY;
if(!SetCommState(hSerial, &dcbSerialParams)){
     //analyse error
}

Finally timeouts need to be set so that the program does not hang up when receiving nothing.

 COMMTIMEOUTS timeouts={0};
timeouts.ReadIntervalTimeout=50;
timeouts.ReadTotalTimeoutConstant=50;
timeouts.ReadTotalTimeoutMultiplier=10;
timeouts.WriteTotalTimeoutConstant=50;
timeouts.WriteTotalTimeoutMultiplier=10;
if(!SetCommTimeouts(hSerial, &timeouts)){
    //handle error
}
return hSerial;

Reading and writing
Reading and writing is analogous to each other.

Reading:
To tell windows that data is going to be send over the serial port, the handle, the data and the amount of data are needed.
The following transmission is a simple fileIO operation.

DWORD readFromSerialPort(HANDLE hSerial, uint8_t * buffer, int buffersize)
{
    DWORD dwBytesRead = 0;
    if(!ReadFile(hSerial, buffer, buffersize, &dwBytesRead, NULL)){
        //handle error
    }
    return dwBytesRead;
}

Writing
The same information is needed when writing to the port.

DWORD writeToSerialPort(HANDLE hSerial, uint8_t * data, int length)
{

	DWORD dwBytesRead = 0;
	if(!WriteFile(hSerial, data, length, &dwBytesRead, NULL)){
		printLastError();
	}
	return dwBytesRead;

}

Closing:
when the serial port is not longer needed, it can be freed by closing the associated handle.

void closeSerialPort(HANDLE hSerial)
{
	CloseHandle(hSerial);
}

Serial Port@msdn