#include <Windows.h>
#include <stdio.h>

void main(void)
{
	HANDLE hComm;                          // Handle to the Serial port
	char  ComPortName[] = "COM3";          // Name of the Serial port(May Change) to be opened,
	DWORD dwCommEvent;
	DWORD dwRead;
	char  chRead;

	hComm = CreateFileA(ComPortName,  // Name of the Port to be Opened
		GENERIC_READ | GENERIC_WRITE, // Read/Write Access
		0,                            // No Sharing, ports cant be shared
		NULL,                         // No Security
		OPEN_EXISTING,                // Open existing port only
		0,                            // Non Overlapped I/O
		NULL);                        // Null for Comm Devices

	if (hComm == INVALID_HANDLE_VALUE) {
		printf("Error! - Port %s can't be opened\n", ComPortName);
		return;
	}
	else {
		printf("Port %s Opened\n ", ComPortName);
	}

	DCB dcbSerialParams = { 0 };
	dcbSerialParams.DCBlength = sizeof(dcbSerialParams);

	if (!GetCommState(hComm, &dcbSerialParams)) {
		printf("Error in GetCommState()");
		CloseHandle(hComm);
		return;
	}

	dcbSerialParams.BaudRate = CBR_9600;
	dcbSerialParams.ByteSize = 8;
	dcbSerialParams.StopBits = ONESTOPBIT;
	dcbSerialParams.Parity = NOPARITY;

	if (!SetCommState(hComm, &dcbSerialParams)) {
		printf("Error!in Setting DCB Structure");
		CloseHandle(hComm);
		return;
	}

	if (!SetCommMask(hComm, EV_RXCHAR)) {
		printf("Error setting communications event mask.\n");
		CloseHandle(hComm);
		return;
	}

	// This loop of reading chars is the fixed version; second sample below the
	// the "Caveat" section in https://msdn.microsoft.com/en-us/library/ff802693.aspx.
	// 
	while (TRUE) {
		if (WaitCommEvent(hComm, &dwCommEvent, NULL)) {
			do {
				if (ReadFile(hComm, &chRead, 1, &dwRead, NULL)) {
					printf("%c", chRead);
				}
				else {
					printf("Error in ReadFile.\n");
					break;
				}
			} while (dwRead != 0);
		}
		else {
			printf("Error in WaitCommEvent.\n");
			break;
		}
	}

	CloseHandle(hComm);
}