simpleWin32SerialReadTest.cpp

// C#:
// var serialPort = new SerialPort("COM7", 115200, Parity.None, 8, StopBits.One);
// serialPort.Open();
// Console.Write(serialPort.ReadChar());

// C++:

#include "clara.hpp"

#include <windows.h>
#include <cstdint>
#include <cstdio>
#include <iostream>

int main(int argc, char* argv[])
{
	std::string portName = "COM7";
	uint32_t baudrate = 115200;
	uint32_t numBytesToRead = 1;
	bool showHelp = false;
	bool purgeComm = false;

	{
	using namespace clara;
	auto cli
		=
		 Help(showHelp)
		+
		Arg(portName, "port")
		("ex. COM7")
		+ Opt(baudrate, "baudrate")
		["-b"]
		("ex. 115200")
		+ Opt(numBytesToRead, "numBytes")
		["-n"]
		("number of bytes to read")
		+ Opt(purgeComm, "flush")
		["-f"]
		("flush port");

	auto result = cli.parse(Args(argc, argv));
	if (!result)
	{
		puts("Error in command line: ");
		puts(result.errorMessage().c_str());
		return 1;
	}
	if (/*argc < 2 ||*/ showHelp)
	{
		std::cout << cli;
		return 0;
	}
	}

	HANDLE port = CreateFileA(("\\\\.\\" + portName).c_str(), GENERIC_READ | GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, 0, nullptr);
	if (port == INVALID_HANDLE_VALUE)
	{
		printf("Could not open port %.*s!\n", portName.length(), portName.c_str());
		return 2;
	}

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

	if (!GetCommState(port, &dcbSerialParams))
		return 3;

	dcbSerialParams.BaudRate = baudrate;
	dcbSerialParams.ByteSize = 8;
	dcbSerialParams.StopBits = 0;
	dcbSerialParams.Parity = 0;
	dcbSerialParams.fOutX = false;
	dcbSerialParams.fInX = false;
	dcbSerialParams.fOutxCtsFlow = false;
	if (!SetCommState(port, &dcbSerialParams))
		return 4;

	COMMTIMEOUTS timeouts = {};
	//timeouts.ReadIntervalTimeout = MAXDWORD;
	timeouts.ReadTotalTimeoutConstant = 5000;

	if (!SetCommTimeouts(port, &timeouts))
		return 5;

	if (purgeComm)
	{
		printf("flushing....\n");
		if (!PurgeComm(port, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR))
		{
			printf("failed: %s\n", windowsErrorString().c_str());
		}
	}

	std::vector<uint8_t> data(numBytesToRead, 0xCD);
	DWORD dwRead;
	printf("trying to read %d bytes...\n", numBytesToRead);
	if (!ReadFile(port, data.data(), numBytesToRead, &dwRead, nullptr))
	{
		printf("error\n");
	}
	else
	{
		data.resize(dwRead);

		printf("successfully read %d bytes:\n", dwRead);
		for (uint8_t d : data)
			printf("%02X ", d);
		printf("\n");
	}

	return 0;
}