C++ program freezes during COM port read - c++

Question

I am trying to write a simple program to send single characters to a program via a COM port and read the answers I get back. I think I have working script where I can at least send commands via the com port, but when the ReadFile function begins it freezes. I have the comm timeout set for 100ms, so I don't think that it is locking the port, but I may be wrong. I am not getting any errors, and no warnings when I compile. I am very new to C++ (normally work with python), so please be as clear a possible with your answers.
// comtest.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include <string>
#include <sstream>
#include <dos.h>
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <windows.h>
int main(int argc, char **argv)
{
std::cout << "TOP! \n";
char buffer[1];
HANDLE file;
COMMTIMEOUTS timeouts;
DWORD read, written;
DCB port;
char init[] = ""; // e.g., "ATZ" to completely reset a modem.
// open the comm port.
file = CreateFile(L"COM1",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
0,
NULL);
std::cout << "file made \n";
// get the current DCB, and adjust a few bits to our liking.
memset(&port, 0, sizeof(port));
port.DCBlength = sizeof(port);
// set short timeouts on the comm port.
timeouts.ReadIntervalTimeout = 100;
timeouts.ReadTotalTimeoutMultiplier = 1;
timeouts.ReadTotalTimeoutConstant = 100;
timeouts.WriteTotalTimeoutMultiplier = 1;
timeouts.WriteTotalTimeoutConstant = 100;
int N = 10;
while (N > 1)
{
std::cout << "i'm in the loop!" << N << " loops left \n";
char command [1];
char * commandbuff;
std::cin >> command;
commandbuff = &command[1];
WriteFile(file, commandbuff, sizeof(commandbuff),&written, NULL);
Sleep(1000);
std::cout << "I just slept \n";
ReadFile(file, buffer, sizeof(buffer), &read, NULL);
N--;
}
// close up and go home.
CloseHandle(file);
return 0;

Answer 1

Your code doesn't appear to actually call SetCommTimeouts, so the timeouts you have defined would have no way to be applied.

Answer 2

Receiving data from a com port, don't start reading unless you have first sent a command or something that gets a response. Then, it's preferable to just read one byte at a time, but if you are sending modbus/at commands like I'm doing and know you're expecting 8 bytes back, then it's ok to use readfile to read 8 bytes. Most of the C++ com port examples have SetCommState, SetCommTimeouts, SetCommMask and WaitCommEvent before you can read that single byte.
Mine had an "&" on the second parameter of ReadFile. MS Visual C++ though.
Status = ReadFile(fileusb, &ReadData, sizeof(ReadData), &NoBytesRead, NULL);