In short: you use CreateFile / open to interface to nano etc outside IDE, right?

Or wrong? I know, try it out, but I d like an informed reply better. So I go ahead and implement an interface in C++ with CreateFile() or in C with open() and read/write to arduino in my own process without the IDE? I want to start from scratch, ie, no library interface support unless I define it (COM, sockets, etc). Anything you should know about arduino drivers to achieve this? Clashes with the IDE, any? I want this C++/C interface to be as standalone as possible, obviously, and not waste time in trying out proofs of concept.

Any PC programming language that can open a serial port over a USB connection can talk to an Arduino.

Make sure that your PC program opens the port and keeps it open until it is completely finished with the Arduino because, normally, the Arduino will reset when the port is opened. That also means that your PC program should allow time for the Arduino reset process before trying to send data to the Arduino.

This Python - Arduino demo may be of interest. The techniques should be suitable for ay language.

...R

and not waste time in trying out proofs of concept.

A proof of concept is NOT a waste of time.

Rambling, incoherent questions like yours are.

Rambling, incoherent questions like yours are.

Learn English first, then stalk all over the internet, (and in person as well?)

... the Arduino will reset when the port is opened. That ...

!!! Bootloader behaviour? Do you know how to solve this issue? Is this the revert to blink lost sketch problem?

syntotic:
Do you know how to solve this issue?

Yes. It is in the example code in the link I gave you.

...R

Sorry, I do not see where your py script solves the connection-reset issue in the arduino. I am not sure python Serial is equivalent to C/C++ open functions, and the same goes fr Java. I d like to be as low level in the PC as you can be in an arduino, though even arduino is hiding behind higher level librarues and code.

It is clear I can use standard comm in C/C++ to emulate Serial() as in the IDE. But the auto-reset-on-port-opening matter is not clear. It is missing a straight state machine to describe the connect-reset-power-unplug states of arduino in relation to a PC. Or in other words, how do you connect through serial to an arduino without having the arduino reset (and possibly losing its script orhiding it with blink)?

syntotic:
Sorry, I do not see where your py script solves the connection-reset issue in the arduino.

It solves the problem by avoiding the problem. It knows that the Arduino will reset and it waits for that to happen. Then it keeps the serial port open so that there are no subsequent resets. I don't understand why your C++ code can't do the same thing.

Or in other words, how do you connect through serial to an arduino without having the arduino reset (and possibly losing its script orhiding it with blink)?

The Arduino will certainly not lose any program when it resets.

If you really do need to prevent the reset there are various things that you can do to the arduino hardware. Google "arduino disable auto reset". But if you do that it makes re-programming the Arduino inconvenient.

Another option is to use a separate USB-TTL cable connected to Pins 0 and 1 (Rx and Tx) rather than using the standard USB connection.

And the Arduino boards that use the 32U4 MCU (Leonardo and Micro) do not normally reset when the serial port is opened. But that can also be very inconvenient when you are developing a program.

...R