How to understand PlatformIO?

Question

Arduino

Hello.
In the process of wandering around the Internet, I suddenly stumbled upon Platform IO.
Googled a little. I found common words that they say "cool toolchain" and all that. Ummm, well, in principle, I understand what a toolchain is, but...
I went to the main page. I see, for example:
BluePill F103C6 Arduino, CMSIS, STM32Cube
And here I am lost. I usually write with Arduino. I tried a little under STM. I was convinced that in STM there are solid Cs and appnotes, from which you can accumulate what you need.
But.
From the line on Platform IO, it seems that STM can be programmed in Arduino Style.
Now, in fact, the question is: what is Platform IO? IDE? Compiler? A set of libraries? They really washed down a bunch of libraries so that it was possible to write Serial.print("hello world"); regardless of the specific microcontroller; and will it work? Or are these 100,500 boards on the list just an opportunity to program them all from one IDE, but there will be no intersections in terms of libraries at all?
PS: Well, so as not to get up twice - can you somehow program the STM32 so that it looks like OOP, and not like copy-paste appnot?

Answer 1

platformio is, firstly, a framework. It sets the general description format and project structure for microcontrollers, being able to install toolchains and assemble projects for different configurations. And like cmake, it can generate project files to work in various IDEs.
Secondly, it is also a plugin for vscode (you can use it without vscode, via the command line).
The thing is nice and easy to use, I like it.

Answer 2

It is an IDE based on the VS Code editor.

but there will be no intersections in terms of libraries at all?

If one platform (for example, Arduino for Atmel and for ESP32) - there will be intersections.