How to process stream in real time?

Question

C++ / C#

I don't even know how to phrase it. So I'll give you an example.
Let's say I decided to make a text editor with syntax highlighting. But the syntax highlighting should not work when I press some button, but in real time.
How is this done? I don't even know how to google it.

Answer 1

Multithreading. One thread waits for input from the keyboard, another one checks and highlights the syntax, the third one draws a clock in the corner, the fourth one in the background saves the current one to a temporary file...

Answer 2

And in "real time" is when?

Answer 3

Realtime is not on windows or Linux
Need a realtime operating system.
But in the background - then "almost immediately" - we have already described above about mogoflow.