What is a "system error"?

Question

C++ / C#

Good afternoon friends!
In the course of a thorough study of the main function in the C language, I came across the concept of "system error". I tried to find a definition of this concept, but could not. Hence the question: what is a system error? It would be great to back up with an example
Thanks for the answer! I could have made a mistake in the tags, I did not know where to put the question

Answer 1

https://msdn.microsoft.com/en-us/library/windows/d...
https://habr.com/post/336012/
Maybe it will become clearer.