How does Notepad determine the encoding of a file?

Question

Character encoding

I create an empty file in far without an extension with ansi 1251 or utf8 encoding.
I open it with notepad, click "save as" and see that notepad already offers ansi or utf, respectively.
How does this happen?

Answer 1

Far, when saving a file in UTF-8, writes a marker (EF BB BF) at the beginning of the BOM file, indicating that all text is further encoded using UTF-8 encoding. And when saving in ANSI - writes nothing. UTF8 may not contain a BOM - in which case it is up to the editor and/or user to determine the encoding. Some editors, analyzing a string, are able to determine the correct encoding with a tangible degree of probability.

Answer 2

Maybe the file is not completely empty?
An empty file is just 0 bytes, with no streams and absolutely no information, not even encoding. That is, it contains absolutely no information at all, at all.
I just checked - I created an empty one, "changed" the encoding to UTF-8 + BOM (because notepad only knows how to use BOM), saved it - voila, the file has become 3 bytes - tell me what's in these 3 bytes?