Notepad++ autocomplete for multiple files (whole project)

Is there a way to tell notepad++ to include multiple files (libraries) or possibly my whole project for autocomplete so I get suggestions for function names that are in another file?

Can Notepad ++ autocomplete?

Notepad++ provides 2 types of features for auto-completion and suggestions: Auto-completion that reads the open file and provide suggestion of words and/or functions within the file.

Does Notepad have autocomplete?

What is Auto-completion. Notepad++ offers automatic completion of various sorts of text after you have entered an initial substring (or prefix), which can save you having to type all of a long word (and potentially save you mistyping it).

Does Notepad ++ have intellisense?

Now the good news! If you are rather a fan of writing your code in a more lightweight editor like Notepad++, you don't have to completely give up the autocomplete support. Even Notepad++ comes with a auto-completion feature.

It seems not such baked solution exists now.

However, you can vote for the following idea in the Idea Torrent: Idea #181: autocompletion across opened documents