Linter swears at the lack of a header file, although everything is in the same folder, what should I do?

Question

Sublime Text

I write:
#include "add.h"
Linter writes:

clang++: error
error - 'add.h' file not found

Although everything is in the same folder, what's the problem?
Everything compiles and works as it should, the problem is purely that the linter does not see the header file

Answer 1

Does the linter know where to look for additional header files? You may need to tell it the path to the folder they are in