May 13, 2021 Erlang
As shown above, some files have an extension of .hrl. T hese are the header files that are used in the .erl file, using the following methods:
-include("File_Name").For example:
-include("mess_interface.hrl").In this case, all the files above are in the same directory as the other files in the messager system.
The .hrl file can contain any legitimate Erlang code, but it usually contains only a few records and macro definitions.