What is an Erlang hrl file?

Question

What is an .hrl file in Erlang/OTP? Is it some sort of library mechanism?

Answer 1

A "header file" akin to a "C" include file.

One needs to invoke the -include directive from an .erl file to use them. Can contain any valid Erlang code.

Answer 2

实际文档是http://www.erlang.org/doc/reference_manual/macros.html

Answer 3

.hrl 文件只是 erlang“头文件”，即包含旨在包含在 .erl 文件中的通用定义的文件。