Snake case

Snake case (sometimes stylized autologically as snake_case) is the naming convention in which each space is replaced with an underscore (_) character, and words are written in lowercase.

[1] A variation is screaming snake case, where words are written in all caps (stylized as SCREAMING_SNAKE_CASE).

[2] This convention is used for constants in programming languages like C/C++, Python, Java, PHP, as well as for environment variables.

However, the convention traditionally had no specific name: the Python programming language style guide refers to it simply as "lower_case_with_underscores".

[3] Within Usenet the term snake_case was first seen in the Ruby community in 2004,[4] used by Gavin Kistner, writing: BTW...what *do* you call that naming style?

Piece of code from a module of the Linux kernel , which uses snake case for identifiers