This page describes the X server's current coding style. While the server was recently reformatted to fit this style, most modules have varied and disparate coding styles. Above all, the cardinal rule is to fit in: make sure your changes reflect the coding style of the surrounding code.
We use the indent command line in this script here: https://gitlab.freedesktop.org/xorg/util/modular/-/blob/master/x-indent.sh with manual editing afterwards to fix the cases where indent gets hopelessly confused.
- Four-space indents (no tabs, not even if your editor wants to collapse eight consecutive spaces down to a single tab)
- 78-column limit
- Function return type (and any modifiers, eg
static) on a line by itself - Opening curly brace on the same line as the control construct:
if (foo) {- Closing braces aligned with the keyword that opened them (K&R not GNU)
elseon a new line from the closing } of the precedingif(i.e. not cuddling)
- Opening curly brace for functions in column 0
- Keywords punctuated like
if (x >= 0) - Functions punctuated like
doSomethingClever(a, b, c); casealigned in the same column as theswitch- If wrapping is required, function arguments to be aligned to the opening parenthesis of that column
- Wrap structs in typedefs
- C-style comments, rather than C++/C99-style
// foo - C89 + some extensions, see https://gitlab.freedesktop.org/xorg/xserver/-/blob/master/doc/c-extensions
Notable objectionable things in the current coding style:
- Most structs have a typedef both for the struct and for a pointer to the struct.