C-mode

C

Library	cc-mode
Command	c-mode
Builtin	yes
Auto-activates for	*.c *.h *.xbm *.xpm *.y *.yacc *.lex *.i *.m

c-mode is the default major mode for editing C source files (.c and .h files). It uses cc-mode.

Basic setup

c-mode is bundled with Emacs by default. No additional setup is required.

Helpful keybindings

[C-M-a]

Go to the beginning of the current function. If you are between 2 functions, go the start of the previous one.

[C-M-e]

Go to the end of the current function. If you are between 2 functions, go to the end of the next one.

Common Customization

Style

Any mode based on cc-mode provides automatic indentation. The default style is gnu. It is the one recommended by the Free Software Foundation for GNU projects but you can use a different one.

Here is a basic list of predefined styles:

gnu

The default style for GNU projects

k&r

What Kernighan and Ritchie, the authors of C used in their book

bsd

What BSD developers use, aka “Allman style” after Eric Allman.

whitesmith

Popularized by the examples that came with Whitesmiths C, an early commercial C compiler.

stroustrup

What Stroustrup, the author of C++ used in his book

ellemtel

Popular C++ coding standards as defined by “Programming in C++, Rules and Recommendations,” Erik Nyquist and Mats Henricson, Ellemtel

linux

What the Linux developers use for kernel development

python

What Python developers use for extension modules

java

The default style for java-mode (see below)

user

When you want to define your own style

You can look the cc-mode documentation for a complete list of builtin style. For visual example of each style you can look the Wikipedia article on indenting style.

• The default style is set via the variable c-default-style
• Use [C-c .] (or M-x c-set-style) to change the indentation style of the current buffer.
• The amount of space use to indent is set via the variable c-basic-offset.

To set the default style to K&R and use 4 spaces, add this to your Emacs configuration file:

; set k&r style
(setq c-default-style "k&r")
; indent with 4 spaces
(setq c-basic-offset 4)

Project Pages

• cc-mode