CStyle

CStyle is a simple tool to check the conformance of C/C++ coding against a predefined style convention for variable / function naming etc.

CStyle uses libclang to parse and identify elements (variable declarations, function names / parameters etc) and then simply checks each against a list of rules.

Installation

git clone https://github.com/alexmurray/cstyle.git
cd cstyle
pip3 install .
cstyle --generate-config > ~/.cstyle
# edit ~/.cstyle as required

Usage

cstyle supports a few command-line arguments:

• --generate-config - Generate a sample configuration file

• --config - Used to specify the path to the configuration file (See Configuration below)

• --msg-template - Used to specify the template string for outputting messages. This is specified as a Python new-style format string. This supports the following named arguments:

  • file - the path to the file
  • line - the line of the message
  • column - the column number of the identifier which the message concerns
  • reason - a human readable description of the message

  The default is '{file}:{line}:{column}: {reason}'

See cstyle --help for more details.

Configuration

CStyle is configured using a configuration file (a sample configuration can be automatically generated with the --generate-config command-line argument). This defaults to ~/.cstyle but a particular configuration can be specified using the --config command-line option.

The configuration file supports some basic options in the Options section:

• ignore_leading_underscores - If set to true ignore any leading underscores in variable and function names - these will be stripped before checking for any possible pointer_prefix or name format etc.

• ignore_goto - If set to true, will ignore all gotos - disables prefer_goto checking.

• prefer_goto - If set to true, will warn when multiple return statements exist in a single function. However, if set to false will warn about any use of goto at all.

• pointer_prefix - If a variable is a pointer, this prefix is checked to exist at the start of the variable name. To disable simply remove this configuration option from the configuration file.

• pointer_prefix_repeat - If set to true (and pointer_prefix is set), then the pointer_prefix is expected to be repeated by the depth of the pointer. i.e. for the argument char **ppArgv, pointer_prefix should be set to p and pointer_prefix_repeat should be true.

• arrays_are_pointers - If a variable is an array, treat it as a pointer for pointer_prefix and related checks.

Rules for naming variables are specified in the Rules section - these specify a libclang kind and the associated regular expression to validate the name. For instance, var_decl is used to specify the regular expression for all variable declarations.

For more information on the various libclang kinds see the libclang documentation for the CursorKind type. NOTE: In the cstyle configuration file, each kind is specified as lowercase without the CXCursor_ prefix, with the CamelCase suffix written in snake_case.

Requirements

• python3
• python-clang

Emacs Integration

To integrate with Emacs there are two options - either standalone or via flycheck.

For standalone usage see cstyle.el.

To integrate with flycheck see flycheck-cstyle.

Vim Integration

To integrate with vim via syntastic see syntastic-cstyle.