NAME¶

cpplint - Static code checker for C++

DESCRIPTION¶

Syntax: cpplint.py [--verbose=#] [--output=emacs|eclipse|vs7|junit|sed|gsed]

[--filter=-x,+y,...] [--counting=total|toplevel|detailed] [--root=subdir] [--repository=path] [--linelength=digits] [--headers=x,y,...] [--recursive] [--exclude=path] [--extensions=hpp,cpp,...] [--includeorder=default|standardcfirst] [--quiet] [--version]

<file> [file] ...

Style checker for C/C++ source files. This is a fork of the Google style checker with minor extensions.

The style guidelines this tries to follow are those in

https://google.github.io/styleguide/cppguide.html

Every problem is given a confidence score from 1-5, with 5 meaning we are certain of the problem, and 1 meaning it could be a legitimate construct. This will miss some errors, and is not a substitute for a code review.

To suppress false-positive errors of a certain category, add a 'NOLINT(category)' comment to the line. NOLINT or NOLINT(*) suppresses errors of all categories on that line.

The files passed in will be linted; at least one file must be provided. Default linted extensions are ['c', 'c++', 'cc', 'cpp', 'cu', 'cuh', 'cxx', 'h', 'h++', 'hh', 'hpp', 'hxx']. Other file types will be ignored. Change the extensions with the --extensions flag.

Flags:

output=emacs|eclipse|vs7|junit|sed|gsed

By default, the output is formatted to ease emacs parsing.

Visual Studio

compatible output (vs7) may also be used.

Further support exists for

eclipse (eclipse), and JUnit (junit). XML parsers such as those used in Jenkins and Bamboo may also be used. The sed format outputs sed commands that should fix some of the errors. Note that this requires gnu sed. If that is installed as gsed on your system (common e.g. on macOS with homebrew) you can use the gsed output format. Sed commands are written to stdout, not stderr, so you should be able to pipe output straight to a shell to run the fixes.

verbose=#

Specify a number 0-5 to restrict errors to certain verbosity levels. Errors with lower verbosity levels have lower confidence and are more likely to be false positives.

quiet

Don't print anything if no errors are found.

filter=-x,+y,...

Specify a comma-separated list of category-filters to apply: only error messages whose category names pass the filters will be printed. (Category names are printed with the message and look like "[whitespace/indent]".) Filters are evaluated left to right. "-FOO" means "do not print categories that start with FOO". "+FOO" means "do print categories that start with FOO".

Examples: --filter=-whitespace,+whitespace/braces

--filter=-whitespace,-runtime/printf,+runtime/printf_format --filter=-,+build/include_what_you_use

To see a list of all the categories used in cpplint, pass no arg:

--filter=

counting=total|toplevel|detailed

The total number of errors found is always printed. If 'toplevel' is provided, then the count of errors in each of the top-level categories like 'build' and 'whitespace' will also be printed. If 'detailed' is provided, then a count is provided for each category like 'build/class'.

repository=path

The top level directory of the repository, used to derive the header guard CPP variable. By default, this is determined by searching for a path that contains .git, .hg, or .svn. When this flag is specified, the given path is used instead. This option allows the header guard CPP variable to remain consistent even if members of a team have different repository root directories (such as when checking out a subdirectory with SVN). In addition, users of non-mainstream version control systems can use this flag to ensure readable header guard CPP variables.

Examples:

Assuming that Alice checks out ProjectName and Bob checks out ProjectName/trunk and trunk contains src/chrome/ui/browser.h, then with no --repository flag, the header guard CPP variable will be:

Alice => TRUNK_SRC_CHROME_BROWSER_UI_BROWSER_H_ Bob => SRC_CHROME_BROWSER_UI_BROWSER_H_

If Alice uses the --repository=trunk flag and Bob omits the flag or uses --repository=. then the header guard CPP variable will be:

Alice => SRC_CHROME_BROWSER_UI_BROWSER_H_ Bob => SRC_CHROME_BROWSER_UI_BROWSER_H_

root=subdir

The root directory used for deriving header guard CPP variable. This directory is relative to the top level directory of the repository which by default is determined by searching for a directory that contains .git, .hg, or .svn but can also be controlled with the --repository flag. If the specified directory does not exist, this flag is ignored.

Examples:

Assuming that src is the top level directory of the repository (and cwd=top/src), the header guard CPP variables for src/chrome/browser/ui/browser.h are:

No flag => CHROME_BROWSER_UI_BROWSER_H_ --root=chrome => BROWSER_UI_BROWSER_H_ --root=chrome/browser => UI_BROWSER_H_ --root=.. => SRC_CHROME_BROWSER_UI_BROWSER_H_

linelength=digits

This is the allowed line length for the project. The default value is 80 characters.

Examples:

--linelength=120

recursive

Search for files to lint recursively. Each directory given in the list of files to be linted is replaced by all files that descend from that directory. Files with extensions not in the valid extensions list are excluded.

exclude=path

Exclude the given path from the list of files to be linted. Relative paths are evaluated relative to the current directory and shell globbing is performed. This flag can be provided multiple times to exclude multiple files.

Examples:

--exclude=one.cc

--exclude=src/*.cc

--exclude=src/*.cc --exclude=test/*.cc

extensions=extension,extension,...

The allowed file extensions that cpplint will check

Examples:

--extensions=c,c++,cc,cpp,cu,cuh,cxx,h,h++,hh,hpp,hxx

includeorder=default|standardcfirst

For the build/include_order rule, the default is to blindly assume angle bracket includes with file extension are c-system-headers (default), even knowing this will have false classifications. The default is established at google. standardcfirst means to instead use an allow-list of known c headers and treat all others as separate group of "other system headers". The C headers included are those of the C-standard lib and closely related ones.

headers=x,y,...

The header extensions that cpplint will treat as .h in checks. Values are automatically added to --extensions list.

(by default, only files with extensions ['cuh', 'h', 'h++', 'hh', 'hpp', 'hxx'] will be assumed to be headers)

Examples:

--headers=cuh,h,h++,hh,hpp,hxx

--headers=hpp,hxx

--headers=hpp

cpplint.py supports per-directory configurations specified in CPPLINT.cfg files. CPPLINT.cfg file can contain a number of key=value pairs. Currently the following options are supported:

set noparent filter=+filter1,-filter2,... exclude_files=regex linelength=80 root=subdir headers=x,y,...

"set noparent" option prevents cpplint from traversing directory tree upwards looking for more .cfg files in parent directories. This option is usually placed in the top-level project directory.

The "filter" option is similar in function to --filter flag. It specifies message filters in addition to the |_DEFAULT_FILTERS| and those specified through --filter command-line flag.

"exclude_files" allows to specify a regular expression to be matched against a file name. If the expression matches, the file is skipped and not run through the linter.

"linelength" allows to specify the allowed line length for the project.

The "root" option is similar in function to the --root flag (see example above). Paths are relative to the directory of the CPPLINT.cfg.

The "headers" option is similar in function to the --headers flag (see example above).

CPPLINT.cfg has an effect on files in the same directory and all sub-directories, unless overridden by a nested configuration file.

Example file:

filter=-build/include_order,+build/include_alpha exclude_files=.*\.cc

The above example disables build/include_order warning and enables build/include_alpha as well as excludes all .cc from being processed by linter, in the current directory (where the .cfg file is located) and all sub-directories.