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__NOTOC__
  
__NOTOC__
−
The C language '''Coding style''' described here is based on the BSD coding style, with some additional elements from the GNU coding standards and the SunOS coding standards.
 +
The C language '''Coding style''' described here is based on the BSD coding style (Kernel Normal Form - KNF), with some additional elements from the GNU coding standards and the SunOS coding standards.
   
 
* [[Coding style/Formatting|Formatting]]
  
* [[Coding style/Formatting|Formatting]]
 
* [[Coding style/Practices|Practices]]
  
* [[Coding style/Practices|Practices]]
  +
* [[Coding style/Style checker|Style checker]]
  +
* [[Coding style/Version control practices|Version control practices]]
  +
* [[Coding style/Transition_strategies|Transition strategies]]
  +
* [[Coding style/Reindenting|Reindenting]]
   
 
== External links ==
  
== External links ==
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* [http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style?rev=HEAD NetBSD <code>/usr/share/misc/style</code>] [http://cvsweb.netbsd.org/bsdweb.cgi/src/share/misc/style (log)]
  
* [http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style?rev=HEAD NetBSD <code>/usr/share/misc/style</code>] [http://cvsweb.netbsd.org/bsdweb.cgi/src/share/misc/style (log)]
 
* [http://www.gnu.org/prep/standards/ GNU coding standards]
  
* [http://www.gnu.org/prep/standards/ GNU coding standards]
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* [http://opensolaris.org/os/community/documentation/getting_started_docs/cstyle.ms.pdf C Style and Coding Standards for SunOS]
 +
* [http://opensolaris.org/os/community/on/cstyle.ms.pdf C Style and Coding Standards for SunOS]
−  
−
== Old version ==
  
−  
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Old content to be moved elsewhere is below.
  
−  
−
----
  
−  
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== WRITING C CODE ==
  
−  
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The code in the krb5 source tree largely follows BSD KNF
  
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(/usr/share/misc/style on NetBSD) except that it uses a four column
  
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basic offset. The style described here is a synthesis of BSD KNF and
  
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the GNU coding standards for the C language. The formatting described
  
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in the "Formatting Your Source Code" section of the GNU coding
  
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standards is mostly what we want, except we use BSD brace style and
  
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BSD-ish conventions for the spacing around operators.
  
−  
−
=== Coding practices for C ===
  
   
  +
== General information ==
   
 
=== Aspects of C style in GNU coding std but not here ===
  
=== Aspects of C style in GNU coding std but not here ===
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=== Emacs cc-mode style ===
  
=== Emacs cc-mode style ===
   
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Putting the following code in your .emacs file will result in mostly
  
  +
Load the elisp file {{trunkref|src/util/krb5-c-style.el}} to get mostly
−
the right thing happening with respect to formatting style. Note that
  
  +
the right thing to happen with respect to formatting style. <code>krb5-c-style.el</code> uses a heuristic to detect whether a file should have the "krb5" C coding style applied. Currently, it uses the combined presence of <code>c-basic-offset:&nbsp;4</code> and <code>indent-tabs-mode:&nbsp;nil</code> as a signal to use the "krb5" style. See [[Coding_style/Transition strategies]] for some details. Also, if you are newly adding the file-local variable settings line to a file, use <code>M-x&nbsp;normal-mode</code> to reinitialize cc-mode with the new settings.
⚫
you may want to turn on auto-newline feature of cc-mode, though that
  
⚫
seems to have some bugs with brace-elseif-brace handling at least in
  
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the version of cc-mode that comes with emacs 20.3.
  
   
−
(defconst krb5-c-style
  
  ⚫
You may want to turn on auto-newline feature of cc-mode, though that
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'("bsd"
 
  ⚫
seems to have some bugs with brace-elseif-brace handling at least in
−
(c-cleanup-list
  
  +
old versions of cc-mode (Emacs 20.3 or so).
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brace-elseif-brace brace-else-brace defun-close-semi)
  
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(c-comment-continuation-stars . "* ")
  
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(c-electric-pound-behavior alignleft)
  
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(c-hanging-braces-alist
  
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(brace-list-open)
  
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(class-open after)
  
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(substatement-open after)
  
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(block-close . c-snug-do-while)
  
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(extern-lang-open after))
  
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(c-hanging-colons-alist
  
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(case-label after)
  
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(label after))
  
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(c-hanging-comment-starter-p)
  
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(c-hanging-comment-ender-p)
  
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(c-indent-comments-syntactically-p . t)
  
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(c-label-minimum-indentation . 0)
  
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(c-special-indent-hook)))
  
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(defun krb5-c-hook ()
  
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(c-add-style "krb5" krb5-c-style t))
  
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(add-hook 'c-mode-common-hook 'krb5-c-hook)
  
   
 
You might also want to try (for Emacs 22 and later):
  
You might also want to try (for Emacs 22 and later):
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(add-hook 'before-save-hook 'copyright-update)
  
(add-hook 'before-save-hook 'copyright-update)
   
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to let you automatically update the year in the top-most copyright notice in a file when you save it.
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which will offer to update the year in the top-most copyright notice in a file when you save it, if it's not already current.
   
 
=== indent.pro settings ===
  
=== indent.pro settings ===
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reasonable approximation to the C coding style described here, though
  
reasonable approximation to the C coding style described here, though
 
some manual cleanup may be necessary. Note that the gindent installed
  
some manual cleanup may be necessary. Note that the gindent installed
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in the gnu locker does not currently handle -psl correctly though.
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in the gnu locker does not currently handle -nut or -psl correctly though.
   
 
<pre>
  
<pre>
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-nbc
  
-nbc
 
-ncdb
  
-ncdb
  +
-ncs
 
-ndj
  
-ndj
 
-nfc1
  
-nfc1
 
-lp
  
-lp
 
-npcs
  
-npcs
  +
-nut
 
-psl
  
-psl
 
-sc
  
-sc
 
-sob
  
-sob
  +
</pre>
  +
  +
=== vim/gvim editor settings ===
  +
These settings allow the vim or gvim editor to conform to the MITKC code style:
  +
  +
<pre>
  +
set shiftwidth=4
  +
set tabstop=8
  +
set softtabstop=4
  +
set expandtab
  +
set nosmartindent
  +
set cindent
  +
set cinoptions=p0,t0,+4,(0,u4,U1,:0
  +
set formatoptions=croq
  +
set comments=sr:/*,mb:*,ex:*/,://
  +
set textwidth=79
 
</pre>
  
</pre>

Latest revision as of 12:59, 2 February 2016

The C language Coding style described here is based on the BSD coding style (Kernel Normal Form - KNF), with some additional elements from the GNU coding standards and the SunOS coding standards.

External links

General information

Aspects of C style in GNU coding std but not here

  • redundant parens to force extra indent of operators of different precedences
  • redundant parens to force general extra indent of expressions that are broken between lines
  • use of ^L characters to break up source files into pages
  • nitpicking about capitalization in comments of variable names when their values are meant
  • commenting usages of static variables
  • casts to void
  • separation of word in names with underscores vs case change
  • enum vs #define'd integer constants
  • 14 char filename limits, MS-DOS filename limits
  • portability
  • system library function quirks
  • internationalization
  • mmap()

Aspects of C style in BSD KNF but not here

  • sorting of header files
  • sorting of struct members
  • separating struct tag decl and struct typedef
  • sorting of var decl
  • lining up var names in decls
  • newline after decls
  • usage of __P
  • usage of getopt
  • not initializing vars in decls
  • stdarg/varargs handling

Emacs cc-mode style

Load the elisp file src/util/krb5-c-style.el (raw | annotated | history) to get mostly the right thing to happen with respect to formatting style. krb5-c-style.el uses a heuristic to detect whether a file should have the "krb5" C coding style applied. Currently, it uses the combined presence of c-basic-offset: 4 and indent-tabs-mode: nil as a signal to use the "krb5" style. See Coding_style/Transition strategies for some details. Also, if you are newly adding the file-local variable settings line to a file, use M-x normal-mode to reinitialize cc-mode with the new settings.

You may want to turn on auto-newline feature of cc-mode, though that seems to have some bugs with brace-elseif-brace handling at least in old versions of cc-mode (Emacs 20.3 or so).

You might also want to try (for Emacs 22 and later): 

       (add-hook 'before-save-hook 'copyright-update)

which will offer to update the year in the top-most copyright notice in a file when you save it, if it's not already current.

indent.pro settings

The following settings for the indent program should produce a reasonable approximation to the C coding style described here, though some manual cleanup may be necessary. Note that the gindent installed in the gnu locker does not currently handle -nut or -psl correctly though. 

-bap
-br
-ce
-ci4
-cli0
-d0
-di8
-i4
-ip4
-l79
-nbc
-ncdb
-ncs
-ndj
-nfc1
-lp
-npcs
-nut
-psl
-sc
-sob

vim/gvim editor settings

These settings allow the vim or gvim editor to conform to the MITKC code style: 

set shiftwidth=4
set tabstop=8
set softtabstop=4
set expandtab
set nosmartindent
set cindent 
set cinoptions=p0,t0,+4,(0,u4,U1,:0
set formatoptions=croq
set comments=sr:/*,mb:*,ex:*/,://
set textwidth=79
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