@setfilename standards.info
@settitle GNU Coding Standards
@c This date is automagically updated when you save this file:
-@set lastupdate February 13, 2013
+@set lastupdate December 17, 2013
@c %**end of header
@dircategory GNU organization
@cindex programming languages
When you want to use a language that gets compiled and runs at high
-speed, the best language to use is C. Using another language is like
-using a non-standard feature: it will cause trouble for users. Even if
-GCC supports the other language, users may find it inconvenient to have
-to install the compiler for that other language in order to build your
-program. For example, if you write your program in C++, people will
-have to install the GNU C++ compiler in order to compile your program.
-
-C has one other advantage over C++ and other compiled languages: more
-people know C, so more people will find it easy to read and modify the
-program if it is written in C.
-
-So in general it is much better to use C, rather than the
-comparable alternatives.
-
-But there are two exceptions to that conclusion:
-
-@itemize @bullet
-@item
-It is no problem to use another language to write a tool specifically
-intended for use with that language. That is because the only people
-who want to build the tool will be those who have installed the other
-language anyway.
-
-@item
-If an application is of interest only to a narrow part of the community,
-then the question of which language it is written in has less effect on
-other people, so you may as well please yourself.
-@end itemize
+speed, the best language to use is C. C++ is ok too, but please don't
+make heavy use of templates. So is Java, if you compile it.
+
+When highest efficiency is not required, other languages commonly used
+in the free software community, such as Scheme, Python, Ruby, and
+Java, are OK too. Scheme, as implemented by GNU@tie{}Guile, plays a
+particular role in the GNU System: it is the preferred language to
+extend programs written in C/C++, and also a fine language for a wide
+range of applications. The more GNU components use Guile and Scheme,
+the more users are able to extend and combine them (@pxref{The Emacs
+Thesis,,, guile, GNU Guile Reference Manual}).
Many programs are designed to be extensible: they include an interpreter
for a language that is higher level than C. Often much of the program
Guile also includes bindings for GTK+/GNOME, making it practical to
write modern GUI functionality within Guile. We don't reject programs
written in other ``scripting languages'' such as Perl and Python, but
-using Guile is very important for the overall consistency of the GNU
-system.
+using Guile is the path that will lead to overall consistency of the
+GNU system.
@node Compatibility
@url{http://www.apache.org/@/licenses}.
@item Artistic
-The Artistic license used for Perl, @url{http://www.perlfoundation.org/@/legal}.
+The Artistic license used for Perl, @url{http://dev.perl.org/licenses/artistic.html}.
@item Expat
The Expat license, @url{http://www.jclark.com/@/xml/@/copying.txt}.
@cindex X.509
The OID (object identifier) 1.3.6.1.4.1.11591 has been assigned to the
-GNU Project (thanks to Werner Koch). These are used for SNMP, LDAP,
-X.509 certificates, and so on. The web site
+GNU Project (thanks to Sergey Poznyakoff). These are used for SNMP,
+LDAP, X.509 certificates, and so on. The web site
@url{http://www.alvestrand.no/objectid} has a (voluntary) listing of
many OID assignments.
@section Formatting Your Source Code
@cindex formatting source code
+@cindex line length
+@cindex length of source lines
+Please keep the length of source lines to 79 characters or less, for
+maximum readability in the widest range of environments.
+
@cindex open brace
@cindex braces, in C source
@cindex function definitions, formatting
@section Mmap
@findex mmap
-Don't assume that @code{mmap} either works on all files or fails
-for all files. It may work on some files and fail on others.
+If you use @code{mmap} to read or write files, don't assume it either
+works on all files or fails for all files. It may work on some files
+and fail on others.
The proper way to use @code{mmap} is to try it on the specific file for
which you want to use it---and if @code{mmap} doesn't work, fall back on
the framework for a beginner to understand the rest of the manual. The
Bison manual provides a good example of how to do this.
-To serve as a reference, a manual should have an Index that list all the
-functions, variables, options, and important concepts that are part of
-the program. One combined Index should do for a short manual, but
-sometimes for a complex package it is better to use multiple indices.
-The Texinfo manual includes advice on preparing good index entries, see
-@ref{Index Entries, , Making Index Entries, texinfo, GNU Texinfo}, and
-see @ref{Indexing Commands, , Defining the Entries of an
+To serve as a reference, a manual should have an Index that lists all
+the functions, variables, options, and important concepts that are
+part of the program. One combined Index should do for a short manual,
+but sometimes for a complex package it is better to use multiple
+indices. The Texinfo manual includes advice on preparing good index
+entries, see @ref{Index Entries, , Making Index Entries, texinfo, GNU
+Texinfo}, and see @ref{Indexing Commands, , Defining the Entries of an
Index, texinfo, GNU Texinfo}.
Don't use Unix man pages as a model for how to write GNU documentation;
@example
--prefix --exec-prefix --bindir --sbindir --libexecdir --sysconfdir
---sharedstatedir --localstatedir --libdir --includedir --oldincludedir
+--sharedstatedir --localstatedir --runstatedir
+--libdir --includedir --oldincludedir
--datarootdir --datadir --infodir --localedir --mandir --docdir
--htmldir --dvidir --pdfdir --psdir
@end example
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