NEWS.stable: log cherry-pick [a228f53]->[0b86eb2] lseek: fix link test

[gnulib.git] / doc / standards.texi

diff --git a/doc/standards.texi b/doc/standards.texi
index 5b56541..bd41a3a 100644 (file)
--- a/doc/standards.texi
+++ b/doc/standards.texi
@@ -3,7 +3,7 @@
 @setfilename standards.info
 @settitle GNU Coding Standards
 @c This date is automagically updated when you save this file:
 @setfilename standards.info
 @settitle GNU Coding Standards
 @c This date is automagically updated when you save this file:

-@set lastupdate September 14, 2009
+@set lastupdate August 24, 2010

 @c %**end of header
 
 @dircategory GNU organization
 @c %**end of header
 
 @dircategory GNU organization


@@ -27,7 +27,7 @@
 The GNU coding standards, last updated @value{lastupdate}.
 
 Copyright @copyright{} 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
 The GNU coding standards, last updated @value{lastupdate}.
 
 Copyright @copyright{} 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,

-2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software
+2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software

 Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document


@@ -81,9 +81,6 @@ programs written in C, but many of the rules and principles are useful
 even if you write in another programming language.  The rules often
 state reasons for writing in a certain way.
 
 even if you write in another programming language.  The rules often
 state reasons for writing in a certain way.
 

-This release of the GNU Coding Standards was last updated
-@value{lastupdate}.
-

 @cindex where to obtain @code{standards.texi}
 @cindex downloading this manual
 If you did not obtain this file directly from the GNU project and
 @cindex where to obtain @code{standards.texi}
 @cindex downloading this manual
 If you did not obtain this file directly from the GNU project and


@@ -92,11 +89,29 @@ Coding Standards from the GNU web server in many
 different formats, including the Texinfo source, PDF, HTML, DVI, plain
 text, and more, at: @uref{http://www.gnu.org/prep/standards/}.
 
 different formats, including the Texinfo source, PDF, HTML, DVI, plain
 text, and more, at: @uref{http://www.gnu.org/prep/standards/}.
 

-Corrections or suggestions for this document should be sent to
-@email{bug-standards@@gnu.org}.  If you make a suggestion, please include a
-suggested new wording for it; our time is limited.  We prefer a context
-diff to the @file{standards.texi} or @file{make-stds.texi} files, but if
-you don't have those files, please mail your suggestion anyway.
+If you are maintaining an official GNU package, in addition to this
+document, please read and follow the GNU maintainer information
+(@pxref{Top, , Contents, maintain, Information for Maintainers of GNU
+Software}).
+
+@cindex @code{gnustandards-commit@@gnu.org} mailing list
+If you want to receive diffs for every change to these GNU documents,
+join the mailing list @code{gnustandards-commit@@gnu.org}, via the web
+interface at
+@url{http://lists.gnu.org/mailman/listinfo/gnustandards-commit}.
+Archives are also available there.
+
+@cindex @code{bug-standards@@gnu.org} email address
+@cindex Savannah repository for gnustandards
+@cindex gnustandards project repository
+Please send corrections or suggestions for this document to
+@email{bug-standards@@gnu.org}.  If you make a suggestion, please
+include a suggested new wording for it, to help us consider the
+suggestion efficiently.  We prefer a context diff to the Texinfo
+source, but if that's difficult for you, you can make a context diff
+for some other version of this document, or propose it in any way that
+makes it clear.  The source repository for this document can be found
+at @url{http://savannah.gnu.org/projects/gnustandards}.

 
 These standards cover the minimum of what is important when writing a
 GNU package.  Likely, the need for additional standards will come up.
 
 These standards cover the minimum of what is important when writing a
 GNU package.  Likely, the need for additional standards will come up.


@@ -114,6 +129,10 @@ The GNU Hello program serves as an example of how to follow the GNU
 coding standards for a trivial program.
 @uref{http://www.gnu.org/software/hello/hello.html}.
 
 coding standards for a trivial program.
 @uref{http://www.gnu.org/software/hello/hello.html}.
 

+This release of the GNU Coding Standards was last updated
+@value{lastupdate}.
+
+

 @node Legal Issues
 @chapter Keeping Free Software Free
 @cindex legal aspects
 @node Legal Issues
 @chapter Keeping Free Software Free
 @cindex legal aspects


@@ -496,7 +515,7 @@ and is not always appropriate, following this policy would have saved
 GCC developers many hours, or even days, per year.
 
 In the case of function-like macros like @code{REVERSIBLE_CC_MODE} in
 GCC developers many hours, or even days, per year.
 
 In the case of function-like macros like @code{REVERSIBLE_CC_MODE} in

-GCC which cannot be simply used in @code{if( ...)} statements, there is
+GCC which cannot be simply used in @code{if (...)} statements, there is

 an easy workaround.  Simply introduce another macro
 @code{HAS_REVERSIBLE_CC_MODE} as in the following example:
 
 an easy workaround.  Simply introduce another macro
 @code{HAS_REVERSIBLE_CC_MODE} as in the following example:
 


@@ -524,6 +543,7 @@ command line interface, and how libraries should behave.
 * User Interfaces::             Standards about interfaces generally.
 * Graphical Interfaces::        Standards for graphical interfaces.
 * Command-Line Interfaces::     Standards for command line interfaces.
 * User Interfaces::             Standards about interfaces generally.
 * Graphical Interfaces::        Standards for graphical interfaces.
 * Command-Line Interfaces::     Standards for command line interfaces.

+* Dynamic Plug-In Interfaces::  Standards for dynamic plug-in interfaces.

 * Option Table::                Table of long options.
 * OID Allocations::             Table of OID slots for GNU.
 * Memory Usage::                When and how to care about memory needs.
 * Option Table::                Table of long options.
 * OID Allocations::             Table of OID slots for GNU.
 * Memory Usage::                When and how to care about memory needs.


@@ -677,7 +697,7 @@ creating temporary files in world-writable directories.  In C, you can
 avoid this problem by creating temporary files in this manner:
 
 @example
 avoid this problem by creating temporary files in this manner:
 
 @example

-fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0600);
+fd = open (filename, O_WRONLY | O_CREAT | O_EXCL, 0600);

 @end example
 
 @noindent
 @end example
 
 @noindent


@@ -836,25 +856,32 @@ multi-column format.
 @node Graphical Interfaces
 @section Standards for Graphical Interfaces
 @cindex graphical user interface
 @node Graphical Interfaces
 @section Standards for Graphical Interfaces
 @cindex graphical user interface

+@cindex interface styles
+@cindex user interface styles

 
 

-@cindex gtk+
+@cindex GTK+

 When you write a program that provides a graphical user interface,
 When you write a program that provides a graphical user interface,

-please make it work with X Windows and the GTK+ toolkit unless the
-functionality specifically requires some alternative (for example,
-``displaying jpeg images while in console mode'').
+please make it work with the X Window System and the GTK+ toolkit
+unless the functionality specifically requires some alternative (for
+example, ``displaying jpeg images while in console mode'').

 
 In addition, please provide a command-line interface to control the
 functionality.  (In many cases, the graphical user interface can be a
 separate program which invokes the command-line program.)  This is
 so that the same jobs can be done from scripts.
 
 
 In addition, please provide a command-line interface to control the
 functionality.  (In many cases, the graphical user interface can be a
 separate program which invokes the command-line program.)  This is
 so that the same jobs can be done from scripts.
 

-@cindex corba
-@cindex gnome
-Please also consider providing a CORBA interface (for use from GNOME), a
-library interface (for use from C), and perhaps a keyboard-driven
-console interface (for use by users from console mode).  Once you are
-doing the work to provide the functionality and the graphical interface,
-these won't be much extra work.
+@cindex CORBA
+@cindex GNOME
+@cindex D-bus
+@cindex keyboard interface
+@cindex library interface
+Please also consider providing a D-bus interface for use from other
+running programs, such as within GNOME.  (GNOME used to use CORBA
+for this, but that is being phased out.)  In addition, consider
+providing a library interface (for use from C), and perhaps a
+keyboard-driven console interface (for use by users from console
+mode).  Once you are doing the work to provide the functionality and
+the graphical interface, these won't be much extra work.

 
 
 @node Command-Line Interfaces
 
 
 @node Command-Line Interfaces


@@ -1022,10 +1049,6 @@ GNU General Public License, @url{http://www.gnu.org/@/licenses/@/gpl.html}.
 @item LGPL
 GNU Lesser General Public License, @url{http://www.gnu.org/@/licenses/@/lgpl.html}.
 
 @item LGPL
 GNU Lesser General Public License, @url{http://www.gnu.org/@/licenses/@/lgpl.html}.
 

-@item GPL/Guile
-GNU GPL with the exception for Guile; for example, GPLv3+/Guile means
-the GNU GPL version 3 or later, with the extra exception for Guile.
-

 @item GPL/Ada
 GNU GPL with the exception for Ada.
 
 @item GPL/Ada
 GNU GPL with the exception for Ada.
 


@@ -1057,12 +1080,12 @@ The non-license that is being in the public domain,
 The license for Python, @url{http://www.python.org/@/2.0.1/@/license.html}.
 
 @item RBSD
 The license for Python, @url{http://www.python.org/@/2.0.1/@/license.html}.
 
 @item RBSD

-The revised (3-clause) BSD, compatible with the GNU GPL,
+The revised (3-clause) BSD, compatible with the GNU GPL,@*

 @url{http://www.xfree86.org/@/3.3.6/@/COPYRIGHT2.html#5}.
 
 @item X11
 The simple non-copyleft license used for most versions of the X Window
 @url{http://www.xfree86.org/@/3.3.6/@/COPYRIGHT2.html#5}.
 
 @item X11
 The simple non-copyleft license used for most versions of the X Window

-system, @url{http://www.xfree86.org/@/3.3.6/@/COPYRIGHT2.html#3}.
+System, @url{http://www.xfree86.org/@/3.3.6/@/COPYRIGHT2.html#3}.

 
 @item Zlib
 The license for Zlib, @url{http://www.gzip.org/@/zlib/@/zlib_license.html}.
 
 @item Zlib
 The license for Zlib, @url{http://www.gzip.org/@/zlib/@/zlib_license.html}.


@@ -1100,6 +1123,44 @@ General help using GNU software: <http://www.gnu.org/gethelp/>
 It is ok to mention other appropriate mailing lists and web pages.
 
 
 It is ok to mention other appropriate mailing lists and web pages.
 
 

+@node Dynamic Plug-In Interfaces
+@section Standards for Dynamic Plug-in Interfaces
+@cindex plug-ins
+@cindex dynamic plug-ins
+
+Another aspect of keeping free programs free is encouraging
+development of free plug-ins, and discouraging development of
+proprietary plug-ins.  Many GNU programs will not have anything like
+plug-ins at all, but those that do should follow these
+practices.
+
+First, the general plug-in architecture design should closely tie the
+plug-in to the original code, such that the plug-in and the base
+program are parts of one extended program.  For GCC, for example,
+plug-ins receive and modify GCC's internal data structures, and so
+clearly form an extended program with the base GCC.
+
+@vindex plugin_is_GPL_compatible
+Second, you should require plug-in developers to affirm that their
+plug-ins are released under an appropriate license.  This should be
+enforced with a simple programmatic check.  For GCC, again for
+example, a plug-in must define the global symbol
+@code{plugin_is_GPL_compatible}, thus asserting that the plug-in is
+released under a GPL-compatible license (@pxref{Plugins,, Plugins,
+gccint, GCC Internals}).
+
+By adding this check to your program you are not creating a new legal
+requirement.  The GPL itself requires plug-ins to be free software,
+licensed compatibly.  As long as you have followed the first rule above
+to keep plug-ins closely tied to your original program, the GPL and AGPL
+already require those plug-ins to be released under a compatible
+license.  The symbol definition in the plug-in---or whatever equivalent
+works best in your program---makes it harder for anyone who might
+distribute proprietary plug-ins to legally defend themselves.  If a case
+about this got to court, we can point to that symbol as evidence that
+the plug-in developer understood that the license had this requirement.
+
+

 @node Option Table
 @section Table of Long Options
 @cindex long option names
 @node Option Table
 @section Table of Long Options
 @cindex long option names


@@ -3518,7 +3579,7 @@ clear explanation of how the earlier version differed.
 
 The change log file is normally called @file{ChangeLog} and covers an
 entire directory.  Each directory can have its own change log, or a
 
 The change log file is normally called @file{ChangeLog} and covers an
 entire directory.  Each directory can have its own change log, or a

-directory can use the change log of its parent directory--it's up to
+directory can use the change log of its parent directory---it's up to

 you.
 
 Another alternative is to record change log information with a version
 you.
 
 Another alternative is to record change log information with a version


@@ -3526,22 +3587,21 @@ control system such as RCS or CVS.  This can be converted automatically
 to a @file{ChangeLog} file using @code{rcs2log}; in Emacs, the command
 @kbd{C-x v a} (@code{vc-update-change-log}) does the job.
 
 to a @file{ChangeLog} file using @code{rcs2log}; in Emacs, the command
 @kbd{C-x v a} (@code{vc-update-change-log}) does the job.
 

-There's no need to describe the full purpose of the changes or how they
-work together.  If you think that a change calls for explanation, you're
-probably right.  Please do explain it---but please put the explanation
-in comments in the code, where people will see it whenever they see the
-code.  For example, ``New function'' is enough for the change log when
-you add a function, because there should be a comment before the
-function definition to explain what it does.
+There's no need to describe the full purpose of the changes or how
+they work together.  However, sometimes it is useful to write one line
+to describe the overall purpose of a change or a batch of changes.  If
+you think that a change calls for explanation, you're probably right.
+Please do explain it---but please put the full explanation in comments
+in the code, where people will see it whenever they see the code.  For
+example, ``New function'' is enough for the change log when you add a
+function, because there should be a comment before the function
+definition to explain what it does.

 
 In the past, we recommended not mentioning changes in non-software
 files (manuals, help files, etc.) in change logs.  However, we've been
 advised that it is a good idea to include them, for the sake of
 copyright records.
 
 
 In the past, we recommended not mentioning changes in non-software
 files (manuals, help files, etc.) in change logs.  However, we've been
 advised that it is a good idea to include them, for the sake of
 copyright records.
 

-However, sometimes it is useful to write one line to describe the
-overall purpose of a batch of changes.
-

 The easiest way to add an entry to @file{ChangeLog} is with the Emacs
 command @kbd{M-x add-change-log-entry}.  An entry should have an
 asterisk, the name of the changed file, and then in parentheses the name
 The easiest way to add an entry to @file{ChangeLog} is with the Emacs
 command @kbd{M-x add-change-log-entry}.  An entry should have an
 asterisk, the name of the changed file, and then in parentheses the name


@@ -4051,13 +4111,13 @@ installing the program should @strong{never} be included in the
 distribution.  So if you do distribute non-source files, always make
 sure they are up to date when you make a new distribution.
 
 distribution.  So if you do distribute non-source files, always make
 sure they are up to date when you make a new distribution.
 

-Make sure that the directory into which the distribution unpacks (as
-well as any subdirectories) are all world-writable (octal mode 777).
-This is so that old versions of @code{tar} which preserve the
-ownership and permissions of the files from the tar archive will be
-able to extract all the files even if the user is unprivileged.
-
-Make sure that all the files in the distribution are world-readable.
+Make sure that all the files in the distribution are world-readable, and
+that directories are world-readable and world-searchable (octal mode 755).
+We used to recommend that all directories in the distribution also be
+world-writable (octal mode 777), because ancient versions of @code{tar}
+would otherwise not cope when extracting the archive as an unprivileged
+user.  That can easily lead to security issues when creating the archive,
+however, so now we recommend against that.

 
 Don't include any symbolic links in the distribution itself.  If the tar
 file contains symbolic links, then people cannot even unpack it on
 
 Don't include any symbolic links in the distribution itself.  If the tar
 file contains symbolic links, then people cannot even unpack it on


@@ -4170,7 +4230,7 @@ documentation.
 By contrast, it is ok to refer to journal articles and textbooks in
 the comments of a program for explanation of how it functions, even
 though they are non-free.  This is because we don't include such
 By contrast, it is ok to refer to journal articles and textbooks in
 the comments of a program for explanation of how it functions, even
 though they are non-free.  This is because we don't include such

-things in the GNU system even they are free---they are outside the
+things in the GNU system even if they are free---they are outside the

 scope of what a software distribution needs to include.
 
 Referring to a web site that describes or recommends a non-free
 scope of what a software distribution needs to include.
 
 Referring to a web site that describes or recommends a non-free