@comment %**start of header
@setfilename gnulib.info
@settitle GNU Gnulib
+@c Define a new index for the magic constants in regex.texi.
+@defcodeindex cn
@syncodeindex fn cp
+@syncodeindex ky cp
@syncodeindex pg cp
+@syncodeindex tp cp
+@syncodeindex vr cp
+@syncodeindex cn cp
@ifclear texi2html
@firstparagraphindent insert
@end ifclear
which is a library of common routines intended to be shared at the
source level.
-Copyright @copyright{} 2004-2010 Free Software Foundation, Inc.
+Copyright @copyright{} 2004-2011 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
* Introduction::
* Invoking gnulib-tool::
* Writing modules::
+* Extending Gnulib::
* Miscellaneous Notes::
* POSIX Substitutes Library:: Building as a separate substitutes library.
* Header File Substitutes:: Overriding system headers.
* Glibc Header File Substitutes:: Overriding system headers.
* Glibc Function Substitutes:: Replacing system functions.
* Particular Modules:: Documentation of individual modules.
+* Regular expressions:: The regex module.
* GNU Free Documentation License:: Copying and sharing this manual.
* Index::
@end menu
@node Writing modules
@chapter Writing modules
-This chapter explains how to write modules of your own, either for your own
-package (to be used with gnulib-tool's @samp{--local-dir} option), or for
+This chapter explains how to write modules of your own, either to
+extend Gnulib for your own package (@pxref{Extending Gnulib}), or for
inclusion in gnulib proper.
The guidelines in this chapter do not necessarily need to be followed for
@end enumerate
+@node Extending Gnulib
+@chapter Extending Gnulib
+
+Gnulib modules are intended to be suitable for widespread use. Most
+problems with Gnulib can and should be fixed in a generic way, so that
+all of Gnulib's users can benefit from the change. But occasionally a
+problem arises that is difficult or undesirable to fix generically, or
+a project that uses Gnulib may need to work around an issue before the
+Gnulib maintainers commit a final fix. Maintainers may also want to
+add their own pools of modules to projects as Gnulib ``staging
+areas.''
+
+The obvious way to make local changes to Gnulib modules is to use
+@command{gnulib-tool} to check out pristine modules, then to modify
+the results in-place. This works well enough for short-lived
+experiments. It is harder to keep modified versions of Gnulib modules
+for a long time, even though Git (or another distributed version
+control systems) can help out a lot with this during the development
+process.
+
+Git, however, doesn't address the distribution issue. When a package
+``foobar'' needs a modified version of, say, @file{stdint.in.h}, it
+either has to put a comment into @file{foobar/autogen.sh} saying
+``Attention! This doesn't work with a pristine Gnulib, you need this
+and that patch after checking out Gnulib,'' or it has to use the
+@samp{--avoid=stdint} option and provide the modified @code{stdint}
+module in a different directory.
+
+The @option{--local-dir} option to @command{gnulib-tool} solves this
+problem. It allows the package to override or augment Gnulib. This
+means:
+
+@itemize @bullet
+@item
+You can store files that are to override Gnulib files or modules.
+
+@item
+You can store context diffs to be applied to Gnulib files.
+
+@item
+You can add modules of your own, that are not (yet) in Gnulib.
+
+@item
+You can also add unstructured amounts of code to the library, by
+grouping the non-Gnulib files of the library in a single kitchen-sink
+``module.'' (This kind of kitchen-sink module is not needed when you
+use the @command{gnulib-tool} option @samp{--makefile-name}.)
+@end itemize
+
+In a release tarball, you can distribute the contents of this
+@option{--local-dir} directory that will be combinable with newer
+versions of Gnulib, barring incompatible changes to Gnulib.
+
+If the @samp{--local-dir=@var{directory}} option is specified, then
+@command{gnulib-tool} looks in @file{@var{directory}} whenever it
+reads a file from the Gnulib directory. Suppose @command{gnulib-tool}
+is looking for @var{file}. Then:
+
+@itemize @bullet
+@item
+If @file{@var{directory}/@var{file}} exists, then @samp{gnulib-tool} uses
+it instead of the file included in Gnulib.
+
+@item
+Otherwise, if @file{@var{directory}/@var{file}.diff} exists, then
+@command{gnulib-tool} uses the file from Gnulib after applying the diff
+using the @command{patch} program.
+
+@item
+Otherwise, @command{gnulib-tool} uses the file included in Gnulib.
+@end itemize
+
+Please make wise use of this option. It also allows you to easily
+hold back modifications you make to Gnulib macros in cases it may be
+better to share them.
+
+
+
@node Miscellaneous Notes
@chapter Miscellaneous Notes
@cindex Out of Memory handling
@cindex Memory allocation failure
-The GSS API does not have a standard error code for the out of memory
-error condition. Instead of adding a non-standard error code, this
-library has chosen to adopt a different strategy. Out of memory
-handling happens in rare situations, but performing the out of memory
-error handling after almost all API function invocations pollute your
-source code and might make it harder to spot more serious problems.
-The strategy chosen improves code readability and robustness.
+The gnulib API does not have a standard error code for the out of memory
+error condition. Instead of adding a non-standard error code, gnulib
+has chosen to adopt a different strategy. Out of memory handling
+happens in rare situations, but performing the out of memory error
+handling after almost all API function invocations pollute your source
+code and might make it harder to spot more serious problems. The
+strategy chosen improves code readability and robustness.
@cindex Aborting execution
For most applications, aborting the application with an error message
when the out of memory situation occurs is the best that can be wished
-for. This is how the library behaves by default.
-
-@vindex xalloc_fail_func
-However, we realize that some applications may not want to have the
-GSS library abort execution in any situation. The GSS library supports
-a hook to let the application regain control and perform its own
-cleanups when an out of memory situation has occurred. The application
-can define a function (having a @code{void} prototype, i.e., no return
-value and no parameters) and set the library variable
-@code{xalloc_fail_func} to that function. The variable should be
+for. This is how the library behaves by default (using
+the @samp{xalloc-die} module).
+
+@vindex xalloc_die
+However, we realize that some applications may not want to abort
+execution in any situation. Gnulib supports a hook to let the
+application regain control and perform its own cleanups when an out of
+memory situation has occurred. The application can define a function
+(having a @code{void} prototype, i.e., no return value and no
+parameters) and set the library variable
+@code{xalloc_die} to that function. The variable should be
declared as follows.
@example
-extern void (*xalloc_fail_func) (void);
+extern void (*xalloc_die) (void);
@end example
-The GSS library will invoke this function if an out of memory error
-occurs. Note that after this the GSS library is in an undefined
-state, so you must unload or restart the application to continue call
-GSS library functions. The hook is only intended to allow the
-application to log the situation in a special way. Of course, care
-must be taken to not allocate more memory, as that will likely also
-fail.
+Gnulib will invoke this function if an out of memory error occurs. Note
+that the function should not return. Of course, care must be taken to
+not allocate more memory, as that will likely also fail.
@node Obsolete modules
Windows 2000 does not have getaddrinfo in its @file{WS2_32.DLL}.
Thus, if you want to assume Windows XP or later, you can add
-AC_DEFINE(WINVER, 0x0501) to avoid compiling to (partial) getaddrinfo
+AC_DEFINE(WINVER, 0x0501) to avoid compiling the (partial) getaddrinfo
implementation.
If you want to support Windows 2000, don't do anything. The
* Quoting::
* error and progname::
* gcd::
-* Regular expressions::
* Searching for Libraries::
* Exported Symbols of Shared Libraries::
* LD Version Scripts::
* Visual Studio Compatibility::
* Supporting Relocation::
* func::
+* configmake::
* warnings::
* manywarnings::
+* Running self-tests under valgrind::
@end menu
@node alloca
@include gcd.texi
-@node Regular expressions
-@section Regular expressions
-
-Gnulib supports many different types of regular expressions; although
-the underlying features are the same or identical, the syntax used
-varies. The descriptions given here for the different types are
-generated automatically.
-
-@include regexprops-generic.texi
-
@include havelib.texi
@include lib-symbol-visibility.texi
@include func.texi
+@include configmake.texi
+
@include warnings.texi
@include manywarnings.texi
+@include valgrind-tests.texi
+
+@node Regular expressions
+@chapter Regular expressions
+
+@menu
+* Overview::
+* Regular Expression Syntax::
+* Common Operators::
+* GNU Operators::
+* GNU Emacs Operators::
+* What Gets Matched?::
+* Programming with Regex::
+* Regular expression syntaxes::
+@end menu
+
+@lowersections
+@include regex.texi
+@raisesections
+
+@node Regular expression syntaxes
+@section Regular expression syntaxes
+
+Gnulib supports many different types of regular expressions; although
+the underlying features are the same or identical, the syntax used
+varies. The descriptions given here for the different types are
+generated automatically.
+
+@include regexprops-generic.texi
+
@node GNU Free Documentation License
@appendix GNU Free Documentation License
projects / gnulib.git / blobdiff