\input texinfo @c -*-texinfo-*-
-@comment $Id: gnulib.texi,v 1.17 2005-09-13 15:06:24 meyering Exp $
+@comment $Id: gnulib.texi,v 1.26 2006-07-19 21:48:14 dprice Exp $
@comment %**start of header
@setfilename gnulib.info
@settitle GNU Gnulib
@syncodeindex pg cp
@comment %**end of header
-@set UPDATED $Date: 2005-09-13 15:06:24 $
+@set UPDATED $Date: 2006-07-19 21:48:14 $
@copying
This manual is for GNU Gnulib (updated @value{UPDATED}),
which is a library of common routines intended to be shared at the
source level.
-Copyright @copyright{} 2004, 2005 Free Software Foundation, Inc.
+Copyright @copyright{} 2004, 2005, 2006 Free Software Foundation, Inc.
@quotation
Permission is granted to copy, distribute and/or modify this document
* Quoting::
* ctime::
* inet_ntoa::
+* gcd::
* Out of memory handling::
* Library version handling::
* Regular expressions::
+* Windows sockets::
+* Libtool and Windows::
@end menu
@end itemize
-@node Quoting
-@section Quoting
+@include quote.texi
-@cindex Quoting
-@findex quote
-@findex quotearg
+@include ctime.texi
-Gnulib provides @samp{quote} and @samp{quotearg} modules to help with
-quoting text, such as file names, in messages to the user. Here's an
-example of using @samp{quote}:
+@include gcd.texi
-@example
-#include <quote.h>
- ...
- error (0, errno, _("cannot change owner of %s"), quote (fname));
-@end example
-
-This differs from
-
-@example
- error (0, errno, _("cannot change owner of `%s'"), fname);
-@end example
-
-@noindent in that @code{quote} escapes unusual characters in
-@code{fname}, e.g., @samp{'} and control characters like @samp{\n}.
-
-@findex quote_n
-However, a caveat: @code{quote} reuses the storage that it returns.
-Hence if you need more than one thing quoted at the same time, you
-need to use @code{quote_n}.
-
-@findex quotearg_alloc
-Also, the quote module is not suited for multithreaded applications.
-In that case, you have to use @code{quotearg_alloc}, defined in the
-@samp{quotearg} module, which is decidedly less convenient.
-
-
-@node ctime
-@section ctime
-@findex ctime
-
-The @code{ctime} function need not be reentrant, and consequently is
-not required to be thread safe. Implementations of @code{ctime}
-typically write the time stamp into static buffer. If two threads
-call @code{ctime} at roughly the same time, you might end up with the
-wrong date in one of the threads, or some undefined string. There is
-a re-entrant interface @code{ctime_r}, that take a pre-allocated
-buffer and length of the buffer, and return @code{NULL} on errors.
-The input buffer should be at least 26 bytes in size. The output
-string is locale-independent. However, years can have more than 4
-digits if @code{time_t} is sufficiently wide, so the length of the
-required output buffer is not easy to determine. Increasing the
-buffer size when @code{ctime_r} return @code{NULL} is not necessarily
-sufficient. The @code{NULL} return value could mean some other error
-condition, which will not go away by increasing the buffer size.
-
-A more flexible function is @code{strftime}. However, note that it is
-locale dependent.
-
-
-@node inet_ntoa
-@section inet_ntoa
-@findex inet_ntoa
-
-The @code{inet_ntoa} function need not be reentrant, and consequently
-is not required to be thread safe. Implementations of
-@code{inet_ntoa} typically write the time stamp into static buffer.
-If two threads call @code{inet_ntoa} at roughly the same time, you
-might end up with the wrong date in one of the threads, or some
-undefined string. Further, @code{inet_ntoa} is specific for
-@acronym{IPv4} addresses.
-
-A protocol independent function is @code{inet_ntop}.
+@include inet_ntoa.texi
@node Out of memory handling
However, we realize that some applications may not want to have the
GSS library abort execution in any situation. The GSS library support
a hook to let the application regain control and perform its own
-cleanups when an out of memory situation has occured. The application
+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
AC_DEFINE something like:
@example
-AC_DEFINE(check_version, stringprep_check_version, [Rename check_version.])
+AC_DEFINE(check_version, stringprep_check_version,
+ [Rename check_version.])
@end example
The @code{stringprep_check_version} function will thus be implemented
@include regexprops-generic.texi
-@node Invoking gnulib-tool
-@chapter Invoking gnulib-tool
+@node Windows sockets
+@section Windows sockets
-@pindex gnulib-tool
-@cindex invoking @command{gnulib-tool}
+There are several issues when building applications that should work
+under Windows. The most problematic part is for applications that use
+sockets.
-Run @samp{gnulib-tool --help}, and use the source.
-@command{gnulib-tool} is the way to import Gnulib modules.
+Hopefully, we can add helpful notes to this section that will help you
+port your application to Windows using gnulib.
-@menu
-* Initial import:: First import of Gnulib modules.
-* Importing updated files:: Subsequent imports.
-* Finishing touches:: Simplifying imports.
-@end menu
+@subsection Getaddrinfo and WINVER
+This was written for the getaddrinfo module, but may be applicable to
+other functions too.
-@node Initial import
-@section Initial import
-@cindex initial import
+The getaddrinfo function exists in ws2tcpip.h and -lws2_32 on Windows
+XP. The function declaration is present if @code{WINVER >= 0x0501}.
+Windows 2000 does not have getaddrinfo in its @file{WS2_32.dll}.
-Gnulib assumes your project uses Autoconf and Automake. Invoking
-@samp{gnulib-tool --import} will copy source files, create a
-@file{Makefile.am} to build them, and generate a @file{gnulib.m4} with
-Autoconf M4 macro declarations used by @file{configure.ac}.
+Thus, if you want to assume Windows XP or later, you can add
+AC_DEFINE(WINVER, 0x0501) to avoid compiling to (partial) getaddrinfo
+implementation.
-Our example will be a library that uses Autoconf, Automake and
-Libtool. It calls @code{strdup}, and you wish to use gnulib to make
-the package portable to C89 (which doesn't have @code{strdup}).
+If you want to support Windows 2000, don't do anything, but be aware
+that gnulib will use its own (partial) getaddrinfo implementation even
+on Windows XP. Currently the code does not attempt to determine if
+the getaddrinfo function is available during runtime.
-@example
-~/src/libfoo$ gnulib-tool --import strdup
-Module list with included dependencies:
- strdup
-File list:
- lib/strdup.c
- lib/strdup.h
- m4/onceonly_2_57.m4
- m4/strdup.m4
-Creating ./lib/Makefile.am...
-Creating ./m4/gnulib.m4...
-Finished.
-
-You may need to add #include directives for the following .h files.
- #include "strdup.h"
-
-Don't forget to add "lib/Makefile"
-to AC_CONFIG_FILES in "./configure.ac" and to mention
-"lib" in SUBDIRS in some Makefile.am.
-~/src/libfoo$
-@end example
+Todo: Make getaddrinfo.c open the WS2_32.DLL and check for the
+getaddrinfo symbol and use it if present, otherwise fall back to our
+own implementation.
-By default, the source code is copied into @file{lib/} and the M4
-macros in @file{m4/}. You can override these paths by using
-@code{--source-base=DIRECTORY} and @code{--m4-base=DIRECTORY}, or by
-adding @samp{gl_SOURCE_BASE(DIRECTORY)} and
-@samp{gl_M4_BASE(DIRECTORY)} to your @file{configure.ac}. Some
-modules also provide other files necessary for building. These files
-are copied into the directory specified by @samp{AC_CONFIG_AUX_DIR} in
-@file{configure.ac} or by the @code{--aux-dir=DIRECTORY} option. If
-neither is specified, the current directory is assumed. If a module
-is automatically added as a dependency is added, that you wish to
-avoid, you may use @code{--avoid=MODULE}, possibly several times. Of
-course, you will then need to implement the same interface as the
-removed module.
-
-@code{gnulib-tool} can make symbolic links instead
-of copying the source files. Use the @code{--symbolic}
-(or @code{-s} for short) option to do this.
-
-@code{gnulib-tool} will overwrite any pre-existing files, in
-particular @file{Makefile.am}. Unfortunately, separating the
-generated @file{Makefile.am} content (for building the gnulib library)
-into a separate file, say @file{gnulib.mk}, that could be included
-by your handwritten @file{Makefile.am} is not possible, due to how
-variable assignments are handled by Automake.
-
-Consequently, it can be a good idea to chose directories that are not
-already used by your projects, to separate gnulib imported files from
-your own files. This approach can also be useful if you want to avoid
-conflicts between other tools (e.g., @code{getextize} that also copy
-M4 files into your package. Simon Josefsson successfully uses a source
-base of @file{gl/}, and a M4 base of @file{gl/m4/}, in several
-packages.
-
-A few manual steps are required to finish the initial import.
-
-First, you need to make sure Autoconf can find the macro definitions
-in @file{gnulib.m4}. Use the @code{ACLOCAL_AMFLAGS} specifier in your
-top-level @file{Makefile.am} file, as in:
+@node Libtool and Windows
+@section Libtool and Windows
-@example
-ACLOCAL_AMFLAGS = -I m4
-@end example
-
-Naturally, replace @file{m4} with the value from @code{--m4-base} or
-@code{gl_M4_BASE}. If the M4 base is @file{gl/m4} you would use:
-
-@example
-ACLOCAL_AMFLAGS = -I gl/m4
-@end example
-
-You are now ready to call the M4 macros in @code{gnulib.m4} from
-@file{configure.ac}. The macro @code{gl_EARLY} must be called as soon
-as possible after verifying that the C compiler is working.
-Typically, this is immediately after @code{AC_PROG_CC}, as in:
-
-@example
-...
-AC_PROG_CC
-gl_EARLY
-...
-@end example
-
-The core part of the gnulib checks are done by the macro
-@code{gl_INIT}. Place it further down in the file, typically where
-you normally check for header files or functions. Or in a separate
-section with other gnulib statements, such as @code{gl_SOURCE_BASE}.
-For example:
+If you want it to be possible to cross-compile your program to MinGW
+and you use Libtool, you need to put:
@example
-...
-# For gnulib.
-gl_INIT
-...
+AC_LIBTOOL_WIN32_DLL
@end example
-@code{gl_INIT} will in turn call the macros related with the
-gnulib functions, be it specific gnulib macros, like @code{gl_FUNC_ALLOCA}
-or autoconf or automake macro like @code{AC_FUNC_ALLOCA} or
-@code{AM_FUNC_GETLINE} so there is no need to call those macros yourself
-when you use the corresponding gnulib modules.
+in your @file{configure.ac}. This sets the correct names for the
+@code{OBJDUMP}, @code{DLLTOOL}, and @code{AS} tools for the build.
-You must also make sure that the gnulib library is built. Add the
-@code{Makefile} in the gnulib source base directory to
-@code{AC_CONFIG_FILES}, as in:
+If you are building a library, you will also need to pass
+@code{-no-undefined} to make sure Libtool produces a DLL for your
+library. From a @file{Makefile.am}:
@example
-AC_CONFIG_FILES(... lib/Makefile ...)
+libgsasl_la_LDFLAGS += -no-undefined
@end example
-If your gnulib source base is @file{gl}, you would use:
-
-@example
-AC_CONFIG_FILES(... gl/Makefile ...)
-@end example
-
-You must also make sure that @code{make} work in the gnulib directory.
-Add the gnulib source base directory to a @code{SUBDIRS} Makefile.am
-statement, as in:
-
-@example
-SUBDIRS = lib
-@end example
-
-or if you, more likely, already have a few entries in @code{SUBDIRS},
-you can add something like:
-
-@example
-SUBDIRS += lib
-@end example
-
-If you are using a gnulib source base of @code{gl}, you would use:
-
-@example
-SUBDIRS += gl
-@end example
-
-Finally, you have to add compiler and linker flags in the appropriate
-source directories, so that you can make use of the gnulib library.
-Since some modules (@samp{getopt}, for example) may copy files into
-the build directory, @file{top_builddir/lib} is needed as well
-as @file{top_srcdir/lib}. For example:
-
-@example
-...
-AM_CPPFLAGS = -I$(top_srcdir)/lib -I$(top_builddir)/lib
-...
-LIBADD = lib/libgnu.a
-...
-@end example
-
-Don't forget to @code{#include} the various header files. In this
-example, you would need to make sure that @samp{#include "strdup.h"}
-is evaluated when compiling all source code files, that want to make
-use of @code{strdup}.
-
-When an include file is provided by the gnulib
-you shouldn't try to include the corresponding system header files
-yourself but let the gnulib header file do it as the ordering
-of the definition for some symbols may be significant.
-
-For example, to use the @code{time_r} gnulib module you should
-use include header file provided by the gnulib, and so
-@samp{#include "time_r.h"}, but you shouldn't explicitely
-@samp{#include <time.h>} as it is already done in @file{time_r.h}
-before the redefinition of some symbols.
-
-@node Importing updated files
-@section Importing updated files
-
-From time to time, you may want to invoke @samp{gnulib-tool --import}
-to update the files in your package. Once you have set up your
-package for gnulib, this step is quite simple. For example:
-
-@example
-~/src/libfoo$ gnulib-tool --import --source-base gl --m4-base gl/m4 strdup
-Module list with included dependencies:
- strdup
-File list:
- lib/strdup.c
- lib/strdup.h
- m4/onceonly_2_57.m4
- m4/strdup.m4
-Creating ./lib/Makefile.am...
-Creating ./m4/gnulib.m4...
-Finished.
-
-Don't forget to add "lib/Makefile"
-to AC_CONFIG_FILES in "./configure.ac" and to mention
-"lib" in SUBDIRS in some Makefile.am.
-~/src/libfoo$
-@end example
-
-If you don't recall how you invoked the tool last time, the commands
-used (and the operations it resulted in) are placed in comments within
-the generated @file{Makefile.am} and @file{gnulib.m4}, as in:
-
-@example
-...
-# Invoked as: gnulib-tool --import strdup
-# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --libtool strdup
-...
-@end example
-
-
-@node Finishing touches
-@section Finishing touches
-
-Invoking @samp{gnulib-tool --import} with the proper parameters (e.g.,
-@samp{--m4-base gl/m4}) and list of modules (e.g., @samp{strdup
-snprintf getline minmax}) can be tedious. To simplify this procedure,
-you may put the command line parameters in your @file{configure.ac}.
-For example:
-
-@example
-...
-AC_PROG_CC
-gl_EARLY
-...
-# For gnulib.
-gl_SOURCE_BASE(gl)
-gl_M4_BASE(gl/m4)
-gl_LIB(libgl)
-gl_MODULES(xmalloc progname strdup dummy exit error getpass-gnu getaddrinfo)
-gl_AVOID(xalloc-die)
-gl_INIT
-...
-@end example
+@include gnulib-tool.texi
-This illustrate all macros defined in @file{gnulib.m4}. With the
-above, importing new files are as simple as running @samp{gnulib-tool
---import} with no additional parameters.
-
-The macros @code{gl_EARLY}, @code{gl_INIT}, @code{gl_SOURCE_BASE}, and
-@code{gl_M4_BASE} have been discussed earlier. The @code{gl_LIB}
-macro can be used if you wish to change the library name (by default
-@file{libgnu.a} or @file{libgnu.la} if you use libtool). The
-@code{gl_MODULES} macro is used to specify which modules to import.
-@code{gl_AVOID} macro is used to specify which modules, that are
-normally automatically added as a dependency, to avoid.
@node Copying This Manual
@appendix Copying This Manual
projects / gnulib.git / blobdiff