The maintainer of a package has many responsibilities. One of them is ensuring that the package will install easily on many platforms, and that the magic we described earlier (see section 2 The User's View) will work for installers and end users.
Of course, there are many possible ways by which GNU
might be integrated in a distribution, and this chapter does not cover
them in all generality. Instead, it details one possible approach which
is especially adequate for many free software distributions following GNU
standards, or even better, Gnits standards, because GNU
is purposely for helping the internationalization of the whole GNU
project, and as many other good free packages as possible. So, the
maintainer's view presented here presumes that the package already has
a ‘configure.ac’ file and uses GNU Autoconf.
gettext may surely be useful for free packages
not following GNU standards and conventions, but the maintainers of such
packages might have to show imagination and initiative in organizing
their distributions so
gettext work for them in all situations.
There are surely many, out there.
gettext methods are now stabilizing, slight adjustments
might be needed between successive
gettext versions, so you
should ideally revise this chapter in subsequent releases, looking
Some free software packages are distributed as
tar files which unpack
in a single directory, these are said to be flat distributions.
Other free software packages have a one level hierarchy of subdirectories, using
for example a subdirectory named ‘doc/’ for the Texinfo manual and
man pages, another called ‘lib/’ for holding functions meant to
replace or complement C libraries, and a subdirectory ‘src/’ for
holding the proper sources for the package. These other distributions
are said to be non-flat.
We cannot say much about flat distributions. A flat
directory structure has the disadvantage of increasing the difficulty
of updating to a new version of GNU
gettext. Also, if you have
many PO files, this could somewhat pollute your single directory.
gettext's libintl sources consist of C sources, shell
sed scripts and complicated Makefile rules, which don't
fit well into an existing flat structure. For these reasons, we
recommend to use non-flat approach in this case as well.
Maybe because GNU
gettext itself has a non-flat structure,
we have more experience with this approach, and this is what will be
described in the remaining of this chapter. Some maintainers might
use this as an opportunity to unflatten their package structure.
There are some works which are required for using GNU
in one of your package. These works have some kind of generality
that escape the point by point descriptions used in the remainder
of this chapter. So, we describe them here.
gettextizeyou should install some other packages first. Ensure that recent versions of GNU
m4, GNU Autoconf and GNU
gettextare already installed at your site, and if not, proceed to do this first. If you get to install these things, beware that GNU
m4must be fully installed before GNU Autoconf is even configured. To further ease the task of a package maintainer the
automakepackage was designed and implemented. GNU
gettextnow uses this tool and the ‘Makefile’s in the ‘intl/’ and ‘po/’ therefore know about all the goals necessary for using
automakeand ‘libintl’ in one project. Those four packages are only needed by you, as a maintainer; the installers of your own package and end users do not really need any of GNU
m4, GNU Autoconf, GNU
gettext, or GNU
automakefor successfully installing and running your package, with messages properly translated. But this is not completely true if you provide internationalized shell scripts within your own package: GNU
gettextshall then be installed at the user site if the end users want to see the translation of shell script messages.
It is worth adding here a few words about how the maintainer should ideally behave with PO files submissions. As a maintainer, your role is to authenticate the origin of the submission as being the representative of the appropriate translating teams of the Translation Project (forward the submission to ‘email@example.com’ in case of doubt), to ensure that the PO file format is not severely broken and does not prevent successful installation, and for the rest, to merely put these PO files in ‘po/’ for distribution.
As a maintainer, you do not have to take on your shoulders the responsibility of checking if the translations are adequate or complete, and should avoid diving into linguistic matters. Translation teams drive themselves and are fully responsible of their linguistic choices for the Translation Project. Keep in mind that translator teams are not driven by maintainers. You can help by carefully redirecting all communications and reports from users about linguistic matters to the appropriate translation team, or explain users how to reach or join their team. The simplest might be to send them the ‘ABOUT-NLS’ file.
Maintainers should never ever apply PO file bug reports themselves, short-cutting translation teams. If some translator has difficulty to get some of her points through her team, it should not be an option for her to directly negotiate translations with maintainers. Teams ought to settle their problems themselves, if any. If you, as a maintainer, ever think there is a real problem with a team, please never try to solve a team's problem on your own.
gettextize program is an interactive tool that helps the
maintainer of a package internationalized through GNU
It is used for two purposes:
gettextfor the first time.
gettextsupport in a package from a previous to a newer version of GNU
This program performs the following tasks:
gettextversions to the form recommended for the current GNU
It can be invoked as follows:
gettextize [ option... ] [ directory ]
and accepts the following options:
AM_GNU_GETTEXTin ‘configure.ac’ should read: ‘AM_GNU_GETTEXT([external])’, and internationalization will not be enabled on systems lacking GNU gettext.
gettextizelogs all changes (file additions, modifications and removals) in a file called ‘ChangeLog’ in each affected directory.
gettextis installed on the system.
gettextizewould normally execute are inhibited and instead only listed on standard output.
If directory is given, this is the top level directory of a
package to prepare for using GNU
gettext. If not given, it
is assumed that the current directory is the top level directory of
such a package.
gettextize provides the following files. However,
no existing file will be replaced unless the option
-f) is specified.
gettextize, if you have one handy. You may also fetch a more recent copy of file ‘ABOUT-NLS’ from Translation Project sites, and from most GNU archive sites.
gettextdistribution (beware the double ‘.in’ in the file name) and a few auxiliary files. If the ‘po/’ directory already exists, it will be preserved along with the files it contains, and only ‘Makefile.in.in’ and the auxiliary files will be overwritten. If ‘--po-dir’ has been specified, this holds for every directory specified through ‘--po-dir’, instead of ‘po/’.
gettextdistribution. Also, if option
-f) is given, the ‘intl/’ directory is emptied first.
automake: A set of
autoconfmacro files is copied into the package's
autoconfmacro repository, usually in a directory called ‘m4/’.
If your site support symbolic links,
gettextize will not
actually copy the files into your package, but establish symbolic
links instead. This avoids duplicating the disk space needed in
all packages. Merely using the ‘-h’ option while creating the
tar archive of your distribution will resolve each link by an
actual copy in the distribution archive. So, to insist, you really
should use ‘-h’ option with
tar within your
goal of your main ‘Makefile.in’.
gettextize will update all ‘Makefile.am’ files
in each affected directory, as well as the top level ‘configure.ac’
or ‘configure.in’ file.
It is interesting to understand that most new files for supporting
gettext facilities in one package go in ‘intl/’,
‘po/’ and ‘m4/’ subdirectories. One distinction between
‘intl/’ and the two other directories is that ‘intl/’ is
meant to be completely identical in all packages using GNU
while the other directories will mostly contain package dependent
gettextize program makes backup files for all files it
replaces or changes, and also write ChangeLog entries about these
changes. This way, the careful maintainer can check after running
gettextize whether its changes are acceptable to him, and
possibly adjust them. An exception to this rule is the ‘intl/’
directory, which is added or replaced or removed as a whole.
It is important to understand that
gettextize can not do the
entire job of adapting a package for using GNU
amount of remaining work depends on whether the package uses GNU
automake or not. But in any case, the maintainer should still
read the section section 13.4 Files You Must Create or Alter after invoking
In particular, if after using ‘gettexize’, you get an error ‘AC_COMPILE_IFELSE was called before AC_GNU_SOURCE’ or ‘AC_RUN_IFELSE was called before AC_GNU_SOURCE’, you can fix it by modifying ‘configure.ac’, as described in section 13.4.5 ‘configure.ac’ at top level.
It is also important to understand that
gettextize is not part
of the GNU build system, in the sense that it should not be invoked
automatically, and not be invoked by someone who doesn't assume the
responsibilities of a package maintainer. For the latter purpose, a
separate tool is provided, see section 13.6.4 Invoking the
Besides files which are automatically added through
there are many files needing revision for properly interacting with
gettext. If you are closely following GNU standards for
Makefile engineering and auto-configuration, the adaptations should
be easier to achieve. Here is a point by point description of the
changes needed in each.
So, here comes a list of files, each one followed by a description of
all alterations it needs. Many examples are taken out from the GNU
gettext 0.19.8.1 distribution itself, or from the GNU
hello distribution (http://www.gnu.org/software/hello).
You may indeed refer to the source code of the GNU
hello packages, as they are intended to be good examples for
using GNU gettext functionality.
The ‘po/’ directory should receive a file named ‘POTFILES.in’. This file tells which files, among all program sources, have marked strings needing translation. Here is an example of such a file:
# List of source files containing translatable strings. # Copyright (C) 1995 Free Software Foundation, Inc. # Common library files lib/error.c lib/getopt.c lib/xmalloc.c # Package source files src/gettext.c src/msgfmt.c src/xgettext.c
Hash-marked comments and white lines are ignored. All other lines list those source files containing strings marked for translation (see section 4.4 How Marks Appear in Sources), in a notation relative to the top level of your whole distribution, rather than the location of the ‘POTFILES.in’ file itself.
When a C file is automatically generated by a tool, like
bison, that doesn't introduce translatable strings by itself,
it is recommended to list in ‘po/POTFILES.in’ the real source file
(ending in ‘.l’ in the case of
flex, or in ‘.y’ in the
bison), not the generated C file.
The ‘po/’ directory should also receive a file named ‘LINGUAS’. This file contains the list of available translations. It is a whitespace separated list. Hash-marked comments and white lines are ignored. Here is an example file:
# Set of available languages. de fr
This example means that German and French PO files are available, so
that these languages are currently supported by your package. If you
want to further restrict, at installation time, the set of installed
languages, this should not be done by modifying the ‘LINGUAS’ file,
but rather by using the
LINGUAS environment variable
(see section 14 The Installer's and Distributor's View).
It is recommended that you add the "languages" ‘en@quot’ and
‘en@boldquot’ to the
en@quot is a
variant of English message catalogs (
en) which uses real quotation
marks instead of the ugly looking asymmetric ASCII substitutes ‘`’
en@boldquot is a variant of
additionally outputs quoted pieces of text in a bold font, when used in
a terminal emulator which supports the VT100 escape sequences (such as
xterm or the Linux console, but not Emacs in M-x shell mode).
These extra message catalogs ‘en@quot’ and ‘en@boldquot’
are constructed automatically, not by translators; to support them, you
need the files ‘Rules-quot’, ‘quot.sed’, ‘boldquot.sed’,
‘firstname.lastname@example.org’, ‘email@example.com’, ‘insert-header.sin’
in the ‘po/’ directory. You can copy them from GNU gettext's ‘po/’
directory; they are also installed by running
The ‘po/’ directory also has a file named ‘Makevars’. It contains variables that are specific to your project. ‘po/Makevars’ gets inserted into the ‘po/Makefile’ when the latter is created. The variables thus take effect when the POT file is created or updated, and when the message catalogs get installed.
The first three variables can be left unmodified if your package has a single message domain and, accordingly, a single ‘po/’ directory. Only packages which have multiple ‘po/’ directories at different locations need to adjust the three first variables defined in ‘Makevars’.
As an alternative to the
XGETTEXT_OPTIONS variables, it is also
possible to specify
xgettext options through the
AM_XGETTEXT_OPTION autoconf macro. See section 13.5.6 AM_XGETTEXT_OPTION in ‘po.m4’.
All files called ‘Rules-*’ in the ‘po/’ directory get appended to the ‘po/Makefile’ when it is created. They present an opportunity to add rules for special PO files to the Makefile, without needing to mess with ‘po/Makefile.in.in’.
GNU gettext comes with a ‘Rules-quot’ file, containing rules for
building catalogs ‘firstname.lastname@example.org’ and ‘email@example.com’. The
effect of ‘firstname.lastname@example.org’ is that people who set their
environment variable to ‘en@quot’ will get messages with proper
looking symmetric Unicode quotation marks instead of abusing the ASCII
grave accent and the ASCII apostrophe for indicating quotations. To
enable this catalog, simply add
en@quot to the ‘po/LINGUAS’
file. The effect of ‘email@example.com’ is that people who set
LANGUAGE to ‘en@boldquot’ will get not only proper quotation
marks, but also the quoted text will be shown in a bold font on terminals
and consoles. This catalog is useful only for command-line programs, not
GUI programs. To enable it, similarly add
en@boldquot to the
Similarly, you can create rules for building message catalogs for the
‘sr@latin’ locale -- Serbian written with the Latin alphabet --
from those for the ‘sr’ locale -- Serbian written with Cyrillic
letters. See section 9.4 Invoking the
‘configure.ac’ or ‘configure.in’ - this is the source from which
autoconf generates the ‘configure’ script.
PACKAGE=gettext VERSION=0.19.8.1 AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE") AC_DEFINE_UNQUOTED(VERSION, "$VERSION") AC_SUBST(PACKAGE) AC_SUBST(VERSION)or, if you are using GNU
automake, by a line like this:
AM_INIT_AUTOMAKE(gettext, 0.19.8.1)Of course, you replace ‘gettext’ with the name of your package, and ‘0.19.8.1’ by its version numbers, exactly as they should appear in the packaged
tarfile name of your distribution (‘gettext-0.19.8.1.tar.gz’, here).
m4macro for triggering internationalization support. Just add this line to ‘configure.ac’:
AM_GNU_GETTEXTThis call is purposely simple, even if it generates a lot of configure time checking and actions. If you have suppressed the ‘intl/’ subdirectory by calling
gettextizewithout ‘--intl’ option, this call should read
AC_OUTPUTdirective, at the end of your ‘configure.ac’ file, needs to be modified in two ways:
AC_OUTPUT([existing configuration files intl/Makefile po/Makefile.in], [existing additional actions])The modification to the first argument to
AC_OUTPUTasks for substitution in the ‘intl/’ and ‘po/’ directories. Note the ‘.in’ suffix used for ‘po/’ only. This is because the distributed file is really ‘po/Makefile.in.in’. If you have suppressed the ‘intl/’ subdirectory by calling
gettextizewithout ‘--intl’ option, then you don't need to add
If, after doing the recommended modifications, a command like ‘aclocal -I m4’ or ‘autoconf’ or ‘autoreconf’ fails with a trace similar to this:
configure.ac:44: warning: AC_COMPILE_IFELSE was called before AC_GNU_SOURCE ../../lib/autoconf/specific.m4:335: AC_GNU_SOURCE is expanded from... m4/lock.m4:224: gl_LOCK is expanded from... m4/gettext.m4:571: gt_INTL_SUBDIR_CORE is expanded from... m4/gettext.m4:472: AM_INTL_SUBDIR is expanded from... m4/gettext.m4:347: AM_GNU_GETTEXT is expanded from... configure.ac:44: the top level configure.ac:44: warning: AC_RUN_IFELSE was called before AC_GNU_SOURCE
you need to add an explicit invocation of ‘AC_GNU_SOURCE’ in the ‘configure.ac’ file - after ‘AC_PROG_CC’ but before ‘AM_GNU_GETTEXT’, most likely very close to the ‘AC_PROG_CC’ invocation. This is necessary because of ordering restrictions imposed by GNU autoconf.
If you haven't suppressed the ‘intl/’ subdirectory, you need to add the GNU ‘config.guess’ and ‘config.sub’ files to your distribution. They are needed because the ‘intl/’ directory has platform dependent support for determining the locale's character encoding and therefore needs to identify the platform.
You can obtain the newest version of ‘config.guess’ and ‘config.sub’ from the ‘config’ project at ‘http://savannah.gnu.org/’. The commands to fetch them are
$ wget -O config.guess 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD' $ wget -O config.sub 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD'
Less recent versions are also contained in the GNU
Normally, ‘config.guess’ and ‘config.sub’ are put at the top level of a distribution. But it is also possible to put them in a subdirectory, altogether with other configuration support files like ‘install-sh’, ‘ltconfig’, ‘ltmain.sh’ or ‘missing’. All you need to do, other than moving the files, is to add the following line to your ‘configure.ac’.
With earlier versions of GNU gettext, you needed to add the GNU ‘mkinstalldirs’ script to your distribution. This is not needed any more. You can remove it if you not also using an automake version older than automake 1.9.
If you do not have an ‘aclocal.m4’ file in your distribution,
the simplest is to concatenate the files ‘codeset.m4’, ‘fcntl-o.m4’,
‘gettext.m4’, ‘glibc2.m4’, ‘glibc21.m4’, ‘iconv.m4’,
‘intdiv0.m4’, ‘intl.m4’, ‘intldir.m4’, ‘intlmacosx.m4’,
‘intmax.m4’, ‘inttypes_h.m4’, ‘inttypes-pri.m4’,
‘lcmessage.m4’, ‘lib-ld.m4’, ‘lib-link.m4’,
‘lib-prefix.m4’, ‘lock.m4’, ‘longlong.m4’, ‘nls.m4’,
‘po.m4’, ‘printf-posix.m4’, ‘progtest.m4’, ‘size_max.m4’,
‘stdint_h.m4’, ‘threadlib.m4’, ‘uintmax_t.m4’,
‘visibility.m4’, ‘wchar_t.m4’, ‘wint_t.m4’, ‘xsize.m4’
‘m4/’ directory into a single file. If you have suppressed the
‘intl/’ directory, only ‘gettext.m4’, ‘iconv.m4’,
‘lib-ld.m4’, ‘lib-link.m4’, ‘lib-prefix.m4’,
‘nls.m4’, ‘po.m4’, ‘progtest.m4’ need to be concatenated.
If you are not using GNU
automake 1.8 or newer, you will need to
add a file ‘mkdirp.m4’ from a newer automake distribution to the
list of files above.
If you already have an ‘aclocal.m4’ file, then you will have
to merge the said macro files into your ‘aclocal.m4’. Note that if
you are upgrading from a previous release of GNU
should most probably replace the macros (
etc.), as they usually
change a little from one release of GNU
gettext to the next.
Their contents may vary as we get more experience with strange systems
If you are using GNU
automake 1.5 or newer, it is enough to put
these macro files into a subdirectory named ‘m4/’ and add the line
ACLOCAL_AMFLAGS = -I m4
to your top level ‘Makefile.am’.
If you are using GNU
automake 1.10 or newer, it is even easier:
Add the line
ACLOCAL_AMFLAGS = --install -I m4
to your top level ‘Makefile.am’, and run ‘aclocal --install -I m4’. This will copy the needed files to the ‘m4/’ subdirectory automatically, before updating ‘aclocal.m4’.
These macros check for the internationalization support functions
and related informations. Hopefully, once stabilized, these macros
might be integrated in the standard Autoconf set, because this
m4 code will be the same for all projects using GNU
gettext releases required to put definitions for
VERSION into an
‘acconfig.h’ file. This is not needed any more; you can remove
them from your ‘acconfig.h’ file unless your package uses them
independently from the ‘intl/’ directory.
The include file template that holds the C macros to be defined by
configure is usually called ‘config.h.in’ and may be
maintained either manually or automatically.
gettextize has created an ‘intl/’ directory, this file
must be called ‘config.h.in’ and must be at the top level. If,
however, you have suppressed the ‘intl/’ directory by calling
gettextize without ‘--intl’ option, then you can choose the
name of this file and its location freely.
If it is maintained automatically, by use of the ‘autoheader’
program, you need to do nothing about it. This is the case in particular
if you are using GNU
If it is maintained manually, and if
gettextize has created an
‘intl/’ directory, you should switch to using ‘autoheader’.
The list of C macros to be added for the sake of the ‘intl/’
directory is just too long to be maintained manually; it also changes
between different versions of GNU
If it is maintained manually, and if on the other hand you have
suppressed the ‘intl/’ directory by calling
without ‘--intl’ option, then you can get away by adding the
following lines to ‘config.h.in’:
/* Define to 1 if translation of program messages to the user's native language is requested. */ #undef ENABLE_NLS
Here are a few modifications you need to make to your main, top-level ‘Makefile.in’ file.
PACKAGE = @PACKAGE@ VERSION = @VERSION@
DISTFILESdefinition, so the file gets distributed.
Makefile.infor it to be further used in the ‘dist:’ goal.
SUBDIRS = doc intl lib src poNote that you must arrange for ‘make’ to descend into the
intldirectory before descending into other directories containing code which make use of the
libintl.hheader file. For this reason, here we mention
distdir = $(PACKAGE)-$(VERSION) dist: Makefile rm -fr $(distdir) mkdir $(distdir) chmod 777 $(distdir) for file in $(DISTFILES); do \ ln $$file $(distdir) 2>/dev/null || cp -p $$file $(distdir); \ done for subdir in $(SUBDIRS); do \ mkdir $(distdir)/$$subdir || exit 1; \ chmod 777 $(distdir)/$$subdir; \ (cd $$subdir && $(MAKE) $@) || exit 1; \ done tar chozf $(distdir).tar.gz $(distdir) rm -fr $(distdir)
Note that if you are using GNU
automake, ‘Makefile.in’ is
automatically generated from ‘Makefile.am’, and all needed changes
to ‘Makefile.am’ are already made by running ‘gettextize’.
Some of the modifications made in the main ‘Makefile.in’ will also be needed in the ‘Makefile.in’ from your package sources, which we assume here to be in the ‘src/’ subdirectory. Here are all the modifications needed in ‘src/Makefile.in’:
PACKAGE = @PACKAGE@ VERSION = @VERSION@
top_srcdirgets defined. This will serve for
cppinclude files. Just add the line:
top_srcdir = @top_srcdir@
subdiras ‘src’, later allowing for almost uniform ‘dist:’ goals in all your ‘Makefile.in’. At list, the ‘dist:’ goal below assume that you used:
subdir = src
mainfunction of your program will normally call
bindtextdomain(see see section 4.2 Triggering
gettextOperations), like this:
bindtextdomain (PACKAGE, LOCALEDIR); textdomain (PACKAGE);To make LOCALEDIR known to the program, add the following lines to ‘Makefile.in’ if you are using Autoconf version 2.60 or newer:
datadir = @datadir@ datarootdir= @datarootdir@ localedir = @localedir@ DEFS = -DLOCALEDIR=\"$(localedir)\" @DEFS@or these lines if your version of Autoconf is older than 2.60:
datadir = @datadir@ localedir = $(datadir)/locale DEFS = -DLOCALEDIR=\"$(localedir)\" @DEFS@Note that
@datadir@defaults to ‘$(prefix)/share’, thus
$(localedir)defaults to ‘$(prefix)/share/locale’.
@LTLIBINTL@as a library.
@LIBINTL@is for use without
@LTLIBINTL@is for use with
libtool. An easy way to achieve this is to manage that it gets into
LIBS, like this:
LIBS = @LIBINTL@ @LIBS@In most packages internationalized with GNU
gettext, one will find a directory ‘lib/’ in which a library containing some helper functions will be build. (You need at least the few functions which the GNU
gettextLibrary itself needs.) However some of the functions in the ‘lib/’ also give messages to the user which of course should be translated, too. Taking care of this, the support library (say ‘libsupport.a’) should be placed before
@LIBS@in the above example. So one has to write this:
LIBS = ../lib/libsupport.a @LIBINTL@ @LIBS@
distdir = ../$(PACKAGE)-$(VERSION)/$(subdir) dist: Makefile $(DISTFILES) for file in $(DISTFILES); do \ ln $$file $(distdir) 2>/dev/null || cp -p $$file $(distdir) || exit 1; \ done
Note that if you are using GNU
automake, ‘Makefile.in’ is
automatically generated from ‘Makefile.am’, and the first three
changes and the last change are not necessary. The remaining needed
‘Makefile.am’ modifications are the following:
<module>_CPPFLAGS = -DLOCALEDIR=\"$(localedir)\"for each specific module or compilation unit, or
AM_CPPFLAGS = -DLOCALEDIR=\"$(localedir)\"for all modules and compilation units together. Furthermore, if you are using an Autoconf version older then 2.60, add this line to define ‘localedir’:
localedir = $(datadir)/locale
@LTLIBINTL@as a library, add the following to ‘Makefile.am’:
<program>_LDADD = @LIBINTL@for each specific program, or
LDADD = @LIBINTL@for all programs together. Remember that when you use
libtoolto link a program, you need to use @LTLIBINTL@ instead of @LIBINTL@ for that program.
gettextize, then to ensure that it will be searched for C preprocessor include files in all circumstances, add something like this to ‘Makefile.am’:
AM_CPPFLAGS = -I../intl -I$(top_srcdir)/intl
Internationalization of packages, as provided by GNU
optional. It can be turned off in two situations:
intl/subdirectory, and the libintl.h header (with its associated libintl library, if any) is not already installed on the system, it is preferable that the package builds without internationalization support, rather than to give a compilation error.
A C preprocessor macro can be used to detect these two cases. Usually,
libintl.h was found and not explicitly disabled, the
ENABLE_NLS macro will be defined to 1 in the autoconf generated
configuration file (usually called ‘config.h’). In the two negative
situations, however, this macro will not be defined, thus it will evaluate
to 0 in C preprocessor expressions.
‘gettext.h’ is a convenience header file for conditional use of
‘<libintl.h>’, depending on the
ENABLE_NLS macro. If
ENABLE_NLS is set, it includes ‘<libintl.h>’; otherwise it
defines no-op substitutes for the libintl.h functions. We recommend
the use of
"gettext.h" over direct use of ‘<libintl.h>’,
so that portability to older systems is guaranteed and installers can
turn off internationalization if they want to. In the C code, you will
The location of
gettext.h is usually in a directory containing
auxiliary include files. In many GNU packages, there is a directory
‘lib/’ containing helper functions; ‘gettext.h’ fits there.
In other packages, it can go into the ‘src’ directory.
Do not install the
gettext.h file in public locations. Every
package that needs it should contain a copy of it on its own.
gettext installs macros for use in a package's
‘configure.ac’ or ‘configure.in’.
See section ‘Introduction’ in The Autoconf Manual.
The primary macro is, of course,
AM_GNU_GETTEXT macro tests for the presence of the GNU gettext
function family in either the C library or a separate
library (shared or static libraries are both supported) or in the package's
‘intl/’ directory. It also invokes
AM_PO_SUBDIRS, thus preparing
the ‘po/’ directories of the package for building.
AM_GNU_GETTEXT accepts up to three optional arguments. The general
AM_GNU_GETTEXT([intlsymbol], [needsymbol], [intldir])
intlsymbol can be ‘external’ or ‘no-libtool’. The default
(if it is not specified or empty) is ‘no-libtool’. intlsymbol
should be ‘external’ for packages with no ‘intl/’ directory.
For packages with an ‘intl/’ directory, you can either use an
intlsymbol equal to ‘no-libtool’, or you can use ‘external’
and override by using the macro
The two ways to specify the existence of an ‘intl/’ directory are
equivalent. At build time, a static library
$(top_builddir)/intl/libintl.a will then be created.
If needsymbol is specified and is ‘need-ngettext’, then GNU
gettext implementations (in libc or libintl) without the
function will be ignored. If needsymbol is specified and is
‘need-formatstring-macros’, then GNU gettext implementations that don't
support the ISO C 99 ‘<inttypes.h>’ formatstring macros will be ignored.
Only one needsymbol can be specified. These requirements can also be
specified by using the macro
AM_GNU_GETTEXT_NEED elsewhere. To specify
more than one requirement, just specify the strongest one among them, or
AM_GNU_GETTEXT_NEED macro several times. The hierarchy
among the various alternatives is as follows: ‘need-formatstring-macros’
intldir is used to find the intl libraries. If empty, the value ‘$(top_builddir)/intl/’ is used.
AM_GNU_GETTEXT macro determines whether GNU gettext is
available and should be used. If so, it sets the
to ‘yes’; it defines
ENABLE_NLS to 1 in the autoconf
generated configuration file (usually called ‘config.h’); it sets
LTLIBINTL to the linker options
for use in a Makefile (
LIBINTL for use without libtool,
LTLIBINTL for use with libtool); it adds an ‘-I’ option to
CPPFLAGS if necessary. In the negative case, it sets
USE_NLS to ‘no’; it sets
to empty and doesn't change
The complexities that
AM_GNU_GETTEXT deals with are the following:
gettextin the C library, for example glibc. Some have it in a separate library
libintlmight have been installed as part of the GNU
libintl, if installed, is not necessarily already in the search path (
CPPFLAGSfor the include file search path,
LDFLAGSfor the library search path).
gettextcannot exploit the GNU mo files, doesn't have the necessary locale dependency features, and cannot convert messages from the catalog's text encoding to the user's locale encoding.
libintl, if installed, is not necessarily already in the run time library search path. To avoid the need for setting an environment variable like
LD_LIBRARY_PATH, the macro adds the appropriate run time search path options to the
LTLIBINTLvariables. This works on most systems, but not on some operating systems with limited shared library support, like SCO.
libintlrelies on POSIX/XSI
iconv. The macro checks for linker options needed to use iconv and appends them to the
AM_GNU_GETTEXT_VERSION macro declares the version number of
the GNU gettext infrastructure that is used by the package.
The use of this macro is optional; only the
autopoint program makes
use of it (see section 13.6 Integrating with Version Control Systems).
AM_GNU_GETTEXT_NEED macro declares a constraint regarding the
GNU gettext implementation. The syntax is
If needsymbol is ‘need-ngettext’, then GNU gettext implementations
(in libc or libintl) without the
ngettext() function will be ignored.
If needsymbol is ‘need-formatstring-macros’, then GNU gettext
implementations that don't support the ISO C 99 ‘<inttypes.h>’
formatstring macros will be ignored.
The optional second argument of
AM_GNU_GETTEXT is also taken into
AM_GNU_GETTEXT_NEED invocations can occur before or after
AM_GNU_GETTEXT invocation; the order doesn't matter.
AM_GNU_GETTEXT_INTL_SUBDIR macro specifies that the
AM_GNU_GETTEXT macro, although invoked with the first argument
‘external’, should also prepare for building the ‘intl/’
AM_GNU_GETTEXT_INTL_SUBDIR invocation can occur before or after
AM_GNU_GETTEXT invocation; the order doesn't matter.
The use of this macro requires GNU automake 1.10 or newer and GNU autoconf 2.61 or newer.
AM_PO_SUBDIRS macro prepares the ‘po/’ directories of the
package for building. This macro should be used in internationalized
programs written in other programming languages than C, C++, Objective C,
Lisp. See section 15 Other Programming Languages for a list of programming languages that support localization
through PO files.
AM_PO_SUBDIRS macro determines whether internationalization
should be used. If so, it sets the
USE_NLS variable to ‘yes’,
otherwise to ‘no’. It also determines the right values for Makefile
variables in each ‘po/’ directory.
AM_XGETTEXT_OPTION macro registers a command-line option to be
used in the invocations of
xgettext in the ‘po/’ directories
of the package.
For example, if you have a source file that defines a function ‘error_at_line’ whose fifth argument is a format string, you can use
xgettext to mark all translatable strings in ‘gettext’
invocations that occur as fifth argument to this function as ‘c-format’.
See section 5.1 Invoking the
xgettext Program for the list of options that
The use of this macro is an alternative to the use of the ‘XGETTEXT_OPTIONS’ variable in ‘po/Makevars’.
AM_ICONV macro tests for the presence of the POSIX/XSI
iconv function family in either the C library or a separate
libiconv library. If found, it sets the
variable to ‘yes’; it defines
HAVE_ICONV to 1 in the autoconf
generated configuration file (usually called ‘config.h’); it defines
ICONV_CONST to ‘const’ or to empty, depending on whether the
second argument of
iconv() is of type ‘const char **’ or
‘char **’; it sets the variables
LTLIBICONV to the linker options for use in a Makefile
LIBICONV for use without libtool,
LTLIBICONV for use with
libtool); it adds an ‘-I’ option to
necessary. If not found, it sets
empty and doesn't change
The complexities that
AM_ICONV deals with are the following:
iconvin the C library, for example glibc. Some have it in a separate library
libiconv, for example OSF/1 or FreeBSD. Regardless of the operating system, GNU
libiconvmight have been installed. In that case, it should be used instead of the operating system's native
libiconv, if installed, is not necessarily already in the search path (
CPPFLAGSfor the include file search path,
LDFLAGSfor the library search path).
libiconvis binary incompatible with some operating system's native
iconv, for example on FreeBSD. Use of an ‘iconv.h’ and ‘libiconv.so’ that don't fit together would produce program crashes.
libiconv, if installed, is not necessarily already in the run time library search path. To avoid the need for setting an environment variable like
LD_LIBRARY_PATH, the macro adds the appropriate run time search path options to the
LIBICONVvariable. This works on most systems, but not on some operating systems with limited shared library support, like SCO.
‘iconv.m4’ is distributed with the GNU gettext package because ‘gettext.m4’ relies on it.
Many projects use version control systems for distributed development
and source backup. This section gives some advice how to manage the
version controlled files.
In a project development with multiple developers, there should be a
single developer who occasionally - when there is desire to upgrade to
gettext version - runs
gettextize and performs the
changes listed in section 13.4 Files You Must Create or Alter, and then commits his changes
to the repository.
It is highly recommended that all developers on a project use the same
version of GNU
gettext in the package. In other words, if a
gettextize, he should go the whole way, make the
necessary remaining changes and commit his changes to the repository.
Otherwise the following damages will likely occur:
gettextspecific portions in ‘configure.ac’, ‘configure.in’ and
Makefile.infiles depend on the
gettextversion, the use of infrastructure files belonging to different
gettextversions can easily lead to build errors.
gettextthan the other developers, the distribution will be less well tested than if all had been using the same
gettextversion. For example, it is possible that a platform specific bug goes undiscovered due to this constellation.
There are basically three ways to deal with generated files in the
context of a version controlled repository, such as ‘configure’
generated from ‘configure.ac’,
Each of these three approaches has different advantages and drawbacks.
m4installed in his PATH; sometimes he even needs particular versions of them. 2b. When a release is made and a commit is made on the generated files, the other developers get conflicts on the generated files when merging the local work back to the repository. Although these conflicts are easy to resolve, they are annoying.
m4installed in his PATH, but also that he needs to perform a package specific pre-build step before being able to "./configure; make".
For the first and second approach, all files modified or brought in
by the occasional
gettextize invocation and update should be
committed into the repository.
For the third approach, the maintainer can omit from the repository
all the files that
gettextize mentions as "copy". Instead, he
adds to the ‘configure.ac’ or ‘configure.in’ a line of the
and adds to the package's pre-build script an invocation of
‘autopoint’. For everyone who checks out the source, this
autopoint invocation will copy into the right place the
gettext infrastructure files that have been omitted from the repository.
The version number used as argument to
the version of the
gettext infrastructure that the package wants
to use. It is also the minimum version number of the ‘autopoint’
program. So, if you write
AM_GNU_GETTEXT_VERSION(0.11.5) then the
developers can have any version >= 0.11.5 installed; the package will work
with the 0.11.5 infrastructure in all developers' builds. When the
maintainer then runs gettextize from, say, version 0.12.1 on the package,
the occurrence of
AM_GNU_GETTEXT_VERSION(0.11.5) will be changed
AM_GNU_GETTEXT_VERSION(0.12.1), and all other developers that
use the CVS will henceforth need to have GNU
gettext 0.12.1 or newer
Since translations are valuable assets as well as the source code, it would make sense to put them under version control. The GNU gettext infrastructure supports two ways to deal with translations in the context of a version controlled repository.
If a POT file is absent when building, it will be generated by
scanning the source files with
xgettext, and then the PO files
are regenerated as a dependency. On the other hand, some maintainers
want to keep the POT file unchanged during the development phase. So,
even if a POT file is present and older than the source code, it won't
be updated automatically. You can manually update it with
$(DOMAIN).pot-update, and commit it at certain point.
Special advices for particular version control systems:
noin the ‘Makevars’ file and do
#: lib/error.c:116are sometimes annoying, since these comments are volatile and may introduce unwanted change to the working copy when building. To mitigate this, you can decide to omit those comments from the PO files in the repository. This is possible with the
--no-locationoption of the
msgmergecommand (6). The drawback is that, if the location information is needed, translators have to recover the location comments by running
autopoint program copies standard gettext infrastructure files
into a source package. It extracts from a macro call of the form
AM_GNU_GETTEXT_VERSION(version), found in the package's
‘configure.in’ or ‘configure.ac’ file, the gettext version
used by the package, and copies the infrastructure files belonging to
this version into the package.
To extract the latest available infrastructure which satisfies a version
requirement, then you can use the form
AM_GNU_GETTEXT_REQUIRE_VERSION(version) instead. For
example, if gettext 0.19.8 is installed on your system
0.19.1 is requested, then the infrastructure files of version
0.19.8 will be copied into a source package.
autopointwould normally execute are inhibited and instead only listed on standard output.
autopoint supports the GNU
gettext versions from 0.10.35
to the current one, 0.19.8. In order to apply
autopoint to a package using a
gettext version newer than
0.19.8, you need to install this same version of GNU
gettext at least.
In packages using GNU
automake, an invocation of
should be followed by invocations of
aclocal and then
autoheader. The reason is that
autopoint installs some
autoconf macro files, which are used by
aclocal to create
‘aclocal.m4’, and the latter is used by
autoconf to create the
package's ‘configure’ script and by
autoheader to create the
package's ‘config.h.in’ include file template.
The name ‘autopoint’ is an abbreviation of ‘auto-po-intl-m4’; the tool copies or updates mostly files in the ‘po’, ‘intl’, ‘m4’ directories.
In projects that use GNU
automake, the usual commands for creating
a distribution tarball, ‘make dist’ or ‘make distcheck’,
automatically update the PO files as needed.
automake is not used, the maintainer needs to perform this
update before making a release:
$ ./configure $ (cd po; make update-po) $ make distclean
Go to the first, previous, next, last section, table of contents.