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<h1 style="text-align: center;">Frequently Asked Questions<br>
for GNU gettext
</h1>
<h1 style="text-align: center;">Questions</h1>
<h3>General</h3>
<ul>
<li><a href="#general_mailinglist">Where is the mailing list?</a></li>
<li><a href="#general_source">Where is the newest gettext source?</a></li>
<li><a href="#general_announce">I want to be notified of new gettext
releases.</a></li>
</ul>
<h3>Problems building GNU gettext</h3>
<ul>
<li><a href="#building_solaris_libasprintf">On Solaris, I get a build
error “text relocations remain” in the <span
style="font-family: monospace;">libasprintf</span> subdirectory</a></li>
<li><a href="#building_rpath_check">During “make check”, some tests
named <span style="font-family: monospace;">rpath-<span
style="font-style: italic;">Nxyz</span></span>
fail: “ld: fatal error ... -lrpathz”</a></li>
<li><a href="#building_install">“make install” fails</a></li>
</ul>
<h3>Problems integrating GNU gettext</h3>
<ul>
<li><a href="#integrating_howto">How do I make use of <span
style="font-family: monospace;">gettext()</span> in my package?</a></li>
<li><a href="#integrating_undefined">I get a linker error “undefined
reference to libintl_gettext”</a></li>
<li><a href="#integrating_abuse_gettextize">gettextize adds multiple
references to the same directories/files
to <span style="font-family: monospace;">Makefile.am</span> and </a><span
style="font-family: monospace;"><a href="#integrating_abuse_gettextize">configure.ac</a><br>
</span></li>
<li><a href="#integrating_noop">My program compiles and links fine,
but doesn't output translated
strings.</a><br>
</li>
</ul>
<h3>GNU gettext on Windows</h3>
<ul>
<li><a href="#windows_woe32">What does Woe32 mean?</a></li>
<li><a href="#windows_howto">How do I compile, link and run a program
that uses the gettext()
function?</a><br>
</li>
<li><a href="#windows_setenv">Setting the <span
style="font-family: monospace;">LANG</span>
environment variable doesn't have any effect</a></li>
</ul>
<h3>Other</h3>
<ul>
<li><a href="#newline">What does this mean: “`msgid' and `msgstr'
entries do not both
end with '\n'”</a></li>
<li><a href="#translit">German umlauts are displayed like “ge"andert”
instead of
“geändert”</a></li>
<li><a href="#localename">The <span style="font-family: monospace;">LANGUAGE</span>
environment variable is ignored after I set <span
style="font-family: monospace;">LANG=en</span></a></li>
<li><a href="#nonascii_strings">I use accented characters in my
source code. How do I tell the
C/C++ compiler in which encoding it is (like <span
style="font-family: monospace;">xgettext</span>'s <span
style="font-family: monospace;">--from-code</span> option)?</a></li>
</ul>
<h1 style="text-align: center;">Answers</h1>
<h3>General</h3>
<h4><a name="general_mailinglist"></a>Where is the mailing list?</h4>
Three mailing lists are available: <br>
<ul>
<li><span style="font-family: monospace;">bug-gnu-gettext@gnu.org</span><br>
This mailing list is for discussion of features and bugs of the GNU
gettext <span style="font-style: italic;">software</span>, including
libintl, the gettext-tools, and its autoconf macros.</li>
<li><span style="font-family: monospace;">translation-i18n@lists.sourceforge.net</span><br>
This mailing list is for methodology questions around
internationalization, and for discussions of translator tools,
including but not limited to GNU gettext.</li>
<li><span style="font-family: monospace;">coordinator@translationproject.org</span><br>
This is the email address of the <a
href="http://translationproject.org/">Free Translation Project</a>,
that is the project which manages the translated message
catalogs for many free software packages. Note that KDE and GNOME
packages are not part of this project; they have their own translation
projects: <a href="http://i18n.kde.org/">i18n.kde.org</a> and <a
href="http://developer.gnome.org/projects/gtp/">gtp</a>.<br>
</li>
</ul>
The <span style="font-family: monospace;">bug-gnu-gettext</span> list
is archived as part of the <a
href="http://mail.gnu.org/archive/html/bug-gnu-utils/"><span
style="font-family: monospace;">bug-gnu-utils</span></a> archives. <span
style="font-family: monospace;">bug-gnu-gettext</span> cannot be
subscribed on its own; to receive its contents by mail, subscribe to <span
style="font-family: monospace;">bug-gnu-utils</span>.<br>
<h4><a name="general_source"></a>Where is the newest gettext source?</h4>
The newest gettext release is available on <span
style="font-family: monospace;">ftp.gnu.org</span> and its mirrors, in
<a href="http://ftp.gnu.org/gnu/gettext/">http://ftp.gnu.org/gnu/gettext/</a>.<br>
<br>
Prereleases are announced on the <a
href="http://mail.gnu.org/pipermail/autotools-announce"><span
style="font-family: monospace;">autotools-announce</span> mailing list</a>.
Note that prereleases are meant for testing and not meant for use in
production environments. Please don't use the “gettextize” program of a
prerelease on projects which you share with other programmers via CVS.<br>
<br>
If you want to live on the bleeding edge, you can also use the
development sources. Instructions for retrieving the gettext CVS are
found <a href="http://savannah.gnu.org/projects/gettext">here</a>.
Note that building from CVS requires special tools (autoconf, automake,
m4, groff, bison, etc.) and requires that you pay attention to the <span
style="font-family: monospace;">README-alpha</span> and <span
style="font-family: monospace;">autogen.sh</span> files in the CVS.<br>
<h4><a name="general_announce"></a>I want to be notified of new gettext
releases.</h4>
If you are interested in stable gettext releases, you can follow the <a
href="http://mail.gnu.org/pipermail/info-gnu"><span
style="font-family: monospace;">info-gnu</span> mailing list</a>. It
is also available as a newsgroup <a
href="nntp://news.gmane.org/gmane.org.fsf.announce"><span
style="font-family: monospace;">gmane.org.fsf.announce</span></a>
through <a href="http://www.gmane.org/"><span
style="font-family: monospace;">gmane.org</span></a>.<br>
<br>
You can also periodically check the download location.<br>
<br>
If you are interested in testing prereleases as well, you can subscribe
to the <a href="http://mail.gnu.org/pipermail/autotools-announce"><span
style="font-family: monospace;">autotools-announce</span> mailing
list</a>.<br>
<h3>Problems building GNU gettext</h3>
<h4><a name="building_solaris_libasprintf"></a>On Solaris, I get a
build error “text relocations remain” in the <span
style="font-family: monospace;">libasprintf</span> subdirectory</h4>
libtool (or more precisely, the version of libtool that was available
at the time the gettext release waas made) doesn't support linking C++
libraries with some versions of GCC. As a workaround, you can configure
gettext with the option <span style="font-family: monospace;">--disable-libasprintf</span>.<br>
<h4><a name="building_rpath_check"></a>During “make check”, some tests
named <span style="font-family: monospace;">rpath-<span
style="font-style: italic;">Nxyz</span></span>
fail: “ld: fatal error ... -lrpathz”</h4>
If only a few among the many rpath tests fail, you can probably ignore
the problem. The rpath tests are sensitive to incomplete shared library
support in the system, and to bugs in libtool that creates the shared
libraries. Some known failures are listed in <span
style="font-family: monospace;">autoconf-lib-link/tests/rpath.README</span>.<br>
<br>
To ignore the problem, just proceed with<br>
<br>
<div style="margin-left: 40px;"><code>cd gettext-tools</code><br>
<code>make check</code><br>
<code>cd ..</code><br>
</div>
<br>
<h4><a name="building_install"></a>“make install” fails</h4>
“<span style="font-family: monospace;">make install DESTDIR=<span
style="font-style: italic;">/some/tempdir</span></span>” can fail with
an error message relating to <span style="font-family: monospace;">libgettextlib</span>
or <span style="font-family: monospace;">libgettextsrc</span>, or can
silently fail to install <span style="font-family: monospace;">libgettextsrc</span>.
On some platforms, this is due to limitations of libtool regarding <span
style="font-family: monospace;">DESTDIR</span>. On other platforms, it
is due to the way the system handles shared libraries, and libtool
cannot work around it. Fortunately, on Linux and other glibc based
systems, <span style="font-family: monospace;">DESTDIR</span> is
supported if no different version of gettext is already installed (i.e.
it works if you uninstall the older gettext before building and
installing the newer one, or if you do a plain “<span
style="font-family: monospace;">make install</span>” before “<span
style="font-family: monospace;">make install DESTDIR=<span
style="font-style: italic;">/some/tempdir</span></span>”). On other
systems, when <span style="font-family: monospace;">DESTDIR</span>
does not work, you can still do “<span style="font-family: monospace;">make
install</span>” and copy the installed files to <span
style="font-family: monospace;"><span style="font-style: italic;">/some/tempdir</span></span>
afterwards.<br>
<br>
If “<span style="font-family: monospace;">make install</span>” without <span
style="font-family: monospace;">DESTDIR</span> fails, it's a bug which
you are welcome to report to the usual bug report address.
<h3>Problems integrating GNU gettext</h3>
<h4><a name="integrating_howto"></a>How do I make use of <span
style="font-family: monospace;">gettext()</span> in my package?</h4>
It's not as difficult as it sounds. Here's the recipe for C or C++
based packages.<br>
<ul>
<li>Add an invocation of <span style="font-family: monospace;">AM_GNU_GETTEXT([external])</span>
to the package's <span style="font-family: monospace;">configure.{ac,in}</span>
file.</li>
<li>Invoke “<span style="font-family: monospace;">gettextize --copy</span>”.
It will do most of the autoconf/automake related work for you.</li>
<li>Add the <span style="font-family: monospace;">gettext.h</span>
file to the package's source directory, and include it in all source
files that contain translatable strings or do output via <span
style="font-family: monospace;">printf</span> or <span
style="font-family: monospace;">fprintf</span>.</li>
<li>In the source file defining the main() function of the program,
add these lines to the header<br>
<div style="margin-left: 40px;"><code><span
style="font-family: monospace;">#include <locale.h></span><br
style="font-family: monospace;">
<span style="font-family: monospace;">#include "gettext.h"</span></code><br>
</div>
and these lines near the beginning of the main() function:<br>
<div style="margin-left: 40px;"><code><span
style="font-family: monospace;">setlocale (LC_ALL, "");</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">bindtextdomain (PACKAGE,
LOCALEDIR);</span><br style="font-family: monospace;">
<span style="font-family: monospace;">textdomain (PACKAGE);</span></code><br>
</div>
</li>
<li>Mark all strings that should be translated with _(), like this: <span
style="font-family: monospace;">_("No errors found.")</span>. While
doing this, try to turn the strings into good English, one entire
sentence per string, not more than one paragraph per string, and use
format strings instead of string concatenation. This is needed so that
the translators can provide accurate translations.</li>
<li>In every source file containing translatable strings, add these lines
to the header:<br>
<div style="margin-left: 40px;"><code><span
style="font-family: monospace;">#include "gettext.h"</span><br
style="font-family: monospace;">
<span style="font-family: monospace;">#define _(string) gettext (string)</span></code><br>
</div>
</li>
<li>In the freshly created <span style="font-family: monospace;">po/</span>
directory, set up the <span style="font-family: monospace;">POTFILES.in</span>
file, and do a “<span style="font-family: monospace;">make update-po</span>”.
Then distribute the generated <span style="font-family: monospace;">.pot</span>
file to your nearest translation project.</li>
<li>Shortly before a release, integrate the translators' <span
style="font-family: monospace;">.po</span> files into the <span
style="font-family: monospace;">po/</span> directory and do “<span
style="font-family: monospace;">make update-po</span>” again.<br>
</li>
</ul>
You find detailed descriptions of how this all works in the GNU gettext
manual, chapters “The Maintainer's View” and “Preparing Program
Sources”.
<h4><a name="integrating_undefined"></a>I get a linker error “undefined
reference to libintl_gettext”</h4>
This error means that the program uses the <span
style="font-family: monospace;">gettext()</span> function after having
included the <span style="font-family: monospace;"><libintl.h></span>
file from GNU gettext (which remaps it to <span
style="font-family: monospace;">libintl_gettext()</span>), however at
link time a function of this name could not be linked in. (It is
expected to come from the <span style="font-family: monospace;">libintl</span>
library, installed by GNU gettext.)<br>
<br>
There are many possible reasons for this error, but in any case you
should consider the <span style="font-family: monospace;">-I</span>, <span
style="font-family: monospace;">-L</span> and <span
style="font-family: monospace;">-l</span> options passed to the
compiler. In packages using <span style="font-family: monospace;">autoconf</span>
generated configure scripts, <span style="font-family: monospace;">-I</span>
options come from the <span style="font-family: monospace;">CFLAGS</span>
and <span style="font-family: monospace;">CPPFLAGS</span> variables
(in Makefiles also <span style="font-family: monospace;">DEFS</span>
and <span style="font-family: monospace;">INCLUDES</span>), <span
style="font-family: monospace;">-L</span> options come from the <span
style="font-family: monospace;">LDFLAGS</span> variable, and <span
style="font-family: monospace;">-l</span> options come from the <span
style="font-family: monospace;">LIBS</span> variable. The first thing
you should check are the values of these variables in your environment
and in the package's <span style="font-family: monospace;">config.status</span>
autoconfiguration result.<br>
<br>
To find the cause of the error, a little analysis is needed. Does the
program's final link command contains the option “-lintl”?<br>
<ul>
<li>If yes:<br>
Find out where the <span style="font-family: monospace;">libintl</span>
comes from. To do this, you have to check for <span
style="font-family: monospace;">libintl.a</span> and <span
style="font-family: monospace;">libintl.so*</span> (<span
style="font-family: monospace;">libintl.dylib</span> on MacOS X) in
each directory given as a -L option, as well as in the compiler's
implicit search directories. (You get these implicit search directories
for gcc by using “<span style="font-family: monospace;">gcc -v</span>”
instead of “<span style="font-family: monospace;">gcc</span>” in the
final link command line; compilers other than GCC usually look in <span
style="font-family: monospace;">/usr/lib</span> and <span
style="font-family: monospace;">/lib</span>.) A shell command like<br>
<div style="margin-left: 40px;"><code>$ for d in /usr/local/lib
/usr/lib /lib; do ls -l $d/libintl.*; done</code><br>
</div>
will show where the <span style="font-family: monospace;">libintl</span>
comes from. By looking at the dates and whether each library defines <span
style="font-family: monospace;">libintl_gettext</span> (via “<span
style="font-family: monospace;">nm <span style="font-style: italic;">path</span>/libintl.so
| grep libintl_gettext</span>”) you can now distinguish three possible
causes of the error:<br>
<ul>
<li>Some older libintl is used instead of the newer one. The fix
is to remove the old library or to reorganize your -L options.</li>
<li>The used libintl is the new one, and it doesn't contain
libintl_gettext. This would be a bug in gettext. If this is the case,
please report it to the usual bug report address.</li>
<li>The used libintl is a static library (libintl.a), there are
no uses of gettext in .o files before the “-lintl” but there are some
after the “-lintl”. In this case the fix is to move the “-lintl” to the
end or near the end of the link command line. The only libintl
dependency that needs to be mentioned after “-lintl” is “-liconv”.</li>
</ul>
</li>
<li>If no:<br>
In this case it's likely a bug in the package you are building: The
package's Makefiles should make sure that “-lintl” is used where needed.<br>
Test whether libintl was found by configure. You can check this by doing<br>
<div style="margin-left: 40px;"><code>$ grep
'\(INTLLIBS\|LIBINTL\)' config.status</code><br>
</div>
and looking whether the value of this autoconf variable is non-empty.<br>
<ul>
<li>If yes: It should be the responsibility of the Makefile to
use the value of this variable in the link command line. Does the
Makefile.in rule for linking the program use <span
style="font-family: monospace;">@INTLLIBS@</span> or <span
style="font-family: monospace;">@LIBINTL@</span>?<br>
<ul>
<li>If no: It's a Makefile.am/in bug.</li>
<li>If yes: Something strange is going on. You need to dig
deeper.</li>
</ul>
Note that <span style="font-family: monospace;">@INTLLIBS@</span> is
for <span style="font-family: monospace;">gettext.m4</span> versions
<= 0.10.40 and <span style="font-family: monospace;">@LIBINTL@</span>
is for <span style="font-family: monospace;">gettext.m4</span>
versions >= 0.11, depending on which <span
style="font-family: monospace;">gettext.m4</span> was used to build
the package's <span style="font-family: monospace;">configure</span> -
regardless of which gettext you have now installed.</li>
<li>If no: So libintl was not found.<br>
Take a look at the package's <span style="font-family: monospace;">configure.in/ac</span>.
Does it invoke AM_GNU_GETTEXT?<br>
<ul>
<li>If no: The gettext maintainers take no responsibilities for
lookalikes named CY_GNU_GETTEXT, AM_GLIB_GNU_GETTEXT, AM_GNOME_GETTEXT
and similar, or for homebrewn autoconf checks. Complain to the package
maintainer.</li>
<li>If yes: It looks like the <span
style="font-family: monospace;">-I</span> and <span
style="font-family: monospace;">-L</span> options were inconsistent.
You should have a <span style="font-family: monospace;">-I<span
style="font-style: italic;">somedir</span>/include</span> in the <span
style="font-family: monospace;">CFLAGS</span> or <span
style="font-family: monospace;">CPPFLAGS</span> if and only if you
also have a <span style="font-family: monospace;">-L<span
style="font-style: italic;">somedir</span>/lib</span> in the <span
style="font-family: monospace;">LDFLAGS</span>. And <span
style="font-family: monospace;"><span style="font-style: italic;">somedir</span>/include</span>
should contain a <span style="font-family: monospace;">libintl.h</span>
if and only if <span style="font-family: monospace;"><span
style="font-style: italic;">somedir</span>/lib</span> contains <span
style="font-family: monospace;">libintl.{a,so}</span>.<br>
This case can also happen if you have configured a GCC < 3.2 with
the same <span style="font-family: monospace;">--prefix</span> option
as you used for GNU libiconv or GNU gettext. This is fatal, because
these versions of GCC implicitly use <span
style="font-family: monospace;">-L<span style="font-style: italic;">prefix</span>/lib</span>
but <span style="font-weight: bold; font-style: italic;">not</span><br
style="font-weight: bold; font-style: italic;">
<span style="font-family: monospace;">-I<span
style="font-style: italic;">prefix</span>/include</span>. The
workaround is to use a different <span style="font-family: monospace;">--prefix</span>
for GCC.<br>
</li>
</ul>
</li>
</ul>
</li>
</ul>
<h4><a name="integrating_abuse_gettextize"></a>gettextize adds multiple
references to the same directories/files
to <span style="font-family: monospace;">Makefile.am</span> and <span
style="font-family: monospace;">configure.ac</span></h4>
If <span style="font-family: monospace;">gettextize</span> is used on
a package, then the <span style="font-family: monospace;">po/</span>, <span
style="font-family: monospace;">intl/</span>, <span
style="font-family: monospace;">m4/</span> directories of the package
are removed, and then <span style="font-family: monospace;">gettextize</span>
is invoked on the package again, it will re-add the <span
style="font-family: monospace;">po/</span>, <span
style="font-family: monospace;">intl/</span>, <span
style="font-family: monospace;">m4/</span> directories and change <span
style="font-family: monospace;">Makefile.am</span>, <span
style="font-family: monospace;">configure.ac</span> and <span
style="font-family: monospace;">ChangeLog</span> accordingly. This is
normal. The second use of <span style="font-family: monospace;">gettextize</span>
here is an abuse of the program. <span style="font-family: monospace;">gettextize</span>
is a wizard intended to transform a <span style="font-style: italic;">working
source package</span> into a <span style="font-style: italic;">working
source package</span> that uses the newest version of gettext. If you
start out from a nonfunctional source package (it is nonfunctional
since you have omitted some directories), you cannot expect that <span
style="font-family: monospace;">gettextize</span> corrects it.<br>
<br>
Often this question arises in packages that use CVS. See the section
“CVS Issues / Integrating with CVS” of the GNU gettext documentation.
This section mentions a program <span style="font-family: monospace;">autopoint</span>
which is designed to reconstruct those files and directories created by
<span style="font-family: monospace;">gettextize</span> that can be
omitted from a CVS repository.<br>
<h4><a name="integrating_noop"></a>My program compiles and links fine,
but doesn't output translated
strings.</h4>
There are several possible reasons. Here is a checklist that allows you
to determine the cause.<br>
<ol>
<li>Check that the environment variables LC_ALL, LC_MESSAGES,
LC_CTYPE, LANG, LANGUAGE together specify a valid locale and language.<br>
To check this, run the commands<br>
<div style="margin-left: 40px;"><code>$ gettext --version</code><br>
<code>$ gettext --help</code><br>
</div>
You should see at least some output in your desired language. If not,
either<br>
<ul>
<li>You have chosen a too exotic language. <span
style="font-family: monospace;">gettext</span> is localized to 33
languages. Choose a less exotic language, such as Galician or
Ukrainian. Or<br>
</li>
<li>There is a problem with your environment variables. Possibly
LC_ALL points to a locale that is not installed, or LC_MESSAGES and
LC_CTYPE are inconsistent.</li>
</ul>
</li>
<li>Check that your program contains a <span
style="font-family: monospace;">setlocale</span> call.<br>
To check this, run your program under ltrace. For example,<br>
<div style="margin-left: 40px;"><code>$ ltrace ./myprog</code><br>
<code>...</code><br>
<code>setlocale(6,
"")
= "de_DE.UTF-8"</code><br>
</div>
If you have no ltrace, you can also do this check by running your
program under the debugger. For example,<br>
<div style="margin-left: 40px;"><code>$ gdb ./myprog</code><br>
<code>(gdb) break main</code><br>
<code>(gdb) run</code><br>
<code>Breakpoint 1, main ()</code><br>
<code>(gdb) break setlocale</code><br>
<code>(gdb) continue</code><br>
<code>Breakpoint 2, setlocale ()</code><br>
<code>;; OK, the breakpoint has been hit, setlocale() is being
called.</code><br>
</div>
Either way, check that the return value of <span
style="font-family: monospace;">setlocale()</span> is non-NULL. A NULL
return value indicates a failure. </li>
<li>Check that your program contains a <span
style="font-family: monospace;">textdomain</span> call, a <span
style="font-family: monospace;">bindtextdomain</span> call referring
to the same message domain, and then really calls the <span
style="font-family: monospace;">gettext</span>, <span
style="font-family: monospace;">dgettext</span> or <span
style="font-family: monospace;">dcgettext</span> function.<br>
To check this, run the program under ltrace. For example,<br>
<div style="margin-left: 40px;"><code>$ ltrace ./myprog</code><br>
<code>...</code><br>
<code>textdomain("hello-c")
= "hello-c"</code><br>
<code>bindtextdomain("hello-c", "/opt/share"...) = "/opt/share"...</code><br>
<code>dcgettext(0, 0x08048691, 5, 0x0804a200, 0x08048689) =
0x4001721f</code><br>
</div>
If you have no ltrace, you can also do this check by running your
program under the debugger. For example,<br>
<div style="margin-left: 40px;"><code>$ gdb ./myprog</code><br>
<code>(gdb) break main</code><br>
<code>(gdb) run</code><br>
<code>Breakpoint 1, main ()</code><br>
<code>(gdb) break textdomain</code><br>
<code>(gdb) break bindtextdomain</code><br>
<code>(gdb) break gettext</code><br>
<code>(gdb) break dgettext</code><br>
<code>(gdb) break dcgettext</code><br>
<code>(gdb) continue</code><br>
<code>Breakpoint 2, textdomain ()</code><br>
<code>(gdb) continue</code><br>
<code>Breakpoint 3, bindtextdomain ()</code><br>
<code>(gdb) continue</code><br>
<code>Breakpoint 6, dcgettext ()</code><br>
</div>
Note that here <span style="font-family: monospace;">dcgettext()</span>
is called instead of the <span style="font-family: monospace;">gettext()</span>
function mentioned in the source code; this is due to an optimization
in <span style="font-family: monospace;"><libintl.h></span>.<br>
When using libintl on a non-glibc system, you have to add a prefix “<span
style="font-family: monospace;">libintl_</span>” to all the function
names mentioned here, because that's what the functions are really
named, under the hood.<br>
If <span style="font-family: monospace;">gettext</span>/<span
style="font-family: monospace;">dgettext</span>/<span
style="font-family: monospace;">dcgettext</span> is not called at all,
the possible cause might be that some autoconf or Makefile macrology
has turned off internationalization entirely (like the <span
style="font-family: monospace;">--disable-nls</span> configuration
option usually does).<br>
</li>
<li>Check that the <span style="font-family: monospace;">.mo</span>
file that contains the translation is really there where the program
expects it.<br>
To check this, run the program under strace and look at the <span
style="font-family: monospace;">open()</span> calls. For example,<br>
<div style="margin-left: 40px;"><code>$ strace ./myprog 2>&1
| grep '^open('</code><br>
<code>open("/etc/ld.so.preload", O_RDONLY) = -1
ENOENT (No such file or directory)</code><br>
<code>open("/etc/ld.so.cache",
O_RDONLY) = 5</code><br>
<code>open("/lib/libc.so.6",
O_RDONLY) = 5</code><br>
<code>open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE)
= 5</code><br>
<code>open("/usr/share/locale/locale.alias", O_RDONLY) = 5</code><br>
<code>open("/opt/share/locale/de/LC_MESSAGES/hello-c.mo", O_RDONLY)
= 5</code><br>
<code>...</code><br>
</div>
A nonnegative <span style="font-family: monospace;">open()</span>
return value means that the file has been found.<br>
If you have no strace, you can also guess the <span
style="font-family: monospace;">.mo</span> file's location: it is<br>
<div style="margin-left: 40px;"><span
style="font-family: monospace;"><span style="font-style: italic;">localedir</span>/<span
style="font-style: italic;">lang</span>/LC_MESSAGES/<span
style="font-style: italic;">domain</span>.mo</span><br>
</div>
where <span style="font-style: italic;">domain</span> is the argument
passed to <span style="font-family: monospace;">textdomain()</span>, <span
style="font-style: italic;">localedir</span> is the second argument
passed to <span style="font-family: monospace;">bindtextdomain()</span>,
and <span style="font-style: italic;">lang</span> is the language (<span
style="font-style: italic;">LL</span>) or language and territory (<span
style="font-style: italic;">LL</span>_<span style="font-style: italic;">CC</span>),
depending on the environment variables checked in step 1.</li>
<li>Check that the .mo file contains a translation for the string
that is being asked for.<br>
To do this, you need to convert the .mo file back to PO file format,
through the command<br>
<div style="margin-left: 40px;"><code>$ msgunfmt </code><span
style="font-family: monospace;"><span style="font-style: italic;">localedir</span>/<span
style="font-style: italic;">lang</span>/LC_MESSAGES/<span
style="font-style: italic;">domain</span>.mo</span><br>
<code></code></div>
and look for an <span style="font-family: monospace;">msgid</span>
that matches the given string.<br>
</li>
</ol>
<h3>GNU gettext on Windows</h3>
<h4><a name="windows_woe32"></a>What does Woe32 mean?</h4>
“Woe32” denotes the Windows 32-bit operating systems for x86: Windows
NT/2000/XP and Windows 95/98/ME. Microsoft uses the term “Win32” to
denote these; this is a psychological trick in order to make everyone
believe that these OSes are a “win” for the user. However, for most
users and developers, they are a source of woes, which is why I call
them “Woe32”.<br>
<h4><a name="windows_howto"></a>How do I compile, link and run a
program that uses the gettext()
function?</h4>
When you use RedHat's cygwin environment, it's as on Unix:<br>
<ul>
<li>You need to add an <span style="font-family: monospace;">-I</span>
option to the compilation command line, so that the compiler finds the <span
style="font-family: monospace;">libintl.h</span> include file, and</li>
<li>You need to add an <span style="font-family: monospace;">-L</span>
option to the link command line, so that the linker finds the <span
style="font-family: monospace;">libintl</span> library.</li>
</ul>
When you use the Mingw environment (either from within cygwin, with <span
style="font-family: monospace;">CC="gcc -mno-cygwin"</span>, or from
MSYS, with <span style="font-family: monospace;">CC="gcc"</span>), I
don't know the details.<br>
<br>
When you use the Microsoft Visual C/C++ (MSVC) compiler, you will
likely use the precompiled Woe32 binaries. For running a program that
uses gettext(), one needs the <span style="font-family: monospace;">.bin.woe32.zip</span>
packages of <span style="font-family: monospace;">gettext-runtime</span>
and <span style="font-family: monospace;">libiconv</span>. As a
developer, you'll also need the <span style="font-family: monospace;">xgettext</span>
and <span style="font-family: monospace;">msgfmt</span> programs that
are contained in the <span style="font-family: monospace;">.bin.woe32.zip</span>
package of <span style="font-family: monospace;">gettext-tools</span>.
Then<br>
<ul>
<li>You need to add an <span style="font-family: monospace;">-MD</span>
option to all compilation and link command lines. MSVC has six
different, mutually incompatible, compilation models (<span
style="font-family: monospace;">-ML</span>, <span
style="font-family: monospace;">-MT</span>, <span
style="font-family: monospace;">-MD</span>, <span
style="font-family: monospace;">-MLd</span>, <span
style="font-family: monospace;">-MTd</span>, <span
style="font-family: monospace;">-MDd</span>); the default is <span
style="font-family: monospace;">-ML</span>. <span
style="font-family: monospace;">intl.dll</span> uses the <span
style="font-family: monospace;">-MD</span> model, therefore the rest
of the program must use <span style="font-family: monospace;">-MD</span>
as well.<br>
</li>
<li>You need to add an <span style="font-family: monospace;">-I</span>
option to the compilation command line, so that the compiler finds the <span
style="font-family: monospace;">libintl.h</span> include file.<br>
</li>
<li>You need to add an <span style="font-family: monospace;">-L</span>
option to the link command line, so that the linker finds the <span
style="font-family: monospace;">intl.lib</span> library.</li>
<li>You need to copy the <span style="font-family: monospace;">intl.dll</span>
and <span style="font-family: monospace;">iconv.dll</span> to the
directory where your <span style="font-family: monospace;">.exe</span>
files are created, so that they will be found at runtime.<br>
</li>
</ul>
<h4><a name="windows_setenv"></a>Setting the <span
style="font-family: monospace;">LANG</span>
environment variable doesn't have any effect</h4>
If neither LC_ALL, LC_MESSAGES nor LANGUAGES is set, it's the LANG
environment variable which determines the language into which gettext()
translates the messages.<br>
<br>
You can test your program by setting the LANG environment variable from
outside the program. In a Windows command interpreter:<br>
<div style="margin-left: 40px;"><code>set LANG=de_DE</code><br>
<code>.\myprog.exe</code><br>
</div>
Or in a Cygwin shell:<br>
<div style="margin-left: 40px;"><code>$ env LANG=de_DE ./myprog.exe</code><br>
</div>
<br>
If this test fails, look at the question “My program compiles and links
fine, but doesn't output translated
strings.” above.<br>
<br>
If this test succeeds, the problem is related in the way you set the
environment variable. Here is a checklist:<br>
<ul>
<li>Check that you are using the <span
style="font-family: monospace;">-MD</span> option in all compilation
and link command lines. Otherwise you might end up calling the <span
style="font-family: monospace;">putenv()</span> function from
Microsoft's <span style="font-family: monospace;">libc.lib</span>,
whereas <span style="font-family: monospace;">intl.dll</span> is using
the <span style="font-family: monospace;">getenv()</span> function
from Mictosoft's <span style="font-family: monospace;">msvcrt.lib</span>.</li>
<li>Check that you set the environment variable using <span
style="font-style: italic;">both</span> <span
style="font-family: monospace;">SetEnvironmentVariable()</span> and <span
style="font-family: monospace;">putenv()</span>. A convenient way to
do so, and to deal with the fact that some Unix systems have <span
style="font-family: monospace;">setenv()</span> and some don't, is the
following function.<br>
<br>
<div style="margin-left: 40px;"><code>#include <string.h></code><br>
<code>#include <stdlib.h></code><br>
<code>#if defined _WIN32</code><br>
<code># include <windows.h></code><br>
<code>#endif</code><br>
<code></code><br>
<code>int my_setenv (const char * name, const char * value) {</code><br>
<code> size_t namelen = strlen(name);</code><br>
<code> size_t valuelen = (value==NULL ? 0 : strlen(value));</code><br>
<code>#if defined _WIN32</code><br>
<code> /* On Woe32, each process has two copies of the
environment variables,</code><br>
<code> one managed by the OS and one
managed by the C library. We set</code><br>
<code> the value in both locations, so that
other software that looks in</code><br>
<code> one place or the other is guaranteed
to see the value. Even if it's</code><br>
<code> a bit slow. See also</code><br>
<code> <<a
href="http://article.gmane.org/gmane.comp.gnu.mingw.user/8272">http://article.gmane.org/gmane.comp.gnu.mingw.user/8272</a>></code><br>
<code> <<a
href="http://article.gmane.org/gmane.comp.gnu.mingw.user/8273">http://article.gmane.org/gmane.comp.gnu.mingw.user/8273</a>></code><br>
<code> <<a
href="http://www.cygwin.com/ml/cygwin/1999-04/msg00478.html">http://www.cygwin.com/ml/cygwin/1999-04/msg00478.html</a>>
*/</code><br>
<code> if (!SetEnvironmentVariableA(name,value))</code><br>
<code> return -1; </code><br>
<code>#endif</code><br>
<code>#if defined(HAVE_PUTENV)</code><br>
<code> char* buffer = (char*)malloc(namelen+1+valuelen+1);</code><br>
<code> if (!buffer)</code><br>
<code> return -1; /* no need to set errno =
ENOMEM */</code><br>
<code> memcpy(buffer,name,namelen);</code><br>
<code> if (value != NULL) {</code><br>
<code> buffer[namelen] = '=';</code><br>
<code> memcpy(buffer+namelen+1,value,valuelen);</code><br>
<code> buffer[namelen+1+valuelen] = 0;</code><br>
<code> } else</code><br>
<code> buffer[namelen] = 0;</code><br>
<code> return putenv(buffer);</code><br>
<code>#elif defined(HAVE_SETENV)</code><br>
<code> return setenv(name,value,1);</code><br>
<code>#else</code><br>
<code> /* Uh oh, neither putenv() nor setenv() ... */</code><br>
<code> return -1;</code><br>
<code>#endif</code><br>
<code>}</code><br>
<code></code></div>
<br>
</li>
</ul>
<h3>Other</h3>
<h4><a name="newline"></a>What does this mean: “`msgid' and `msgstr'
entries do not both end
with '\n'”</h4>
It means that when the original string ends in a newline, your
translation must also end in a newline. And if the original string does
not end in a newline, then your translation should likewise not have a
newline at the end.<br>
<h4><a name="translit"></a>German umlauts are displayed like
“ge"andert” instead of “geändert”</h4>
This symptom occurs when the <span style="font-family: monospace;">LC_CTYPE</span>
facet of the locale is not set; then gettext() doesn't know which
character set to use, and converts all messages to ASCII, as far as
possible.<br>
<br>
If the program is doing<br>
<code><br>
setlocale (LC_MESSAGES, "");<br>
<br>
</code>then change it to<br>
<code><br>
setlocale (LC_CTYPE, "");<br>
setlocale (LC_MESSAGES, "");<br>
</code><br>
or do both of these in a single call:<br>
<code><br>
setlocale (LC_ALL, "");<br>
</code><br>
If the program is already doing<br>
<code><br>
setlocale (LC_ALL, "");<br>
</code><br>
then the symptom can still occur if the user has not set <span
style="font-family: monospace;">LANG</span>, but instead has set <span
style="font-family: monospace;">LC_MESSAGES</span> to a valid locale
and has set <span style="font-family: monospace;">LC_CTYPE</span> to
nothing or an invalid locale. The fix for the user is then to set <span
style="font-family: monospace;">LANG</span> instead of <span
style="font-family: monospace;">LC_MESSAGES</span>.<br>
<h4><a name="localename"></a>The <span style="font-family: monospace;">LANGUAGE</span>
environment variable is ignored after I set <span
style="font-family: monospace;">LANG=en</span></h4>
This is because “en” is a language name, but not a valid locale name.
The <span style="font-family: monospace;">ABOUT-NLS</span> file
says:<br>
<blockquote>
In the <span style="font-family: monospace;">LANGUAGE</span>
environment variable, but not in the <span
style="font-family: monospace;">LANG</span> environment variable, <span
style="font-style: italic;">LL</span>_<span style="font-style: italic;">CC</span><span
style="font-family: monospace;"> </span>combinations can be
abbreviated as <span style="font-style: italic;">LL</span> to
denote the language's main dialect.</blockquote>
Why is <span style="font-family: monospace;">LANG=en</span> not
allowed? Because <span style="font-family: monospace;">LANG</span> is
a setting for the entire locale, including monetary information, and
this depends on the country: en_GB, en_AU, en_ZA all have different
currencies.<br>
<h4><a name="nonascii_strings"></a>I use accented characters in my
source code. How do I tell the
C/C++ compiler in which encoding it is (like <span
style="font-family: monospace;">xgettext</span>'s <span
style="font-family: monospace;">--from-code</span> option)?</h4>
Short answer: If you want your program to be useful to other people,
then <span style="font-style: italic;">don't use accented characters</span>
(or other non-ASCII characters) in string literals <span
style="font-style: italic;">in the source code</span>. Instead, use
only ASCII for string literals, and use <span
style="font-family: monospace;">gettext()</span> to retrieve their
display-ready form.<br>
<br>
Long explanation:<br>
The reason is that the ISO C standard specifies that the character set
at compilation time can be different from the character set at
execution time.<br>
The character encoding at compilation time is the one which determines
how the source files are interpreted and also how string literals are
stored in the compiled code. This character encoding is generally
unspecified; for recent versions of GCC, it depends on the LC_CTYPE
locale in effect during the compilation process.<br>
The character encoding at execution time is the one which determines
how standard functions like <span style="font-family: monospace;">isprint()</span>,
<span style="font-family: monospace;">wcwidth()</span> etc. work and
how strings written to standard output should be encoded. This
character encoding is specified by POSIX to depend on the LC_CTYPE
locale in effect when the program is executed; see also the description
in the <span style="font-family: monospace;">ABOUT-NLS</span> file.<br>
Strings in the compiled code are not magically converted between the
time the program is compiled and the time it is run.<br>
<br>
Therefore what could you do to get accented characters to work?<br>
<br>
Can you ensure that the execution character set is the same as the
compilation character set? Even if your program is to be used only in a
single country, this is not realistically possible. For example, in
Germany there are currently three character encodings in use: UTF-8,
ISO-8859-15 and ISO-8859-1. Therefore you would have to explicitly
convert the accented strings from the compilation character set to the
execution character set at runtime, for example through iconv().<br>
<br>
Can you ensure that the compilation character set is the one in which
your source files are stored? This is not realistically possible
either: For compilers other than GCC, there is no way to specify the
compilation character set. So let's assume for a moment that everyone
uses GCC; then you will specify the LC_CTYPE or LC_ALL environment
variable in the Makefile. But for this you have to assume that everyone
has a locale in a given encoding. Be it UTF-8 or ISO-8859-1 - this is
not realistic. People often have no locale installed besides the one
they use.<br>
<br>
Use of wide strings <span style="font-family: monospace;">L"..."</span>
doesn't help solving the problem, because on systems like FreeBSD or
Solaris, the way how wide string literals are stored in compiled code
depends on the compilation character set, just as it does for
narrow strings <span style="font-family: monospace;">"..."</span>.
Moreover, wide strings have problems of their own.<br>
<br>
Use of ISO C 99 Unicode escapes "\u<span style="font-style: italic;">xxxx</span>"
doesn't help either because these characters are converted to the
compilation character set at compile time; so again, since you can't
guarantee that the compilation character set is not ASCII, you're
risking compilation errors just as if the real character had been used
in the source instead of the Unicode escape.<br>
<br>
So, in summary, there is no way to make accented characters in string
literals work in C/C++.<br>
<br>
You might then wonder what <span style="font-family: monospace;">xgettext</span>'s
<span style="font-family: monospace;">--from-code</span> option is good
for. The answer is<br>
<ol>
<li>For the comments in C/C++ source code. The compiler ignores them.<br>
</li>
<li>For other programming languages like Java, for which the compiler
converts all string literals to UTF-8.</li>
</ol>
<br>
<hr style="width: 100%; height: 2px;">
<address>GNU gettext FAQ<br>
Bruno Haible <<a href="mailto:bruno@clisp.org">bruno@clisp.org</a>></address>
<p>Last modified: 24 February 2004
</p>
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