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5 <title>GNU gettext FAQ</title>
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7 <body>
8 <h1 style="text-align: center;">Frequently Asked Questions<br>
9 for GNU gettext
10 </h1>
11 <h1 style="text-align: center;">Questions</h1>
12 <h3>General</h3>
13 <ul>
14 <li><a href="#general_mailinglist">Where is the mailing list?</a></li>
15 <li><a href="#general_source">Where is the newest gettext source?</a></li>
16 <li><a href="#general_announce">I want to be notified of new gettext
17 releases.</a></li>
18 </ul>
19 <h3>Problems building GNU gettext</h3>
20 <ul>
21 <li><a href="#building_solaris_libasprintf">On Solaris, I get a build
22 error text relocations remain in the <span
23 style="font-family: monospace;">libasprintf</span> subdirectory</a></li>
24 <li><a href="#building_rpath_check">During make check, some tests
25 named <span style="font-family: monospace;">rpath-<span
26 style="font-style: italic;">Nxyz</span></span>
27 fail: ld: fatal error ... -lrpathz</a></li>
28 <li><a href="#building_install">make install fails</a></li>
29 </ul>
30 <h3>Problems integrating GNU gettext</h3>
31 <ul>
32 <li><a href="#integrating_howto">How do I make use of <span
33 style="font-family: monospace;">gettext()</span> in my package?</a></li>
34 <li><a href="#integrating_undefined">I get a linker error undefined
35 reference to libintl_gettext</a></li>
36 <li><a href="#integrating_abuse_gettextize">gettextize adds multiple
37 references to the same directories/files
38 to <span style="font-family: monospace;">Makefile.am</span> and </a><span
39 style="font-family: monospace;"><a href="#integrating_abuse_gettextize">configure.ac</a><br>
40 </span></li>
41 <li><a href="#integrating_noop">My program compiles and links fine,
42 but doesn't output translated
43 strings.</a><br>
44 </li>
45 </ul>
46 <h3>GNU gettext on Windows</h3>
47 <ul>
48 <li><a href="#windows_woe32">What does Woe32 mean?</a></li>
49 <li><a href="#windows_howto">How do I compile, link and run a program
50 that uses the gettext()
51 function?</a><br>
52 </li>
53 <li><a href="#windows_setenv">Setting the <span
54 style="font-family: monospace;">LANG</span>
55 environment variable doesn't have any effect</a></li>
56 </ul>
57 <h3>Other</h3>
58 <ul>
59 <li><a href="#newline">What does this mean: `msgid' and `msgstr'
60 entries do not both
61 end with '\n'</a></li>
62 <li><a href="#translit">German umlauts are displayed like ge"andert
63 instead of
64 gendert</a></li>
65 <li><a href="#localename">The <span style="font-family: monospace;">LANGUAGE</span>
66 environment variable is ignored after I set <span
67 style="font-family: monospace;">LANG=en</span></a></li>
68 <li><a href="#nonascii_strings">I use accented characters in my
69 source code. How do I tell the
70 C/C++ compiler in which encoding it is (like <span
71 style="font-family: monospace;">xgettext</span>'s <span
72 style="font-family: monospace;">--from-code</span> option)?</a></li>
73 </ul>
74 <h1 style="text-align: center;">Answers</h1>
75 <h3>General</h3>
76 <h4><a name="general_mailinglist"></a>Where is the mailing list?</h4>
77 Three mailing lists are available: <br>
78 <ul>
79 <li><span style="font-family: monospace;">bug-gnu-gettext (a] gnu.org</span><br>
80 This mailing list is for discussion of features and bugs of the GNU
81 gettext <span style="font-style: italic;">software</span>, including
82 libintl, the gettext-tools, and its autoconf macros.</li>
83 <li><span style="font-family: monospace;">translation-i18n (a] lists.sourceforge.net</span><br>
84 This mailing list is for methodology questions around
85 internationalization, and for discussions of translator tools,
86 including but not limited to GNU gettext.</li>
87 <li><span style="font-family: monospace;">translation (a] iro.umontreal.ca</span><br>
88 This is the email address of the <a
89 href="http://www.iro.umontreal.ca/contrib/po/HTML/">Free Translation
90 Project</a>, that is the project which manages the translated message
91 catalogs for many free software packages. Note that KDE and GNOME
92 packages are not part of this project; they have their own translation
93 projects: <a href="http://i18n.kde.org/">i18n.kde.org</a> and <a
94 href="http://developer.gnome.org/projects/gtp/">gtp</a>.<br>
95 </li>
96 </ul>
97 The <span style="font-family: monospace;">bug-gnu-gettext</span> list
98 is archived as part of the <a
99 href="http://mail.gnu.org/archive/html/bug-gnu-utils/"><span
100 style="font-family: monospace;">bug-gnu-utils</span></a> archives. <span
101 style="font-family: monospace;">bug-gnu-gettext</span> cannot be
102 subscribed on its own; to receive its contents by mail, subscribe to <span
103 style="font-family: monospace;">bug-gnu-utils</span>.<br>
104 <h4><a name="general_source"></a>Where is the newest gettext source?</h4>
105 The newest gettext release is available on <span
106 style="font-family: monospace;">ftp.gnu.org</span> and its mirrors, in
107 <a href="http://ftp.gnu.org/gnu/gettext/">http://ftp.gnu.org/gnu/gettext/</a>.<br>
108 <br>
109 Prereleases are announced on the <a
110 href="http://mail.gnu.org/pipermail/autotools-announce"><span
111 style="font-family: monospace;">autotools-announce</span> mailing list</a>.
112 Note that prereleases are meant for testing and not meant for use in
113 production environments. Please don't use the gettextize program of a
114 prerelease on projects which you share with other programmers via CVS.<br>
115 <br>
116 If you want to live on the bleeding edge, you can also use the
117 development sources. Instructions for retrieving the gettext CVS are
118 found <a href="http://savannah.gnu.org/projects/gettext">here</a>.
119 Note that building from CVS requires special tools (autoconf, automake,
120 m4, groff, bison, etc.) and requires that you pay attention to the <span
121 style="font-family: monospace;">README-alpha</span> and <span
122 style="font-family: monospace;">autogen.sh</span> files in the CVS.<br>
123 <h4><a name="general_announce"></a>I want to be notified of new gettext
124 releases.</h4>
125 If you are interested in stable gettext releases, you can follow the <a
126 href="http://mail.gnu.org/pipermail/info-gnu"><span
127 style="font-family: monospace;">info-gnu</span> mailing list</a>. It
128 is also available as a newsgroup <a
129 href="nntp://news.gmane.org/gmane.org.fsf.announce"><span
130 style="font-family: monospace;">gmane.org.fsf.announce</span></a>
131 through <a href="http://www.gmane.org/"><span
132 style="font-family: monospace;">gmane.org</span></a>.<br>
133 <br>
134 You can also periodically check the download location.<br>
135 <br>
136 If you are interested in testing prereleases as well, you can subscribe
137 to the <a href="http://mail.gnu.org/pipermail/autotools-announce"><span
138 style="font-family: monospace;">autotools-announce</span> mailing
139 list</a>.<br>
140 <h3>Problems building GNU gettext</h3>
141 <h4><a name="building_solaris_libasprintf"></a>On Solaris, I get a
142 build error text relocations remain in the <span
143 style="font-family: monospace;">libasprintf</span> subdirectory</h4>
144 libtool (or more precisely, the version of libtool that was available
145 at the time the gettext release waas made) doesn't support linking C++
146 libraries with some versions of GCC. As a workaround, you can configure
147 gettext with the option <span style="font-family: monospace;">--disable-libasprintf</span>.<br>
148 <h4><a name="building_rpath_check"></a>During make check, some tests
149 named <span style="font-family: monospace;">rpath-<span
150 style="font-style: italic;">Nxyz</span></span>
151 fail: ld: fatal error ... -lrpathz</h4>
152 If only a few among the many rpath tests fail, you can probably ignore
153 the problem. The rpath tests are sensitive to incomplete shared library
154 support in the system, and to bugs in libtool that creates the shared
155 libraries. Some known failures are listed in <span
156 style="font-family: monospace;">autoconf-lib-link/tests/rpath.README</span>.<br>
157 <br>
158 To ignore the problem, just proceed with<br>
159 <br>
160 <div style="margin-left: 40px;"><code>cd gettext-tools</code><br>
161 <code>make check</code><br>
162 <code>cd ..</code><br>
163 </div>
164 <br>
165 <h4><a name="building_install"></a>make install fails</h4>
166 <span style="font-family: monospace;">make install DESTDIR=<span
167 style="font-style: italic;">/some/tempdir</span></span> can fail with
168 an error message relating to <span style="font-family: monospace;">libgettextlib</span>
169 or <span style="font-family: monospace;">libgettextsrc</span>, or can
170 silently fail to install <span style="font-family: monospace;">libgettextsrc</span>.
171 On some platforms, this is due to limitations of libtool regarding <span
172 style="font-family: monospace;">DESTDIR</span>. On other platforms, it
173 is due to the way the system handles shared libraries, and libtool
174 cannot work around it. Fortunately, on Linux and other glibc based
175 systems, <span style="font-family: monospace;">DESTDIR</span> is
176 supported if no different version of gettext is already installed (i.e.
177 it works if you uninstall the older gettext before building and
178 installing the newer one, or if you do a plain <span
179 style="font-family: monospace;">make install</span> before <span
180 style="font-family: monospace;">make install DESTDIR=<span
181 style="font-style: italic;">/some/tempdir</span></span>). On other
182 systems, when <span style="font-family: monospace;">DESTDIR</span>
183 does not work, you can still do <span style="font-family: monospace;">make
184 install</span> and copy the installed files to <span
185 style="font-family: monospace;"><span style="font-style: italic;">/some/tempdir</span></span>
186 afterwards.<br>
187 <br>
188 If <span style="font-family: monospace;">make install</span> without <span
189 style="font-family: monospace;">DESTDIR</span> fails, it's a bug which
190 you are welcome to report to the usual bug report address.
191 <h3>Problems integrating GNU gettext</h3>
192 <h4><a name="integrating_howto"></a>How do I make use of <span
193 style="font-family: monospace;">gettext()</span> in my package?</h4>
194 It's not as difficult as it sounds. Here's the recipe for C or C++
195 based packages.<br>
196 <ul>
197 <li>Add an invocation of <span style="font-family: monospace;">AM_GNU_GETTEXT([external])</span>
198 to the package's <span style="font-family: monospace;">configure.{ac,in}</span>
199 file.</li>
200 <li>Invoke <span style="font-family: monospace;">gettextize --copy</span>.
201 It will do most of the autoconf/automake related work for you.</li>
202 <li>Add the <span style="font-family: monospace;">gettext.h</span>
203 file to the package's source directory, and include it in all source
204 files that contain translatable strings or do output via <span
205 style="font-family: monospace;">printf</span> or <span
206 style="font-family: monospace;">fprintf</span>.</li>
207 <li>In the source file defining the main() function of the program,
208 add these lines to the header<br>
209 <div style="margin-left: 40px;"><code><span
210 style="font-family: monospace;">#include <locale.h></span><br
211 style="font-family: monospace;">
212 <span style="font-family: monospace;">#include "gettext.h"</span></code><br>
213 </div>
214 and these lines near the beginning of the main() function:<br>
215 <div style="margin-left: 40px;"><code><span
216 style="font-family: monospace;">setlocale (LC_ALL, "");</span><br
217 style="font-family: monospace;">
218 <span style="font-family: monospace;">bindtextdomain (PACKAGE,
219 LOCALEDIR);</span><br style="font-family: monospace;">
220 <span style="font-family: monospace;">textdomain (PACKAGE);</span></code><br>
221 </div>
222 </li>
223 <li>Mark all strings that should be translated with _(), like this: <span
224 style="font-family: monospace;">_("No errors found.")</span>. While
225 doing this, try to turn the strings into good English, one entire
226 sentence per string, not more than one paragraph per string, and use
227 format strings instead of string concatenation. This is needed so that
228 the translators can provide accurate translations.</li>
229 <li>In every source file containing translatable strings, add these lines
230 to the header:<br>
231 <div style="margin-left: 40px;"><code><span
232 style="font-family: monospace;">#include "gettext.h"</span><br
233 style="font-family: monospace;">
234 <span style="font-family: monospace;">#define _(string) gettext (string)</span></code><br>
235 </div>
236 </li>
237 <li>In the freshly created <span style="font-family: monospace;">po/</span>
238 directory, set up the <span style="font-family: monospace;">POTFILES.in</span>
239 file, and do a <span style="font-family: monospace;">make update-po</span>.
240 Then distribute the generated <span style="font-family: monospace;">.pot</span>
241 file to your nearest translation project.</li>
242 <li>Shortly before a release, integrate the translators' <span
243 style="font-family: monospace;">.po</span> files into the <span
244 style="font-family: monospace;">po/</span> directory and do <span
245 style="font-family: monospace;">make update-po</span> again.<br>
246 </li>
247 </ul>
248 You find detailed descriptions of how this all works in the GNU gettext
249 manual, chapters The Maintainer's View and Preparing Program
250 Sources.
251 <h4><a name="integrating_undefined"></a>I get a linker error undefined
252 reference to libintl_gettext</h4>
253 This error means that the program uses the <span
254 style="font-family: monospace;">gettext()</span> function after having
255 included the <span style="font-family: monospace;"><libintl.h></span>
256 file from GNU gettext (which remaps it to <span
257 style="font-family: monospace;">libintl_gettext()</span>), however at
258 link time a function of this name could not be linked in. (It is
259 expected to come from the <span style="font-family: monospace;">libintl</span>
260 library, installed by GNU gettext.)<br>
261 <br>
262 There are many possible reasons for this error, but in any case you
263 should consider the <span style="font-family: monospace;">-I</span>, <span
264 style="font-family: monospace;">-L</span> and <span
265 style="font-family: monospace;">-l</span> options passed to the
266 compiler. In packages using <span style="font-family: monospace;">autoconf</span>
267 generated configure scripts, <span style="font-family: monospace;">-I</span>
268 options come from the <span style="font-family: monospace;">CFLAGS</span>
269 and <span style="font-family: monospace;">CPPFLAGS</span> variables
270 (in Makefiles also <span style="font-family: monospace;">DEFS</span>
271 and <span style="font-family: monospace;">INCLUDES</span>), <span
272 style="font-family: monospace;">-L</span> options come from the <span
273 style="font-family: monospace;">LDFLAGS</span> variable, and <span
274 style="font-family: monospace;">-l</span> options come from the <span
275 style="font-family: monospace;">LIBS</span> variable. The first thing
276 you should check are the values of these variables in your environment
277 and in the package's <span style="font-family: monospace;">config.status</span>
278 autoconfiguration result.<br>
279 <br>
280 To find the cause of the error, a little analysis is needed. Does the
281 program's final link command contains the option -lintl?<br>
282 <ul>
283 <li>If yes:<br>
284 Find out where the <span style="font-family: monospace;">libintl</span>
285 comes from. To do this, you have to check for <span
286 style="font-family: monospace;">libintl.a</span> and <span
287 style="font-family: monospace;">libintl.so*</span> (<span
288 style="font-family: monospace;">libintl.dylib</span> on MacOS X) in
289 each directory given as a -L option, as well as in the compiler's
290 implicit search directories. (You get these implicit search directories
291 for gcc by using <span style="font-family: monospace;">gcc -v</span>
292 instead of <span style="font-family: monospace;">gcc</span> in the
293 final link command line; compilers other than GCC usually look in <span
294 style="font-family: monospace;">/usr/lib</span> and <span
295 style="font-family: monospace;">/lib</span>.) A shell command like<br>
296 <div style="margin-left: 40px;"><code>$ for d in /usr/local/lib
297 /usr/lib /lib; do ls -l $d/libintl.*; done</code><br>
298 </div>
299 will show where the <span style="font-family: monospace;">libintl</span>
300 comes from. By looking at the dates and whether each library defines <span
301 style="font-family: monospace;">libintl_gettext</span> (via <span
302 style="font-family: monospace;">nm <span style="font-style: italic;">path</span>/libintl.so
303 | grep libintl_gettext</span>) you can now distinguish three possible
304 causes of the error:<br>
305 <ul>
306 <li>Some older libintl is used instead of the newer one. The fix
307 is to remove the old library or to reorganize your -L options.</li>
308 <li>The used libintl is the new one, and it doesn't contain
309 libintl_gettext. This would be a bug in gettext. If this is the case,
310 please report it to the usual bug report address.</li>
311 <li>The used libintl is a static library (libintl.a), there are
312 no uses of gettext in .o files before the -lintl but there are some
313 after the -lintl. In this case the fix is to move the -lintl to the
314 end or near the end of the link command line. The only libintl
315 dependency that needs to be mentioned after -lintl is -liconv.</li>
316 </ul>
317 </li>
318 <li>If no:<br>
319 In this case it's likely a bug in the package you are building: The
320 package's Makefiles should make sure that -lintl is used where needed.<br>
321 Test whether libintl was found by configure. You can check this by doing<br>
322 <div style="margin-left: 40px;"><code>$ grep
323 '\(INTLLIBS\|LIBINTL\)' config.status</code><br>
324 </div>
325 and looking whether the value of this autoconf variable is non-empty.<br>
326 <ul>
327 <li>If yes: It should be the responsibility of the Makefile to
328 use the value of this variable in the link command line. Does the
329 Makefile.in rule for linking the program use <span
330 style="font-family: monospace;">@INTLLIBS@</span> or <span
331 style="font-family: monospace;">@LIBINTL@</span>?<br>
332 <ul>
333 <li>If no: It's a Makefile.am/in bug.</li>
334 <li>If yes: Something strange is going on. You need to dig
335 deeper.</li>
336 </ul>
337 Note that <span style="font-family: monospace;">@INTLLIBS@</span> is
338 for <span style="font-family: monospace;">gettext.m4</span> versions
339 <= 0.10.40 and <span style="font-family: monospace;">@LIBINTL@</span>
340 is for <span style="font-family: monospace;">gettext.m4</span>
341 versions >= 0.11, depending on which <span
342 style="font-family: monospace;">gettext.m4</span> was used to build
343 the package's <span style="font-family: monospace;">configure</span> -
344 regardless of which gettext you have now installed.</li>
345 <li>If no: So libintl was not found.<br>
346 Take a look at the package's <span style="font-family: monospace;">configure.in/ac</span>.
347 Does it invoke AM_GNU_GETTEXT?<br>
348 <ul>
349 <li>If no: The gettext maintainers take no responsibilities for
350 lookalikes named CY_GNU_GETTEXT, AM_GLIB_GNU_GETTEXT, AM_GNOME_GETTEXT
351 and similar, or for homebrewn autoconf checks. Complain to the package
352 maintainer.</li>
353 <li>If yes: It looks like the <span
354 style="font-family: monospace;">-I</span> and <span
355 style="font-family: monospace;">-L</span> options were inconsistent.
356 You should have a <span style="font-family: monospace;">-I<span
357 style="font-style: italic;">somedir</span>/include</span> in the <span
358 style="font-family: monospace;">CFLAGS</span> or <span
359 style="font-family: monospace;">CPPFLAGS</span> if and only if you
360 also have a <span style="font-family: monospace;">-L<span
361 style="font-style: italic;">somedir</span>/lib</span> in the <span
362 style="font-family: monospace;">LDFLAGS</span>. And <span
363 style="font-family: monospace;"><span style="font-style: italic;">somedir</span>/include</span>
364 should contain a <span style="font-family: monospace;">libintl.h</span>
365 if and only if <span style="font-family: monospace;"><span
366 style="font-style: italic;">somedir</span>/lib</span> contains <span
367 style="font-family: monospace;">libintl.{a,so}</span>.<br>
368 This case can also happen if you have configured a GCC < 3.2 with
369 the same <span style="font-family: monospace;">--prefix</span> option
370 as you used for GNU libiconv or GNU gettext. This is fatal, because
371 these versions of GCC implicitly use <span
372 style="font-family: monospace;">-L<span style="font-style: italic;">prefix</span>/lib</span>
373 but <span style="font-weight: bold; font-style: italic;">not</span><br
374 style="font-weight: bold; font-style: italic;">
375 <span style="font-family: monospace;">-I<span
376 style="font-style: italic;">prefix</span>/include</span>. The
377 workaround is to use a different <span style="font-family: monospace;">--prefix</span>
378 for GCC.<br>
379 </li>
380 </ul>
381 </li>
382 </ul>
383 </li>
384 </ul>
385 <h4><a name="integrating_abuse_gettextize"></a>gettextize adds multiple
386 references to the same directories/files
387 to <span style="font-family: monospace;">Makefile.am</span> and <span
388 style="font-family: monospace;">configure.ac</span></h4>
389 If <span style="font-family: monospace;">gettextize</span> is used on
390 a package, then the <span style="font-family: monospace;">po/</span>, <span
391 style="font-family: monospace;">intl/</span>, <span
392 style="font-family: monospace;">m4/</span> directories of the package
393 are removed, and then <span style="font-family: monospace;">gettextize</span>
394 is invoked on the package again, it will re-add the <span
395 style="font-family: monospace;">po/</span>, <span
396 style="font-family: monospace;">intl/</span>, <span
397 style="font-family: monospace;">m4/</span> directories and change <span
398 style="font-family: monospace;">Makefile.am</span>, <span
399 style="font-family: monospace;">configure.ac</span> and <span
400 style="font-family: monospace;">ChangeLog</span> accordingly. This is
401 normal. The second use of <span style="font-family: monospace;">gettextize</span>
402 here is an abuse of the program. <span style="font-family: monospace;">gettextize</span>
403 is a wizard intended to transform a <span style="font-style: italic;">working
404 source package</span> into a <span style="font-style: italic;">working
405 source package</span> that uses the newest version of gettext. If you
406 start out from a nonfunctional source package (it is nonfunctional
407 since you have omitted some directories), you cannot expect that <span
408 style="font-family: monospace;">gettextize</span> corrects it.<br>
409 <br>
410 Often this question arises in packages that use CVS. See the section
411 CVS Issues / Integrating with CVS of the GNU gettext documentation.
412 This section mentions a program <span style="font-family: monospace;">autopoint</span>
413 which is designed to reconstruct those files and directories created by
414 <span style="font-family: monospace;">gettextize</span> that can be
415 omitted from a CVS repository.<br>
416 <h4><a name="integrating_noop"></a>My program compiles and links fine,
417 but doesn't output translated
418 strings.</h4>
419 There are several possible reasons. Here is a checklist that allows you
420 to determine the cause.<br>
421 <ol>
422 <li>Check that the environment variables LC_ALL, LC_MESSAGES,
423 LC_CTYPE, LANG, LANGUAGE together specify a valid locale and language.<br>
424 To check this, run the commands<br>
425 <div style="margin-left: 40px;"><code>$ gettext --version</code><br>
426 <code>$ gettext --help</code><br>
427 </div>
428 You should see at least some output in your desired language. If not,
429 either<br>
430 <ul>
431 <li>You have chosen a too exotic language. <span
432 style="font-family: monospace;">gettext</span> is localized to 33
433 languages. Choose a less exotic language, such as Galician or
434 Ukrainian. Or<br>
435 </li>
436 <li>There is a problem with your environment variables. Possibly
437 LC_ALL points to a locale that is not installed, or LC_MESSAGES and
438 LC_CTYPE are inconsistent.</li>
439 </ul>
440 </li>
441 <li>Check that your program contains a <span
442 style="font-family: monospace;">setlocale</span> call.<br>
443 To check this, run your program under ltrace. For example,<br>
444 <div style="margin-left: 40px;"><code>$ ltrace ./myprog</code><br>
445 <code>...</code><br>
446 <code>setlocale(6,
447 "")
448 = "de_DE.UTF-8"</code><br>
449 </div>
450 If you have no ltrace, you can also do this check by running your
451 program under the debugger. For example,<br>
452 <div style="margin-left: 40px;"><code>$ gdb ./myprog</code><br>
453 <code>(gdb) break main</code><br>
454 <code>(gdb) run</code><br>
455 <code>Breakpoint 1, main ()</code><br>
456 <code>(gdb) break setlocale</code><br>
457 <code>(gdb) continue</code><br>
458 <code>Breakpoint 2, setlocale ()</code><br>
459 <code>;; OK, the breakpoint has been hit, setlocale() is being
460 called.</code><br>
461 </div>
462 Either way, check that the return value of <span
463 style="font-family: monospace;">setlocale()</span> is non-NULL. A NULL
464 return value indicates a failure. </li>
465 <li>Check that your program contains a <span
466 style="font-family: monospace;">textdomain</span> call, a <span
467 style="font-family: monospace;">bindtextdomain</span> call referring
468 to the same message domain, and then really calls the <span
469 style="font-family: monospace;">gettext</span>, <span
470 style="font-family: monospace;">dgettext</span> or <span
471 style="font-family: monospace;">dcgettext</span> function.<br>
472 To check this, run the program under ltrace. For example,<br>
473 <div style="margin-left: 40px;"><code>$ ltrace ./myprog</code><br>
474 <code>...</code><br>
475 <code>textdomain("hello-c")
476 = "hello-c"</code><br>
477 <code>bindtextdomain("hello-c", "/opt/share"...) = "/opt/share"...</code><br>
478 <code>dcgettext(0, 0x08048691, 5, 0x0804a200, 0x08048689) =
479 0x4001721f</code><br>
480 </div>
481 If you have no ltrace, you can also do this check by running your
482 program under the debugger. For example,<br>
483 <div style="margin-left: 40px;"><code>$ gdb ./myprog</code><br>
484 <code>(gdb) break main</code><br>
485 <code>(gdb) run</code><br>
486 <code>Breakpoint 1, main ()</code><br>
487 <code>(gdb) break textdomain</code><br>
488 <code>(gdb) break bindtextdomain</code><br>
489 <code>(gdb) break gettext</code><br>
490 <code>(gdb) break dgettext</code><br>
491 <code>(gdb) break dcgettext</code><br>
492 <code>(gdb) continue</code><br>
493 <code>Breakpoint 2, textdomain ()</code><br>
494 <code>(gdb) continue</code><br>
495 <code>Breakpoint 3, bindtextdomain ()</code><br>
496 <code>(gdb) continue</code><br>
497 <code>Breakpoint 6, dcgettext ()</code><br>
498 </div>
499 Note that here <span style="font-family: monospace;">dcgettext()</span>
500 is called instead of the <span style="font-family: monospace;">gettext()</span>
501 function mentioned in the source code; this is due to an optimization
502 in <span style="font-family: monospace;"><libintl.h></span>.<br>
503 When using libintl on a non-glibc system, you have to add a prefix <span
504 style="font-family: monospace;">libintl_</span> to all the function
505 names mentioned here, because that's what the functions are really
506 named, under the hood.<br>
507 If <span style="font-family: monospace;">gettext</span>/<span
508 style="font-family: monospace;">dgettext</span>/<span
509 style="font-family: monospace;">dcgettext</span> is not called at all,
510 the possible cause might be that some autoconf or Makefile macrology
511 has turned off internationalization entirely (like the <span
512 style="font-family: monospace;">--disable-nls</span> configuration
513 option usually does).<br>
514 </li>
515 <li>Check that the <span style="font-family: monospace;">.mo</span>
516 file that contains the translation is really there where the program
517 expects it.<br>
518 To check this, run the program under strace and look at the <span
519 style="font-family: monospace;">open()</span> calls. For example,<br>
520 <div style="margin-left: 40px;"><code>$ strace ./myprog 2>&1
521 | grep '^open('</code><br>
522 <code>open("/etc/ld.so.preload", O_RDONLY) = -1
523 ENOENT (No such file or directory)</code><br>
524 <code>open("/etc/ld.so.cache",
525 O_RDONLY) = 5</code><br>
526 <code>open("/lib/libc.so.6",
527 O_RDONLY) = 5</code><br>
528 <code>open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE)
529 = 5</code><br>
530 <code>open("/usr/share/locale/locale.alias", O_RDONLY) = 5</code><br>
531 <code>open("/opt/share/locale/de/LC_MESSAGES/hello-c.mo", O_RDONLY)
532 = 5</code><br>
533 <code>...</code><br>
534 </div>
535 A nonnegative <span style="font-family: monospace;">open()</span>
536 return value means that the file has been found.<br>
537 If you have no strace, you can also guess the <span
538 style="font-family: monospace;">.mo</span> file's location: it is<br>
539 <div style="margin-left: 40px;"><span
540 style="font-family: monospace;"><span style="font-style: italic;">localedir</span>/<span
541 style="font-style: italic;">lang</span>/LC_MESSAGES/<span
542 style="font-style: italic;">domain</span>.mo</span><br>
543 </div>
544 where <span style="font-style: italic;">domain</span> is the argument
545 passed to <span style="font-family: monospace;">textdomain()</span>, <span
546 style="font-style: italic;">localedir</span> is the second argument
547 passed to <span style="font-family: monospace;">bindtextdomain()</span>,
548 and <span style="font-style: italic;">lang</span> is the language (<span
549 style="font-style: italic;">LL</span>) or language and territory (<span
550 style="font-style: italic;">LL</span>_<span style="font-style: italic;">CC</span>),
551 depending on the environment variables checked in step 1.</li>
552 <li>Check that the .mo file contains a translation for the string
553 that is being asked for.<br>
554 To do this, you need to convert the .mo file back to PO file format,
555 through the command<br>
556 <div style="margin-left: 40px;"><code>$ msgunfmt </code><span
557 style="font-family: monospace;"><span style="font-style: italic;">localedir</span>/<span
558 style="font-style: italic;">lang</span>/LC_MESSAGES/<span
559 style="font-style: italic;">domain</span>.mo</span><br>
560 <code></code></div>
561 and look for an <span style="font-family: monospace;">msgid</span>
562 that matches the given string.<br>
563 </li>
564 </ol>
565 <h3>GNU gettext on Windows</h3>
566 <h4><a name="windows_woe32"></a>What does Woe32 mean?</h4>
567 Woe32 denotes the Windows 32-bit operating systems for x86: Windows
568 NT/2000/XP and Windows 95/98/ME. Microsoft uses the term Win32 to
569 denote these; this is a psychological trick in order to make everyone
570 believe that these OSes are a win for the user. However, for most
571 users and developers, they are a source of woes, which is why I call
572 them Woe32.<br>
573 <h4><a name="windows_howto"></a>How do I compile, link and run a
574 program that uses the gettext()
575 function?</h4>
576 When you use RedHat's cygwin environment, it's as on Unix:<br>
577 <ul>
578 <li>You need to add an <span style="font-family: monospace;">-I</span>
579 option to the compilation command line, so that the compiler finds the <span
580 style="font-family: monospace;">libintl.h</span> include file, and</li>
581 <li>You need to add an <span style="font-family: monospace;">-L</span>
582 option to the link command line, so that the linker finds the <span
583 style="font-family: monospace;">libintl</span> library.</li>
584 </ul>
585 When you use the Mingw environment (either from within cygwin, with <span
586 style="font-family: monospace;">CC="gcc -mno-cygwin"</span>, or from
587 MSYS, with <span style="font-family: monospace;">CC="gcc"</span>), I
588 don't know the details.<br>
589 <br>
590 When you use the Microsoft Visual C/C++ (MSVC) compiler, you will
591 likely use the precompiled Woe32 binaries. For running a program that
592 uses gettext(), one needs the <span style="font-family: monospace;">.bin.woe32.zip</span>
593 packages of <span style="font-family: monospace;">gettext-runtime</span>
594 and <span style="font-family: monospace;">libiconv</span>. As a
595 developer, you'll also need the <span style="font-family: monospace;">xgettext</span>
596 and <span style="font-family: monospace;">msgfmt</span> programs that
597 are contained in the <span style="font-family: monospace;">.bin.woe32.zip</span>
598 package of <span style="font-family: monospace;">gettext-tools</span>.
599 Then<br>
600 <ul>
601 <li>You need to add an <span style="font-family: monospace;">-MD</span>
602 option to all compilation and link command lines. MSVC has six
603 different, mutually incompatible, compilation models (<span
604 style="font-family: monospace;">-ML</span>, <span
605 style="font-family: monospace;">-MT</span>, <span
606 style="font-family: monospace;">-MD</span>, <span
607 style="font-family: monospace;">-MLd</span>, <span
608 style="font-family: monospace;">-MTd</span>, <span
609 style="font-family: monospace;">-MDd</span>); the default is <span
610 style="font-family: monospace;">-ML</span>. <span
611 style="font-family: monospace;">intl.dll</span> uses the <span
612 style="font-family: monospace;">-MD</span> model, therefore the rest
613 of the program must use <span style="font-family: monospace;">-MD</span>
614 as well.<br>
615 </li>
616 <li>You need to add an <span style="font-family: monospace;">-I</span>
617 option to the compilation command line, so that the compiler finds the <span
618 style="font-family: monospace;">libintl.h</span> include file.<br>
619 </li>
620 <li>You need to add an <span style="font-family: monospace;">-L</span>
621 option to the link command line, so that the linker finds the <span
622 style="font-family: monospace;">intl.lib</span> library.</li>
623 <li>You need to copy the <span style="font-family: monospace;">intl.dll</span>
624 and <span style="font-family: monospace;">iconv.dll</span> to the
625 directory where your <span style="font-family: monospace;">.exe</span>
626 files are created, so that they will be found at runtime.<br>
627 </li>
628 </ul>
629 <h4><a name="windows_setenv"></a>Setting the <span
630 style="font-family: monospace;">LANG</span>
631 environment variable doesn't have any effect</h4>
632 If neither LC_ALL, LC_MESSAGES nor LANGUAGES is set, it's the LANG
633 environment variable which determines the language into which gettext()
634 translates the messages.<br>
635 <br>
636 You can test your program by setting the LANG environment variable from
637 outside the program. In a Windows command interpreter:<br>
638 <div style="margin-left: 40px;"><code>set LANG=de_DE</code><br>
639 <code>.\myprog.exe</code><br>
640 </div>
641 Or in a Cygwin shell:<br>
642 <div style="margin-left: 40px;"><code>$ env LANG=de_DE ./myprog.exe</code><br>
643 </div>
644 <br>
645 If this test fails, look at the question My program compiles and links
646 fine, but doesn't output translated
647 strings. above.<br>
648 <br>
649 If this test succeeds, the problem is related in the way you set the
650 environment variable. Here is a checklist:<br>
651 <ul>
652 <li>Check that you are using the <span
653 style="font-family: monospace;">-MD</span> option in all compilation
654 and link command lines. Otherwise you might end up calling the <span
655 style="font-family: monospace;">putenv()</span> function from
656 Microsoft's <span style="font-family: monospace;">libc.lib</span>,
657 whereas <span style="font-family: monospace;">intl.dll</span> is using
658 the <span style="font-family: monospace;">getenv()</span> function
659 from Mictosoft's <span style="font-family: monospace;">msvcrt.lib</span>.</li>
660 <li>Check that you set the environment variable using <span
661 style="font-style: italic;">both</span> <span
662 style="font-family: monospace;">SetEnvironmentVariable()</span> and <span
663 style="font-family: monospace;">putenv()</span>. A convenient way to
664 do so, and to deal with the fact that some Unix systems have <span
665 style="font-family: monospace;">setenv()</span> and some don't, is the
666 following function.<br>
667 <br>
668 <div style="margin-left: 40px;"><code>#include <string.h></code><br>
669 <code>#include <stdlib.h></code><br>
670 <code>#if defined _WIN32</code><br>
671 <code># include <windows.h></code><br>
672 <code>#endif</code><br>
673 <code></code><br>
674 <code>int my_setenv (const char * name, const char * value) {</code><br>
675 <code> size_t namelen = strlen(name);</code><br>
676 <code> size_t valuelen = (value==NULL ? 0 : strlen(value));</code><br>
677 <code>#if defined _WIN32</code><br>
678 <code> /* On Woe32, each process has two copies of the
679 environment variables,</code><br>
680 <code> one managed by the OS and one
681 managed by the C library. We set</code><br>
682 <code> the value in both locations, so that
683 other software that looks in</code><br>
684 <code> one place or the other is guaranteed
685 to see the value. Even if it's</code><br>
686 <code> a bit slow. See also</code><br>
687 <code> <<a
688 href="http://article.gmane.org/gmane.comp.gnu.mingw.user/8272">http://article.gmane.org/gmane.comp.gnu.mingw.user/8272</a>></code><br>
689 <code> <<a
690 href="http://article.gmane.org/gmane.comp.gnu.mingw.user/8273">http://article.gmane.org/gmane.comp.gnu.mingw.user/8273</a>></code><br>
691 <code> <<a
692 href="http://www.cygwin.com/ml/cygwin/1999-04/msg00478.html">http://www.cygwin.com/ml/cygwin/1999-04/msg00478.html</a>>
693 */</code><br>
694 <code> if (!SetEnvironmentVariableA(name,value))</code><br>
695 <code> return -1; </code><br>
696 <code>#endif</code><br>
697 <code>#if defined(HAVE_PUTENV)</code><br>
698 <code> char* buffer = (char*)malloc(namelen+1+valuelen+1);</code><br>
699 <code> if (!buffer)</code><br>
700 <code> return -1; /* no need to set errno =
701 ENOMEM */</code><br>
702 <code> memcpy(buffer,name,namelen);</code><br>
703 <code> if (value != NULL) {</code><br>
704 <code> buffer[namelen] = '=';</code><br>
705 <code> memcpy(buffer+namelen+1,value,valuelen);</code><br>
706 <code> buffer[namelen+1+valuelen] = 0;</code><br>
707 <code> } else</code><br>
708 <code> buffer[namelen] = 0;</code><br>
709 <code> return putenv(buffer);</code><br>
710 <code>#elif defined(HAVE_SETENV)</code><br>
711 <code> return setenv(name,value,1);</code><br>
712 <code>#else</code><br>
713 <code> /* Uh oh, neither putenv() nor setenv() ... */</code><br>
714 <code> return -1;</code><br>
715 <code>#endif</code><br>
716 <code>}</code><br>
717 <code></code></div>
718 <br>
719 </li>
720 </ul>
721 <h3>Other</h3>
722 <h4><a name="newline"></a>What does this mean: `msgid' and `msgstr'
723 entries do not both end
724 with '\n'</h4>
725 It means that when the original string ends in a newline, your
726 translation must also end in a newline. And if the original string does
727 not end in a newline, then your translation should likewise not have a
728 newline at the end.<br>
729 <h4><a name="translit"></a>German umlauts are displayed like
730 ge"andert instead of gendert</h4>
731 This symptom occurs when the <span style="font-family: monospace;">LC_CTYPE</span>
732 facet of the locale is not set; then gettext() doesn't know which
733 character set to use, and converts all messages to ASCII, as far as
734 possible.<br>
735 <br>
736 If the program is doing<br>
737 <code><br>
738 setlocale (LC_MESSAGES, "");<br>
739 <br>
740 </code>then change it to<br>
741 <code><br>
742 setlocale (LC_CTYPE, "");<br>
743 setlocale (LC_MESSAGES, "");<br>
744 </code><br>
745 or do both of these in a single call:<br>
746 <code><br>
747 setlocale (LC_ALL, "");<br>
748 </code><br>
749 If the program is already doing<br>
750 <code><br>
751 setlocale (LC_ALL, "");<br>
752 </code><br>
753 then the symptom can still occur if the user has not set <span
754 style="font-family: monospace;">LANG</span>, but instead has set <span
755 style="font-family: monospace;">LC_MESSAGES</span> to a valid locale
756 and has set <span style="font-family: monospace;">LC_CTYPE</span> to
757 nothing or an invalid locale. The fix for the user is then to set <span
758 style="font-family: monospace;">LANG</span> instead of <span
759 style="font-family: monospace;">LC_MESSAGES</span>.<br>
760 <h4><a name="localename"></a>The <span style="font-family: monospace;">LANGUAGE</span>
761 environment variable is ignored after I set <span
762 style="font-family: monospace;">LANG=en</span></h4>
763 This is because en is a language name, but not a valid locale name.
764 The <span style="font-family: monospace;">ABOUT-NLS</span> file
765 says:<br>
766 <blockquote>
767 In the <span style="font-family: monospace;">LANGUAGE</span>
768 environment variable, but not in the <span
769 style="font-family: monospace;">LANG</span> environment variable, <span
770 style="font-style: italic;">LL</span>_<span style="font-style: italic;">CC</span><span
771 style="font-family: monospace;"> </span>combinations can be
772 abbreviated as <span style="font-style: italic;">LL</span> to
773 denote the language's main dialect.</blockquote>
774 Why is <span style="font-family: monospace;">LANG=en</span> not
775 allowed? Because <span style="font-family: monospace;">LANG</span> is
776 a setting for the entire locale, including monetary information, and
777 this depends on the country: en_GB, en_AU, en_ZA all have different
778 currencies.<br>
779 <h4><a name="nonascii_strings"></a>I use accented characters in my
780 source code. How do I tell the
781 C/C++ compiler in which encoding it is (like <span
782 style="font-family: monospace;">xgettext</span>'s <span
783 style="font-family: monospace;">--from-code</span> option)?</h4>
784 Short answer: If you want your program to be useful to other people,
785 then <span style="font-style: italic;">don't use accented characters</span>
786 (or other non-ASCII characters) in string literals <span
787 style="font-style: italic;">in the source code</span>. Instead, use
788 only ASCII for string literals, and use <span
789 style="font-family: monospace;">gettext()</span> to retrieve their
790 display-ready form.<br>
791 <br>
792 Long explanation:<br>
793 The reason is that the ISO C standard specifies that the character set
794 at compilation time can be different from the character set at
795 execution time.<br>
796 The character encoding at compilation time is the one which determines
797 how the source files are interpreted and also how string literals are
798 stored in the compiled code. This character encoding is generally
799 unspecified; for recent versions of GCC, it depends on the LC_CTYPE
800 locale in effect during the compilation process.<br>
801 The character encoding at execution time is the one which determines
802 how standard functions like <span style="font-family: monospace;">isprint()</span>,
803 <span style="font-family: monospace;">wcwidth()</span> etc. work and
804 how strings written to standard output should be encoded. This
805 character encoding is specified by POSIX to depend on the LC_CTYPE
806 locale in effect when the program is executed; see also the description
807 in the <span style="font-family: monospace;">ABOUT-NLS</span> file.<br>
808 Strings in the compiled code are not magically converted between the
809 time the program is compiled and the time it is run.<br>
810 <br>
811 Therefore what could you do to get accented characters to work?<br>
812 <br>
813 Can you ensure that the execution character set is the same as the
814 compilation character set? Even if your program is to be used only in a
815 single country, this is not realistically possible. For example, in
816 Germany there are currently three character encodings in use: UTF-8,
817 ISO-8859-15 and ISO-8859-1. Therefore you would have to explicitly
818 convert the accented strings from the compilation character set to the
819 execution character set at runtime, for example through iconv().<br>
820 <br>
821 Can you ensure that the compilation character set is the one in which
822 your source files are stored? This is not realistically possible
823 either: For compilers other than GCC, there is no way to specify the
824 compilation character set. So let's assume for a moment that everyone
825 uses GCC; then you will specify the LC_CTYPE or LC_ALL environment
826 variable in the Makefile. But for this you have to assume that everyone
827 has a locale in a given encoding. Be it UTF-8 or ISO-8859-1 - this is
828 not realistic. People often have no locale installed besides the one
829 they use.<br>
830 <br>
831 Use of wide strings <span style="font-family: monospace;">L"..."</span>
832 doesn't help solving the problem, because on systems like FreeBSD or
833 Solaris, the way how wide string literals are stored in compiled code
834 depends on the compilation character set, just as it does for
835 narrow strings <span style="font-family: monospace;">"..."</span>.
836 Moreover, wide strings have problems of their own.<br>
837 <br>
838 Use of ISO C 99 Unicode escapes "\u<span style="font-style: italic;">xxxx</span>"
839 doesn't help either because these characters are converted to the
840 compilation character set at compile time; so again, since you can't
841 guarantee that the compilation character set is not ASCII, you're
842 risking compilation errors just as if the real character had been used
843 in the source instead of the Unicode escape.<br>
844 <br>
845 So, in summary, there is no way to make accented characters in string
846 literals work in C/C++.<br>
847 <br>
848 You might then wonder what <span style="font-family: monospace;">xgettext</span>'s
849 <span style="font-family: monospace;">--from-code</span> option is good
850 for. The answer is<br>
851 <ol>
852 <li>For the comments in C/C++ source code. The compiler ignores them.<br>
853 </li>
854 <li>For other programming languages like Java, for which the compiler
855 converts all string literals to UTF-8.</li>
856 </ol>
857 <br>
858 <hr style="width: 100%; height: 2px;">
859 <address>GNU gettext FAQ<br>
860 Bruno Haible <<a href="mailto:bruno (a] clisp.org">bruno (a] clisp.org</a>></address>
861 <p>Last modified: 24 February 2004
862 </p>
863 </body>
864 </html>
865