path: root/doc/gettext.info-4

This is gettext.info, produced by makeinfo version 4.0 from
gettext.texi.

INFO-DIR-SECTION GNU Gettext Utilities
START-INFO-DIR-ENTRY
* Gettext: (gettext).                           GNU gettext utilities.
* gettextize: (gettext)gettextize Invocation.   Prepare a package for gettext.
* msgfmt: (gettext)msgfmt Invocation.           Make MO files out of PO files.
* msgmerge: (gettext)msgmerge Invocation.       Update two PO files into one.
* xgettext: (gettext)xgettext Invocation.       Extract strings into a PO file.
END-INFO-DIR-ENTRY

   This file provides documentation for GNU `gettext' utilities.  It
also serves as a reference for the free Translation Project.

   Copyright (C) 1995, 1996, 1997, 1998, 2001 Free Software Foundation,
Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.


File: gettext.info,  Node: gettext,  Next: Comparison,  Prev: catgets,  Up: Programmers

About `gettext'
===============

   The definition of the `gettext' interface comes from a Uniforum
proposal and it is followed by at least one major Unix vendor (Sun) in
its last developments.  It is not specified in any official standard,
though.

   The main points about this solution is that it does not follow the
method of normal file handling (open-use-close) and that it does not
burden the programmer so many task, especially the unique key handling.
Of course here is also a unique key needed, but this key is the message
itself (how long or short it is).  See *Note Comparison:: for a more
detailed comparison of the two methods.

   The following section contains a rather detailed description of the
interface.  We make it that detailed because this is the interface we
chose for the GNU `gettext' Library.  Programmers interested in using
this library will be interested in this description.

* Menu:

* Interface to gettext::        The interface
* Ambiguities::                 Solving ambiguities
* Locating Catalogs::           Locating message catalog files
* Charset conversion::          How to request conversion to Unicode
* Plural forms::                Additional functions for handling plurals
* GUI program problems::        Another technique for solving ambiguities
* Optimized gettext::           Optimization of the *gettext functions


File: gettext.info,  Node: Interface to gettext,  Next: Ambiguities,  Prev: gettext,  Up: gettext

The Interface
-------------

   The minimal functionality an interface must have is a) to select a
domain the strings are coming from (a single domain for all programs is
not reasonable because its construction and maintenance is difficult,
perhaps impossible) and b) to access a string in a selected domain.

   This is principally the description of the `gettext' interface.  It
has an global domain which unqualified usages reference.  Of course this
domain is selectable by the user.

     char *textdomain (const char *domain_name);

   This provides the possibility to change or query the current status
of the current global domain of the `LC_MESSAGE' category.  The
argument is a null-terminated string, whose characters must be legal in
the use in filenames.  If the DOMAIN_NAME argument is `NULL', the
function return the current value.  If no value has been set before,
the name of the default domain is returned: _messages_.  Please note
that although the return value of `textdomain' is of type `char *' no
changing is allowed.  It is also important to know that no checks of
the availability are made.  If the name is not available you will see
this by the fact that no translations are provided.

To use a domain set by `textdomain' the function

     char *gettext (const char *msgid);

   is to be used.  This is the simplest reasonable form one can imagine.
The translation of the string MSGID is returned if it is available in
the current domain.  If not available the argument itself is returned.
If the argument is `NULL' the result is undefined.

   One things which should come into mind is that no explicit
dependency to the used domain is given.  The current value of the
domain for the `LC_MESSAGES' locale is used.  If this changes between
two executions of the same `gettext' call in the program, both calls
reference a different message catalog.

   For the easiest case, which is normally used in internationalized
packages, once at the beginning of execution a call to `textdomain' is
issued, setting the domain to a unique name, normally the package name.
In the following code all strings which have to be translated are
filtered through the gettext function.  That's all, the package speaks
your language.


File: gettext.info,  Node: Ambiguities,  Next: Locating Catalogs,  Prev: Interface to gettext,  Up: gettext

Solving Ambiguities
-------------------

   While this single name domain work good for most applications there
might be the need to get translations from more than one domain.  Of
course one could switch between different domains with calls to
`textdomain', but this is really not convenient nor is it fast.  A
possible situation could be one case discussing while this writing:  all
error messages of functions in the set of common used functions should
go into a separate domain `error'.  By this mean we would only need to
translate them once.

For this reasons there are two more functions to retrieve strings:

     char *dgettext (const char *domain_name, const char *msgid);
     char *dcgettext (const char *domain_name, const char *msgid,
                      int category);

   Both take an additional argument at the first place, which
corresponds to the argument of `textdomain'.  The third argument of
`dcgettext' allows to use another locale but `LC_MESSAGES'.  But I
really don't know where this can be useful.  If the DOMAIN_NAME is
`NULL' or CATEGORY has an value beside the known ones, the result is
undefined.  It should also be noted that this function is not part of
the second known implementation of this function family, the one found
in Solaris.

   A second ambiguity can arise by the fact, that perhaps more than one
domain has the same name.  This can be solved by specifying where the
needed message catalog files can be found.

     char *bindtextdomain (const char *domain_name,
                           const char *dir_name);

   Calling this function binds the given domain to a file in the
specified directory (how this file is determined follows below).
Especially a file in the systems default place is not favored against
the specified file anymore (as it would be by solely using
`textdomain').  A `NULL' pointer for the DIR_NAME parameter returns the
binding associated with DOMAIN_NAME.  If DOMAIN_NAME itself is `NULL'
nothing happens and a `NULL' pointer is returned.  Here again as for
all the other functions is true that none of the return value must be
changed!

   It is important to remember that relative path names for the
DIR_NAME parameter can be trouble.  Since the path is always computed
relative to the current directory different results will be achieved
when the program executes a `chdir' command.  Relative paths should
always be avoided to avoid dependencies and unreliabilities.


File: gettext.info,  Node: Locating Catalogs,  Next: Charset conversion,  Prev: Ambiguities,  Up: gettext

Locating Message Catalog Files
------------------------------

   Because many different languages for many different packages have to
be stored we need some way to add these information to file message
catalog files.  The way usually used in Unix environments is have this
encoding in the file name.  This is also done here.  The directory name
given in `bindtextdomain's second argument (or the default directory),
followed by the value and name of the locale and the domain name are
concatenated:

     DIR_NAME/LOCALE/LC_CATEGORY/DOMAIN_NAME.mo

   The default value for DIR_NAME is system specific.  For the GNU
library, and for packages adhering to its conventions, it's:
     /usr/local/share/locale

LOCALE is the value of the locale whose name is this `LC_CATEGORY'.
For `gettext' and `dgettext' this `LC_CATEGORY' is always
`LC_MESSAGES'.(1) The value of the locale is determined through
`setlocale (LC_CATEGORY, NULL)'.  (2) `dcgettext' specifies the locale
category by the third argument.

   ---------- Footnotes ----------

   (1) Some system, eg Ultrix, don't have `LC_MESSAGES'.  Here we use a
more or less arbitrary value for it, namely 1729, the smallest positive
integer which can be represented in two different ways as the sum of
two cubes.

   (2) When the system does not support `setlocale' its behavior in
setting the locale values is simulated by looking at the environment
variables.


File: gettext.info,  Node: Charset conversion,  Next: Plural forms,  Prev: Locating Catalogs,  Up: gettext

How to specify the output character set `gettext' uses
------------------------------------------------------

   `gettext' not only looks up a translation in a message catalog.  It
also converts the translation on the fly to the desired output character
set.  This is useful if the user is working in a different character set
than the translator who created the message catalog, because it avoids
distributing variants of message catalogs which differ only in the
character set.

   The output character set is, by default, the value of `nl_langinfo
(CODESET)', which depends on the `LC_CTYPE' part of the current locale.
But programs which store strings in a locale independent way (e.g.
UTF-8) can request that `gettext' and related functions return the
translations in that encoding, by use of the `bind_textdomain_codeset'
function.

   Note that the MSGID argument to `gettext' is not subject to
character set conversion.  Also, when `gettext' does not find a
translation for MSGID, it returns MSGID unchanged - independently of
the current output character set.  It is therefore recommended that all
MSGIDs be US-ASCII strings.

 - Function: char * bind_textdomain_codeset (const char *DOMAINNAME,
          const char *CODESET)
     The `bind_textdomain_codeset' function can be used to specify the
     output character set for message catalogs for domain DOMAINNAME.
     The CODESET argument must be a valid codeset name which can be used
     for the `iconv_open' function, or a null pointer.

     If the CODESET parameter is the null pointer,
     `bind_textdomain_codeset' returns the currently selected codeset
     for the domain with the name DOMAINNAME. It returns `NULL' if no
     codeset has yet been selected.

     The `bind_textdomain_codeset' function can be used several times.
     If used multiple times with the same DOMAINNAME argument, the
     later call overrides the settings made by the earlier one.

     The `bind_textdomain_codeset' function returns a pointer to a
     string containing the name of the selected codeset.  The string is
     allocated internally in the function and must not be changed by the
     user.  If the system went out of core during the execution of
     `bind_textdomain_codeset', the return value is `NULL' and the
     global variable ERRNO is set accordingly.


File: gettext.info,  Node: Plural forms,  Next: GUI program problems,  Prev: Charset conversion,  Up: gettext

Additional functions for plural forms
-------------------------------------

   The functions of the `gettext' family described so far (and all the
`catgets' functions as well) have one problem in the real world which
have been neglected completely in all existing approaches.  What is
meant here is the handling of plural forms.

   Looking through Unix source code before the time anybody thought
about internationalization (and, sadly, even afterwards) one can often
find code similar to the following:

        printf ("%d file%s deleted", n, n == 1 ? "" : "s");

After the first complaints from people internationalizing the code
people either completely avoided formulations like this or used strings
like `"file(s)"'.  Both look unnatural and should be avoided.  First
tries to solve the problem correctly looked like this:

        if (n == 1)
          printf ("%d file deleted", n);
        else
          printf ("%d files deleted", n);

   But this does not solve the problem.  It helps languages where the
plural form of a noun is not simply constructed by adding an `s' but
that is all.  Once again people fell into the trap of believing the
rules their language is using are universal.  But the handling of plural
forms differs widely between the language families.  For example, Rafal
Maszkowski `<rzm@mat.uni.torun.pl>' reports:

     In Polish we use e.g. plik (file) this way:
          1 plik
          2,3,4 pliki
          5-21 pliko'w
          22-24 pliki
          25-31 pliko'w
     and so on (o' means 8859-2 oacute which should be rather okreska,
     similar to aogonek).

   There are two things which can differ between languages (and even
inside language families);

   * The form how plural forms are build differs.  This is a problem
     with language which have many irregularities.  German, for
     instance, is a drastic case.  Though English and German are part
     of the same language family (Germanic), the almost regular forming
     of plural noun forms (appending an `s') is hardly found in German.

   * The number of plural forms differ.  This is somewhat surprising for
     those who only have experiences with Romanic and Germanic languages
     since here the number is the same (there are two).

     But other language families have only one form or many forms.  More
     information on this in an extra section.

   The consequence of this is that application writers should not try to
solve the problem in their code.  This would be localization since it is
only usable for certain, hardcoded language environments.  Instead the
extended `gettext' interface should be used.

   These extra functions are taking instead of the one key string two
strings and an numerical argument.  The idea behind this is that using
the numerical argument and the first string as a key, the implementation
can select using rules specified by the translator the right plural
form.  The two string arguments then will be used to provide a return
value in case no message catalog is found (similar to the normal
`gettext' behavior).  In this case the rules for Germanic language is
used and it is assumed that the first string argument is the singular
form, the second the plural form.

   This has the consequence that programs without language catalogs can
display the correct strings only if the program itself is written using
a Germanic language.  This is a limitation but since the GNU C library
(as well as the GNU `gettext' package) are written as part of the GNU
package and the coding standards for the GNU project require program
being written in English, this solution nevertheless fulfills its
purpose.

 - Function: char * ngettext (const char *MSGID1, const char *MSGID2,
          unsigned long int N)
     The `ngettext' function is similar to the `gettext' function as it
     finds the message catalogs in the same way.  But it takes two
     extra arguments.  The MSGID1 parameter must contain the singular
     form of the string to be converted.  It is also used as the key
     for the search in the catalog.  The MSGID2 parameter is the plural
     form.  The parameter N is used to determine the plural form.  If no
     message catalog is found MSGID1 is returned if `n == 1', otherwise
     `msgid2'.

     An example for the us of this function is:

          printf (ngettext ("%d file removed", "%d files removed", n), n);

     Please note that the numeric value N has to be passed to the
     `printf' function as well.  It is not sufficient to pass it only to
     `ngettext'.

 - Function: char * dngettext (const char *DOMAIN, const char *MSGID1,
          const char *MSGID2, unsigned long int N)
     The `dngettext' is similar to the `dgettext' function in the way
     the message catalog is selected.  The difference is that it takes
     two extra parameter to provide the correct plural form.  These two
     parameters are handled in the same way `ngettext' handles them.

 - Function: char * dcngettext (const char *DOMAIN, const char *MSGID1,
          const char *MSGID2, unsigned long int N, int CATEGORY)
     The `dcngettext' is similar to the `dcgettext' function in the way
     the message catalog is selected.  The difference is that it takes
     two extra parameter to provide the correct plural form.  These two
     parameters are handled in the same way `ngettext' handles them.

   Now, how do these functions solve the problem of the plural forms?
Without the input of linguists (which was not available) it was not
possible to determine whether there are only a few different forms in
which plural forms are formed or whether the number can increase with
every new supported language.

   Therefore the solution implemented is to allow the translator to
specify the rules of how to select the plural form.  Since the formula
varies with every language this is the only viable solution except for
hardcoding the information in the code (which still would require the
possibility of extensions to not prevent the use of new languages).  The
details are explained in the GNU `gettext' manual.  Here only a a bit
of information is provided.

   The information about the plural form selection has to be stored in
the header entry of the PO file (the one with the empty `msgid' string).
The plural form information looks like this:

     Plural-Forms: nplurals=2; plural=n == 1 ? 0 : 1;

   The `nplurals' value must be a decimal number which specifies how
many different plural forms exist for this language.  The string
following `plural' is an expression which is using the C language
syntax.  Exceptions are that no negative number are allowed, numbers
must be decimal, and the only variable allowed is `n'.  This expression
will be evaluated whenever one of the functions `ngettext',
`dngettext', or `dcngettext' is called.  The numeric value passed to
these functions is then substituted for all uses of the variable `n' in
the expression.  The resulting value then must be greater or equal to
zero and smaller than the value given as the value of `nplurals'.

The following rules are known at this point.  The language with families
are listed.  But this does not necessarily mean the information can be
generalized for the whole family (as can be easily seen in the table
below).(1)

Only one form:
     Some languages only require one single form.  There is no
     distinction between the singular and plural form.  An appropriate
     header entry would look like this:

          Plural-Forms: nplurals=1; plural=0;

     Languages with this property include:

    Finno-Ugric family
          Hungarian

    Asian family
          Japanese

    Turkic/Altaic family
          Turkish

Two forms, singular used for one only
     This is the form used in most existing programs since it is what
     English is using.  A header entry would look like this:

          Plural-Forms: nplurals=2; plural=n != 1;

     (Note: this uses the feature of C expressions that boolean
     expressions have to value zero or one.)

     Languages with this property include:

    Germanic family
          Danish, Dutch, English, German, Norwegian, Swedish

    Finno-Ugric family
          Finnish

    Latin/Greek family
          Greek

    Semitic family
          Hebrew

    Romanic family
          Italian, Spanish

    Artificial
          Esperanto

Two forms, singular used for zero and one
     Exceptional case in the language family.  The header entry would
     be:

          Plural-Forms: nplurals=2; plural=n>1;

     Languages with this property include:

    Romanic family
          French

Three forms, special cases for one and two
     The header entry would be:

          Plural-Forms: nplurals=3; plural=n==1 ? 0 : n==2 ? 1 : 2;

     Languages with this property include:

    Celtic
          Gaeilge

Three forms, special case for one and all numbers ending in 2, 3, or 4
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
                        plural=n==1 ? 0 : n%10>=2 && n%10<=4 ? 1 : 2;

     Languages with this property include:

    Slavic family
          Russian

Three forms, special case for one and some numbers ending in 2, 3, or 4
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
              plural=n==1 ? 0 : \
                     n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2;

     (Continuation in the next line is possible.)

     Languages with this property include:

    Slavic family
          Polish

Four forms, special case for one and all numbers ending in 2, 3, or 4
     The header entry would look like this:

          Plural-Forms: nplurals=4; \
                        plural=n==1 ? 0 : \
                               n%10==2 ? 1 : n%10==3 || n%10==4 ? 2 : 3;

     Languages with this property include:

    Slavic family
          Slovenian

   ---------- Footnotes ----------

   (1) Additions are welcome.  Send appropriate information to
<bug-glibc-manual@gnu.org>.


File: gettext.info,  Node: GUI program problems,  Next: Optimized gettext,  Prev: Plural forms,  Up: gettext

How to use `gettext' in GUI programs
------------------------------------

   One place where the `gettext' functions, if used normally, have big
problems is within programs with graphical user interfaces (GUIs).  The
problem is that many of the strings which have to be translated are very
short.  They have to appear in pull-down menus which restricts the
length.  But strings which are not containing entire sentences or at
least large fragments of a sentence may appear in more than one
situation in the program but might have different translations.  This is
especially true for the one-word strings which are frequently used in
GUI programs.

   As a consequence many people say that the `gettext' approach is
wrong and instead `catgets' should be used which indeed does not have
this problem.  But there is a very simple and powerful method to handle
these kind of problems with the `gettext' functions.

As as example consider the following fictional situation.  A GUI program
has a menu bar with the following entries:

     +------------+------------+--------------------------------------+
     | File       | Printer    |                                      |
     +------------+------------+--------------------------------------+
     | Open     | | Select   |
     | New      | | Open     |
     +----------+ | Connect  |
                  +----------+

   To have the strings `File', `Printer', `Open', `New', `Select', and
`Connect' translated there has to be at some point in the code a call
to a function of the `gettext' family.  But in two places the string
passed into the function would be `Open'.  The translations might not
be the same and therefore we are in the dilemma described above.

   One solution to this problem is to artificially enlengthen the
strings to make them unambiguous.  But what would the program do if no
translation is available?  The enlengthened string is not what should be
printed.  So we should use a little bit modified version of the
functions.

   To enlengthen the strings a uniform method should be used.  E.g., in
the example above the strings could be chosen as

     Menu|File
     Menu|Printer
     Menu|File|Open
     Menu|File|New
     Menu|Printer|Select
     Menu|Printer|Open
     Menu|Printer|Connect

   Now all the strings are different and if now instead of `gettext'
the following little wrapper function is used, everything works just
fine:

       char *
       sgettext (const char *msgid)
       {
         char *msgval = gettext (msgid);
         if (msgval == msgid)
           msgval = strrchr (msgid, '|') + 1;
         return msgval;
       }

   What this little function does is to recognize the case when no
translation is available.  This can be done very efficiently by a
pointer comparison since the return value is the input value.  If there
is no translation we know that the input string is in the format we used
for the Menu entries and therefore contains a `|' character.  We simply
search for the last occurrence of this character and return a pointer
to the character following it.  That's it!

   If one now consistently uses the enlengthened string form and
replaces the `gettext' calls with calls to `sgettext' (this is normally
limited to very few places in the GUI implementation) then it is
possible to produce a program which can be internationalized.

   The other `gettext' functions (`dgettext', `dcgettext' and the
`ngettext' equivalents) can and should have corresponding functions as
well which look almost identical, except for the parameters and the
call to the underlying function.

   Now there is of course the question why such functions do not exist
in the GNU gettext package?  There are two parts of the answer to this
question.

   * They are easy to write and therefore can be provided by the
     project they are used in.  This is not an answer by itself and
     must be seen together with the second part which is:

   * There is no way the gettext package can contain a version which
     can work everywhere.  The problem is the selection of the
     character to separate the prefix from the actual string in the
     enlenghtened string.  The examples above used `|' which is a quite
     good choice because it resembles a notation frequently used in
     this context and it also is a character not often used in message
     strings.

     But what if the character is used in message strings.  Or if the
     chose character is not available in the character set on the
     machine one compiles (e.g., `|' is not required to exist for
     ISO C; this is why the `iso646.h' file exists in ISO C programming
     environments).

   There is only one more comment to be said.  The wrapper function
above require that the translations strings are not enlengthened
themselves.  This is only logical.  There is no need to disambiguate
the strings (since they are never used as keys for a search) and one
also saves quite some memory and disk space by doing this.


File: gettext.info,  Node: Optimized gettext,  Prev: GUI program problems,  Up: gettext

Optimization of the *gettext functions
--------------------------------------

   At this point of the discussion we should talk about an advantage of
the GNU `gettext' implementation.  Some readers might have pointed out
that an internationalized program might have a poor performance if some
string has to be translated in an inner loop.  While this is unavoidable
when the string varies from one run of the loop to the other it is
simply a waste of time when the string is always the same.  Take the
following example:

     {
       while (...)
         {
           puts (gettext ("Hello world"));
         }
     }

When the locale selection does not change between two runs the resulting
string is always the same.  One way to use this is:

     {
       str = gettext ("Hello world");
       while (...)
         {
           puts (str);
         }
     }

But this solution is not usable in all situation (e.g. when the locale
selection changes) nor does it lead to legible code.

   For this reason, GNU `gettext' caches previous translation results.
When the same translation is requested twice, with no new message
catalogs being loaded in between, `gettext' will, the second time, find
the result through a single cache lookup.


File: gettext.info,  Node: Comparison,  Next: Using libintl.a,  Prev: gettext,  Up: Programmers

Comparing the Two Interfaces
============================

   The following discussion is perhaps a little bit colored.  As said
above we implemented GNU `gettext' following the Uniforum proposal and
this surely has its reasons.  But it should show how we came to this
decision.

   First we take a look at the developing process.  When we write an
application using NLS provided by `gettext' we proceed as always.  Only
when we come to a string which might be seen by the users and thus has
to be translated we use `gettext("...")' instead of `"..."'.  At the
beginning of each source file (or in a central header file) we define

     #define gettext(String) (String)

   Even this definition can be avoided when the system supports the
`gettext' function in its C library.  When we compile this code the
result is the same as if no NLS code is used.  When  you take a look at
the GNU `gettext' code you will see that we use `_("...")' instead of
`gettext("...")'.  This reduces the number of additional characters per
translatable string to _3_ (in words: three).

   When now a production version of the program is needed we simply
replace the definition

     #define _(String) (String)

by

     #include <libintl.h>
     #define _(String) gettext (String)

Additionally we run the program `xgettext' on all source code file
which contain translatable strings and that's it: we have a running
program which does not depend on translations to be available, but which
can use any that becomes available.

   The same procedure can be done for the `gettext_noop' invocations
(*note Special cases::).  One usually defines `gettext_noop' as a no-op
macro.  So you should consider the following code for your project:

     #define gettext_noop(String) (String)
     #define N_(String) gettext_noop (String)

   `N_' is a short form similar to `_'.  The `Makefile' in the `po/'
directory of GNU `gettext' knows by default both of the mentioned short
forms so you are invited to follow this proposal for your own ease.

   Now to `catgets'.  The main problem is the work for the programmer.
Every time he comes to a translatable string he has to define a number
(or a symbolic constant) which has also be defined in the message
catalog file.  He also has to take care for duplicate entries,
duplicate message IDs etc.  If he wants to have the same quality in the
message catalog as the GNU `gettext' program provides he also has to
put the descriptive comments for the strings and the location in all
source code files in the message catalog.  This is nearly a Mission:
Impossible.

   But there are also some points people might call advantages speaking
for `catgets'.  If you have a single word in a string and this string
is used in different contexts it is likely that in one or the other
language the word has different translations.  Example:

     printf ("%s: %d", gettext ("number"), number_of_errors)
     
     printf ("you should see %d %s", number_count,
             number_count == 1 ? gettext ("number") : gettext ("numbers"))

   Here we have to translate two times the string `"number"'.  Even if
you do not speak a language beside English it might be possible to
recognize that the two words have a different meaning.  In German the
first appearance has to be translated to `"Anzahl"' and the second to
`"Zahl"'.

   Now you can say that this example is really esoteric.  And you are
right!  This is exactly how we felt about this problem and decide that
it does not weight that much.  The solution for the above problem could
be very easy:

     printf ("%s %d", gettext ("number:"), number_of_errors)
     
     printf (number_count == 1 ? gettext ("you should see %d number")
                               : gettext ("you should see %d numbers"),
             number_count)

   We believe that we can solve all conflicts with this method.  If it
is difficult one can also consider changing one of the conflicting
string a little bit.  But it is not impossible to overcome.

   `catgets' allows same original entry to have different translations,
but `gettext' has another, scalable approach for solving ambiguities of
this kind: *Note Ambiguities::.


File: gettext.info,  Node: Using libintl.a,  Next: gettext grok,  Prev: Comparison,  Up: Programmers

Using libintl.a in own programs
===============================

   Starting with version 0.9.4 the library `libintl.h' should be
self-contained.  I.e., you can use it in your own programs without
providing additional functions.  The `Makefile' will put the header and
the library in directories selected using the `$(prefix)'.

   One exception of the above is found on HP-UX 10.01 systems.  Here
the C library does not contain the `alloca' function (and the HP
compiler does not generate it inlined).  But it is not intended to
rewrite the whole library just because of this dumb system.  Instead
include the `alloca' function in all package you use the `libintl.a' in.


File: gettext.info,  Node: gettext grok,  Next: Temp Programmers,  Prev: Using libintl.a,  Up: Programmers

Being a `gettext' grok
======================

   To fully exploit the functionality of the GNU `gettext' library it
is surely helpful to read the source code.  But for those who don't want
to spend that much time in reading the (sometimes complicated) code here
is a list comments:

   * Changing the language at runtime

     For interactive programs it might be useful to offer a selection
     of the used language at runtime.  To understand how to do this one
     need to know how the used language is determined while executing
     the `gettext' function.  The method which is presented here only
     works correctly with the GNU implementation of the `gettext'
     functions.

     In the function `dcgettext' at every call the current setting of
     the highest priority environment variable is determined and used.
     Highest priority means here the following list with decreasing
     priority:

       1. `LANGUAGE'

       2. `LC_ALL'

       3. `LC_xxx', according to selected locale

       4. `LANG'

     Afterwards the path is constructed using the found value and the
     translation file is loaded if available.

     What is now when the value for, say, `LANGUAGE' changes.  According
     to the process explained above the new value of this variable is
     found as soon as the `dcgettext' function is called.  But this
     also means the (perhaps) different message catalog file is loaded.
     In other words: the used language is changed.

     But there is one little hook.  The code for gcc-2.7.0 and up
     provides some optimization.  This optimization normally prevents
     the calling of the `dcgettext' function as long as no new catalog
     is loaded.  But if `dcgettext' is not called the program also
     cannot find the `LANGUAGE' variable be changed (*note Optimized
     gettext::).  A solution for this is very easy.  Include the
     following code in the language switching function.

            /* Change language.  */
            setenv ("LANGUAGE", "fr", 1);
          
            /* Make change known.  */
            {
              extern int  _nl_msg_cat_cntr;
              ++_nl_msg_cat_cntr;
            }

     The variable `_nl_msg_cat_cntr' is defined in `loadmsgcat.c'.  The
     programmer will find himself in need for a construct like this only
     when developing programs which do run longer and provide the user
     to select the language at runtime.  Non-interactive programs (like
     all these little Unix tools) should never need this.



File: gettext.info,  Node: Temp Programmers,  Prev: gettext grok,  Up: Programmers

Temporary Notes for the Programmers Chapter
===========================================

* Menu:

* Temp Implementations::        Temporary - Two Possible Implementations
* Temp catgets::                Temporary - About `catgets'
* Temp WSI::                    Temporary - Why a single implementation
* Temp Notes::                  Temporary - Notes


File: gettext.info,  Node: Temp Implementations,  Next: Temp catgets,  Prev: Temp Programmers,  Up: Temp Programmers

Temporary - Two Possible Implementations
----------------------------------------

   There are two competing methods for language independent messages:
the X/Open `catgets' method, and the Uniforum `gettext' method.  The
`catgets' method indexes messages by integers; the `gettext' method
indexes them by their English translations.  The `catgets' method has
been around longer and is supported by more vendors.  The `gettext'
method is supported by Sun, and it has been heard that the COSE
multi-vendor initiative is supporting it.  Neither method is a POSIX
standard; the POSIX.1 committee had a lot of disagreement in this area.

   Neither one is in the POSIX standard.  There was much disagreement
in the POSIX.1 committee about using the `gettext' routines vs.
`catgets' (XPG).  In the end the committee couldn't agree on anything,
so no messaging system was included as part of the standard.  I believe
the informative annex of the standard includes the XPG3 messaging
interfaces, "...as an example of a messaging system that has been
implemented..."

   They were very careful not to say anywhere that you should use one
set of interfaces over the other.  For more on this topic please see
the Programming for Internationalization FAQ.


File: gettext.info,  Node: Temp catgets,  Next: Temp WSI,  Prev: Temp Implementations,  Up: Temp Programmers

Temporary - About `catgets'
---------------------------

   There have been a few discussions of late on the use of `catgets' as
a base.  I think it important to present both sides of the argument and
hence am opting to play devil's advocate for a little bit.

   I'll not deny the fact that `catgets' could have been designed a lot
better.  It currently has quite a number of limitations and these have
already been pointed out.

   However there is a great deal to be said for consistency and
standardization.  A common recurring problem when writing Unix software
is the myriad portability problems across Unix platforms.  It seems as
if every Unix vendor had a look at the operating system and found parts
they could improve upon.  Undoubtedly, these modifications are probably
innovative and solve real problems.  However, software developers have
a hard time keeping up with all these changes across so many platforms.

   And this has prompted the Unix vendors to begin to standardize their
systems.  Hence the impetus for Spec1170.  Every major Unix vendor has
committed to supporting this standard and every Unix software developer
waits with glee the day they can write software to this standard and
simply recompile (without having to use autoconf) across different
platforms.

   As I understand it, Spec1170 is roughly based upon version 4 of the
X/Open Portability Guidelines (XPG4).  Because `catgets' and friends
are defined in XPG4, I'm led to believe that `catgets' is a part of
Spec1170 and hence will become a standardized component of all Unix
systems.


File: gettext.info,  Node: Temp WSI,  Next: Temp Notes,  Prev: Temp catgets,  Up: Temp Programmers

Temporary - Why a single implementation
---------------------------------------

   Now it seems kind of wasteful to me to have two different systems
installed for accessing message catalogs.  If we do want to remedy
`catgets' deficiencies why don't we try to expand `catgets' (in a
compatible manner) rather than implement an entirely new system.
Otherwise, we'll end up with two message catalog access systems
installed with an operating system - one set of routines for packages
using GNU `gettext' for their internationalization, and another set of
routines (catgets) for all other software.  Bloated?

   Supposing another catalog access system is implemented.  Which do we
recommend?  At least for Linux, we need to attract as many software
developers as possible.  Hence we need to make it as easy for them to
port their software as possible.  Which means supporting `catgets'.  We
will be implementing the `libintl' code within our `libc', but does
this mean we also have to incorporate another message catalog access
scheme within our `libc' as well?  And what about people who are going
to be using the `libintl' + non-`catgets' routines.  When they port
their software to other platforms, they're now going to have to include
the front-end (`libintl') code plus the back-end code (the non-`catgets'
access routines) with their software instead of just including the
`libintl' code with their software.

   Message catalog support is however only the tip of the iceberg.
What about the data for the other locale categories.  They also have a
number of deficiencies.  Are we going to abandon them as well and
develop another duplicate set of routines (should `libintl' expand
beyond message catalog support)?

   Like many parts of Unix that can be improved upon, we're stuck with
balancing compatibility with the past with useful improvements and
innovations for the future.


File: gettext.info,  Node: Temp Notes,  Prev: Temp WSI,  Up: Temp Programmers

Temporary - Notes
-----------------

   X/Open agreed very late on the standard form so that many
implementations differ from the final form.  Both of my system (old
Linux catgets and Ultrix-4) have a strange variation.

   OK.  After incorporating the last changes I have to spend some time
on making the GNU/Linux `libc' `gettext' functions.  So in future
Solaris is not the only system having `gettext'.


File: gettext.info,  Node: Translators,  Next: Maintainers,  Prev: Programmers,  Up: Top

The Translator's View
*********************

* Menu:

* Trans Intro 0::               Introduction 0
* Trans Intro 1::               Introduction 1
* Discussions::                 Discussions
* Organization::                Organization
* Information Flow::            Information Flow


File: gettext.info,  Node: Trans Intro 0,  Next: Trans Intro 1,  Prev: Translators,  Up: Translators

Introduction 0
==============

   Free software is going international!  The Translation Project is a
way to get maintainers, translators and users all together, so free
software will gradually become able to speak many native languages.

   The GNU `gettext' tool set contains _everything_ maintainers need
for internationalizing their packages for messages.  It also contains
quite useful tools for helping translators at localizing messages to
their native language, once a package has already been
internationalized.

   To achieve the Translation Project, we need many interested people
who like their own language and write it well, and who are also able to
synergize with other translators speaking the same language.  If you'd
like to volunteer to _work_ at translating messages, please send mail
to your translating team.

   Each team has its own mailing list, courtesy of Linux International.
You may reach your translating team at the address `LL@li.org',
replacing LL by the two-letter ISO 639 code for your language.
Language codes are _not_ the same as country codes given in ISO 3166.
The following translating teams exist:

     Chinese `zh', Czech `cs', Danish `da', Dutch `nl', Esperanto `eo',
     Finnish `fi', French `fr', Irish `ga', German `de', Greek `el',
     Italian `it', Japanese `ja', Indonesian `in', Norwegian `no',
     Polish `pl', Portuguese `pt', Russian `ru', Spanish `es', Swedish
     `sv' and Turkish `tr'.

For example, you may reach the Chinese translating team by writing to
`zh@li.org'.  When you become a member of the translating team for your
own language, you may subscribe to its list.  For example, Swedish
people can send a message to `sv-request@li.org', having this message
body:

     subscribe

   Keep in mind that team members should be interested in _working_ at
translations, or at solving translational difficulties, rather than
merely lurking around.  If your team does not exist yet and you want to
start one, please write to `translation@iro.umontreal.ca'; you will
then reach the coordinator for all translator teams.

   A handful of GNU packages have already been adapted and provided
with message translations for several languages.  Translation teams
have begun to organize, using these packages as a starting point.  But
there are many more packages and many languages for which we have no
volunteer translators.  If you would like to volunteer to work at
translating messages, please send mail to
`translation@iro.umontreal.ca' indicating what language(s) you can work
on.


File: gettext.info,  Node: Trans Intro 1,  Next: Discussions,  Prev: Trans Intro 0,  Up: Translators

Introduction 1
==============

   This is now official, GNU is going international!  Here is the
announcement submitted for the January 1995 GNU Bulletin:

     A handful of GNU packages have already been adapted and provided
     with message translations for several languages.  Translation
     teams have begun to organize, using these packages as a starting
     point.  But there are many more packages and many languages for
     which we have no volunteer translators.  If you'd like to
     volunteer to work at translating messages, please send mail to
     `translation@iro.umontreal.ca' indicating what language(s) you can
     work on.

   This document should answer many questions for those who are curious
about the process or would like to contribute.  Please at least skim
over it, hoping to cut down a little of the high volume of e-mail
generated by this collective effort towards internationalization of
free software.

   Most free programming which is widely shared is done in English, and
currently, English is used as the main communicating language between
national communities collaborating to free software.  This very document
is written in English.  This will not change in the foreseeable future.

   However, there is a strong appetite from national communities for
having more software able to write using national language and habits,
and there is an on-going effort to modify free software in such a way
that it becomes able to do so.  The experiments driven so far raised an
enthusiastic response from pretesters, so we believe that
internationalization of free software is dedicated to succeed.

   For suggestion clarifications, additions or corrections to this
document, please e-mail to `translation@iro.umontreal.ca'.


File: gettext.info,  Node: Discussions,  Next: Organization,  Prev: Trans Intro 1,  Up: Translators

Discussions
===========

   Facing this internationalization effort, a few users expressed their
concerns.  Some of these doubts are presented and discussed, here.

   * Smaller groups

     Some languages are not spoken by a very large number of people, so
     people speaking them sometimes consider that there may not be all
     that much demand such versions of free software packages.
     Moreover, many people being _into computers_, in some countries,
     generally seem to prefer English versions of their software.

     On the other end, people might enjoy their own language a lot, and
     be very motivated at providing to themselves the pleasure of
     having their beloved free software speaking their mother tongue.
     They do themselves a personal favor, and do not pay that much
     attention to the number of people beneficiating of their work.

   * Misinterpretation

     Other users are shy to push forward their own language, seeing in
     this some kind of misplaced propaganda.  Someone thought there
     must be some users of the language over the networks pestering
     other people with it.

     But any spoken language is worth localization, because there are
     people behind the language for whom the language is important and
     dear to their hearts.

   * Odd translations

     The biggest problem is to find the right translations so that
     everybody can understand the messages.  Translations are usually a
     little odd.  Some people get used to English, to the extent they
     may find translations into their own language "rather pushy,
     obnoxious and sometimes even hilarious."  As a French speaking
     man, I have the experience of those instruction manuals for goods,
     so poorly translated in French in Korea or Taiwan...

     The fact is that we sometimes have to create a kind of national
     computer culture, and this is not easy without the collaboration of
     many people liking their mother tongue.  This is why translations
     are better achieved by people knowing and loving their own
     language, and ready to work together at improving the results they
     obtain.

   * Dependencies over the GPL

     Some people wonder if using GNU `gettext' necessarily brings their
     package under the protective wing of the GNU General Public
     License, when they do not want to make their program free, or want
     other kinds of freedom.  The simplest answer is yes.

     The mere marking of localizable strings in a package, or
     conditional inclusion of a few lines for initialization, is not
     really including GPL'ed code.  However, the localization routines
     themselves are under the GPL and would bring the remainder of the
     package under the GPL if they were distributed with it.  So, I
     presume that, for those for which this is a problem, it could be
     circumvented by letting to the end installers the burden of
     assembling a package prepared for localization, but not providing
     the localization routines themselves.