[PATCH v5 2/4] posix: let the getopt caller set the translation context

Vivien Kraus vivien@planete-kraus.eu
Wed Jun 4 22:06:16 GMT 2025


Option names are typically one word, so they could be translated
differently in different parts of the program.  The use of a context
lets the translator pick the most appropriate translation when used in
the command-line.

Another possibility would be to prepend two dashes to the option name
before translation, such that it would be obvious this is the
command-line option name.  However, it would be difficult to mark this
string for translation (to be processed by xgettext).

The context is now mandatory.

pgettext_expr is not available yet, so we use a custom function to
combine the context and the long option name.

This creates a new global variable / reentrant state field, optctxt,
so that the caller can override it.
---
 manual/getopt.texi      | 14 +++++++++++++-
 posix/Versions          |  3 +++
 posix/bits/getopt_ext.h |  7 +++++++
 posix/getopt.c          | 27 ++++++++++++++++----------
 posix/getopt1.c         | 43 +++++++++++++++++++++++++++++++++++++----
 posix/getopt_int.h      |  6 ++++--
 posix/tstgetoptl.c      |  6 +++++-
 posix/tstgetoptl.po     |  2 ++
 8 files changed, 90 insertions(+), 18 deletions(-)

diff --git a/manual/getopt.texi b/manual/getopt.texi
index 36d409e1f7..15994400dd 100644
--- a/manual/getopt.texi
+++ b/manual/getopt.texi
@@ -53,6 +53,16 @@ This variable is set by @code{getopt} to point at the value of the
 option argument, for those options that accept arguments.
 @end deftypevar
 
+@deftypevar {const char *} optctxt
+In order to match translated option names, @code{getopt} looks the
+names in the current textdomain. Since option names may be short words
+instead of long sentences, they may have different translations in
+other places of the program.  @xref{Contexts, , Using contexts for
+solving ambiguities, gettext, the GNU Gettext manual}, for more
+information.  If this is @code{NULL}, then the translated option names
+will not be processed.
+@end deftypevar
+
 @deftypefun int getopt (int @var{argc}, char *const *@var{argv}, const char *@var{options})
 @standards{POSIX.2, unistd.h}
 @safety{@prelim{}@mtunsafe{@mtasurace{:getopt} @mtsenv{}}@asunsafe{@ascuheap{} @ascuintl{} @asulock{} @asucorrupt{}}@acunsafe{@acsmem{} @aculock{} @acucorrupt{}}}
@@ -215,7 +225,9 @@ The @code{struct option} structure has these fields:
 @item const char *name
 This field is the name of the option.  It is a string.  In order for
 @command{getopt_long} to accept either the long option name or its
-translated form, you should mark this string for translation.
+translated form, you should mark this string for translation with a
+translation context, and set @code{optctxt} to the translation
+context.
 
 @item int has_arg
 This field says whether the option takes an argument.  It is an integer,
diff --git a/posix/Versions b/posix/Versions
index 0624d24bcc..76af54306e 100644
--- a/posix/Versions
+++ b/posix/Versions
@@ -159,6 +159,9 @@ libc {
   GLIBC_2.35 {
     posix_spawn_file_actions_addtcsetpgrp_np;
   }
+  GLIBC_2.42 {
+    optctxt;
+  }
   GLIBC_PRIVATE {
     __libc_fork; __libc_pread; __libc_pwrite;
     __nanosleep_nocancel; __pause_nocancel;
diff --git a/posix/bits/getopt_ext.h b/posix/bits/getopt_ext.h
index 42be8ec38e..07d9407b64 100644
--- a/posix/bits/getopt_ext.h
+++ b/posix/bits/getopt_ext.h
@@ -26,6 +26,13 @@
 
 __BEGIN_DECLS
 
+#ifdef __USE_GNU
+/* Callers store the translation context in which to retrieve option
+   names.  If unset, the option names will not be translated. */
+
+extern const char *optctxt;
+#endif
+
 /* Describe the long-named options requested by the application.
    The LONG_OPTIONS argument to getopt_long or getopt_long_only is a vector
    of 'struct option' terminated by an element containing a name which is
diff --git a/posix/getopt.c b/posix/getopt.c
index 9540821e1f..28f0be03f8 100644
--- a/posix/getopt.c
+++ b/posix/getopt.c
@@ -182,17 +182,19 @@ exchange (char **argv, struct _getopt_data *d)
   d->__last_nonopt = d->optind;
 }
 
-/* Return 1 iff a translation for opt_name has been found and it
-   matches the substring from argument, length argument_length.
+/* Return 1 iff translation_context is not NULL, a translation for
+   opt_name has been found and it matches the substring from argument,
+   length argument_length.
 */
 static const int
-match_translated_option_name (char *(*translate) (const char *msgid),
+match_translated_option_name (char *(*translate) (const char *, const char *),
                               const char *argument, size_t argument_length,
+                              const char *translation_context,
                               const char *opt_name)
 {
   const char *translated = opt_name;
   if (translate)
-    translated = translate (opt_name);
+    translated = translate (translation_context, opt_name);
   return (!strncmp (translated, argument, argument_length)
           && argument_length == strlen (translated));
 }
@@ -210,7 +212,7 @@ process_long_option (int argc, char **argv, const char *optstring,
 		     const struct option *longopts, int *longind,
 		     int long_only, struct _getopt_data *d,
 		     int print_errors, const char *prefix,
-                     char *(*translate) (const char *msgid))
+                     char *(*translate) (const char *, const char *))
 {
   char *nameend;
   size_t namelen;
@@ -241,7 +243,9 @@ process_long_option (int argc, char **argv, const char *optstring,
       /* Didn't find an exact match, try with translated option
          names. */
       for (p = longopts, option_index = 0; p->name; p++, option_index++)
-        if (match_translated_option_name (translate, d->__nextchar, namelen, p->name))
+        if (match_translated_option_name (translate,
+                                          d->__nextchar, namelen,
+                                          d->optctxt, p->name))
           {
             /* Exact match found with translation.  */
             pfound = p;
@@ -365,7 +369,7 @@ process_long_option (int argc, char **argv, const char *optstring,
   /* We have found a matching long option.  Consume it.  */
   d->optind++;
   d->__nextchar = NULL;
-  translated_option_name = translate (pfound->name);
+  translated_option_name = translate (d->optctxt, pfound->name);
   if (*nameend)
     {
       /* Don't test has_arg with >, because some C compilers don't
@@ -531,7 +535,7 @@ int
 _getopt_internal_r (int argc, char **argv, const char *optstring,
 		    const struct option *longopts, int *longind,
 		    int long_only, struct _getopt_data *d, int posixly_correct,
-                    char *(*translate) (const char *msgid))
+                    char *(*translate) (const char *, const char *))
 {
   int print_errors = d->opterr;
 
@@ -766,12 +770,15 @@ _getopt_internal_r (int argc, char **argv, const char *optstring,
 int
 _getopt_internal (int argc, char **argv, const char *optstring,
 		  const struct option *longopts, int *longind, int long_only,
-		  int posixly_correct, char *(*translate) (const char *))
+		  int posixly_correct,
+                  char *(*translate) (const char *, const char *),
+                  const char *ctxt)
 {
   int result;
 
   getopt_data.optind = optind;
   getopt_data.opterr = opterr;
+  getopt_data.optctxt = ctxt;
 
   result = _getopt_internal_r (argc, argv, optstring, longopts,
 			       longind, long_only, &getopt_data,
@@ -794,7 +801,7 @@ _getopt_internal (int argc, char **argv, const char *optstring,
   {								\
     return _getopt_internal (argc, (char **)argv, optstring,	\
 			     NULL, NULL, 0, POSIXLY_CORRECT,    \
-                             NULL);                             \
+                             NULL, NULL);                       \
   }
 
 #ifdef _LIBC
diff --git a/posix/getopt1.c b/posix/getopt1.c
index 6bf0087344..387ad8d8c9 100644
--- a/posix/getopt1.c
+++ b/posix/getopt1.c
@@ -26,13 +26,48 @@
 
 #include "getopt.h"
 #include "getopt_int.h"
+#include <stdlib.h>
+#include <string.h>
+
+/* Callers store an optional context to enable option name
+   translation. */
+
+const char *optctxt = NULL;
+
+/* FIXME: use pgettext_expr. */
+static char *
+do_translate (const char *context, const char *msgid)
+{
+  char *full_msgid;
+  const char *translated = msgid;
+
+  if (context)
+    {
+      full_msgid = malloc (strlen (context) + 1 /* ^D */ + strlen (msgid) + 1);
+      if (msgid)
+        {
+          strcpy (full_msgid, context);
+          full_msgid[strlen (context)] = '\004';
+          strcpy (full_msgid + strlen (context) + 1, msgid);
+          translated = gettext (full_msgid);
+          if (!strcmp (translated, full_msgid))
+            {
+              translated = msgid;
+            }
+        }
+      free (full_msgid);
+    }
+  else
+    translated = msgid;
+  return (char *) translated;
+}
 
 int
 getopt_long (int argc, char *__getopt_argv_const *argv, const char *options,
 	     const struct option *long_options, int *opt_index)
 {
   return _getopt_internal (argc, (char **) argv, options, long_options,
-			   opt_index, 0, 0, gettext);
+			   opt_index, 0, 0, do_translate, optctxt);
 }
 
 int
@@ -41,7 +76,7 @@ _getopt_long_r (int argc, char **argv, const char *options,
 		struct _getopt_data *d)
 {
   return _getopt_internal_r (argc, argv, options, long_options, opt_index,
-			     0, d, 0, gettext);
+			     0, d, 0, do_translate);
 }
 
 /* Like getopt_long, but '-' as well as '--' can indicate a long option.
@@ -55,7 +90,7 @@ getopt_long_only (int argc, char *__getopt_argv_const *argv,
 		  const struct option *long_options, int *opt_index)
 {
   return _getopt_internal (argc, (char **) argv, options, long_options,
-			   opt_index, 1, 0, gettext);
+			   opt_index, 1, 0, do_translate, optctxt);
 }
 
 int
@@ -64,7 +99,7 @@ _getopt_long_only_r (int argc, char **argv, const char *options,
 		     struct _getopt_data *d)
 {
   return _getopt_internal_r (argc, argv, options, long_options, opt_index,
-			     1, d, 0, gettext);
+			     1, d, 0, do_translate);
 }
 
 
diff --git a/posix/getopt_int.h b/posix/getopt_int.h
index b15b21256a..1d091979c3 100644
--- a/posix/getopt_int.h
+++ b/posix/getopt_int.h
@@ -29,7 +29,8 @@ extern int _getopt_internal (int ___argc, char **___argv,
 			     const char *__shortopts,
 			     const struct option *__longopts, int *__longind,
 			     int __long_only, int __posixly_correct,
-                             char *(*translate) (const char *msgid));
+                             char *(*translate) (const char *, const char *),
+                             const char *__optctxt);
 
 
 /* Reentrant versions which can handle parsing multiple argument
@@ -71,6 +72,7 @@ struct _getopt_data
   int opterr;
   int optopt;
   char *optarg;
+  const char *optctxt;
 
   /* Internal members.  */
 
@@ -107,7 +109,7 @@ extern int _getopt_internal_r (int ___argc, char **___argv,
 			       const struct option *__longopts, int *__longind,
 			       int __long_only, struct _getopt_data *__data,
 			       int __posixly_correct,
-                               char *(*translate) (const char *msgid));
+                               char *(*translate) (const char *, const char *));
 
 extern int _getopt_long_r (int ___argc, char **___argv,
 			   const char *__shortopts,
diff --git a/posix/tstgetoptl.c b/posix/tstgetoptl.c
index 04b07093e4..bffd56f47d 100644
--- a/posix/tstgetoptl.c
+++ b/posix/tstgetoptl.c
@@ -15,6 +15,8 @@
    precedence over translated options, by translated "optional" as
    "required". */
 
+#define TRANSLATION_CONTEXT "command-line option"
+
 static int
 prepare_localedir (void)
 {
@@ -31,7 +33,7 @@ prepare_localedir (void)
       return -1;
     }
   /* Check that the catalog is OK: */
-  if (strcmp (gettext ("color"), "colour") != 0)
+  if (strcmp (gettext (TRANSLATION_CONTEXT "\004" "color"), "colour") != 0)
     {
       fputs ("The mo file does not work.\n", stderr);
       return -1;
@@ -42,6 +44,7 @@ prepare_localedir (void)
 int
 main (int argc, char **argv)
 {
+  static const char *translation_context = TRANSLATION_CONTEXT;
   static const struct option options[] =
     {
       {"required", required_argument, NULL, 'r'},
@@ -68,6 +71,7 @@ main (int argc, char **argv)
       fputs ("Error while setting up localedir.\n", stderr);
       return 1;
     }
+  optctxt = translation_context;
   while ((c = getopt_long (argc, argv, "abc:", options, NULL)) >= 0)
     switch (c)
       {
diff --git a/posix/tstgetoptl.po b/posix/tstgetoptl.po
index 25cd595790..e060c0d6e3 100644
--- a/posix/tstgetoptl.po
+++ b/posix/tstgetoptl.po
@@ -16,10 +16,12 @@ msgstr ""
 "Plural-Forms: nplurals=2; plural=(n != 1);\n"
 
 #: xxx.c:yy
+msgctxt "command-line option"
 msgid "color"
 msgstr "colour"
 
 # This is to make sure the translator cannot redirect options.
 #: xxx.c:yy
+msgctxt "command-line option"
 msgid "optional"
 msgstr "required"
-- 
2.49.0



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