+argmatch_invalid (const char *context, const char *value, ptrdiff_t problem)
+{
+ char const *format = (problem == -1
+ ? _("invalid argument %s for %s")
+ : _("ambiguous argument %s for %s"));
+
+ error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
+ quote_n (1, context));
+}
+
+/* List the valid arguments for argmatch.
+ ARGLIST is the same as in argmatch.
+ VALLIST is a pointer to an array of values.
+ VALSIZE is the size of the elements of VALLIST */
+void
+argmatch_valid (const char *const *arglist,
+ const char *vallist, size_t valsize)
+{
+ size_t i;
+ const char *last_val = NULL;
+
+ /* We try to put synonyms on the same line. The assumption is that
+ synonyms follow each other */
+ fprintf (stderr, _("Valid arguments are:"));
+ for (i = 0; arglist[i]; i++)
+ if ((i == 0)
+ || memcmp (last_val, vallist + valsize * i, valsize))
+ {
+ fprintf (stderr, "\n - `%s'", arglist[i]);
+ last_val = vallist + valsize * i;
+ }
+ else
+ {
+ fprintf (stderr, ", `%s'", arglist[i]);
+ }
+ putc ('\n', stderr);
+}
+
+/* Never failing versions of the previous functions.
+
+ CONTEXT is the context for which argmatch is called (e.g.,
+ "--version-control", or "$VERSION_CONTROL" etc.). Upon failure,
+ calls the (supposed never to return) function EXIT_FN. */
+
+ptrdiff_t
+__xargmatch_internal (const char *context,
+ const char *arg, const char *const *arglist,
+ const char *vallist, size_t valsize,
+ argmatch_exit_fn exit_fn)
+{
+ ptrdiff_t res = argmatch (arg, arglist, vallist, valsize);
+ if (res >= 0)
+ /* Success. */
+ return res;
+
+ /* We failed. Explain why. */
+ argmatch_invalid (context, arg, res);
+ argmatch_valid (arglist, vallist, valsize);
+ (*exit_fn) ();
+
+ return -1; /* To please the compilers. */
+}
+
+/* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
+ return the first corresponding argument in ARGLIST */
+const char *
+argmatch_to_argument (const char *value,
+ const char *const *arglist,
+ const char *vallist, size_t valsize)
+{
+ size_t i;
+
+ for (i = 0; arglist[i]; i++)
+ if (!memcmp (value, vallist + valsize * i, valsize))
+ return arglist[i];
+ return NULL;
+}
+
+#ifdef TEST
+/*
+ * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
+ */
+char *program_name;
+
+/* When to make backup files. */
+enum backup_type
+{
+ /* Never make backups. */
+ no_backups,
+
+ /* Make simple backups of every file. */
+ simple_backups,
+
+ /* Make numbered backups of files that already have numbered backups,
+ and simple backups of the others. */
+ numbered_existing_backups,
+
+ /* Make numbered backups of every file. */
+ numbered_backups
+};
+
+/* Two tables describing arguments (keys) and their corresponding
+ values */
+static const char *const backup_args[] =