From 2897b231a6b71ee17d47d3d63f1112b2641a476c Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Mon, 4 Sep 2023 15:31:36 +0200
Subject: [PATCH] intl: Treat C.UTF-8 locale like C locale (BZ# 16621)

The wiki page https://sourceware.org/glibc/wiki/Proposals/C.UTF-8
says that "Setting LC_ALL=C.UTF-8 will ignore LANGUAGE just like it
does with LC_ALL=C." This patch implements it.

* intl/dcigettext.c (guess_category_value): Treat C.<encoding> locale
like the C locale.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
---
 intl/dcigettext.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/intl/dcigettext.c b/intl/dcigettext.c
index 7886ac9545e3..27063886d2e8 100644
--- a/intl/dcigettext.c
+++ b/intl/dcigettext.c
@@ -1560,8 +1560,12 @@ guess_category_value (int category, const char *categoryname)
      2. The precise output of some programs in the "C" locale is specified
 	by POSIX and should not depend on environment variables like
 	"LANGUAGE" or system-dependent information.  We allow such programs
-        to use gettext().  */
-  if (strcmp (locale, "C") == 0)
+        to use gettext().
+     Ignore LANGUAGE and its system-dependent analogon also if the locale is
+     set to "C.UTF-8" or, more generally, to "C.<encoding>", because that's
+     the by-design behaviour for glibc, see
+     <https://sourceware.org/glibc/wiki/Proposals/C.UTF-8>.  */
+  if (locale[0] == 'C' && (locale[1] == '\0' || locale[1] == '.'))
     return locale;
 
   /* The highest priority value is the value of the 'LANGUAGE' environment
-- 
2.42.0