On Windows (x86_64-w64-mingw32), I see the following warning:
$ gnulib-tool --create-testdir --dir testdir1
$ cd testdir1
$ ./configure CFLAGS='-Wdiscarded-qualifiers'
$ cd glllib
$ make setlocale.o
depbase=`echo setlocale.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
gcc -DHAVE_CONFIG_H -DEXEEXT=\".exe\" -DEXEEXT=\".exe\" -DNO_XMALLOC
-DEXEEXT=\".exe\" -I. -I.. -DGNULIB_STRICT_CHECKING=1 -I/mingw64/include
-Wdiscarded-qualifiers -MT setlocale.o -MD -MP -MF $depbase.Tpo -c -o
setlocale.o setlocale.c &&\
mv -f $depbase.Tpo $depbase.Po
setlocale.c: In function 'setlocale_single':
setlocale.c:889:12: warning: return discards 'const' qualifier from pointer
target type [-Wdiscarded-qualifiers]
889 | return setlocale_messages (locale);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
The attached patch fixes it by casting away the const. Another
reasonable solution is changing the definition of setlocale_messages to
return a plain "char *". However, I think it would be a bit strange for
it to have a different prototype than setlocale_messages_null. I've left
it unpushed in case you prefer the other solution, Bruno.
Collin
>From 868ed28fde7b9d1b8176303b6aba205170dc4559 Mon Sep 17 00:00:00 2001
Message-ID: <868ed28fde7b9d1b8176303b6aba205170dc4559.1780797990.git.collin.fu...@gmail.com>
From: Collin Funk <[email protected]>
Date: Sat, 6 Jun 2026 19:05:41 -0700
Subject: [PATCH] setlocale: Silence a -Wdiscarded-qualifiers warning on
Windows.
* lib/setlocale.c (setlocale_single): Cast away the const from
setlocale_messages.
---
ChangeLog | 6 ++++++
lib/setlocale.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index e194208c19..d788795f59 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2026-06-06 Collin Funk <[email protected]>
+
+ setlocale: Silence a -Wdiscarded-qualifiers warning on Windows.
+ * lib/setlocale.c (setlocale_single): Cast away the const from
+ setlocale_messages.
+
2026-06-06 Bruno Haible <[email protected]>
mbrtowc: Fix handling of s==NULL on all possible platforms.
diff --git a/lib/setlocale.c b/lib/setlocale.c
index d40e1e2efd..adaefec8a1 100644
--- a/lib/setlocale.c
+++ b/lib/setlocale.c
@@ -886,7 +886,7 @@ static char *
setlocale_single (int category, const char *locale)
{
if (category == LC_MESSAGES)
- return setlocale_messages (locale);
+ return (char *) setlocale_messages (locale);
else
return setlocale_unixlike (category, locale);
}
--
2.54.0
