From: Tomasz Kamiński <tkaminsk@redhat.com>
Date: Wed, 8 Oct 2025 13:14:04 +0000 (+0200)
Subject: libstdc++: Fix type in computation of _M_weekday_index.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=43f524c1c4f1aa79e3c443b45af9464a8b8943b1;p=thirdparty%2Fgcc.git

libstdc++: Fix type in computation of _M_weekday_index.

The value should use divide instead of modulo, as given 1st of month
being weekday X (Mon, Tue, ...), 01 is always X[1], 08 is X[2], e.t.c.

This values is currently not observable, as there is no user-accessible
format specifier that will print it, however it may be exposed in future.

libstdc++-v3/ChangeLog:

	* include/bits/chrono_io.h (_ChronoData::_M_fill_day): Replace
	'%' by '/'.
---

diff --git a/libstdc++-v3/include/bits/chrono_io.h b/libstdc++-v3/include/bits/chrono_io.h
index 79a44d128b1..690c10d79ce 100644
--- a/libstdc++-v3/include/bits/chrono_io.h
+++ b/libstdc++-v3/include/bits/chrono_io.h
@@ -463,7 +463,7 @@ namespace __format
       {
 	_M_day = __d;
 	__parts -= _ChronoParts::_Day;
-	_M_weekday_index = ((unsigned)__d + 6u) % 7u;
+	_M_weekday_index = ((unsigned)__d + 6u) / 7u;
 	__parts -= _ChronoParts::_WeekdayIndex;
 	return __parts;
       }