From 339d339e9dfbffd6f5fd1f7c03281f1f34704a8c Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Mon, 16 Sep 2024 13:54:14 +0200
Subject: [PATCH] corelib/time: fix (easy) -Wunused-const-variable warnings in
 _p.h's

Make the constexpr variables inline to silence Clang.

There's another batch of such warnings for the _data_p.h files, and
they are actually pointing to a real problem: If two TUs include these
headers, the static constexpr tables actually get duplicated. Created
QTBUG-128930 to track the issue.

Amends 6d97cf0e573f11ae1fae11441e6fa747c34be21c and
fa9244700e016403b162932211023c65f4bb0d6b.

Pick-to: 6.7 6.5
Task-number: QTBUG-126219
Change-Id: Idb0cd55e424a870be6127fdf8399d01e9f3e9ac8
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 5064cb6feff6178cf3c307790ba028514c3d3040)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/time/qcalendarmath_p.h |  6 +++---
 src/corelib/time/qdatetime_p.h     | 11 +++++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/corelib/time/qcalendarmath_p.h b/src/corelib/time/qcalendarmath_p.h
index c785803ce3d..03153b0eed1 100644
--- a/src/corelib/time/qcalendarmath_p.h
+++ b/src/corelib/time/qcalendarmath_p.h
@@ -108,10 +108,10 @@ template <unsigned b, typename Int> constexpr Int qMod(Int a) { return qDivMod<b
 
 namespace QRomanCalendrical {
 // Julian Day number of Gregorian 1 BCE, February 29th:
-constexpr qint64 LeapDayGregorian1Bce = 1721119;
+inline constexpr qint64 LeapDayGregorian1Bce = 1721119;
 // Aside from (maybe) some turns of centuries, one year in four is leap:
-constexpr unsigned FourYears = 4 * 365 + 1;
-constexpr unsigned FiveMonths = 31 + 30 + 31 + 30 + 31; // Mar-Jul or Aug-Dec.
+inline constexpr unsigned FourYears = 4 * 365 + 1;
+inline constexpr unsigned FiveMonths = 31 + 30 + 31 + 30 + 31; // Mar-Jul or Aug-Dec.
 
 constexpr auto yearMonthToYearDays(int year, int month)
 {
diff --git a/src/corelib/time/qdatetime_p.h b/src/corelib/time/qdatetime_p.h
index 02b047dd737..a1aa7fd76a4 100644
--- a/src/corelib/time/qdatetime_p.h
+++ b/src/corelib/time/qdatetime_p.h
@@ -129,20 +129,31 @@ Q_DECLARE_OPERATORS_FOR_FLAGS(QDateTimePrivate::TransitionOptions)
 namespace QtPrivate {
 namespace DateTimeConstants {
 using namespace std::chrono;
+inline
 constexpr qint64 SECS_PER_MIN = minutes::period::num;
+inline
 constexpr qint64 SECS_PER_HOUR = hours::period::num;
+inline
 constexpr qint64 SECS_PER_DAY = SECS_PER_HOUR * 24; // std::chrono::days is C++20
 
+inline
 constexpr qint64 MINS_PER_HOUR = std::ratio_divide<hours::period, minutes::period>::num;
 
+inline
 constexpr qint64 MSECS_PER_SEC = milliseconds::period::den;
+inline
 constexpr qint64 MSECS_PER_MIN = SECS_PER_MIN * MSECS_PER_SEC;
+inline
 constexpr qint64 MSECS_PER_HOUR = SECS_PER_HOUR * MSECS_PER_SEC;
+inline
 constexpr qint64 MSECS_PER_DAY = SECS_PER_DAY * MSECS_PER_SEC;
 
+inline
 constexpr qint64 JULIAN_DAY_FOR_EPOCH = 2440588; // result of QDate(1970, 1, 1).toJulianDay()
 
+inline
 constexpr qint64 JulianDayMax = Q_INT64_C( 784354017364);
+inline
 constexpr qint64 JulianDayMin = Q_INT64_C(-784350574879);
 }
 }