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| author | Ivan Solovev <ivan.solovev@qt.io> | 2024-05-23 16:56:59 +0200 |
|---|---|---|
| committer | Ivan Solovev <ivan.solovev@qt.io> | 2024-06-07 08:14:59 +0200 |
| commit | b1ae4334ea11f6942c7ce37a80a3aa98a3447809 (patch) | |
| tree | ad80f74b708a258580cf0360ea4a030e5d87a175 /src/corelib/global/qcompare.cpp | |
| parent | d6e1df3513c7d5b6e93d68583fc4c1febb7bcd85 (diff) | |
Deprecate Qt::compareThreeWay() overload for pointers
compareThreeWay() was supposed to be an operator<=>(), but for C++17.
The idea was that at some point when we unconditionally demand C++20,
people could just replace all the usages of compareThreeWay() with
operator<=>().
However, the Qt::compareThreeWay() overload for pointers is different
from the operator<=>() for pointers, because it is actually using
std::less{} or std::compare_three_way{} to do the comparison, thus
avoiding an UB. This is not bad as such, but can potentially lead to
UB when mass-replacing all compareThreeWay() calls with operator<=>().
To avoid this problem, deprecate the overload, and suggest to use
the Qt::totally_ordered_wrapper together with the respective overload
instead.
Found in API Review.
[ChangeLog][QtCore][QtCompare] Deprecate Qt::compareThreeWay()
overload for pointers.
Pick-to: 6.8
Change-Id: I9c57871145dc3cb9656d6006db88b48a1553bef4
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Diffstat (limited to 'src/corelib/global/qcompare.cpp')
| -rw-r--r-- | src/corelib/global/qcompare.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/corelib/global/qcompare.cpp b/src/corelib/global/qcompare.cpp index d32f4ca251f..5a2ad0e2ee4 100644 --- a/src/corelib/global/qcompare.cpp +++ b/src/corelib/global/qcompare.cpp @@ -1274,9 +1274,12 @@ CHECK(strong, equivalent); \l Qt::partial_ordering::unordered is returned. */ +#if QT_DEPRECATED_SINCE(6, 8) /*! \fn template <typename LeftType, typename RightType, Qt::if_compatible_pointers<LeftType, RightType> = true> Qt::compareThreeWay(const LeftType *lhs, const RightType *rhs) \since 6.7 + \deprecated [6.8] Wrap the pointers into Qt::totally_ordered_wrapper and + use the respective Qt::compareThreeWay() overload instead. \relates <QtCompare> \overload @@ -1289,6 +1292,7 @@ CHECK(strong, equivalent); Returns an instance of \l Qt::strong_ordering that represents the relation between \a lhs and \a rhs. */ +#endif // QT_DEPRECATED_SINCE(6, 8) /*! \fn template <class Enum, Qt::if_enum<Enum> = true> Qt::compareThreeWay(Enum lhs, Enum rhs) |