1 files changed, 53 insertions, 0 deletions
diff --git a/src/corelib/global/qvolatile_p.h b/src/corelib/global/qvolatile_p.h
new file mode 100644
index 0000000000..36787ecd87
--- /dev/null
+++ b/src/corelib/global/qvolatile_p.h
@@ -0,0 +1,53 @@
+// Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QVOLATILE_P_H
+#define QVOLATILE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of a number of Qt sources files.  This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/private/qglobal_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtPrivate {
+template <typename T>
+using if_volatile = std::enable_if_t<std::is_volatile_v<T>, bool>;
+
+//
+// C++20-deprecated volatile compound operations, rewritten as separated operations
+//
+
+// these functions return `auto`, not `T`, to strip cv-qualifiers without having
+// to mention the `volatile` keyword
+
+template <typename T, QtPrivate::if_volatile<T> = true>
+auto volatilePreIncrement(T &x) {
+    auto y = x;
+    ++y;
+    x = y;
+    return y;
+}
+
+template <typename T, QtPrivate::if_volatile<T> = true>
+auto volatilePreDecrement(T &x)
+{
+    auto y = x;
+    --y;
+    x = y;
+    return y;
+}
+} // namespace QtPrivate
+
+QT_END_NAMESPACE
+
+#endif // QVOLATILE_H