qt 6.5.1 original

src/corelib/global/qcompare_impl.h

@@ -0,0 +1,33 @@
+// Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#if 0
+#pragma qt_sync_skip_header_check
+#pragma qt_sync_stop_processing
+#endif
+
+#ifndef QCOMPARE_IMPL_H
+#define QCOMPARE_IMPL_H
+
+#include <QtCore/qglobal.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QtPrivate {
+
+// [cmp.categories.pre] / 3, but using a safe bool trick
+// and also rejecting std::nullptr_t (unlike the example)
+class CompareAgainstLiteralZero {
+public:
+    using SafeZero = void (CompareAgainstLiteralZero::*)();
+    Q_IMPLICIT constexpr CompareAgainstLiteralZero(SafeZero) noexcept {}
+
+    template <typename T, std::enable_if_t<!std::is_same_v<T, int>, bool> = false>
+    CompareAgainstLiteralZero(T) = delete;
+};
+
+} // namespace QtPrivate
+
+QT_END_NAMESPACE
+
+#endif // QCOMPARE_IMPL_H