diff options
Diffstat (limited to 'src/qml/qml/qqmlprivate.h')
| -rw-r--r-- | src/qml/qml/qqmlprivate.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/src/qml/qml/qqmlprivate.h b/src/qml/qml/qqmlprivate.h index d6a9e73763..db0535c292 100644 --- a/src/qml/qml/qqmlprivate.h +++ b/src/qml/qml/qqmlprivate.h @@ -187,6 +187,23 @@ namespace QQmlPrivate = QQmlPrivate::createSingletonInstance<T>; }; + // from https://en.cppreference.com/w/cpp/language/static: + // If a const non-inline (since C++17) static data member or a constexpr + // static data member (since C++11)(until C++17) is odr-used, a definition + // at namespace scope is still required, but it cannot have an initializer. + // + // If a static data member is declared constexpr, it is implicitly inline + // and does not need to be redeclared at namespace scope. This redeclaration + // without an initializer (formerly required as shown above) is still + // permitted, but is deprecated. + // + // TL;DR: redundant definitions for static constexpr are required in c++11 + // but deprecated in c++17. + template<typename T> + constexpr CreateIntoFunction Constructors<T, true>::createInto; + template<typename T> + constexpr CreateSingletonFunction Constructors<T, true>::createSingletonInstance; + template<typename T> struct Constructors<T, false> { @@ -194,6 +211,12 @@ namespace QQmlPrivate static constexpr CreateSingletonFunction createSingletonInstance = nullptr; }; + // see comment above over the Constructors<T, true> definitions. + template<typename T> + constexpr CreateIntoFunction Constructors<T, false>::createInto; + template<typename T> + constexpr CreateSingletonFunction Constructors<T, false>::createSingletonInstance; + template<typename T, bool IsVoid = std::is_void<T>::value> struct ExtendedType; @@ -205,6 +228,12 @@ namespace QQmlPrivate static constexpr const QMetaObject *staticMetaObject = nullptr; }; + // see comment above over the Constructors<T, true> definitions. + template<typename T> + constexpr const CreateParentFunction ExtendedType<T, true>::createParent; + template<typename T> + constexpr const QMetaObject* ExtendedType<T, true>::staticMetaObject; + // If it's not void, we actually want an error if the ctor or the metaobject is missing. template<typename T> struct ExtendedType<T, false> @@ -213,6 +242,12 @@ namespace QQmlPrivate static constexpr const QMetaObject *staticMetaObject = &T::staticMetaObject; }; + // see comment above over the Constructors<T, true> definitions. + template<typename T> + constexpr const CreateParentFunction ExtendedType<T, false>::createParent; + template<typename T> + constexpr const QMetaObject* ExtendedType<T, false>::staticMetaObject; + template<class From, class To, int N> struct StaticCastSelectorClass { @@ -577,6 +612,10 @@ namespace QQmlPrivate static constexpr bool Value = false; }; + // see comment above over the Constructors<T, true> definitions. + template<typename T, class C> + constexpr bool QmlSingleton<T, C>::Value; + template<class T> struct QmlSingleton<T, QmlVoidT<typename T::QmlIsSingleton>> { |