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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\macro Q_DECLARE_TYPEINFO(Type, Flags)
\relates <QTypeInfo>
You can use this macro to specify information about a custom type
\a Type. With accurate type information, Qt's \l{Container Classes}
{generic containers} can choose appropriate storage methods and
algorithms.
\a Flags can be one of the following:
\list
\li \c Q_PRIMITIVE_TYPE specifies that \a Type can be created by
zero-initializing its storage, requires no operation to be properly
destroyed, and for which memcpy()ing creates a valid independent
copy of the object.
\li \c Q_RELOCATABLE_TYPE specifies that \a Type has a constructor
and/or a destructor but can be moved in memory using \c
memcpy().
\li \c Q_MOVABLE_TYPE is the same as \c Q_RELOCATABLE_TYPE. Prefer to use
\c Q_RELOCATABLE_TYPE in new code. Note: despite the name, this
has nothing to do with move constructors or C++ move semantics.
\li \c Q_COMPLEX_TYPE (the default) specifies that \a Type has
constructors and/or a destructor and that it may not be moved
in memory.
\endlist
Example of a "primitive" type:
\snippet code/src_corelib_global_qglobal.cpp 38
An example of a non-POD "primitive" type is QUuid: Even though
QUuid has constructors (and therefore isn't POD), every bit
pattern still represents a valid object, and memcpy() can be used
to create a valid independent copy of a QUuid object.
Example of a relocatable type:
\snippet code/src_corelib_global_qglobal.cpp 39
Qt will try to detect the class of a type using
\l {https://en.cppreference.com/w/cpp/types/is_trivial} {std::is_trivial_v<T>}
to identify primitive
types and it will require both
\l {https://en.cppreference.com/w/cpp/types/is_trivially_copyable} {std::is_trivially_copyable_v<T>}
and
\l {https://en.cppreference.com/w/cpp/types/is_destructible} {std::is_trivially_destructible_v<T>}
to identify relocatable types.
Use this macro to tune the behavior.
For instance many types would be candidates for Q_RELOCATABLE_TYPE despite
not being trivially-copyable.
*/
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