llvm-project/clang-tools-extra/docs/AddOverrideTransform.rst

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.. index:: Add-Override Transform
======================
Add-Override Transform
======================
The Add-Override Transform adds the ``override`` specifier to member
functions that override a virtual function in a base class and that
don't already have the specifier. The transform is enabled with the
:option:`-add-override` option of :program:`cpp11-migrate`.
For example:
.. code-block:: c++
class A {
public:
virtual void h() const;
};
class B : public A {
public:
void h() const;
// The declaration of h is transformed to
void h() const override;
};
Using Expands-to-Override Macros
================================
Like LLVM's ``LLVM_OVERRIDE``, several projects have macros that conditionally
expand to the ``override`` keyword when compiling with C++11 features enabled.
To maintain compatibility with non-C++11 builds, the Add-Override Transform
supports detection and use of these macros instead of using the ``override``
keyword directly. Specify ``-override-macros`` on the command line to the
Migrator to enable this behavior.
Known Limitations
=================
* This transform will not insert the override keyword if a method is
pure. At the moment it's not possible to track down the pure
specifier location.
.. code-block:: c++
class B : public A {
public:
virtual void h() const = 0;
// The declaration of h is NOT transformed to
virtual void h() const override = 0;
};