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+CMake Source Code Guide
+***********************
+
+The following is a guide to the CMake source code for developers.
+See documentation on `CMake Development`_ for more information.
+
+.. _`CMake Development`: README.rst
+
+C++ Code Style
+==============
+
+We use `clang-format`_ version **3.8** to define our style for C++ code in
+the CMake source tree. See the `.clang-format`_ configuration file for our
+style settings. Use the `Utilities/Scripts/clang-format.bash`_ script to
+format source code. It automatically runs ``clang-format`` on the set of
+source files for which we enforce style. The script also has options to
+format only a subset of files, such as those that are locally modified.
+
+.. _`clang-format`: http://clang.llvm.org/docs/ClangFormat.html
+.. _`.clang-format`: ../../.clang-format
+.. _`Utilities/Scripts/clang-format.bash`: ../../Utilities/Scripts/clang-format.bash
+
+C++ Subset Permitted
+====================
+
+CMake supports compiling as C++98 in addition to C++11 and C++14.
+In order to support building on older toolchains some constructs
+need to be handled with care:
+
+* Use ``CM_AUTO_PTR`` instead of ``std::auto_ptr``.
+
+ The ``std::auto_ptr`` template is deprecated in C++11. We want to use it
+ so we can build on C++98 compilers but we do not want to turn off compiler
+ warnings about deprecated interfaces in general. Use the ``CM_AUTO_PTR``
+ macro instead.
+
+* Use ``CM_EQ_DELETE;`` instead of ``= delete;``.
+
+ Defining functions as *deleted* is not supported in C++98. Using
+ ``CM_EQ_DELETE`` will delete the functions if the compiler supports it and
+ give them no implementation otherwise. Calling such a function will lead
+ to compiler errors if the compiler supports *deleted* functions and linker
+ errors otherwise.
+
+* Use ``CM_DISABLE_COPY(Class)`` to mark classes as non-copyable.
+
+ The ``CM_DISABLE_COPY`` macro should be used in the private section of a
+ class to make sure that attempts to copy or assign an instance of the class
+ lead to compiler errors even if the compiler does not support *deleted*
+ functions. As a guideline, all polymorphic classes should be made
+ non-copyable in order to avoid slicing. Classes that are composed of or
+ derived from non-copyable classes must also be made non-copyable explicitly
+ with ``CM_DISABLE_COPY``.
+
+* Use ``size_t`` instead of ``std::size_t``.
+
+ Various implementations have differing implementation of ``size_t``.
+ When assigning the result of ``.size()`` on a container for example,
+ the result should be assigned to ``size_t`` not to ``std::size_t``,
+ ``unsigned int`` or similar types.