Help/dev: Adopt C++ subset rules in coding guide

Move the C++ subset rules from the `cmake-developer(7)` into our
dedicated coding guide since they do not need to be in user-facing
documentation.

1 files changed, 21 insertions, 0 deletions

diff --git a/Help/dev/source.rst b/Help/dev/source.rst
index f70e477..3ac9aca 100644
--- a/Help/dev/source.rst
+++ b/Help/dev/source.rst
@@ -19,3 +19,24 @@ 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 ``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.