Refactoring: Third-parties public headers are under cm3p prefix

Fixes: #20666

1 files changed, 15 insertions, 0 deletions

diff --git a/Help/dev/source.rst b/Help/dev/source.rst
index 65a6adf..0ccb8f4 100644
--- a/Help/dev/source.rst
+++ b/Help/dev/source.rst
@@ -163,6 +163,18 @@ It is allowed to pass raw pointers between objects to enable objects sharing.
 A raw pointer **must** not be deleted. Only the object(s) owning the smart
 pointer are allowed to delete dynamically allocated memory.
 
+Third Parties
+=============
+
+To build CMake, some third parties are needed. Under ``Utilities``
+directory, are versions of these third parties which can be used as an
+alternate to the ones provided by the system.
+
+To enable the selection of the third parties between the system and CMake ones,
+in CMake sources, third parties headers must be prefixed by ``cm3p/``
+(for example: ``<cm3p/json/reader.h>``). These wrappers are located under
+``Utilities/cm3p`` directory.
+
 Source Tree Layout
 ==================
 
@@ -208,6 +220,9 @@ The CMake source tree is organized as follows.
   * ``Utilities/std/cmext``:
     Extensions to the C++ STL.
 
+  * ``Utilities/cm3p``:
+    Public headers for third parties needed to build CMake.
+
   * ``Utilities/Sphinx/``:
     Sphinx configuration to build CMake user documentation.