Add a directory property to list subdirectories

Add a SUBDIRECTORIES directory property to allow project code to
traverse the directory structure of itself as CMake sees it.

1 files changed, 15 insertions, 0 deletions

diff --git a/Help/prop_dir/SUBDIRECTORIES.rst b/Help/prop_dir/SUBDIRECTORIES.rst
new file mode 100644
index 0000000..2c2ea77
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+++ b/Help/prop_dir/SUBDIRECTORIES.rst
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+SUBDIRECTORIES
+--------------
+
+This read-only directory property contains a
+:ref:`;-list <CMake Language Lists>` of subdirectories processed so far by
+the :command:`add_subdirectory` or :command:`subdirs` commands.  Each entry is
+the absolute path to the source directory (containing the ``CMakeLists.txt``
+file).  This is suitable to pass to the :command:`get_property` command
+``DIRECTORY`` option.
+
+.. note::
+
+  The :command:`subdirs` command does not process its arguments until
+  after the calling directory is fully processed.  Therefore looking
+  up this property in the current directory will not see them.