Help: Document relation of properties to the rest of the buildsystem.

1 files changed, 18 insertions, 10 deletions

diff --git a/Help/prop_dir/INCLUDE_DIRECTORIES.rst b/Help/prop_dir/INCLUDE_DIRECTORIES.rst
index 6c5782f..baba49b 100644
--- a/Help/prop_dir/INCLUDE_DIRECTORIES.rst
+++ b/Help/prop_dir/INCLUDE_DIRECTORIES.rst
@@ -4,15 +4,23 @@ INCLUDE_DIRECTORIES
 List of preprocessor include file search directories.
 
 This property specifies the list of directories given so far to the
-include_directories command.  This property exists on directories and
-targets.  In addition to accepting values from the include_directories
-command, values may be set directly on any directory or any target
-using the set_property command.  A target gets its initial value for
-this property from the value of the directory property.  A directory
-gets its initial value from its parent directory if it has one.  Both
-directory and target property values are adjusted by calls to the
-include_directories command.
+:command:`include_directories` command.
+
+This property is used to populate the :prop_tgt:`INCLUDE_DIRECTORIES`
+target property, which is used by the generators to set the include
+directories for the compiler.
+
+In addition to accepting values from that command, values may be set
+directly on any directory using the :command:`set_property` command.  A
+directory gets its initial value from its parent directory if it has one.
+The intial value of the :prop_tgt:`INCLUDE_DIRECTORIES` target property
+comes from the value of this property.  Both directory and target property
+values are adjusted by calls to the :command:`include_directories` command.
 
 The target property values are used by the generators to set the
-include paths for the compiler.  See also the include_directories
-command.
+include paths for the compiler.
+
+Contents of ``INCLUDE_DIRECTORIES`` may use "generator expressions" with
+the syntax ``$<...>``.  See the :manual:`cmake-generator-expressions(7)`
+manual for available expressions.  See the :manual:`cmake-buildsystem(7)`
+manual for more on defining buildsystem properties.