Help: Document limitations of the OBJECT_DEPENDS source file property

Help/prop_sf/OBJECT_DEPENDS.rst

@@ -3,9 +3,12 @@ OBJECT_DEPENDS
 
 Additional files on which a compiled object file depends.
 
-Specifies a semicolon-separated list of full-paths to files on which
-any object files compiled from this source file depend.  An object
-file will be recompiled if any of the named files is newer than it.
+Specifies a :ref:`;-list <CMake Language Lists>` of full-paths to
+files on which any object files compiled from this source file depend.
+On :ref:`Makefile Generators` and the :generator:`Ninja` generator an
+object file will be recompiled if any of the named files is newer than it.
+:ref:`Visual Studio Generators` and the :generator:`Xcode` generator
+cannot implement such compilation dependencies.
 
 This property need not be used to specify the dependency of a source
 file on a generated header file that it includes.  Although the
@@ -14,5 +17,5 @@ necessary.  If the generated header file is created by a custom
 command in the same target as the source file, the automatic
 dependency scanning process will recognize the dependency.  If the
 generated header file is created by another target, an inter-target
-dependency should be created with the add_dependencies command (if one
-does not already exist due to linking relationships).
+dependency should be created with the :command:`add_dependencies`
+command (if one does not already exist due to linking relationships).