Dependency: Add detail about defining deps in package.xml, CMakeLists…

….txt

source/Tutorials/Intermediate/Dependency/Rosdep.rst

@@ -97,6 +97,8 @@ They specify in what situation each of the dependencies are required in.
 
 These dependencies are manually populated in the ``package.xml`` file by the package's creators and should be an exhaustive list of any non-builtin libraries and packages it requires.
 
+You can find more in detail about the `types of dependencies and how to define them in package.xml and CMakeLists.txt Catkin's document <./define_dependencies.rst>`_.
+
 How does rosdep work?
 ---------------------
 

source/Tutorials/Intermediate/Dependency/define_dependencies.rst

@@ -0,0 +1,61 @@
+Defining dependencies in your ament package
+===========================================
+
+**Goal:** Understand the types of dependencies supported by ``ament`` package.
+
+**Tutorial level:** Intermediate
+
+**Time:** 5 minutes
+
+.. contents:: Contents
+   :depth: 2
+   :local:
+
+ament package dependencies
+--------------------------
+
+When your package depends on C++ packages, source or binary, there are usually several kinds of dependencies which must be declared in your ``package.xml`` and ``CMakeLists.txt`` files. This document describes about package.xml. For CMakeLists.txt, see `ament_cmake documentation <../../../How-To-Guides/Ament-CMake-Documentation.rst>`_.
+
+package.xml
+-----------
+
+Your package dependencies must be declared in ``package.xml``. If they are missing or incorrect, you may still be able to build from source and run tests in your own workspace, but ``ament/ROS`` toolsuite, e.g. ``colcon``, `rosdep <Rosdep.rst>`_, may not function. Also `release into public registry <../../../How-To-Guides/Releasing/>`_ would not be an option. Others rely on this information to install the software they need for using your package.
+
+``<depend>``
+''''''''''''
+
+It is generally sufficient to mention each ROS package dependency once, like this::
+
+  <depend>rclcpp</depend>
+
+Sometimes, you may need or want more granularity for certain dependencies. The following sections explain how to do that.  If in doubt, use the ``<depend>`` tag, it's simpler.
+
+``<build_depend>``
+''''''''''''''''''
+
+If you only use some particular dependency for building your package, and not at execution time, you can use the ``<build_depend>`` tag.
+For example, the ROS ``angles`` package only provides C++ headers and CMake configuration files::
+
+  <build_depend>angles</build_depend>
+
+With this type of dependency, an installed binary of your package does not require the angles package to be installed.
+
+**But**, that could create a problem if your package exports a header that includes the ``<angles/angles.h>`` header.  In that case you also need a ``<build_export_depend>``.
+
+``<build_export_depend>``
+'''''''''''''''''''''''''
+
+If you export a header that includes ``<angles/angles.h>``, it will be needed by other packages that ``<build_depend>`` on yours::
+
+  <build_export_depend>angles</build_export_depend>
+
+This mainly applies to headers and CMake configuration files.  Library packages referenced by libraries you export should normally specify ``<depend>``, because they are also needed at execution time.
+
+``<exec_depend>``
+'''''''''''''''''
+
+This tag declares dependencies for shared libraries, executables, Python modules, launch scripts and other files required when running your package.  For example, the ROS ``launch_xml`` package provides
+launch scripts, which are only needed at execution time::
+
+  <exec_depend>launch_xml</exec_depend>
+