C++ catkin library dependencies

Catkin libraries are provided by ROS packages whether you install them from Ubuntu packages or build from source.

When your package depends on a catkin C++ library, there are usually several kinds of dependencies which must be declared in your package.xml and CMakeLists.txt files.


Your package dependencies are declared in package.xml. If they are missing or incorrect, you may be able to build from source and run tests in your own workspace, but your package will not work correctly when released to the ROS community. Others rely on this information to install the software they need for using your package.


It is generally sufficient to mention each ROS package dependency once, like this:


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.


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:


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>.


If you export a header that includes <angles/angles.h>, it will be needed by other packages that <build_depend> on yours:


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.


This tag declares dependencies for shared libraries, executables, Python modules, launch scripts and other files required when running your package. For example, the ROS openni_launch package provides launch scripts, which are only needed at execution time:



CMake does not know about package.xml dependencies, although catkin does. For your code to compile, the CMakeLists.txt must explicitly declare how to resolve all of your header and library references.

Finding the library

First, CMake needs to find the library. For catkin dependencies, this is easy:

find_package(catkin REQUIRED COMPONENTS roscpp)

This find_package() call defines CMake variables that will be needed later for the compile and linkedit steps. List all additional catkin dependencies in the same command:

find_package(catkin REQUIRED COMPONENTS angles roscpp std_msgs)

Make sure all these packages are also mentioned in your package.xml using a <depend> or <build_depend> tag.

Include directories

Before compiling, collect all the header paths you found earlier:

include_directories(include ${catkin_INCLUDE_DIRS})

The include parameter is needed only if that subdirectory of your package contains headers used to compile your programs.

Exporting interfaces

You must declare the library and header packages needed by all the interfaces you export to other ROS packages:

catkin_package(CATKIN_DEPENDS angles roscpp std_msgs)

Make sure all these packages are also mentioned in your package.xml using a <depend> or <build_export_depend> tag.

The catkin_package() command is only called once. It may need additional parameters, depending on what else your package exports.

Next steps

If your package also depends on non-catkin libraries provided by the operating system, you must provide C++ system library dependencies, too.

Then, you are ready for Building and installing C++ libraries and headers and Building and installing C++ executables.