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CMake Modules for building OMNeT++ projects and integrating with you CMake supporting editor.

These CMake modules were originally developed against OMNeT+ 5.X, but should also work with OMNeT++ 6.0 and beyond.

We are currently building our 📝 documentation website at https://omnetpp.github.io/cmake. Though this documentation is still work-in-progress, you may already have a look at it!

The following is one of many other ways to do it.

1. Add the repository as a git submodule to your repository in cmake.¹

   git submodule add https://github.com/omnetpp/cmake.git cmake

   ⚠ Note: If you have other CMake modules it is recommended that you replace cmake with cmake/omnet and so forth here and in the following steps.

2. Update and/or initialise the submodule.¹

   git submodule update --init --recursive

3. Create a minimal CMakeLists.txt in the root repository folder.

   project(YourProject)
   
   # It is recommended to increase the minimum version to your current
   cmake_minimum_required(VERSION 3.1)
   
   # Change "cmake" if you put the submodule in a different directory
   set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
   
   find_package(OmnetPP 6.0 REQUIRED)
   
   # Load the CMake commands for OMNeT++
   include(OmnetppHelpers)

4. Update your CMakeLists.txt with your OMNeT++ project details

   # Uncomment the following if you have external dependencies like INET
   #find_path(INET_DIR NAMES src/inet/package.ned DOC "INET root directory")
   #import_opp_target(inet ${INET_DIR}/src/Makefile)
   
   # Define your library/simulation sources
   set(SOURCES
       src/a.cc
       src/b.cc)
   
   add_library(project_library SHARED ${SOURCES})
   
   # Define your messages as well
   set(MESSAGE_SOURCES
       messages/a.msg
       messages/b.msg)
   
   generate_opp_message(project_library
       MESSAGE_FILES ${MESSAGE_SOURCES})
   
   # You will need to tweak and add the additional properties for your project
   set_target_properties(project_library PROPERTIES
       OUTPUT_NAME my_project_sim
       NED_FOLDERS src)
   
   # Link the libraries you need for your project; add "inet" if necessary
   target_link_libraries(project_library opp_interface)
   
   # This creates an OMNet++ CMake run for you
   add_opp_run(project_name 
       CONFIG omnetpp.ini 
       DEPENDENCY project_library)

• generate_opp_message(<target> MESSAGE_FILES <file1> ...)
  Generates and links a message file to a given target.

• import_opp_target(<opp_makemake_target> <Makefile> [ <cmake_target_file> ])
  Imports a target from a Makefile created by opp_makemake.
  ⚠ Note: The target must have the same name as in the Makefile!

• add_opp_build_target(<name>)
  Adds a build target with a given name.

• add_opp_run(<name> [ CONFIG <file> | WORKING_DIRECTORY <dir> | NED_FOLDERS <dir1> ... ] DEPENDENCY <target> )
  Adds a build target with a given name based on the given dependency.

• add_opp_test(<name> [CONFIG <file> | RUN <entry> | SIMTIME_LIMIT <limit> | SUFFIX <name>]) Adds a test target with a given name.

OmnetPP::header is a bare interface target with at least the compile definitions and include directories set for the found OMNeT++ setup. Additionally, the following OMNeT++ libraries are provided as imported library targets:

• OmnetPP::cmdenv
• OmnetPP::common
• OmnetPP::envir
• OmnetPP::eventlog
• OmnetPP::layout
• OmnetPP::main
• OmnetPP::nedxml
• OmnetPP::qtenv
• OmnetPP::qtenv-osg
• OmnetPP::scave
• OmnetPP::sim
• OmnetPP::tkenv

For the full motivation and background please see Raphael Riebl's presentation at the 2015 OMNeT++ Summit.

Some benefits include:

• CMake is widely used for C/C++ projects
• Convenient user interfaces available for configuring builds
• Solid dependency handling, both internal and external
• More accessible syntax compared to Makefiles
• Several IDEs support the CMake build system
• Support OMNeT++ 6.0 preview releases (by @thor)

There have been some changes which might require fixes or future improvements. These are primarily changes to make the proof-of-concept employed in Artery also work with OMNet++ 6.0. However, there are also some minor oddities and questions, uncertainties and the likes of which.

• opp_cmake.py will not take a lot of automatic definitions into account when importing a project
• clean_opp_messages() is unavailable as message files are no longer gathered in a single folder for buliding
• include path needs to be adjusted manually if #include "generated_m.h" is used
• add_opp_run doesn't seem to utilise the parameter NED_FOLDERS

The CMake modules were based on those in the OMNet++ V2X simulation framework in riebl/artery, which is licensed as GPL-2.0.

• Source repository riebl/artery
• Presentation at 2015 OMNet++ Summit

1: You could also just download the files and put them where you'd like, or if you want to contribute, fork it and add that repository as a submodule! ↩

2: You may exchange the paths as you wish, but make sure to update them later on too. ↩