How to configure a C/C++ project with Eclipse and CMake

Changing the user name in Eclipse

Using CMake Eclipse CDT4

In-Source Builds

Out-Of-Source Builds

Version Control Integration in Eclipse

Accessing the Source and Advanced Editing Features

Discussion about limitations

Manual Method

Create an Eclipse Project

Create Eclipse Make Targets

Set Up the Eclipse CDT Builder

Build the Project

Source

I'm not an expert in CMake. Actually, I always programmed in Geany which is the most simple IDE and I run cmake . and make directly from the terminal or modifying a little bit the Geany configuration. Now, I'm starting to work with Eclipse (since is one of the most used environments for many many different programming languages). It was not easy to create a project which works with CMake (I want my programs to be as cross-platform as possible, so this was a requirement). The main reference site for this is the CMake WikiSite.

I will explain here two types: the recommended method and the manual method.

Changing the user name in Eclipse

I know this is not the correct place for this one, but it is just a small trick. The variable ${user} in Eclipse takes the OS name, and this one is probably not the best for our templates. Just go to eclipse.ini (in the root folder of Eclipse) and add the following line:

-Duser.name=<Insert name>

A brief example of my eclipse.ini (the necessary part, the .ini is larger):

__openFile__
-vmargs
-Dosgi.requiredJavaVersion=1.6
-XX:MaxPermSize=256m
-Xms40m
-Xmx384m
-Duser.name=Javier V. Gómez

Using CMake Eclipse CDT4

Starting with version 2.6.0 CMake includes a generator for Eclipse CDT 4.0 or newer. It works together with the Makefile generators (i.e. "Unix Makefiles", "MinGW Makefiles", "MSYS Makefiles", and maybe "NMake Makefiles"). This generator creates a set of .project/.cproject files that can be imported in Eclipse as an "Existing Eclipse project".

Note that CMake 2.4.x users may follow instructions provided here in order to setup an Eclipse+CMake usage manually.

Using the Eclipse CDT4 generator isn't different than using any other CMake generator. It works for in-source and out-of-source builds. In this example, we'll assume that the source tree of the project is /home/eric/certi_src.

Be sure to have a proper CMakeLists.txt file in the src directory. For instance, if you get an error such as Undefined Reference when you import into Eclipse, make sure you have the TARGET_LINK_LIBRARIES set correctly.

TARGET_LINK_LIBRARIES(AwesomeProjectMain ITKCommon ITKIO ITKBasicFilters)

On Linux, these libraries may exist in the bin subdirectory under the ITK Root Directory with a .a extension.

Create a build directory, go there and run CMake (see below for commandline). Make sure you set your CMAKE_BUILD_TYPE to Debug if you want to debug your project with gdb inside of Eclipse CDT. This is not done automatically (especially when using cmake-gui)

mkdir /home/eric/certi_build
cd /home/eric/certi_build
cmake -G"Eclipse CDT4 - Unix Makefiles" -D CMAKE_BUILD_TYPE=Debug ../certi_src

Important Note: Your project name should be different from your executable name and different from your build folder name. Otherwise, Eclipse will NOT pick up your executable as you build them.

Since my build folder name is certi_build, a CMakeLists.txt file like below should work (notice the difference in project name and executable name)

PROJECT(AwesomeProject)
ADD_EXECUTABLE(AwesomeProjectMain
  main.cpp
  util.h
  util.cpp
)

You will now find two Eclipse files in your build tree:

certi_build/.project
certi_build/.cproject

Import the created project file into Eclipse - Import project using Menu File->Import. - Select General->Existing projects into workspace. - Browse where your build tree is and select the root build tree directory. Keep "Copy projects into workspace" unchecked. - You get a fully functional eclipse project.

You can edit your CMakeLists.txt file inside of Eclipse CDT, a plugin called CMakeEd can help you with this task. When you edit your CMakeLists.txt file, you are recommended to delete your project and reimport it.

In-Source Builds

In-Source builds are fully supported by the Eclipse project generator.

Out-Of-Source Builds

Eclipse has two issues with out-of-source builds, the project generator tries to work around them as best as it can. The details are described below.

Version Control Integration in Eclipse

Eclipse supports version control systems, e.g. cvs and svn, but for them to work, the project files must be at the root of the source tree. This is not the case with out-of-source builds. The only way to get version control for your project in Eclipse is to have a separate project in the source tree for this purpose. You can either create this project manually or tell CMake to create it for you when creating your project files:

cmake -G"Eclipse CDT4 - Unix Makefiles" -DECLIPSE_CDT4_GENERATE_SOURCE_PROJECT=TRUE ../certi_src

This will create your normal project in the build tree and additionally an extra project in the source tree, we call it the source-project. In Eclipse you can then import this source-project the same way as you import the normal project. This way you'll have two (or more) projects, one for browsing the sources and doing version control, the other for building your project.

Accessing the Source and Advanced Editing Features

Eclipse has advanced support for editing C/C++ sources, including code navigation, autocompletion etc. For that to work the sources must be inside the project (the additional source-project from above is not inside the project). The Eclipse project generator therefore creates a linked resource to the source tree in the Eclipse project. This makes the C/C++ features work.

This linked resource isn't created if the build directory is a subdirectory of the source directory because Eclipse doesn't allow to load projects which have linked resources pointing to a parent directory. So we recommend to create your build directories not as children, but as siblings to the source directory. E.g.:

/path/to/source
/path/to/build

Discussion about limitations

If you would like to monitor the changes to the EclipseCDT4 support, you can view the following links which contain the git history log for changes to the two main files: - http://cmake.org/gitweb?p=cmake.git;a=blob;f=Source/cmExtraEclipseCDT4Generator.h;hb=HEADcmExtraEclipseCDT4Generator.h - http://cmake.org/gitweb?p=cmake.git;a=blob;f=Source/cmExtraEclipseCDT4Generator.cxx;hb=HEADcmExtraEclipseCDT4Generator.cxx

Eclipse assumes project files (i.e. .project and .cproject) must be at the root of the project tree and a project may be handled by a versioning system (CVS, SVN, ...) if the root project tree is.

This assumption clashes with the fact that CMake generated files should stay in the build tree whereas source files (which are usually those handled by a versioning system) reside in the source tree.

There has been a fair amount of discussion regarding this problem of the Eclipse CDT4 Generator:

Manual Method

Create an Eclipse Project

Create an Eclipse CDT (C/C++ Development Tooling) project using the File > New > C++ Project command for your C++ project, or File > New > C Project for a C project.

Do not create the project using the CMake Eclipse project generator.

Create Eclipse Make Targets

The conventional approach to using CMake with Eclipse is to create an external tool in Eclipse. However, a Make Target is simpler, and because it is stored in the Eclipse .project file, you can check it into your version control system and it will work in every one of your working copies, on every computer.

Create a Make Target for each configuration that you want to build. Here I assume that you have the usual Release and Debug configurations:

Display the Make Target window using the Window > Show View > Make Target menu command. It should appear on the right, with the Outline window.
Select the folder for the project for which you want to add CMake. CMake will run with this folder as its working directory.
Right click on the folder and select New from the context menu. The Create Make Target dialog will appear.
- Type Target name CMake Release
- In Make target, deselect Same as the target name, and make sure that the Make target field is empty
- In Build Command, deselect Use builder settings and set the Build command to cmake -E chdir Release/ cmake -G "Unix Makefiles" ../ -DCMAKE_BUILD_TYPE:STRING=Release
- Click OK
Repeat, this time for Target name CMake Debug, and Build command, cmake -E chdir Debug/ cmake -G "Unix Makefiles" ../ -DCMAKE_BUILD_TYPE:STRING=Debug
Create the Release/ and Debug/ directories mkdir Release Debug

Set Up the Eclipse CDT Builder

Next, set up the CDT builder to run the Makefiles that CMake builds.

Right click on a CDT project. In the context menu, select Properties.
- On the left, select C/C++ Build
- Set Configuration to Release
- Choose the Builder Settings tab
- Deselect Use default build command
- Specify the Build command: make -C ${ConfigName}
Deselect Generate Makefiles automatically
Make the Build directory field blank
Choose the Behavior tab
- Select Build (Incremental build) and specify the target name all
- Select Clean and specify the target name clean
Set Configuration to Debug
- Choose the Builder Settings tab
  - Set all values exactly the same as the Release configuration
- Choose the Behavior tab
  - Set all values exactly the same as the Release configuration
- Click OK

Build the Project

Use CMake to generate an out-of-source GNU Make build system:

In the Make Targets window, double click on CMake Release or CMake Debug to generate the GNU Make build system in Release/ or Debug/, respectively
If necessary, edit your CMakeLists.txt control files
Delete the contents of the corresponding build directory. For example: rm -r Release/* and repeat.

Actually, for minor edits to your CMakeLists.txt control files, you need not delete the build directory. However, I cannot tell you exactly what the threshold for minor edits is.

Now, build the project the usual way with Eclipse:

Select the configuration to build (Release of Debug) with the Project > Build Configurations > Set Active command
Build with the Project > Build Project command
Edit your source code files, and repeat

Source

This information was directly taken from CMake.org and Voom.net. Thank you for sharing with open-source license! This page pretends to be as a connection point for the author of this wiki (I'm just trying to avoid googling about it everytime I need this info :) )

Categories
news