How to enable C++11/C++0x support in Eclipse CDT?

Question

Eclipse 3.7.1 CDT 1.4.1 GCC 4.6.2

This is an example of a piece of C++11 code:

auto text = std::unique_ptr(new char[len]);

Answer 1

I can't yet comment so am writing my own answer:

It's related to __GXX_EXPERIMENTAL_CXX0X__ and it's valid for Eclipse Juno and CDT 8.x.

Some parts of this answer are already covered in other answers but I want it to be coherent.

To make it possible to build using stdc++11, one have to add specific flag for compiler. You can do that via project properties. To modify project properties RMB andProject properties or ALT + ENTER. Then C/C++ Build -> Settings -> Tool Settings -> GCC C++ Compiler -> Miscellaneous -> Other Flags. Put -std=c++11 at the end of line, for GCC it will look something like: -c -fmessage-length=0 -std=c++11. By adding -stdc++11 flag compiler (GCC) will declare __GXX_EXPERIMENTAL_CXX0X__ by itself.

At this point you can build project using all the goodness of C++11.

The problem is that Eclipse has it's own parser to check for errors - that's why you're still getting all the nasty errors in Eclipse editor, while at the same time you can build and run project without any. There is a way to solve this problem by explicitly declaring __GXX_EXPERIMENTAL_CXX0X__ flag for the project, one can do that (just like Carsten Greiner said): C/C++ General -> Paths and Symbols -> Symbols -> GNU C++. Click "Add..." and past __GXX_EXPERIMENTAL_CXX0X__ (ensure to append and prepend two underscores) into "Name" and leave "Value" blank. And now is the extra part I wanted to cover in comment to the first answer, go to: C/C++ General -> Preprocessor Include Path Macros etc. -> Providers, and Select CDT Managed Build Setting Entries then click APPLY and go back to Entries tab, under GNU C++ there should be now CDT Managed Build Setting Entries check if inside there is defined __GXX_EXPERIMENTAL_CXX0X__ if it is -> APPLY and rebuild index you should be fine at this point.

Answer 2

Instruction For Eclipse CDT 4.4 Luna and 4.5 Mars

First, before creating project, configure Eclipse syntax parser:

Window -> Preferences -> C/C++ -> Build -> Settings -> Discovery -> CDT GCC Build-in Compiler Settings

in the text box entitled Command to get compiler specs append -std=c++11

Now you can create project, configuration depends on what kind of project you created:

For project created as: File -> New -> Project -> C/C++ -> C++ Project

Right click on created project and open

Properties -> C/C++ Build -> Settings -> Tool Settings -> GCC C++ Compiler -> Dialect

Put -std=c++11 into text box entitled other dialect flags or select ISO C++11 from the Language standard drop down.

For CMake project

Generate eclipse project files (inside your project)

mkdir build
cd build
cmake -G"Eclipse CDT4 - Unix Makefiles" -D CMAKE_BUILD_TYPE=Debug ..

Then import generated directory to eclipse as standard eclipse project. Right click project and open

Properties -> C/C++ General -> Preprocessor Include Paths, Marcos etc. -> Providers

enable CDT GCC Build-in Compiler Settings and move it higher than Contributed PathEntry Containers (This is important)

Last Common Step

recompile, regenerate Project ->C/C++ Index and restart Eclipse.

Answer 3

Eclipse C/C++ does not recognize the symbol std::unique_ptr even though you have included the C++11 memory header in your file.

Assuming you are using the GNU C++ compiler, this is what I did to fix:

Project -> Properties -> C/C++ General -> Preprocessor Include Paths -> GNU C++ -> CDT User Setting Entries

1. Click on the "Add..." button

2. Select "Preprocessor Macro" from the dropdown menu

   Name: __cplusplus     Value:  201103L
   

3. Hit Apply, and then OK to go back to your project

4. Then rebuild you C++ index: Projects -> C/C++ Index -> Rebuild

Answer 4

For me on Eclipse Neon I followed Trismegistos answer here above , YET I also added an additional step:

• Go to project --> Properties --> C++ General --> Preprocessor Include paths,Macros etc. --> Providers --> CDT Cross GCC Built-in Compiler Settings, append the flag "-std=c++11"

Hit apply and OK.

Cheers,

Guy.

Answer 5

I don't know if it is only me, the highest ranked solution doesn't work for me, my eclipse version is just normal eclipse platform installed by using sudo apt-get install eclipse in Ubuntu But I found a solution which adopts method together from both the highest ranked solution and the second, what I did to make it work is described as below (Note that the other steps like creating a C++ project etc. is ignored for simplicity)

Once you have created the C++ project

(1) C/C++ General -> Paths and Symbols -> Symbols -> GNU C++. Click "Add..." and paste GXX_EXPERIMENTAL_CXX0X (ensure to append and prepend two underscores) into "Name" and leave "Value" blank.

(2) Under C/C++ Build (at project settings), find the Preprocessor Include Path and go to the Providers Tab. Deselect all except CDT GCC Builtin Compiler Settings. Then untag Share settings entries … . Add the option -std=c++11 to the text box called Command to get compiler specs

After performed above 2 and 2 only steps, it works, the eclipse is able to resolve the unique_ptr, I don't know why this solution works, hope that it can help people.