Getting Started: Emacs & C++ (w/ cmake) (On the fly syntax highlighting)

I am a recent convert to emacs. My vast majority of development is in Java EE and I have not found an easy way to get the functionality in eclipse into emacs. So I still use eclipse for this.

However, I like to tinker with C++ and I wanted to get some of the CDT functionality into emacs. In truth, I have used very little CDT so my expectations from emacs will be set differently. Considering that emacs has been used for C/C++ development for decades, I am hopeful that it will be more feature-rich than eclipse or any of the other IDE’s like Anjuta, Code::Blocks etc (both I have tried to use).

First things first. In the world of Java, I am a massive fan of maven which makes build management so easy and simple. Having used it now for years, it is easy to forget how much of a learning curve it had to get started.

Autotools are a massive pain to use and has a very steep learning curve. I have used it in the past to set up build environments and it works fine. pkg-config is pretty awesome and in a lot of ways, maven does pale in comparison. i.e. instead of having maven pull in dependencies, you just use your systems package manager like apt-get or yum and it installs the libraries for you.

Long story short, I am using cmake which has the added advantage of being a little more cross-platform (i.e. supported in Windows as well as *nix). If you haven’t used CMake before, let me tell you – it’s a heck of a lot easier to get used to than Autotools. Just go through their tutorial and you should be off.

The next thing I wanted to sort out was on the fly syntax checking. This makes life a lot easier and means that you can write and correct syntax errors etc without having to build manually.

Flymake is what you want to use for this. The later versions of emacs comes with Flymake so you won’t necessary need to install it to get started. However, flymake doesn’t (unfortunately) just work magically out of the box and requires a little configuration.

After hunting around for a bit, and finally from the EmacsWiki Flymake page, found a couple of options cpputils-make and cmake-project. Cmake-project seemed simpler and I opted for that. I also tried installing cpputils-make and didn’t have any issues with that either.

There is one thing you need to be aware of though – both these tools expect you to do out-of-source-builds. This essentially requires you to create a build folder (called bin for cmake-project and build for cpputils-make) and generate the Makefile etc. in there.

This is the preferred way with CMake anyway so it’ll be better to do build in that way. It’ll also  make it easier to have different builds (Debug/Release etc.)

The easiest way to install either of these is through marmalade. If you don’t already have it installed – it is so easy – just follow the instructions on their homepage. You can then install by running

M-x package-install cmake-project


M-x package-install cpputils-cmake

add the following to your .emacs file for cmake project. Instructions for cpputils-make can be found on their github page

(require ‘cmake-project)

Do a full build on your sources first by going to the bin or build directory and generating the makefiles by using cmake (cmake .. or cmake ../src depending on how you set up cmake) and then make.

You can then initialise the mode within emacs

M-x cmake-project-mode    (for cmake

You may have to also enable flymake

M-x flymake-mode

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