Building Development GAP

Building Development GAP

For many years, the development process of GAP was not open to the general public. Now you can see (and contribute to!) the day-to-day development at GAP’s github page. This page will show you how to install GAP’s development version.

WARNING: While the development version of GAP is usually in a good state (I use it for most of my day-to-day work), it is occasionally broken and some packages may not work. Use at your own risk!

Over time this page will probably get out of date, or not work on some machines. If these instructions don’t work, please give me a buzz at I’m going to assume you are happy with working in a unix terminal and moving around directories.


Getting and building GAP needs a basic set of development tools. These are:

  • git: For downloading from github (there are GUIs available, but we will use the command line here).
  • make: A program used for building large (and small) software projects
  • gcc or clang: A compiler for the C language (some other compilers might work, but in particular Visual Studio on Windows will not)!
  • autoconf and automake: Special programs for setting up GAP’s build system (you don’t need these if you download a release of GAP).

Getting these is different on each operating system. Here is the most popular ones. On windows in particular, make sure you follow these instructions!

  • Mac OS X : The easiest method is to install Xcode from the App Store. After installing it, open a terminal and type clang. You might get prompted to accept some licenses, or install some extra packages.

    You also need autoconf and automake. The easiest way to get these is to install either homebrew or macports. I recommend homebrew. First go to the homebrew webpage and follow the instructions, then type brew install automake autoconf.

  • Linux : You will need to install gcc, make, git, automake and autoconf. First check if these programs are already on your system (they often are). If not, you will have to install them. You should look at your linux’s documentation, but the two most common methods are:

    • Ubuntu / Debian sudo apt-get install gcc make git automake autoconf
    • Redhat / CentOS sudo yum install gcc make git automake autoconf
  • Windows : GAP uses a tool called Cygwin, which provides a unix-like environment on windows. Grab the cygwin installer from the Cygin website, and while installing select the packages make, gcc, git, automake and autoconf.


Now pop along to gap’s github page. There are many git tutorials out there, but for now let’s skip all of that, and just grab the latest git version:

git clone

Now, we need to build GAP. Go into GAP’s source directory, configure and make GAP.

cd gap

While we have now built GAP, without any packages GAP isn’t very useful (without at least GAPDoc, GAP doesn’t even really work!)

You can get the bare minimal set of packages needed to make GAP work by running

make bootstrap-pkg-minimal

but you probably want all the packages, so type:

make bootstrap-pkg-full

Note that while this downloads all packages, many packages have to be built before they are useful. To build packages, go into the pkg directory and then run the script:

cd pkg

Almost certainly, some packages will fail to build, as they have extra dependancies. Don’t worry unless you want them all. Some packages are VERY hard to build!

Assuming everything went well, try running bin/, and you should have a working GAP. Well done!

Development Packages

One reason you might be reading this guide is to run development versions of packages. In each case, you need to follow some simple rules:

  • If you already have a copy of the package in pkg, then move it out (GAP will try to make sure it loads the most recent version of any package, but it is easier to only have one copy of each package).

  • git clone the development package into the pkg directory

  • Do any necessary building.

Let’s do this with an example – the profiling package!

# Assuming we are in the GAP directory
cd pkg
# Clean out old package
rm -rf profiling*
# Grab new copy
git clone
# Build package (this command will build most packages that need compiling)

You can check this worked by starting gap and typing LoadPackage("profiling");.