aliBuild prerequisites for macOS

ALICE software on macOS is supported on a best effort basis. Even though we systematically check macOS builds there is no guarantee that software builds or runs correctly. Support requests might have low priority. We were able to successfully build on:

• Catalina (10.15)
• Big Sur (11.0)

With very short update cycles of macOS, refrain from updating until we list the latest version of macOS as verified.

On 25/10/2021 Apple released macOS Monterey (12.0) which as of now is unable to compile ALICE software or its dependencies. It is therefore strongly advised to not upgrade until further notice.

In November 2020, Apple started a transition to theier own ARM based processor archtecture called "Apple Silicon" on the Mac. These differ significantly from the current Macs based on Intel X86 processors. In the forseeable future, these ARM based Macs will not be able to run ALICE code as software packages we depend on are not yet available for this platform. However with a big Mac community at ALICE we expect support to come once this is possible.

Get Xcode

Xcode bundles the necessary tools to build software in the apple ecosystem including compilers, build systems and version control

• Download it from the App Store
• Open once installed. It will ask to install additional components - approve the action.
• Open a terminal (Applicaions>Utilities>Terminal) and install the command line tools using:

  sudo xcode-select --install
  

• approve the license conditions by

  sudo xcodebuild -license
  

Get Homebrew

Homebrew is a command-line package manager for macOS used to install software packages similar to yum on CentOS or apt on Ubuntu. There are several different package managers for macOS, but Homebrew is by far the most poppular , and the only one we support.

• Install Homebrew using the instructions on their webpage.
• Once installed detect any problems regarding Homebrew and your system using

  brew doctor
  

Install the required packages

Note that Homebrew does not run as root. Do not prepend sudo to any of the following commands.

• Install the prerequisites and aliBuild via:

  brew install alisw/system-deps/o2-full-deps alisw/system-deps/alibuild
  

  Various users have reported that this might terminate with an error. The solution oddly enough seems to be to execute the above command multiple times until brew does not complain anymore.

• If you have just upgraded your Xcode or macOS, you should run brew reinstall instead, in order to force the reinstallation of already installed packages. You also might want to run brew cleanup at the end to free up some space.

• Edit or create ~/.zprofile and add

  export PATH="/usr/local/opt/gettext/bin:/usr/local/bin:$PATH"
  

• Close Terminal and reopen it to apply changes.

(Recommended) Exclude your work directory from Spotlight

The mac search engine (Spotlight) will be indexing the build directory which can have severe effects on your system performance. To avoid that, you can exclude your working directory (we are assuming ~/alice - create if not yet existing). Go to (Apple) menu>System preferences>Spotlight. In the Privacy tab, hit the + button. Now select the ~/alice directory and confirm.

You are now ready for installing aliBuild and start building ALICE software