CMake

Cmake is a build system for C++ projects. It is an alternative to autotools.

Installing

Downloading

You can either visit http://www.cmake.org and download the binary, or you can use wget:

$ wget http://www.cmake.org/files/v2.8/cmake-X.Y.Z.tar.gz

and untar it using tar:

$ tar xvzf cmake-X.Y.Z.tar.gz

Configuring

Cmake is straightforward to install. It is intended to replace autotools, but it still uses autotools to build it - but a little differently.

You can configure it by running:

$ ./bootstrap --prefix=/path/to/cmake/build

Then you can type make and make install, and you're good to go. Don't forget to add /path/to/cmake/build/bin to your $PATH!

Advantages and Disadvantages

Disadvantages

Finding Packages

Using the CMake function find_package() can cause many difficulties, because Cmake has an unusual way of dealing with software dependencies. Unlike GNU autotools, you can't always point CMake to a path where you built something and expect it to "just work". (Boost is an excellent example of this.)

CMake contains pre-existing "rules" for finding things that can make life difficult for people who specify --prefix when they install things. CMake contains a list of rules in /path/to/cmake/X.X/Modules/cmake-X.X/. These rules will be in files named Find(Package).cmake (e.g. FindBoost.cmake).

While these can be customized, they are cryptic and can take a long time to try and figure out. Due to these esoteric "find rules", it can be difficult to get CMake to "pick up" on custom installs of third-party packages like Boost. This isn't the case with all third-party packages, just the ones for which "find rules" exist.

Presentations

Professor James Sutherland's presentation on using CMake, part of the 2010 Scientific Computing Summer Workshop, is here: File:CMake Sutherland.pdf

This presentation contains an example of a "Hello World" program built with CMake.

References

• Explanation of how the find_package() function works: http://www.itk.org/Wiki/CMake:How_To_Find_Libraries