Auto-Detect Dependencies when Building .debs Using CMake

CMake (via CPack) as a great feature that allows you to automatically generate Debian/Ubuntu (.deb) packages. One of the annoying things to do when you create a package is listing its dependencies. CMake asks you do it via the CPACK_DEBIAN_PACKAGE_DEPENDS variable. For example:

set (CPACK_DEBIAN_PACKAGE_DEPENDS "libc6 (>=2.7-18)")

But what happens when you work on a more complex project? Keeping track of all the dependencies by hand is a tedious task. Debian provides a tool named dpkg-shlibdeps which makes this task easier by updating the debian/control file with dependencies extracted from the dynamic libraries needed by a given executable. Luckily since CMake 2.8.3, CMake also supports running this tool automatically to figure out the required dependencies. The documentation is sparse, and I had hard time finding how to do so (I actually found it via a bug report and a commit message, but afterwards I’ve seen it the official documentation too). To enable it, you need to add the following line to your CMakeLists.txt file:

# autogenerate dependency information
set (CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)