Is it possible to build Boost with CMake? [closed]

Question

Rather than include static libraries in my source tree in a cross-compiled project I'd like to add boost directly into cmake and build it. Is this available?

Answer 1

We've struggled with this a fair bit too at my workplace. While I certainly can't claim to know the "best" way, I can offer the following thoughts on my experiences.

We initially just required devs to install boost separately and had CMake do its normal checks in the form of a find_package(Boost...) call. This was easy, but not automated, and caused problems for devs with older versions of boost already installed.

We then changed tack and added a copy of the boost sources which we cloned from one of the projects you mentioned above. I can't recall the specifics, but I think it was a precursor to the one currently being worked on in the Ryppl project. The main point was that it already had support for CMake; the boost libraries were actual CMake targets added via add_library calls, which made them easier to work with in the CMake code.

While this solved the previous problems by automating the use of boost in our project, it ultimately became a maintenance nightmare. The boost project we had cloned from changed radically and is now very dependent on Ryppl-specific CMake functions. We didn't want to add Ryppl as a dependency, so we changed tack again!

We looked at the projects you mentioned in your question, and likewise found none of them to be usable.

Our current setup makes use of CMake's ExternalProject module. This allows us to download and build boost to our build tree.

Advantages:

• Low maintenance
• Automated, so all devs use the same version built with the same flags
• Keeps our own source tree free from third-party code
• Multiple copies of boost can happily co-exist (so no chance of accidentally linking to a copy built with a different compiler/stdlib combination)

Disadvantages

• Deleting your build tree means having to download and build boost from scratch. This could be ameliorated by e.g. downloading to a fixed location (say, system temp dir), so the download/unzip step could be skipped if an existing copy of the boost sources is found.
• The boost libraries are not proper CMake targets (i.e. they haven't been added via add_library calls)

Here's a link to our CMake code. There are a few ways in which this needs improved, but it currently works reasonably well for us.

I hope that soon this answer becomes out of date and a decent, modularised, CMake-compatible solution becomes available.