[ryandrake]

"Decades old" often means that it is mature, has relatively few bugs, and is not going to soon go through some major API-breaking re-architecture just because the maintainer wants to experiment with a new framework-of-the-week. "Written in plain C" means I will likely be able to call/integrate it into my project with little fuss. These are both things to actively look for when browsing for open source libraries.