Dynamically loaded extension libraries for GNU AWK
...These extensions work with GNU AWK version 4.1.1 or later. We have created a framework for packaging gawk extensions, and we welcome further contributions. Recent additions include haru, redis, and select for I/O multiplexing.
Haru is a free, cross platform, open-sourced software library for generating PDF written in ANSI-C. It can work as both a static-library (.a, .lib) and a shared-library (.so, .dll).