Libev

Libev is an exceptional event loop software with remarkable features that rival other software in its category. The software is well-designed, and loosely modelled after libevent, but with little to no limitations and bugs. It has gained widespread applicability in programs like GNU Virtual Private Ethernet and rxvt-unicode packages. It comes with an array of stunning features, including child/pid watchers and periodic timers based on wallclock to provide more precise time (in absolute terms) and the ability to create timers with relative timeouts.

Additionally, the software has exceptional epoll/kqueue/ports support, which makes it fast and reliable, and it also boasts of an easy-to-use design. The software has also been designed with a fast timer management system built-in, time jump detection, and correction feature that enables it to maintain an accurate sense of time with ease.

The software is designed to be used as a substitute for libevent using its emulation API or directly embedded into your programs without the need for complex configuration support. As a bonus, it has a fully documented perl interface that is full-featured, making it easy for users to leverage when developing programs.

Overall, if you're looking for a high-performance event loop software with a wide range of features compatible with multiple applications, Libev is the software for you.