I have worked hard on liblogging-stdlog, which aims at becoming the new enhanced syslog() API call. The library is thread- and signal-safe and offers support for multiple log drivers, just like log4j does.
More elaborate description is here: https://github.com/rsyslog/liblogging
As the lib is becoming ready for prime time, I would really appreciate if some folks could have a look at the code and check for problems and/or offer suggestions in regard to the API.
It is only the code inside ./stdlog (roughly 1400 lines of code, including header files, empty lines and comments): https://github.com/rsyslog/liblogging/tree/master/stdlog
The man page is available here: https://github.com/rsyslog/liblogging/blob/master/stdlog/stdlog.rst
All feedback is very welcome!