zlog is a reliable, high efficent, thread safe, flexsible, clear model, pure c logging library. Actually, in the c world there is NO good logging library for application like logback in java or log4cxx in c++. printf can work, but can not be easily redirected or reformat, syslog is slow and is designed for system use. So I write zlog. It is faster, safer and more powerful than log4c. So it can be widely used.
Please refer to zlog for more details.