zlog is a C in-memory logging library. It allocates a buffer in memory for efficient logging. The library flushs the buffer to the log file (or stdout) when the buffer is full. The program can also explicitly flush the log, or create a flushing thread (provided by the library) to flush the buffer every a period of time.
An example program named example.c for how to use zlog can be found in the source code.
Download the source code of zlog. Licensed under GPLv3.
Bug report/feedback to Zhiqiang Ma.