about qnx slogger utility


I’m trying to study the the source code for slogf(). It is found in the code that , there used a variable _slogfd (the file descriptor of “/dev/slog”). I have searched for its definition. but i found its extern declaration in <sys/slog.h> header file. I didn’t see its definition. According to my understanding, extern declaration will never provide a storage space. I would lke to know where it is defined. Pls reply :frowning:

In the c library (libc).