typedef void(* VortexLogHandler)(const char *file, int line, VortexDebugLevel log_level, const char *message, va_list args)

Handler definition that allows a client to print log messages itself.

This function is used by:

fileThe file that produced the log.
lineThe line where the log was produced.
log_levelThe level of the log
messageThe message being reported.
argsArguments for the message.