I am reading through some syslog-ng documentation, and in the section about filter functions, it says that the
program() filter matches...
...messages by using a regular expression against the program name field of log messages.
The documentation also includes similar definitions for other filter functions.
How is the program name field set in a log message? Is there some documentation somewhere which summarises this for the various fields? I couldn't find it in the documentation I have ("The syslog-ng Administrator Guide").