Re: Directory for FileAppender

[Curt Arnold]

In the current CVS HEAD (see 
http://issues.apache.org/jira/browse/LOGCXX-76), I've emulated a couple 
of the Java properties (java.io.tmpdir, user.home, user.dir) that can 
now be used in both log4j and log4cxx for providing a base for file 
specifications.  The real missing one is the directory of the current 
configuration file which one might assume would be used to resolve 
relative paths included in configuration files, but isn't.  See 
http://marc.theaimsgroup.com/?l=log4j-dev&m=110992261803810&w=2 for 
comments on log4j on this.  I'd expect that I may introduce 
"${base.dir}" in both log4j and log4cxx to represent it and likely 
change the default resolution for new namespace XML configuration 
files.

The syntax for property expansion is ${propname}, so you can do:
log4j.appender.D3.File=${user.home}/mylogfile
You could also use environment variables (log4cxx only):
log4j.appender.D3.File=${LOG_BASE}/mylogfile