Re: programmatically creating new logger instances?

On Jan 15, 2007, at 8:55 AM, Mark Toohey wrote:

> I'm in the process of adding an interface to log4cxx to allow it to  
> be used with
> some existed C applications. We need to be able to log to different  
> files from
> each module. I wanted to do this by creating separate loggers for  
> each module
> and attaching separate appenders to each one. How can I create new  
> loggers (I
> would like to do it programmatically if possible)?
New loggers are created in response to a getLogger call when the  
logger name has not been previously requested.  So you could have a  
statement like:
log4cxx::LoggerPtr logger(Logger::getLogger("module1"));

as a static member of a class or in a compilation module.  Any  
subsequent request to the identically named logger will return a  
reference to the same logger.
The next step would be to attach appenders to the loggers either  
through a configuration file or programmatically.  I'm freehanded the  
following code snippet to demonstrate creating a FileAppender and  
attaching it to a logger.  It may have have some errors but it should  
be sufficient for you to get the idea.
FileAppenderPtr file(new FileAppender());
file->setFile("module1.log");
//
//   a call to activateOptions() is necessary to finish the  
configuration of an appender
//      before attaching it to a logger
file->activateOptions();
LoggerPtr logger(Logger::getLogger("module1"));
logger->addAppender(file);