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From "Stephen Bartnikowski" <sbartnikow...@barkinglizards.com>
Subject RE: Use of operator<<
Date Tue, 18 Mar 2008 15:25:48 GMT
> -----Original Message-----
> From: Josh Kelley [mailto:joshkel@gmail.com] 
> Sent: Tuesday, March 18, 2008 9:10 AM
> To: log4cxx-user@logging.apache.org
> Subject: Use of operator<<
> 
> I saw that I can use the << operator within the LOG4CXX_DEBUG, etc.
> macros; e.g.:
> 
>     LOG4CXX_DEBUG(logger, "Read " << path << " and got " << out);
> 
> This seems very convenient (and a whole lot more convenient 
> than formatting strings myself or having to use something 
> like boost::format for every log statement), but as far as I 
> can tell, it's undocumented.  Is this use of operator<< 
> officially supported, or is it an implementation detail that 
> I should not be relying upon?
> 
> If it is supported, then can I add a wiki page about it?  If 
> it's not supported, then is there a recommended way of doing 
> formatted logging?
> 
> Thanks.
> 
> Josh Kelley
> 

Hi Josh,

As far as I can tell support was dropped for those macros, which made me sad
too. But it's not too hard to cook up some macros of your own. I did it like
this:

#define LOGGING_DEBUG(message) { \
   if ((*pLogger)->isDebugEnabled()) {\
      log4cxx::logstream oss(*pLogger, log4cxx::Level::getDebug());\
      oss.setLocation(LOG4CXX_LOCATION);\
      oss << message;\
      oss.end_message();}}

This assumes you have the following declared and initialized:
log4cxx::LoggerPtr* pLogger;

Hope this helps you out. I don't know if there's an official way for doing
this.

- Stephen


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