Re: [boost] Re: [Q]: What is the recommended logging facility for boost: log4cpp or ??

From: John Torjo (john.lists_at_[hidden])
Date: 2004-10-22 13:22:46

> 
> I disagree. Like most things STL it should be independent of a stream 
> back end. And ideally independent of a formatting front end. It should 
> only be a tagging, filtering, and multiplexing interface.

internally, I use std::stringstream
> 
>> * Thread-safe (e.g. two threads can't have their output intermixed in
>> the output file/stream/whatever like they would with simple ostream<<
>> operators)
> 
> Yes, but only if needed. It might not be appropriate depending on the 
> front end or back end. For example you might be dumping the "output" to 
> a database which would create individual debug records. No need for 
> thread safety at the log level in that case.

indeed! that's what my lib does. You can choose to have a thread-safe 
writer, but only if you wish.

> 
>> * Multiple possible output media (files, sockets, syslog, Windows
>> event log, etc)
> 
> 
> Multiplexing.
> 
yup, we have that ;)

>> * Multiple named channels each with configurable "threshold" (e.g.
>> error, warning, debug, etc)
> 
> 
> And configurable, so that you can program what each one does on both the 
> front end and to which back end they go to.

yup, we have that.

> 
>> * Messages which won't be logged shouldn't even go through the
>> formatting step.  I'm pretty sure this cannot be done in a single call
>> w/o macros though.  For example:
>>
>>     BOOST_LOG (boost::log::debug, "This is a debug message: " <<
>> some_expensive_to_stream_class);
>>
>> Which would expand to something like:
>>
>>     if (boost::log::is_enabled_for (boost::log::debug)) {
>>         ostringstream __os; os << "This is a debug message: " <<
>> some_expensive_to_stream_class;
>>         boost::log::force_write (boost::log::debug, os.str ());
>>     }

yup, we have that.
> 
> 
> It's possible without macros for some compilers using careful template 
> instaciations.

In my case, there's one macro: BOOST_LOG.

Best,
John

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