Re: [boost] A meta-proposal for logging

From: Michael Lacher (michael.lacher_at_[hidden])
Date: 2007-04-05 10:28:16

Greer, Joe wrote:
> 
>> -----Original Message-----
>> From: boost-bounces_at_[hidden]
> [mailto:boost-bounces_at_[hidden]]
>> On Behalf Of Richard Day
>>
>> Simple examples.
>>
>> DBG_LOG( "Null pointer we are now dying a hard death" );
>> vs
>> logger << CLASS_WARNING << "File not found : " << filename << endl;
>>
>> With two completely different in many respects requirements satisfying
>> everyones needs is the issue.
>>
> [Joe] I agree.  In fact, in the system I currently use, my usage pattern
> is a hybrid.  My log messages look something like:
> 
> CDBG(TRACE, "network") << "Some network related message." << endl;
> 

Maybe optional log information (channel, type, loglevel, ...) could all 
be passed similar to manipulators in std::stream. This would keep the 
basic interface clean (just << operator) and extensible. There would be 
no need to anticipate numbers/types of function arguments.

If people prefer a functional interface, then they could go for either

#define MYLOG1(LEVEL,CHANNEL,MESSAGE) logger << setLevel(LEVEL) << 
setChannel(CHANNEL) << MESSAGE << endl

MYLOG1(WARNING,"Debug","Caught Exception: " << e.what());

or

#define MYLOG2(LEVEL,CHANNEL) logger << setLevel(LEVEL) << 
setChannel(CHANNEL)

MYLOG2(WARNING,"Debug") << "Caught Exception: " << e.what() << endl;

Of course a commonly used subset of such macros could be provided.

Michael