Re: [boost] [logging] Interest check on logging library.

Subject: Re: [boost] [logging] Interest check on logging library.
From: Gordon Woodhull (gordon_at_[hidden])
Date: 2009-01-04 05:05:59

On Jan 1, 2009, at 7:22 PM, Andrey Semashev wrote:
> Gordon Woodhull wrote:
>> I believe what Jason is talking about is compile-time filtering  
>> where the compiler actually does know the answer and is able to  
>> eliminate code.  The "trivial 'if'" is gone after optimization.   
>> This seems like a very nice feature to me.
>
> I agree that this is a very useful feature. One of my points in the  
> reply to Jason was that there are simpler and more efficient ways to  
> do it than employing metaprogramming and hoping that the optimizer  
> does the rest.

I like the idea of expression templates for logging and find Jason's  
syntax somewhat compelling, allowing different output to different  
sinks from the same line.  But I recognize that macros are going to be  
the best solution for many projects, and it seems hard to match the  
sureness that they'll completely compile away.

> Although lazy functions solve the problem, they complicate logging a  
> lot. If you just want to put to log the result of a function call,  
> you have to create a lambda expression or some functional wrapper  
> for that call. I know, this is quite simple with Phoenix or Lambda,  
> but this is still quite an amount of scaffolding for such a trivial  
> task.

Yeah, it might be annoying to have to lazify every item that might  
cost processor time!