Re: [boost] Re: Re: Logging Library -- Formal Review Request

From: Caleb Epstein (caleb.epstein_at_[hidden])
Date: 2005-04-29 21:51:59

On 4/29/05, Gennadiy Rozental <gennadiy.rozental_at_[hidden]> wrote:
> 
> "Darren Cook" <darren_at_[hidden]> wrote in message
> news:4272B304.3000100_at_dcook.org...
> >> Another thing (from the same domain) that I found especially difficult to
> >> deal with in my logging implementation is "intermixed logging":
> >>
> >> BOOST_LOG(..)  << "Print result of f(): " << f();
> >>
> >> ...
> >> void f() {
> >>    BOOST_LOG(..)  << "Enter f()";
> >> ...
> >>    BOOST_LOG(..)  << "Exit f()";
> >> }
> >>
> >> Now to make it properly formatter isn't trivial at all.
> >
> > (For the example to make sense f() shouldn't be void; I've assumed it is
> > int).
> 
> Yep. My fault.
> 
> > Can a logging library really help here? Don't you have to write:
> >  int f_ret=f();BOOST_LOG(..)  << "Print result of f(): "<<f_ret;
> 
> No. It's not really convinient isn't it?
> 
> I understand that f log statements will interfere with original log
> statement. The trick is to make sure that all prefixes are printed
> correctly:
> 
> a.cpp:14: Print result of f():
> b.cpp:75: Enter f()
> b.cpp:95: Exit f()
> a.cpp:14:  1234

The proposed implementation yields this (modulo any prefixes):

Enter f()
Exit f()
Print result of f(): 1234

Because each message is built up in a temporary stream and then fired
off to the logger in its entirety.

Gennadiy: to do what you suggest would seem to me to require (a) no
buffering and (b) an interface which is likely not thread-safe.  Or am
I missing something.

-- 
Caleb Epstein
caleb dot epstein at gmail dot com