RE: [boost] null ostream (was Logging library)

From: Jeff Garland (jeff_at_[hidden])
Date: 2002-04-09 11:38:56

Ernie Makris wrote:
> One way I've been toying with zero impact, is the following:
>
> template <bool cond>
> struct DebugSys {
>   enum { R = 0 };
> };
>
> template <>
> struct DebugSys<true> {
>   enum { R = 1 };
> };
>
> if( DebugSys<DBUGFLAG>::R )
>   logger << log_debug << "Starting server....";
>
> most, if not all compilers remove the unreachable code when R evaluates to
> 0, when DBUGFLAG = false. It's a little bit ugly, but it forgoes macros, and
> your program has a single source source set. Rather than two versions of the
> set. It makes debugging easier. The compiler decides when to remove the code
> altogether.

This is the same result as null ostream, different interface.  I personally prefer the zero client
code impact of null stream.

> One of the drawbacks to this technique is, you cannot switch , dynamically,
> logging on and off when log statements are written this way. The code no
> longer exists.

Right, neither of these apply if you want dynamically switchable tracing capabilities...

Jeff