Re: [boost] [interprocess] default constructors

Subject: Re: [boost] [interprocess] default constructors
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2008-12-03 01:38:04

Ion Gaztañaga wrote:

> I think there is no overhead.

The overhead I'm talking about is that allowing an empty state in the 
object might have a cost.

A simple example is that if you have a function release(resource&), that 
releases a valid resource, and you want to wrap that resource using 
RAII, you have to write the destructor as

if(!is_empty)
     release(res);

instead of simply

release(res);

So you need to maintain a boolean (size overhead) and perform a 
branching (runtime overhead).

Usually, however, at least the size overhead can be eliminated since 
there is a special resource value reserved for the null resource.