[boost] Re: Singleton

From: Darryl Green (darryl.green_at_[hidden])
Date: 2005-01-12 03:45:36

Noah Stein <noah <at> acm.org> writes:

> > On Behalf Of Jason Hise
> >         T * p = reinterpret_cast < T * > ( new char [ sizeof ( T ) ] );
> 
> Your Create() function in AllocateUsingNew isn't guaranteed to work for all
> classes.  The type of the singleton class might have alignment restrictions.
> char has no alignment restrictions; therefore, the program may crash when
> trying to initialize the singleton.  I believe boost::aligned_storage is
> your friend in this situation.

Are you sure there is a problem here? Doesn't 5.3.4/10 allow this. The 
explanatory note reads in part:

"...this constraint on array allocation overhead permits the common idiom of 
allocating character arrays into which objects of other types will later be 
placed."