Re: [boost] More on is_stateless<>

From: Anthony Williams (anthwil_at_[hidden])
Date: 2002-09-23 09:31:39

Douglas Gregor writes:
 > On Sunday 22 September 2002 10:37 pm, David Abrahams wrote:
 > > And finally, what's up with any_pointer? A union with constructors? Ya
 > > learn something new every day!
 > > That's really weird, though: it's non-POD, yet the compiler can copy it?
 > > I guess this is another argument for loosening the restrictions on PODs.
 > 
 > Is it non-POD? 9/4 says:
 > 
 > "...Similarly, a POD-union is an aggregate union that has no nonstatic data 
 > members of type pointer to member, non-POD-struct, non-POD-union (or array of 
 > such types) or reference, and has no userdefined copy assignment operator and 
 > no userdefined destructor."
 > 
 > Doesn't say anything about user-defined constructors, but I'm not a POD-guru.

That's because it is an "aggregate union" --- the definition of an aggregate
precludes constructors.

Anthony