decltype

[Graziano Servizi <Graziano.Servizi@xxxxxxxxxx>]

Could you kindly explain to me how and when the decltype keyword do have 
a tilde character prefixed?
I'm unable to figure out the cases in which such a syntax would be used 
and I found it as an example of an "id-expression" together with the 
name of a destructor: should be to explicitly call a destructor of some 
class?
Thanks...

                                 G. Servizi