Re: About variant

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Sun, 30 Dec 2007 08:37:35 -0500

Message-ID:

<e6TONouSIHA.5524@TK2MSFTNGP05.phx.gbl>

"sawer" <sawer@discussions.microsoft.com> wrote in message
news:BDF0B3D8-DE5F-420C-8D08-0B0232F7B4CB@microsoft.com

Oleautomation compatible types list contains :
VARIANT_BOOL, double, float, long, short, BSTR, DATE, IDispatch*,
IUnknown*, CY/CURRENCY, SAFEARRAY

because VARIANT support these. But why do they add VARIANT type to
that list. Isn't VARIANT wrapper for that types? Why does vartype
include VARIANT? Are there 2 types of VARIANT?

A VARIANT may refer to another VARIANT. The referring variant is set to
the type (VT_VARIANT | VT_BYREF) and its pvarVal member points to the
second variant. Only one level of indirection is allowed. This is used
to pass [out] and [in, out] parameters through IDispatch::Invoke
--
With best wishes,
Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925