Re: sizeof

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 5 Aug 2009 12:34:05 -0400
Message-ID:
<#nYbNqeFKHA.3800@TK2MSFTNGP04.phx.gbl>
Jeremy <mutexed@gmail.com> wrote:

I wanted to use it to count the number of arguments represented by
__VA_ARGS__ in a macro, knowing they were a specific type.


If you are happy to limit yourself to some fixed maximum number, you
could do something like this:

namespace detail {
template <typename T1>
char (&size_calculator(T1))[1];

template <typename T1, typename T2>
char (&size_calculator(T1, T2))[2];

template <typename T1, typename T2, typename T3>
char (&size_calculator(T1, T2, T3))[3];

// Follow the pattern up to a desired maximum.
// You don't need to implement these functions, just declare them.
}

#define ArgCount(...) sizeof(detail::size_calculator(__VA_ARGS__))

If you only need to count ints, then size_calculator doesn't need to be
a template.
--
With best wishes,
    Igor Tandetnik

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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
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