[boost] Re: call_traits aka parameter_traits

From: Darin Adler (darin_at_[hidden])
Date: 1999-11-28 19:59:39

> This has one disadvantage that I know of:
> 
> 1) It requires a working version of <limits>.

Oops!

One more big disadvantage:

    2) It will pass a UDT by value if that UDT is a numeric type and
numeric_limits is specialized for the type.

I think that's a fatal flaw in my proposed change.

This makes me think of the "type traits" proposal. I do want to avoid the
pitfall of a single catch-all traits template, but I'd also like to avoid
listing "bool, signed char, unsigned char, short, unsigned short, wchar_t,
int, unsigned int, long, unsigned long" more than once. Once reason is that
I want to add "long long" to that list as compilers add support for it (due
to C9X).

Things like is_scalar, is_array, is_pointer, is_reference may also be useful
and could perhaps go into something like type_traits without creating a
slippery slope.

    -- Darin