Re: [boost] Interval Wrinkles (MSVC 7 bugs)

From: Reece Dunn (msclrhd_at_[hidden])
Date: 2003-04-15 09:28:21

> > > using namespace boost::numeric; // BEFORE
> > > #include "stats.hpp"

> > It shouldn't be needed. 'abs' is defined in the same namespace than
> > 'interval' so the name resolution should find the correct version of
> > 'abs'. Am I missing something here?

According to the standard, this is correct via Koenig lookup.

>It seems to be needed. I too suspect the  MSVC 7.0 compiler. With luck 7.1 
>will
>be better.

MSVC 7.0 only supports Koenig lookup for *operators*. This is why doing 
things like overloading the << operator for streams works when defined in 
the same namespace as the associated type.

I assume that they have fixed this in 7.1.

> > This code: > using boost::numeric::interval_lib::pi; > I a = pi<I>(); > 
>works with GCC and Intel CC., but MSVC 7.0 says:

>typedef boost::numeric::interval<double> I;
>using boost::numeric::interval_lib::pi;
>a = pi<I>();

>testInterval.cpp(65) : error C2275: 'I' : illegal use of this type as an
>expression
>         testInterval.cpp(59) : see declaration of 'I' testInterval.cpp(65) 
>: error C2059: syntax error : ')'

I think this is because MSVC 7.0 does not properly support using templates. 
That is, it has a problem deducing that pi is a template function, so treats 
the '<' as a less than operator rather than a template operator.

>but

>I pi_d = boost::numeric::interval_lib::pi< boost::numeric::interval<double> 
> >();
>I pi_d1 = boost::numeric::interval_lib::pi<I>();

>are OK,

These work because MSVC can locate the pi function and deduce that is a 
template type.

>so am I in bad company in my (lack of) understanding of C++ :-(

-rhd-
mailto:msclrhd_at_[hidden]

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