Re: Using std::less_equl predicate with std::min()

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 12 Jan 2010 08:44:18 -0500
Message-ID:
<O#pZa14kKHA.4872@TK2MSFTNGP05.phx.gbl>
Vladimir Grigoriev wrote:

In fact without any serious reason the Microsoft compiler prevents =

from

compiling of a valid code.


Yours is not a valid code, it exhibits undefined behavior. The C++ =
standard requires that the predicate be a strict weak ordering, and =
less_equal isn't.

In my opinion it is one mode serious bug of the
Microsoft compiler.


It's not a bug, it's a feature.

I have not seen any reasonable explanation why this code
may not be compiled.


To be precise, it compiled - it failed at run time. Anyway, MSVC's STL =
implementation is doing you a favor by turning an instance of undefined =
behavior into a hard error, so you can find and fix your bug more =
easily.

It seems that Microsoft inserted this check everywhere
in its library without any thought about consequences


No - it inserted this check _because_ it thought about consequences.
--
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

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