Evaluation of #elif - trying again

From	Edward Diener<eldiener@tropicsoft.invalid>
Newsgroups	comp.std.c++
Subject	Evaluation of #elif - trying again
Date	2011-09-11 09:13 -0700
Organization	A noiseless patient Spider
Message-ID	<j4ijc0$gqv$1@dont-email.me> (permalink)

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Since no one answered my previous post I will try again and rephrase
some of my question.

In code such as:

#if SOME_MACRO(x)
#elif ANOTHER_MACRO(y)
#endif

is ANOTHER_MACRO expanded and evaluated for C++ correctness even when
the result of SOME_MACRO's expansion is 1.

In other words what does the standard say about whether or not the C++
preprocessor considers paths which are not taken in #if - #elif - #endif
and #if - #else - #endif constructs and whether the code in those
untaken paths need to be valid C++ or not ? By path I also mean the
evaluation of #elif in the first case when the corresponding #if is not 0.

Is this considered to be purely a compiler decision that has nothing to
do with the C++ standard or is there some C++ standard rule which says
whether or not an untaken preprocessor path is parsed for valid C++ code ?


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Evaluation of #elif - trying again Edward Diener<eldiener@tropicsoft.invalid> - 2011-09-11 09:13 -0700
  Re: Evaluation of #elif - trying again Marc <marc.glisse@gmail.com> - 2011-09-11 17:47 -0700
    Re: Evaluation of #elif - trying again Edward Diener<eldiener@tropicsoft.invalid> - 2011-09-25 08:26 -0700
      Re: Evaluation of #elif - trying again Marc<marc.glisse@gmail.com> - 2011-09-26 09:00 -0700
      Re: Evaluation of #elif - trying again David Krauss<potswa@gmail.com> - 2011-10-12 09:34 -0700
        Re: Evaluation of #elif - trying again Edward Diener<eldiener@tropicsoft.invalid> - 2011-10-13 22:42 -0700
          Re: Evaluation of #elif - trying again Francis Glassborow <francis.glassborow@btinternet.com> - 2011-10-14 12:02 -0700
          Re: Evaluation of #elif - trying again Dave Abrahams <dave@boostpro.com> - 2011-10-14 12:02 -0700
            Re: Evaluation of #elif - trying again Edward Diener<eldiener@tropicsoft.invalid> - 2011-10-15 09:30 -0700

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