Re: [boost] Preprocessor: requirements on macro args

From: Vesa Karvonen (vesa_karvonen_at_[hidden])
Date: 2002-04-08 10:56:36

David Abrahams:
>The docs for BOOST_PP_BOOL(X) say:
>
>    Expands to 0 if X == 0 and 1 if X != 0.
>
>So I expected:
>
>    BOOST_PP_BOOL(const volatile) == 1
>
>However, that's not the case. I think this problem is endemic in the
>docs. How do I know which macros expect numeric arguments?

Yes, I should probably describe the parameter requirements more explicitly. 
The reason why it is not explicitly stated, is because all logical, 
comparison and arithmetic operations expect decimal integer literals. This 
is intuitive, because decomposing arbitrary token[ sequence]s using the 
preprocessor is impossible.

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