defining a comment?
Len Reed
lbr at holos0.UUCP
Thu Sep 15 23:33:21 AEST 1988
>From article <13544 at mimsy.UUCP>, by chris at mimsy.UUCP (Chris Torek):
> In article <5438 at techunix.BITNET> benny at techunix.BITNET (Benny Pinkas) writes:
>>Can I use the Preprocessor to define a comment?
>
>>#define STARTCOM /*
>
> This is rather dubious.
>
>>Usually the text after the /* is considered as a comment and is not part
>>of the macro definition.
>
> Why should you care? You cannot (portably) view the text (if any) emitted
> by the preprocessor, which may well be an integral part of the compiler.
You misunderstand. On Xenix and MSC 5.x (where I've tried this) consider:
#define COMMENT /*
#define CLOSE_COMMENT */
The pre-processor considers these two lines to be functionally equivalent
to the single line:
#define COMMENT /* #define CLOSE_COMMENT */
which is no different than
#define COMMENT
This is because comment structures are parsed in the 1st pass before #defines.
Comments are not stored in the pre-processor lookup table.
Later when you say:
COMMENT
A whole bunch of stuff
CLOSE_COMMENT
the compiler tries to compile
A whole bunch of stuff
CLOSE_COMMENT
and messes up.
--
- Len Reed
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