Comments and pragma lines

[Mark Hall]

In article <9007 at smoke.BRL.MIL> gwyn at brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>In article <48957 at pyramid.pyramid.com> markhall at pyramid.UUCP ( me ? ) writes:
>-#pragma rotate lid counterclockwise    /* store pointers in
>-					* Best Foods 
>-					* Mayonaise Jars.
>-					*/
>-Is it legal to start the comment on the pragma line?  From what I read*
>-in the standard, it is illegal.
>
>How about explaining how you deduce that?  I'm sure the comment was
>supposed to have been replaced by a space character before the #pragma
>line was ever (pre)processed.

Did *I* post that noise here?  Dang.  I meant to send it to
rec.humor.funny.  Yes, of course, how stupid of me.

The rest of the question still may be of interest.  I was working on
the `future' cpp and was wondering what I should do about gracefully
ignoring #pragma's that were not supported by our compiler.  If the
following pragma were legal:

>-#pragma sunbakedchars ^%*#%/*!@

then how in the world would my cpp be able to tell, without knowing the
special semantics of `sunbakedchars', that the /* was not an open
comment?  If my `cpp' grabbed it as an open comment, it could wreak havoc
on an otherwise legal program . . . .

The question I should have asked (wait, I did ask it!) was whether this
is legal.  After having actually read the pertinent sections of XJ311
(no really, I read them this time),  I see that /* can only occur as an
open comment or within a string/char literal.  So if you see /* outside
of a " or ' string, you have yerself an open comment.

Hooray for the tokenization of preprocessor directives.

Sorry for the messing up the S/N ratio.  It was getting good for a 
while there.

-Mark Hall (smart mailer): markhall at pyramid.pyramid.com 
     (uucp paths): {amdahl|decwrl|sun|seismo|ames}!pyramid!markhall