Hi there,
here is a problem I have encountered that may be of interest to both
the GCC and the DOXYGEN communities.
Consider the following 4 non-empty lines of C text:
#if 0
/* I would like not to see this. */
int x;
#endif
Put these 4 lines into a file called foo.c and then
try
gcc -E -P -C foo.c
Here is the behavior I observe with different (official and unofficial)
versions of gcc:
egcs-2.91.66 (kgcc) produces a blank line
egcs-2.95.3 produces a blank line
gcc 2.96-85 (RedHat) produces the comment I would like not to see
gcc 3.0.1 produces the comment I would like not to see
gcc 3.1 20011006 prints nothing (GOOD!)
This issue is quite relevant if one uses doxygen
(http://www.doxygen.org/), since there comments are relevant (whence
the use of `-C'). A situation where the behavior of gcc 2.96-85 and
gcc 3.0.1 may byte you is the following:
#if 0
/*! A comment referring to x. */
int x;
#endif
int y;
Doxygen uses special comments like the above (notice the exclamation
mark) for documentation. When using doxygen is fed with text coming
from the GCC preprocessor, gcc 2.96-85 (RedHat) and gcc 3.0.1
cause a comment for (disregarded) x to be applied to y.
There are other tools that look inside comments to derive useful
information: these are also affected as well.
I wrote this message because I believe it is important not to
overlook the issue. I have quickly checked the standard documents,
but I have not found anything that prescribes the behavior
that I consider "desirable". I have also checked the documentation
of the `-C' option but this is also somewhat ambiguous on the subject.
A last question: even though the CVS HEAD version is OK
(for my purposes, at least), what will gcc 3.0.2 do?
All the best,
Roberto
--
Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara@cs.unipr.it
CVSROOT: /cvs/ppl
Module name: ppl
Changes by: hill(a)cs.unipr.it 2001-10-19 18:13:25
Modified files:
doc : definitions.dox
Log message:
Generators and associated terminology now defined in the user section.
There is now some repetition of definitions in the developer's section.
Patches:
http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/doc/definitions.dox.diff?cvsr…
CVSROOT: /cvs/ppl
Module name: w3ppl
Changes by: roberto(a)cs.unipr.it 2001-10-19 16:35:19
Modified files:
htdocs/Download: Download.raw
Log message:
Completed (even though we may want to add more tips for non-experts).
Patches:
http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/w3ppl/htdocs/Download/Download.ra…
