commenting out 'cout' using preprocessor macro

[qazmlp]

I hope comp.lang.c will not find the following question as a
complete off-topic.

I would like to remove ie.comment out the 'cout' statements during
compilation(act ually preprocessing) time.
The statements like this:
cout<<"somethin g\n" ;
should be made as
// cout<<"somethin g\n" ;
I tried for the following. But, It doesn't seem to be working.
//--------START
#ifdef DEBUG
#define COUT std::cout
#else
#define COUT \/\/
#endif

int main()
{
COUT<<"HELLO\n" <<std::endl ;
}

//--------END
If you can solve the above problem, please suggest a way for taking
care of
commenting out the 'cout' statements that spans in more than 1 line.
eg:

12 COUT<<"HELLO\n"
13 <<"WORLD\n" ;

[Samuele Armondi]

"Samuele Armondi" <sa************ ****@hotmail.co m> wrote in message
news:3f******** @mk-nntp-1.news.uk.world online.com...

"qazmlp" <qa********@red iffmail.com> wrote in message
news:db******** *************** ***@posting.goo gle.com...

I hope comp.lang.c will not find the following question as a
complete off-topic.

[snip...] But you would need to be 100% sure that the code in question does not use
the << _anywhere_. Hope this helps anyway!
S. Armondi

Sorry, ignore all the \ in the declaration of the MyStream class. They are
not needed.
S. Armondi

[Bill Cunningham]

after the phase 3 of the translation in both languages.

Victor

What exactly is phase 3 translation? Into assembly or RTL perhaps?

Bill

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[Jeff]

"Victor Bazarov" <v.********@att Abi.com> wrote in message news:vj******** ****@corp.super news.com...

"Jeff" <no****@notexis t.com> wrote...

"qazmlp" <qa********@red iffmail.com> wrote in message
news:db******** *************** ***@posting.goo gle.com...

I hope comp.lang.c will not find the following question as a
complete off-topic.

I would like to remove ie.comment out the 'cout' statements during
compilation(act ually preprocessing) time.
The statements like this:
cout<<"somethin g\n" ;
should be made as
// cout<<"somethin g\n" ;
Sorry, it is off-topic here. cout is a part of C++, not C.

Sorry, Jeff, statements explaining what is off-topic in
comp.lang.c are off-topic in comp.lang.c++. And give "qazmlp"
a break, he expressed his hope, didn't he?

Sorry, Victor, statements explaining the other is off-topic here is also off-topic.

Unfortunately, you are off-topic now.

(Just to remind you, we have the right to protect our c.l.c group from off-topic by kindly notifying
the OP. It is usual on Usenet and I am not the first one. If you insist that the OP is not off-topic
here, you can give your opinion)
Victor

--
Jeff

[Jack Klein]

On Fri, 8 Aug 2003 23:57:54 -0400, "Bill Cunningham" <so**@some.ne t>
wrote in comp.lang.c:

after the phase 3 of the translation in both languages.

Victor

What exactly is phase 3 translation? Into assembly or RTL perhaps?

Bill

The original ANSI/ISO C language standard (1989/1990) provided a
high-level definition of the translation process that an
implementation performs in producing executable code from a source
file. These have persisted to the present in later versions of the C
standard and have been incorporated into the C++ standard.

Like everything else in C and C++, the "as-if" rule applies, meaning
that a compiler does not have use separate passes to perform all of
these operations. It can do them in parallel as long as the proper
ordering is used.

They are too long to quote here in full, but the two that are relevant
to this question are that in phase 3, "Each comment is replaced by one
space character", and in phase 4, "Preprocess ing directives are
executed and macro invocations are expanded".

So there is no way of including a comment in the expansion of a macro.
The early lexical analysis step removes comments before the
preprocessor expands macros.

An overview of the 8 phases of translation:

1 through 6 deals with parsing and preprocessor issues. At the end of
phase 6 the program is a series of tokens, without white space, with
all comments removed and macros expanded.

Phase 7 actually analyses and translates the program into some sort of
output format, generally referred to as an object file.

Phase 8 is after compilation, usually performed by a separate tool
called a linker. It resolves references between different source
files and to library modules and generally produces the final
executable output file.

--
Jack Klein
Home: http://JK-Technology.Com
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[Victor Bazarov]

"Jeff" <no****@notexis t.com> wrote...

[...]
Sorry, Victor, statements explaining the other is off-topic here is also off-topic.

REALLY?
Unfortunately, you are off-topic now.

(Just to remind you, we have the right to protect our c.l.c group from off-topic by kindly notifying the OP. It is usual on Usenet and I am not the first one. If you insist that the OP is not off-topic here, you can give your opinion)

I already have. If you need it again, go to my first reply to you
and re-read it.

[John L Fjellstad]

qazmlp wrote:

I would like to remove ie.comment out the 'cout' statements during
compilation(act ually preprocessing) time.

I saw this in a computer mag once (either C++ journal or something like
that):

#ifdef DEBUG
#define SLASH(s) /##s
#define COMMENT SLASH(/)
#else
#define COMMENT std::cout
#endif

Unfortunately, I don't know how portable this is (someone could probably
explain why it won't work). I could get it working on VisualC++ v6, but
had problems with GCC v2.9x. Think it worked in aCC (the HPUX compiler)

--
John L. Fjellstad

[Martin Dickopp]

John L Fjellstad <jo*******@fjel lstad.org> writes:

I saw this in a computer mag once (either C++ journal or something like
that):

#ifdef DEBUG
#define SLASH(s) /##s
#define COMMENT SLASH(/)
#else
#define COMMENT std::cout
#endif

Unfortunately, I don't know how portable this is (someone could probably
explain why it won't work).

Comments are removed (or rather replaced by a whitespace character) in
translation phase 3, while preprocessing directives are executed and macros
are expanded in translation phase 4. Therefore, `//' is not a meaningful
preprocessing token at the point when `COMMENT' is expanded.

Martin

[John L Fjellstad]

Martin Dickopp wrote:

Comments are removed (or rather replaced by a whitespace character) in
translation phase 3, while preprocessing directives are executed and
macros are expanded in translation phase 4. Therefore, `//' is not a
meaningful preprocessing token at the point when `COMMENT' is expanded.

Do you know if this is in the C++ standard, or if it is left to the
implementation?

--
John L. Fjellstad

[Martin Dickopp]

John L Fjellstad <jo*******@fjel lstad.org> writes:

Martin Dickopp wrote:

Comments are removed (or rather replaced by a whitespace character) in
translation phase 3, while preprocessing directives are executed and
macros are expanded in translation phase 4. Therefore, `//' is not a
meaningful preprocessing token at the point when `COMMENT' is expanded.

Do you know if this is in the C++ standard, or if it is left to the
implementation?

This behavior is required by the C++ standard (section 2.1#1) as well as the
C standard (section 5.1.1.2#1).

Martin
(Followup-To: comp.lang.c++ ignored, since the discussion seems meaningful
to both C and C++.)