[Bug preprocessor/45696] New: Continuation character gets lost or not taken into account

[Bug preprocessor/45696] New: Continuation character gets lost or not taken into account

[John dot Tytgat at aaug dot net]

Using gcc 4.6.0 20100915 trunk revision 164317

Using the preprocessor on following piece:

--8<--
error_identifiers: \
        kErr_AlreadyWaitingForGDB("Already waiting for a GDB to connect")
--8<--

gcc -E gives me:

--8<--
# 1 "test-preprocess.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "test-preprocess.c"
error-identifiers:
 kErr_AlreadyWaitingForGDB("Already waiting for a GDB to connect")
--8<--

I.e. the continuation character got lost or was not taken into account.  Either
I expect it to survive the preprocessing, either it should have been taken into
account like e.g. with gcc 4.1.2:

--8<--
# 1 "test-preprocess.c"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "test-preprocess.c"
error-identifiers: kErr_AlreadyWaitingForGDB("Already waiting for a GDB to
connect")
--8<--


-- 
           Summary: Continuation character gets lost or not taken into
                    account
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: John dot Tytgat at aaug dot net
 GCC build triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2010-09-16 23:55 -------
C preprocessor is not a generic preprocessor.  The continuation character is
removed so the correct line number is used.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[John dot Tytgat at aaug dot net]

------- Comment #2 from John dot Tytgat at aaug dot net  2010-09-17 00:04 -------
I don't understand why the continuation character should be removed. For the C
parser that character is not special (only for the C preprocessor it is), nor
it confuses its line number accountancy.  Or am I mistaken ?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2010-09-17 00:06 -------
(In reply to comment #2)
> I don't understand why the continuation character should be removed. For the C
> parser that character is not special (only for the C preprocessor it is), nor
> it confuses its line number accountancy.  Or am I mistaken ?

You are confused.  It is removed so that the column information for the call to
AlreadyWaitingForGDB is on the correct line.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2010-09-17 07:09 -------
You can use gcc -E -P, then it doesn't print # <lineno> <file>
lines and puts the label and fn on the same line (as, without the line notes
locations aren't preserved anyway).
As Andrew wrote, gcc -E is a C/C++ preprocessor, and the semantics of
label:
 fn (args)
is the same as
label: fn (args)
and the former maintains better the location info.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[manu at gcc dot gnu dot org]

------- Comment #5 from manu at gcc dot gnu dot org  2010-09-17 08:54 -------
I have seen this question/bug reported a couple of times in bugzilla and a few
more in gcc-help, so I added a FAQ:

http://gcc.gnu.org/wiki/FAQ#cpp_continuation_discarded

I suggest that it is rather more useful to answer such questions in the wiki
and then always provide a link. Moreover, the answers in the wiki tend to be
more satisfactory and clear (if not, they can be gradually improved).
Otherwise, the same questions are answered again and again but the answers tend
to not be uniform in terms of clarity and quality.


-- 

manu at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |manu at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

[Bug preprocessor/45696] Continuation character gets lost or not taken into account

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45696

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gccbugzilla@trash-mail.com

--- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-17 14:18:56 UTC ---
*** Bug 47328 has been marked as a duplicate of this bug. ***