[Bug preprocessor/18200] New: Spurious "backslash-newline at end of file" warning

[Bug preprocessor/18200] New: Spurious "backslash-newline at end of file" warning

[ftg at adelphia dot net]

If the preprocessor finds a backslash-newline continuation on the next-to-last
line of a file which does not end with a newline (the file, not the next-to-last
line), it gives the warning.

Here's a 2-line file:

#define  MYMACRO(x)          \
         x

and here it is in hex, to show the lack of a final newline:

[ftg@ftgme2 tmp]$ od -t x ~/tmp/test.defs
0000000 66656423 20656e69 4d594d20 4f524341
0000020 20297828 20202020 20202020 200a5c20
0000040 20202020 20202020 00000078
0000051

then:

[ftg@ftgme2 tmp]$ gcc -v -P -CC -I. -E -x c test.defs
Reading specs from /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/specs
Configured with: ../configure --prefix=/usr --libdir=/usr/lib
--with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --enable-long-long
--enable-__cxa_atexit --enable-clocale=gnu --disable-libunwind-exceptions
--enable-languages=c,c++,ada,f77,objc,java --host=i586-mandrake-linux-gnu
--with-system-zlib
Thread model: posix
gcc version 3.4.1 (Mandrakelinux 10.1 3.4.1-4mdk)
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/cc1 -E -quiet -CC -v -I. -P
test.defs -mtune=pentium
ignoring nonexistent directory
"/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/../../../../i586-mandrake-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 .
 /usr/local/include
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/include
 /usr/include
End of search list.
test.defs:1:30: warning: backslash-newline at end of file


If I add a newline as the last byte of the file, the warning is not given.  The
warning is spurious because the backslash-newline is not at the end of the file.
 Even if the warning has value in the case where the backslash-newline is
followed only by whitespace, that isn't the case here.

-- 
           Summary: Spurious "backslash-newline at end of file" warning
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ftg at adelphia dot net
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18200

[Bug preprocessor/18200] Spurious "backslash-newline at end of file" warning

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-28 16:14 -------
The warning is pretty clear at what it means:
test.defs:1:30: warning: backslash-newline at end of file

I don't see where the problem is.  Also it is undefined in the C standard to have a file not in a new line.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18200

[Bug preprocessor/18200] Spurious "backslash-newline at end of file" warning

[ftg at adelphia dot net]

------- Additional Comments From ftg at adelphia dot net  2004-10-28 16:27 -------
I don't agree that it's clear.  The file does not end with a backslash-newline
as the message states, and the message gives one no idea of what to do to
correct it.

If it is indeed the case that a file which does not end with a newline is
illegal in C, then that's the message that should be issued.  However, it is
quite easy to create such files with modern editors such as KDE Kate.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18200