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| Author |
mixing C and C++ libs
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| Uwe Mayer 2004-10-26, 3:56 am |
| Hi,
I have problems linking a c++ program to a C static archive (.a). I don't
know wether this is at all possible nor am I sure that this is the source
of my problems, but the g++ outputs the following:
g++ sf2raw.c \
-I../Smartspace/Development/Infrastructure/sources/sffile \
-I/usr/include/qt3 \
-lqt-mt -L$(QTDIR) \
-L ../Smartspace/Development/Infrastructure/sources/sffile \
../Smartspace/Development/Infrastructure/sources/sffile/libsffile.a \
-o sf2raw
/tmp/cckWYOAh.o(.text+0x297): In function `main':
: undefined reference to `sf_file_attach(int, sf_file_error*)'
/tmp/cckWYOAh.o(.text+0x2bd): In function `main':
: undefined reference to `sf_file_get_type(sf_file*, sf_file_error*)'
[...] //some more "undefined reference" errors
/tmp/cckWYOAh.o(.text+0x7d2): In function `main':
: undefined reference to `sf_file_detach(sf_file*, sf_file_error*)'
/tmp/cckWYOAh.o(.gnu.linkonce.t._Z19handle_sf_fileErrorPKc+0x1e): In
function `handle_sf_fileError(char const*)':
: undefined reference to `sf_file_perror(sf_file_error const*, char const*)'
collect2: ld returned 1 exit status
The sf_file_attach, etc. are defined in sffile.h, which reside in the above
include folder and there is also its object file sffile.o and the
libsffile.a.
sf2raw.c was originally a C program, so is all the Smartspace stuff, but I
changed the source of sf2raw.c to compile with g++ in order to be able to
link it against the qt libraries.
Anyone an idea what's wrong with the above?
Thanks in advance
Uwe
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| DINH Viet Hoa 2004-10-26, 3:56 am |
| Uwe Mayer wrote :
> The sf_file_attach, etc. are defined in sffile.h, which reside in the above
> include folder and there is also its object file sffile.o and the
> libsffile.a.
is there some :
#ifdef _cplusplus
extern "C" {
#endif
/* content_of_h_file */
#ifdef _cplusplus
}
#endif
in you sffile.h ?
--
DINH V. Hoa,
"j'arr�te l'al " -- Arsunique
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| Uwe Mayer 2004-10-26, 3:56 am |
| Tuesday 26 October 2004 09:30 am DINH Viet Hoa wrote:
> Uwe Mayer wrote :
>
[color=darkred]
> is there some :
>
> #ifdef _cplusplus
> extern "C" {
> #endif
>
> /* content_of_h_file */
>
> #ifdef _cplusplus
> }
> #endif
>
> in you sffile.h ?
no. :(
Is that all to be added?
Thanks,
Uwe
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| Nils O. Sel�sdal 2004-10-26, 9:00 am |
| Uwe Mayer wrote:
> Tuesday 26 October 2004 09:30 am DINH Viet Hoa wrote:
>
>
>
>
>
>
>
> no. :(
>
> Is that all to be added?
Yes, the C++ compiler have to be told that the code is C,
else it will apply C++ check/namemangling/etc to it.
--
Nils O. Sel�sdal
www.utelsystems.com
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| Uwe Mayer 2004-10-26, 9:00 am |
| Tuesday 26 October 2004 09:47 am "Nils O. Selåsdal" wrote:
> Yes, the C++ compiler have to be told that the code is C,
> else it will apply C++ check/namemangling/etc to it.
Graphic! It worked. I had to compile the sffile with g++, too, of course.
But: I guess it won't work with ordinary C programs any more, right?
I'd go symlink the .c file to a .cc file and modify the Makefile to produce
two versions of the archife.
Is there any naming convention for libs /archives which have to be present
as both C and C++ binaries?
Thanks,
Uwe
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| Nils O. Selåsdal 2004-10-26, 9:00 am |
| Uwe Mayer wrote:
> Tuesday 26 October 2004 09:47 am "Nils O. Selåsdal" wrote:
>
>
>
>
> Graphic! It worked. I had to compile the sffile with g++, too, of course.
> But: I guess it won't work with ordinary C programs any more, right?
hmm, you shouldn't need that though. You did apply the
extern "C" .. to all C header files ?
--
Nils O. Selåsdal
www.utelsystems.com
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| Uwe Mayer 2004-10-26, 3:58 pm |
| Tuesday 26 October 2004 13:24 pm "Nils O. Selåsdal" wrote:
[color=darkred]
> hmm, you shouldn't need that though. You did apply the
> extern "C" .. to all C header files ?
The archive really only exists from one header file. I modified this one. I
just wondered wether other C programs that are compiled with gcc can link
to this archive which was created with g++.
Ciao
Uwe
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| Paul Pluzhnikov 2004-10-26, 3:58 pm |
| Uwe Mayer <merkosh@hadiko.de> writes:
> I just wondered wether other C programs that are compiled with gcc can link
> to this archive which was created with g++.
Rather than "just wonder", you should read-up on C++ name mangling.
Once you *understand* how it works and why 'extern "C"' was
necessary, you can answer your own question (and make the first
step to becoming enlightened :)
Yes, archive libraries created from objects compiled with g++
can be linked into "plain C" programs, prvided none of the C++
features (exceptions, constructors, operator new, etc.) were used
in the source.
Cheers,
--
In order to understand recursion you must first understand recursion.
Remove /-nsp/ for email.
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