undefined reference to `opj_version'

[GoogleCodeExporter]

I'm trying to compile a simple example program that uses openjpeg 2.0.0.

The example program is:
extern int opj_version();
int main(void){ opj_version(); }

I'm compiling it with: i686-w64-mingw32-gcc ./test-openjpeg.c -lopenjp2

I get the error:
/tmp/cci01N0F.o:test-openjpeg.c:(.text+0xc): undefined reference to 
`opj_version'
collect2: error: ld returned 1 exit status

When running: i686-w64-mingw32-nm 
'/home/kyle/software/ffmpeg/pkgs/openjpeg/openjpeg-2.0.0-win32/lib/libopenjp2.a'
 | grep opj_version

I get the output:
00000228 T _opj_version@0

Does anyone know why I might be having this issue? I can provide any further 
details.

Original issue reported on code.google.com by zera...@gmail.com on 9 Dec 2012 at 4:57

[GoogleCodeExporter]

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <openjpeg.h>

int main(void)
{
    printf("OPJ2 version is %s\n",opj_version());

    return 0;
}

This simple program version2.c I have compiled with:

gcc version2.c -o version2 -I/usr/local/opj2/include/openjpeg-2.0/openjpeg.h 
-L/usr/local/opj2/lib -lopenjp2

And called:

./version2

OPJ2 version is 2.0.0

winfried

Original comment by szukw...@arcor.de on 10 Dec 2012 at 6:13

[GoogleCodeExporter]

I tried to compile your example program and got a failed result.

Here is my output:

$ cat ./version2.c 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <openjpeg.h>

int main(void)
{
    printf("OPJ2 version is %s\n",opj_version());

    return 0;
}

$ i686-w64-mingw32-gcc version2.c -o version2 
"-I/home/kyle/software/ffmpeg/pkgs/openjpeg/openjpeg-2.0.0-win32/include/openjpe
g-2.0" "-L/home/kyle/software/ffmpeg/pkgs/openjpeg/openjpeg-2.0.0-win32/lib" 
-lopenjp2
/tmp/cc0A0ds4.o:version2.c:(.text+0xf): undefined reference to 
`_imp__opj_version@0'
collect2: error: ld returned 1 exit status

So now I get an undefined reference to `_imp__opj_version@0'

Original comment by zera...@gmail.com on 10 Dec 2012 at 4:30

[GoogleCodeExporter]

The 'imp' prefix usually means: I expect a dynamic library.
Is there a 'bin/openjp2.dll' on your system?

winfried

Original comment by szukw...@arcor.de on 10 Dec 2012 at 8:20

[GoogleCodeExporter]

I compile the lib statically, and there are no .dll files present.

Original comment by zera...@gmail.com on 10 Dec 2012 at 9:39

[GoogleCodeExporter]

I compile openjpeg with:
-DCMAKE_C_COMPILER=i686-w64-mingw32-gcc -DCMAKE_SYSTEM_NAME=Windows-GNU 
-DCMAKE_CXX_COMPILER=i686-w64-mingw32-g++ 
-DCMAKE_INSTALL_PREFIX=/home/kyle/software/ffmpeg/pkgs/openjpeg/openjpeg-2.0.0-w
in32 -DBUILD_SHARED_LIBS:bool=off 
-DZLIB_INCLUDE_DIR=/home/kyle/software/ffmpeg/pkgs/zlib/zlib-1.2.7/include 
-DZLIB_LIBRARY=/home/kyle/software/ffmpeg/pkgs/zlib/zlib-1.2.7/lib 
-DBUILD_THIRDPARTY=1 -DCMAKE_C_FLAGS=-DOPJ_STATIC ../source/openjpeg-2.0.0

openjpeg compiles fine, and I don't run into any errors until I try to use the 
lib.

Original comment by zera...@gmail.com on 11 Dec 2012 at 3:43

[GoogleCodeExporter]

I fixed this issue by manually editing the code and commenting out all 
"__declspec(dllexport)" and "__declspec(dllimport)".

I then compiled with:
-DOPJ_STATIC -DDLL_EXPORT=

It seems to be working now.

Original comment by zera...@gmail.com on 12 Dec 2012 at 2:20

[GoogleCodeExporter]

Looks like I spoke too soon.

When trying to compile the original code I had issues with:
extern int opj_version();
int main(void){ opj_version(); }

I get the error again.

The code that compiled was:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <openjpeg.h>

int main(void)
{
    printf("OPJ2 version is %s\n",opj_version());

    return 0;
}

I'm not sure why that works and the other doesn't though.

I still think this issue is related to a dll/dynamic lib issue but I can't 
confirm that.

If any information is needed let me know, I would like to see this issue 
resolved.

Original comment by zera...@gmail.com on 12 Dec 2012 at 4:09

[GoogleCodeExporter]

The prototype of opj_version is :
OPJ_API const char * OPJ_CALLCONV opj_version(void);

It is not int opj_version();

So your test program is wrong.

You should not try to redefine the openjpeg headers content yourself, just 
stick with "#include <openjpeg.h>" and you should be safe.

Original comment by julien.m...@gmail.com on 17 Dec 2012 at 1:39

[GoogleCodeExporter]

Closing as invalid. Thanks Julien for catching this !

Original comment by mathieu.malaterre on 17 Dec 2012 at 1:41

• Changed state: Invalid

[GoogleCodeExporter]

Also, the name of the functions in the public API can be mangled.
Another reason to say that defining the openjpeg headers content yourself is 
wrong.

Original comment by julien.m...@c-s.fr on 17 Dec 2012 at 1:42