Re: Cygwin64 libjpeg-turbo missing/damaged library file

[Bill Hammond <billsc26 at hotmail dot com>]

>>I am having trouble compiling an application that uses the libjpeg libraries under cygwin64.
>>
>>My program has compiled and run under cygwin32 for a long time. I can compile and run it
>>under cygwin64 when I build and link against my own libjpeg.a. When I try and download the
>>libjpeg-turbo libraries for cygwin64, it all comes apart. The "libjpeg-turbo" package is
>>source only, and when I install "libjpeg-devel" and link against it with "-ljpeg", all the
>>jpeg function calls are undefined.
>>
>>I am using the cygwin64 installer. Is there a problem with the cygwin64 libjpeg package(s),
>>or am I not doing something right?
>
>Hi Bill,
>
>could you show your link instruction ?
>
>Have you a small test case ?
>FYI the turbo devel package is : libturbojpeg-devel
>
>Regards
>Marco

So I installed the libturbojpeg-devel package, but I also had to install the libjpeg-devel
package to get the proper include files added to /usr/include ("jconfig.h", "jerror.h" and
so on).

I can successfully link my program against my own libjpeg with:

cc -g -lm -flto imgopt.o support.o ../common/jpeg.o ../common/gifread.o
../common/gifwrite.o ../common/image.o ../common/misc.o ../common/file.o
../common/fuzzy.o ../jpeg-8c/libjpeg.a -o a.exe

When I try and link against the system libraries (same when I use -lturbojpeg):

cc -g -lm -ljpeg -flto imgopt.o support.o ../common/jpeg.o ../common/gifread.o
../common/gifwrite.o ../common/image.o ../common/misc.o ../common/file.o
../common/fuzzy.o -o a.exe

none of the libjpeg functions resolves:

/tmp/cc4EItUr.ltrans4.ltrans.o: In function `jpeg_write':
/home/proj/../common/jpeg.c:340: undefined reference to `jpeg_std_error'
/home/proj/../common/jpeg.c:340:(.text+0x102): relocation truncated to fit: R_X86_64_PC32
against undefined symbol `jpeg_std_error'
/home/proj/../common/jpeg.c:349: undefined reference to `jpeg_destroy_compress'

etc...

I thought this might be another -flto problem, but compiling and linking without it makes no
difference.

Thanks!

- B 		 	   		  
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