Compilation problem on Qt c++ on mac os x 10.8.5

SGaist

Go the run panel in the Projects panel.

If it's not there, add a DYLD_LIBRARY_PATH environment variable in the "Run environment" part and as value put the path to the folder containing libPvAPI.dylib (if it already exists, add the path to the current list)

studentvision

thanks a lot,

It is progressing. I got a new errors. I learned a lots today. I cleaned and rebuild my project but I got this error.

@dyld: Symbol not found: __cg_jpeg_resync_to_restart
Referenced from: /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
Expected in: /opt/local/lib//libJPEG.dylib
in /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO@

studentvision

Hello,

I did some research on google, developers suggests that we have to avoid use DYLD_LIBRARY_PATH because there is dynamic-linking-conflict between different libjpeg dynamic libraries on OSX . ("Conflict between dynamic linking priority in OSX?":http://stackoverflow.com/questions/17643509/conflict-between-dynamic-linking-priority-in-osx)

SGaist

Indeed, that's why I generally ensure that common dependencies I might have between libraries comes from a common place

studentvision

Hello,

I resolved the problem by put the library given in the SDK on the project folder. But, really I can not why when I configure it like:

@DYLD_LIBRARY_PATH=/opt/local/bin@ it did not work and I get an error like @dyld: Symbol not found: __cg_jpeg_resync_to_restart
Referenced from: /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
Expected in: /opt/local/lib//libJPEG.dylib
in /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO@
but when I copied the library form /opt/local/bin to the project folder, it work fine ??!! Any explication please ?

SGaist

@DYLD_LIBRARY_PATH=/opt/local/bin@

you are pointing to the bin folder, the dylibs are in

@DYLD_LIBRARY_PATH=/opt/local/lib@

studentvision

Hello,

Sorry, I made a mistake in my last post.

In fact, I put@ DYLD_LIBRARY_PATH=/opt/local/lib@ but it does not work but when I copied the library form /opt/local/lib to the project folder, it work fine ??!! Any explication please ?

SGaist

Have a look at your application with otool -L you'll see what is linked.

Then you also have the search order which is important

studentvision

Hello,
I run this command

@otool -L main .o@
but I did not get any output ?

SGaist

Not on main.o on the executable generated

studentvision

Hello,

I run @otool -L ListAllPrsilicaCameras@

I get these output:
@ListAllPrsilicaCameras:
libPvAPI.dylib (compatibility version 0.0.0, current version 0.0.0)
libPvJNI.dylib (compatibility version 0.0.0, current version 0.0.0)
/opt/local/lib/libjpeg.9.dylib (compatibility version 11.0.0, current version 11.0.0)
/Users/kifaraaouig/Qt/5.2.0/clang_64/lib/QtCore.framework/Versions/5/QtCore (compatibility version 5.2.0, current version 5.2.0)
/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 60.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)@
I remark that the problem is in
@libPvAPI.dylib@

When i put @DYLD_LIBRARY_PATH=/opt/local/lib@

I get the error mentioned earlier but when I changed it like:

@DYLD_LIBRARY_PATH=the project folder@

What is the problem ?

hskoglund

Hi, welcome to Mac's version of DLL hell :-)

I think it's because your app's otool -L references /opt/local/lib/libjpeg.9.dylib and otool -L on Apple's ImageIO.Framework (the one that gave the error message on Page 1) references /System/Library/Frameworks/ImageIO.framework/Versions/A/Resources/libJPEG.dylib.

When you use the copied DLLs in your project's folder, I think the ImageIO.Framework loads Apple's libpjpeg.dylib and all is ok, but maybe in /opt/local/lib there's a symbolic link called libpjpeg.dylib, so in that case ImageIO.Framework thinks /opt/local/lib's libpjpeg.dylib is kosher to use (and hence the error, because it's not).

Make sense? Anyway I think you need a more complete understanding exactly what dlls/dylibs are loaded. You can try with the lsof utility like this (first start your app and then open Terminal and type lsof -c and the first few letters of your app):
lsof -c ListA

Or lsof -c ListA | sort
(in this case it's useful with a big Terminal window :-)

sandy.martel

To trace what shared libraries get loaded in which order see:

@man dyld@

more precisely the variable DYLD_PRINT_LIBRARIES

in short:

@export DYLD_PRINT_LIBRARIES=1
/path/to/your/app
@

studentvision

Hello,

At the end, it is impossible to fix that in the case of

@ DYLD_LIBRARY_PATH=/opt/local/lib@