Desktop Qt 5.8.0 MinGW 32bit Windows app using ImageMagick libs

smoyertech

I have a working Desktop Qt 5.8.0 MinGW 32bit Windows project app, and want to try using ImageMagick to read various image formats. I downloaded the pre-built "ImageMagick-i686-pc-mingw32.tar.gz" binary release, since I do not want to use the MSVC compiled binary release.

I am getting undefined references when building my Qt project. We have had no problems building with ImageMagick and running on Linux, only with Windows.

Has anyone had any success using ImageMagick libraries with QT/MinGW on Windows? If so can you share your success?

SGaist

Hi,

What exact error are you getting ?

How does your .pro file look like ?

smoyertech

Here is the .pro file:

QT += core

TARGET = libcc_imagechunks
TEMPLATE = lib

DEFINES += LIBCC_IMAGECHUNKS_LIBRARY

SOURCES += cc_imagechunks.cpp

HEADERS += cc_imagechunks.hpp

win32 {
INCLUDEPATH += "C:/Workspace/Qt/ImgAnnotation/ImageMagic-i686-pc-mingw32-6.8.5/include/ImageMagick-6"
LIBS += -L"C:/Workspace/Qt/ImgAnnotation/ImageMagic-i686-pc-mingw32-6.8.5/bin" \
-lMagick++-6.Q16-1 \
-lMagickCore-6.Q16-1 \
-lMagickWand-6.Q16-1
}

It generates lots of undefined references:

debug/cc_imagechunks.o: In function ZN14CC_ImageChunks21initializeImageMagickEv': C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../CC_ImageChunks/SAVE/cc_imagechunks.cpp:85: undefined reference to Magick::CoderInfo::nameabi:cxx11 const'
debug/cc_imagechunks.o: In function ZN14CC_ImageChunks12setImageTypeEv': C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../CC_ImageChunks/SAVE/cc_imagechunks.cpp:114: undefined reference to Magick::Image::ping(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../CC_ImageChunks/SAVE/cc_imagechunks.cpp:130: undefined reference to Magick::Image::magick[abi:cxx11]() const' debug/cc_imagechunks.o: In function ZN14CC_ImageChunks14IMReadToOCVMatEv':
C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../CC_ImageChunks/SAVE/cc_imagechunks.cpp:144: undefined reference to Magick::Image::read(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../CC_ImageChunks/SAVE/cc_imagechunks.cpp:160: undefined reference to Magick::Image::write(int, int, unsigned int, unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, MagickCore::StorageType, void*)'
debug/cc_imagechunks.o: In function ZN6Magick13coderInfoListINSt7__cxx114listINS_9CoderInfoESaIS3_EEEEEvPT_NS3_9MatchTypeES8_S8_': C:\Workspace\Qt\ImgAnnotation\build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug/../ImageMagic-i686-pc-mingw32-6.8.5/include/ImageMagick-6/Magick++/STL.h:2080: undefined reference to Magick::CoderInfo::CoderInfo(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
collect2.exe: error: ld returned 1 exit status
Makefile.Debug:63: recipe for target 'debug\libcc_imagechunks.dll' failed
mingw32-make[1]: Leaving directory 'C:/Workspace/Qt/ImgAnnotation/build-cc_imagechunks-Desktop_Qt_5_8_0_MinGW_32bit-Debug'
Makefile:34: recipe for target 'debug' failed
mingw32-make[1]: *** [debug\libcc_imagechunks.dll] Error 1
mingw32-make: *** [debug] Error 2
07:16:33: The process "C:\Qt\Tools\mingw530_32\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project cc_imagechunks (kit: Desktop Qt 5.8.0 MinGW 32bit)
When executing step "Make"
07:16:33: Elapsed time: 00:10.

SGaist

Are you sure you have an 32bit ImageMagick build ?

smoyertech

Yes, the download we are using is ImageMagick-i686-pc-mingw32.tar.gz, so we are presuming 32-bit. I do not know how to confirm it is a 32-bit build.

SGaist

You can use Dependency Walker for that.

Did you modify the C++11 related flags in your .pro file ?

smoyertech

Thanks, I confirmed the ImageMagick dlls are 32 bit.

I added "DEFINES += __MINGW32__" in the .pro file but that did not remove the undefined reference errors. Do you know if there are other defines I need to add?

smoyertech

I found the root cause of the issue.

The following link explains about how changes were made to the C++ compiler necessary to conform to the 2011 C++ standard. The ImageMagick binary release built using the MinGW compiler was built prior to the the compiler changes and the Qt 5.8 MinGW compiler was built more recently.

https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html

The following simple change to the .pro file fixed the problem:

# Force pre C++11 style name mangling in order to be compatible with pre-built MinGW ImageMagick DLLs
DEFINES += "_GLIBCXX_USE_CXX11_ABI=0"

SGaist

That's a sneaky one !

Glad you found out and thanks for sharing !