LINK1104: "D:\Windows.obj" file not found while building a simple opencv project.

Somesh Singh

@koahnig
Without opencv it builds fine..
like the example files given by the qt builds without any problem.
I am not sure if the environment is not set as required or i am not including some paths.
can you please help me with this.

SGaist

I missed on thing: you don't link against .dll files, you link against .lib files, you should start by fixing that.

Somesh Singh

@SGaist
I am just using the .pro file
the Cmake file is just me trying to figure out a way to loop back to working conditions with opencv.
but the .pro file gives me this error.

SGaist

As already written, fix the LIBS statement to link against the OpenCV libraries properly.

You can use Qt Creator add library feature for that.

Somesh Singh

@SGaist
I fixed that ...its still the same.
I think it has to do something with some header files maybe

SGaist

Does it happen when you try to link against the HighGui library ?

Somesh Singh

@SGaist yeah it still shows the same error.
i even tried including the libraries one by one..it still does not work
Do you think my code has some problems??

SGaist

Do you mean, you have that problem when you link any of the OpenCV libraries ?

Somesh Singh

@SGaist Yes
I tried using MingW compiler and it works fine with the building of the CmakeLists.txt file and i get the required output.
its just the compiler MSVC15 2017 x64 that i s not able to build the project.
Even with the Cmake it does not run as intended.

SGaist

On Windows, you can't mix and match C++ libraries built with different compilers. The only exception currently is VS2017 being backward compatible with VS2015.

Somesh Singh

@SGaist
So why am i getting the error for the ".obj" file not found
As shown in the example that i posted..its just configured to be used with Qt 5.12.0MSVC2017 x64
So why does it not work.

i was just trying different ways to make it work with a different compiler to check the integrity of my program .

SGaist

You should compare the Makefile generated by your CMake project and the one from the .pro file

Somesh Singh

@SGaist
Is there something specific that i should be looking for??
I am not an expert in debugging by just looking at the 2 files.

kshegunov

@Somesh-Singh said in LINK1104: "D:\Windows.obj" file not found while building a simple opencv project.:

So why am i getting the error for the ".obj" file not found

@SGaist said in LINK1104: "D:\Windows.obj" file not found while building a simple opencv project.:

On Windows, you can't mix and match C++ libraries built with different compilers. The only exception currently is VS2017 being backward compatible with VS2015.

Let's go back a step. Firstly your LIBS variable is incorrect. Secondly you're linking system libraries which from the code example it seems you shouldn't. And thirdly, if a set of libraries worked with mingw then they were compiled with mingw (hence the quote from @SGaist). That set of libraries can not, and shall not be used with msvc, ever. You need a set of libraries compiled with msvc to use them in an application built with msvc. This also extends to the msvc version - for example msvc2015 isn't backwards compatible, so you likely need to match the versions as well.

Somesh Singh

@kshegunov

I have specific set of libraries for both mingw and msvc.
Also, i linked the system libraries in the .pro file as it was not accepting them from the system variables "PATH"
My issue is just during the compilation with opencv.

For eg., Qt has its included examples just to try out for beginners, those examples run completely fine, which means the problem lies somewhere in the code itself which i wrote.

0_1549927377207_2c5e7161-0e8d-46f7-a940-69a67ad3e1ed-image.png

these are all the compilers i have which are seperately

0_1549927469876_fbd57746-4af4-4f11-9815-73b8d8dda0c1-image.png

I need to get my default compiler to work with opencv.
thats my end goal

kshegunov

Okay, let me rephrase:

INCLUDEPATH += "D:\Windows Kits\10\Include\10.0.17763.0\ucrt"
INCLUDEPATH += "D:\Windows Kits\10\Include\10.0.17763.0\ucrt\sys"

Why do you need this?

LIBS += D:\Windows Kits\10\Lib\10.0.17763.0\um\x64\shell32.lib

What part of the system API you're using, so you need this one? (may be the source of your error too).

LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_core400.dll
LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_highgui400.dll
LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_imgcodecs400.dll
LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_imgproc400.dll
LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_features2d400.dll
LIBS += D:\OpenCV\opencv\build\bin\Release\opencv_calib3d400.dll

One does not link .dlls, one links against them with the help of a .lib.
https://doc.qt.io/qt-5/qmake-variable-reference.html#libs

PS.
Did you compile opencv with the version of msvc you're trying the build the application with?

Somesh Singh

@kshegunov i changed the .dll to .lib

the only reason i included the shell32.lib file was because it shows that it cannot find the specified file before giving me the error that "Cannot find file D:\Windows.obj"

Also i built opencv using both MSVS 2017 x64 and mingw x86.
the build was succesfull without any errors in the process.

SGaist

Then you have to ensure the path you are using points to the OpenCV version built by the same compiler as you are currently using for your application.

Somesh Singh

@SGaist I have tried adding all the paths to the system variable path manager but its still the same.
Does my Qt have any configuration issues while compiling or building.
I also ran configure.bat from the source folder to properly configure the environment but still no progress.

SGaist

Did you try to use a pre-built version of OpenCV ?