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

[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.

these are all the compilers i have which are seperately

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 ?

[Somesh Singh]

@SGaist
Where can i get the prebuilt version.
i used OpenCV 4.0.0 from the website. and built it from scratch.
Do you think i might have excluded some packages from Cmake while building and configuring.

[SGaist]

https://opencv.org/releases.html

Version 4.0.1 is available as it seems.