lnk2019 with opencv treshold

SGaist

You are missing the "-l" in your LIBS lines.

superdu

hum, but they are presents in makefile.debug

i also try again this notation but still the same problem

LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_calib3d
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_core
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_dnn
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_features2d
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_flann
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_highgui
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_imgcodecs
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_imgproc
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_ml
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_objdetect
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_photo
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_stitching
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_video
LIBS += -L"C:/src/vcpkg/vcpkg/packages/opencv4_x64-windows/lib" -lopencv_videoio

SGaist

So if you build in debug mode it works ?

superdu

no... i dont know why but i feel if we find the problem that will be something really stupid. and if not i will just try to compile by hand opencv but that should work like that

SGaist

Are these static or dynamic librairies ?

In any case, what I would do is simplify things with the LIBS part to only link to opencv_core and only use symbols from that library in the sample application.

This will restrict the scope of the issue.

superdu

i just checked it with lib.exe and libs file containes dll. its dynamics library

superdu

ok so i compile by hand opencv following this step: https://wiki.qt.io/How_to_setup_Qt_and_openCV_on_Windows_with_MSVC2017#Building_OpenCV

the two difference is i use msvc 2019 and opencv 4.5.1.

compilation seems to be a succes but when i try to us it in qt the application crash without any information

SGaist

If there's a crash then it likely is that the dlls are not found at run time. Go to the Run part of the Project panel and update the PATH environment variable there so that the folder containing the OpenCV dlls are found.

superdu

Ok my bad. i already added to path but i didnt restart my computer. i just restart it and that work well.

result: no more problem and treshold function work. thank you so much for your time!

SGaist

Then you did it in the wrong place. Do not alter your machine's PATH, do it in Qt Creator as I explained above.