Symbols not found for architecture x86_64 MacOS Yosemite

saeedBaba

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15:19:32: Running steps for project opencv_test_qmake...
15:19:33: Starting: "/Users/apple/Qt6/6.1.1/clang_64/bin/qmake" /usr/local/lib/C++Project/Qt6/opencv_test_qmake/opencv_test_qmake.pro -spec macx-clang CONFIG+=debug CONFIG+=x86_64 CONFIG+=qml_debug
Info: creating stash file /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/.qmake.stash
15:19:33: The process "/Users/apple/Qt6/6.1.1/clang_64/bin/qmake" exited normally.
15:19:33: Starting: "/usr/bin/make" -f /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/Makefile qmake_all
make: Nothing to be done for `qmake_all'.
15:19:33: The process "/usr/bin/make" exited normally.
15:19:33: Starting: "/usr/bin/make" -j8
/Users/apple/Qt6/6.1.1/clang_64/libexec/uic ../opencv_test_qmake/dialog.ui -o ui_dialog.h
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o main.o ../opencv_test_qmake/main.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o dialog.o ../opencv_test_qmake/dialog.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -dM -E -o moc_predefs.h /Users/apple/Qt6/6.1.1/clang_64/mkspecs/features/data/dummy.cpp
/Users/apple/Qt6/6.1.1/clang_64/libexec/moc -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB --include /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/moc_predefs.h -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -I/usr/local/lib/C++Project/Qt6/opencv_test_qmake -I/usr/local/include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1 -I/Library/Developer/CommandLineTools/usr/lib/clang/12.0.5/include -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include -I/Library/Developer/CommandLineTools/usr/include -F/Users/apple/Qt6/6.1.1/clang_64/lib ../opencv_test_qmake/dialog.h -o moc_dialog.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o moc_dialog.o moc_dialog.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -stdlib=libc++ -headerpad_max_install_names  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wl,-rpath,@executable_path/../Frameworks -Wl,-rpath,/Users/apple/Qt6/6.1.1/clang_64/lib -o opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake main.o dialog.o moc_dialog.o   -F/Users/apple/Qt6/6.1.1/clang_64/lib -L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_features2d -lopencv_highgui -lopencv_calib3d -opencv_imcodec -framework QtWidgets -framework QtGui -framework AppKit -framework ImageIO -framework Metal -framework QtCore -framework DiskArbitration -framework IOKit -framework AGL -framework OpenGL   
Undefined symbols for architecture x86_64:
  "cv::imread(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, int)", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake] Error 1
15:19:36: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project opencv_test_qmake (kit: Desktop Qt 6.1.1 clang 64bit)
When executing step "Make"
15:19:36: Elapsed time: 00:03.

jsulm

@saeedBaba I don't see -lopencv_imcodec in the linker call.
Please post your current pro file, it looks like you forgot to put - in -opencv_imcodec -> should be -lopencv_imcodec
And I think it should be: -lopencv_imgcodecs

saeedBaba

@jsulm said in Symbols not found for architecture x86_64 MacOS Yosemite:

-lopencv_imcodec

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    dialog.cpp

HEADERS += \
    dialog.h

FORMS += \
    dialog.ui

#INCLUDEPATH += /usr/local/Cellar/opencv/4.5.2_4/include/opencv4

#LIBS += -L/usr/local/Cellar/opencv/4.5.2_4/lib \
#     -lopencv_core \
#     -lopencv_imgproc \
#     -lopencv_features2d\
#     -lopencv_highgui
#     -lopencv_imcodec
#     -lopencv_calib3d


#INCLUDEPATH += /usr/local/include/opencv4

#LIBS += -L/usr/local/lib \
#     -lopencv_core \
#     -lopencv_imgproc \
#     -lopencv_features2d\
#     -lopencv_highgui
#     -lopencv_calib3d
#     -lopencv_imcodec

#QMAKE_MACOSX_DEPLOYMENT_TARGET = 11.0

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

macx {
    INCLUDEPATH += /usr/local/include/opencv4

    QMAKE_MACOSX_DEPLOYMENT_TARGET = 11.0

    LIBS += -L/usr/local/lib
    LIBS += -lopencv_core -lopencv_imgproc -lopencv_features2d -lopencv_highgui -lopencv_calib3d -lopencv_imcodec

}

LOG:

/Users/apple/Qt6/6.1.1/clang_64/bin/qmake -o Makefile ../opencv_test_qmake/opencv_test_qmake.pro -spec macx-clang CONFIG+=debug CONFIG+=x86_64 CONFIG+=qml_debug
/Library/Developer/CommandLineTools/usr/bin/clang++ -stdlib=libc++ -headerpad_max_install_names  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wl,-rpath,@executable_path/../Frameworks -Wl,-rpath,/Users/apple/Qt6/6.1.1/clang_64/lib -o opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake main.o dialog.o moc_dialog.o   -F/Users/apple/Qt6/6.1.1/clang_64/lib -L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_features2d -lopencv_highgui -lopencv_calib3d -lopencv_imcodec -framework QtWidgets -framework QtGui -framework AppKit -framework ImageIO -framework Metal -framework QtCore -framework DiskArbitration -framework IOKit -framework AGL -framework OpenGL   
ld: library not found for -lopencv_imcodec
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake] Error 1
15:39:26: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project opencv_test_qmake (kit: Desktop Qt 6.1.1 clang 64bit)
When executing step "Make"
15:39:26: Elapsed time: 00:00.

jsulm

@saeedBaba said in Symbols not found for architecture x86_64 MacOS Yosemite:

-lopencv_imcodec

-lopencv_imgcodecs

saeedBaba

THANKS ALOT!

IT IS FINALLY WORKING!!!!

can you give me a reputation so I can post faster?

one more question:
How can I know what libraries to include for the future? how should I check?

jsulm

@saeedBaba said in Symbols not found for architecture x86_64 MacOS Yosemite:

How can I know what libraries to include for the future? how should I check?

In case of OpenCV you can see in the documentation URL: https://docs.opencv.org/3.4/d4/da8/group__imgcodecs.html and from the include header (at least in this case):

#include <opencv2/imgcodecs.hpp>

saeedBaba

@jsulm said in Symbols not found for architecture x86_64 MacOS Yosemite:

https://docs.opencv.org/3.4/d4/da8/group__imgcodecs.html

for example, I get the same error for this code:
1- where should I check for what to include?

#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include <iostream>

using namespace cv;
using namespace std;

void drawText(Mat & image);

int main()
{
    cout << "Built with OpenCV " << CV_VERSION << endl;
    Mat image;
    VideoCapture capture;
    capture.open(0);
    if(capture.isOpened())
    {
        cout << "Capture is opened" << endl;
        for(;;)
        {
            capture >> image;
            if(image.empty())
                break;
            drawText(image);
            imshow("Sample", image);
            if(waitKey(10) >= 0)
                break;
        }
    }
    else
    {
        cout << "No capture" << endl;
        image = Mat::zeros(480, 640, CV_8UC1);
        drawText(image);
        imshow("Sample", image);
        waitKey(0);
    }
    return 0;
}

void drawText(Mat & image)
{
    putText(image, "Hello OpenCV",
            Point(20, 50),
            FONT_HERSHEY_COMPLEX, 1, // font face and scale
            Scalar(255, 255, 255), // white
            1, LINE_AA); // line thickness and type
}

2- Is there any way to include the whole thing in .pro file and then just include required hpp in the cpp file? I do the same thing when using CMake.

jsulm

@saeedBaba said in Symbols not found for architecture x86_64 MacOS Yosemite:

Is there any way to include the whole thing in .pro file

You should only link what is really needed. Else you will have to provide libs which are not used by your app making your package unnecessary big.

"I get the same error for this code" - if it is the same error, then the solution is also same.
But I guess the error is not same? Please post the error.

saeedBaba

Log file for the code with videocapture .

16:21:02: Running steps for project opencv_test_qmake...
16:21:02: Starting: "/Users/apple/Qt6/6.1.1/clang_64/bin/qmake" /usr/local/lib/C++Project/Qt6/opencv_test_qmake/opencv_test_qmake.pro -spec macx-clang CONFIG+=debug CONFIG+=x86_64 CONFIG+=qml_debug
Info: creating stash file /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/.qmake.stash
16:21:03: The process "/Users/apple/Qt6/6.1.1/clang_64/bin/qmake" exited normally.
16:21:03: Starting: "/usr/bin/make" -f /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/Makefile qmake_all
make: Nothing to be done for `qmake_all'.
16:21:03: The process "/usr/bin/make" exited normally.
16:21:03: Starting: "/usr/bin/make" -j8
/Users/apple/Qt6/6.1.1/clang_64/libexec/uic ../opencv_test_qmake/dialog.ui -o ui_dialog.h
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o main.o ../opencv_test_qmake/main.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -dM -E -o moc_predefs.h /Users/apple/Qt6/6.1.1/clang_64/mkspecs/features/data/dummy.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o dialog.o ../opencv_test_qmake/dialog.cpp
/Users/apple/Qt6/6.1.1/clang_64/libexec/moc -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB --include /usr/local/lib/C++Project/Qt6/build-opencv_test_qmake-Desktop_Qt_6_1_1_clang_64bit-Debug/moc_predefs.h -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -I/usr/local/lib/C++Project/Qt6/opencv_test_qmake -I/usr/local/include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1 -I/Library/Developer/CommandLineTools/usr/lib/clang/12.0.5/include -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include -I/Library/Developer/CommandLineTools/usr/include -F/Users/apple/Qt6/6.1.1/clang_64/lib ../opencv_test_qmake/dialog.h -o moc_dialog.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++1z  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wall -Wextra -fPIC -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../opencv_test_qmake -I. -I../../../../include/opencv4 -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtWidgets.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtGui.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/lib/QtCore.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I. -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/AGL.framework/Headers -I/Users/apple/Qt6/6.1.1/clang_64/mkspecs/macx-clang -F/Users/apple/Qt6/6.1.1/clang_64/lib -o moc_dialog.o moc_dialog.cpp
/Library/Developer/CommandLineTools/usr/bin/clang++ -stdlib=libc++ -headerpad_max_install_names  -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=11.0 -Wl,-rpath,@executable_path/../Frameworks -Wl,-rpath,/Users/apple/Qt6/6.1.1/clang_64/lib -o opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake main.o dialog.o moc_dialog.o   -F/Users/apple/Qt6/6.1.1/clang_64/lib -L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_features2d -lopencv_highgui -lopencv_calib3d -lopencv_imgcodecs -framework QtWidgets -framework QtGui -framework AppKit -framework ImageIO -framework Metal -framework QtCore -framework DiskArbitration -framework IOKit -framework AGL -framework OpenGL   


Undefined symbols for architecture x86_64:
  "cv::VideoCapture::open(int, int)", referenced from:
      _main in main.o
  "cv::VideoCapture::VideoCapture()", referenced from:
      _main in main.o
  "cv::VideoCapture::~VideoCapture()", referenced from:
      _main in main.o
  "cv::VideoCapture::operator>>(cv::Mat&)", referenced from:
      _main in main.o
  "cv::VideoCapture::isOpened() const", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [opencv_test_qmake.app/Contents/MacOS/opencv_test_qmake] Error 1
16:21:06: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project opencv_test_qmake (kit: Desktop Qt 6.1.1 clang 64bit)
When executing step "Make"
16:21:06: Elapsed time: 00:04.

jsulm

@saeedBaba

#include <opencv2/videoio.hpp>

So, it is -lopencv_videoio

saeedBaba

Thanks.

How did you find it?
How should I find future libraries to include?

jsulm

@saeedBaba said in Symbols not found for architecture x86_64 MacOS Yosemite:

How did you find it?

From the include file name. This is very OpenCV specific, maybe there is some documentation/explanation in that project.

saeedBaba

@jsulm said in Symbols not found for architecture x86_64 MacOS Yosemite:

opencv2/videoio.hpp

What I am asking is that, do you just google

opencv2/videoio.hpp

or there is a documentation link you look into?

jsulm

@saeedBaba I googled for cv::VideoCapture and got https://docs.opencv.org/3.4/d8/dfe/classcv_1_1VideoCapture.html where you can see the include:

#include <opencv2/videoio.hpp>

And in case of OpenCV it looks like a header file corresponds to a lib: videoio.hpp -> opencv_videoio
But this is so in case of OpenCV, not necesserily every lib out there!

Qt does it more clear: it tells you what to add to pro file to use a class. For example in https://doc.qt.io/qt-5/qwidget.html you can see:

QT += widgets

saeedBaba

@jsulm said in Symbols not found for architecture x86_64 MacOS Yosemite:

https://docs.opencv.org/3.4/d8/dfe/classcv_1_1VideoCapture.html

but this link does not mention anything about -lopencv_videoio
How did you find that?

jsulm

@saeedBaba Again: I deduce the lib name from the include file.

#include <opencv2/videoio.hpp>

So, header file name is videoio.hpp, lib name is opencv_videoio

saeedBaba

Hi there

I need to install opencv on qt on windows device. I was wondering if you could give me a link to an instruction or tutorial, preferably one that foes not need to alter Cmake since I have had download issues with cmake before.

Thanks

jsulm

@saeedBaba Official documentation is here: https://docs.opencv.org/3.4/d3/d52/tutorial_windows_install.html
You should consider asking in an OpenCV forum if you have problems building it, as OpenCV has nothing to do with Qt.