代码非常简单，就一个cpp文件，但是里面涉及opencv的cv::Mat/cv::imread/cv::imshow/cv::waitKey在用cmake构建时全部报错。
将涉及cv的部分注释掉，只保留一个std::cout<<“hello world!”<<std::endl;的话是可以正常构建，运行的，也就是说，cmake和c++本身没问题。#include <iostream> #include <opencv2/core.hpp> #include <opencv2/imgcodecs.hpp> #include <opencv2/highgui.hpp> int main(void) { std::cout<<“hello world!”<<std::endl; cv::Mat img1 = cv::imread(“wallhaven-105871.jpg”,cv::IMREAD_COLOR); cv::imshow(“img1”, img1); cv::waitKey(0); return 0; }
build时具体的报错信息为：[build] [ 50%] Linking CXX executable hello.exe [build] D:/keypro/mingw64posix/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: CMakeFiles\hello.dir/objects.a(helloworld.cpp.obj): in function `main’: [build] D:/WORK/opencvproj/helloworld.cpp:9: undefined reference to `cv::imread(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int)’ [build] D:/keypro/mingw64posix/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:/WORK/opencvproj/helloworld.cpp:10: undefined reference to `cv::imshow(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, cv::_InputArray const&)’ [build] D:/keypro/mingw64posix/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:/WORK/opencvproj/helloworld.cpp:11: undefined reference to `cv::waitKey(int)’ [build] D:/keypro/mingw64posix/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:/WORK/opencvproj/helloworld.cpp:13: undefined reference to `cv::Mat::~Mat()’ [build] D:/keypro/mingw64posix/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:/WORK/opencvproj/helloworld.cpp:13: undefined reference to `cv::Mat::~Mat()’
以下为CMakeLists.txt:cmake_minimum_required(VERSION 3.19) project(hello) set(OpenCV_DIR “D:/WORK/opencv/build/x64/vc16/lib”) find_package(OpenCV REQUIRED CONFIG) # 此处的find_package是可以正常找到opencv的 include_directories(${OpenCV_INCLUDE_DIRS}) # dll lib文件所在目录均被加入链接路径 link_directories( D:/WORK/opencv/build/x64/vc16/lib) link_directories( D:/WORK/opencv/build/x64/vc16/bin) add_executable(hello helloworld.cpp) # opencv库里所有lib dll文件都链接了 target_link_libraries(${PROJECT_NAME} opencv_world470 opencv_world470d opencv_world470.dll opencv_world470d.dll)
完全没有头绪…望大佬解答！
问题1:OpenCV_DIR设置错误
如果你用自己编译的,应该这样写:set(OpenCV_DIR E:/work/opencv-4.6.0/build/install)
opencv编译以后,不执行make install,它是不会把所有include 和lib拷贝到一起的
你上面用set(OpenCV_DIR)
但是后面target_link_libraries 应该写成:target_link_libraries(${PROJECT_NAME} opencv_world470)
即可
问题2: 看你输出Link正确出了hello.exe link_load libraries错误
最大可能性就是没把opencv_world470.dll 设置到环境目录
你可以拷贝opencv_world470.dll 到hello.exe同一目录下
或者 设置opencv_world470.dll到环境变量
# opencv库里所有lib dll文件都链接了 target_link_libraries(${PROJECT_NAME} opencv_world470 opencv_world470d opencv_world470.dll opencv_world470d.dll)
链接不需要 dll，dll 是你在运行的时候才需要的，你的后缀呢？opencv_world470 应该是 opencv_world470.lib 吧？把文件名写全了试试：# opencv库里所有lib dll文件都链接了 target_link_libraries(${PROJECT_NAME} opencv_world470.lib opencv_world470d.lib)
