macOS通过Homebrew安装OpenCV后CMake调用pkg-config链接报错如何解决

• CMake配置未传递OpenCV库文件的搜索路径给链接器，brew安装的OpenCV默认存放在非系统默认的链接路径下，仅传递库名的情况下链接器无法定位到对应文件
• 当前使用的${OPENCV4_LIBRARIES}变量仅包含库名称，不携带路径信息，缺少-L对应的搜索路径参数

方案1：补充链接路径（最小修改现有配置） #

在target_link_libraries配置前添加库搜索路径声明即可，修改后的完整CMakeLists.txt如下：

cmake_minimum_required(VERSION 3.20)
project(opencv_projects)

set(CMAKE_CXX_STANDARD 14)

find_package(PkgConfig REQUIRED)
pkg_check_modules(OPENCV4 REQUIRED opencv4)

add_executable(opencv_projects main.cpp)

# 新增此行，传递OpenCV库的搜索路径
target_link_directories(opencv_projects PUBLIC ${OPENCV4_LIBRARY_DIRS})

target_link_libraries(opencv_projects ${OPENCV4_LIBRARIES})
target_include_directories(opencv_projects PUBLIC ${OPENCV4_INCLUDE_DIRS})
target_compile_options(opencv_projects PUBLIC ${OPENCV4_CFLAGS_OTHER})

方案2：使用带全路径的链接变量 #

pkg_check_modules生成的${OPENCV4_LINK_LIBRARIES}变量已经包含所有OpenCV库的全路径，不需要额外配置搜索路径，直接替换链接参数即可：

# 将原来的${OPENCV4_LIBRARIES}替换为${OPENCV4_LINK_LIBRARIES}
target_link_libraries(opencv_projects ${OPENCV4_LINK_LIBRARIES})

方案3：使用OpenCV原生CMake配置（更推荐） #

OpenCV官方提供了原生CMake配置文件，兼容性优于pkg-config调用，直接替换原有pkg-config相关配置即可：

cmake_minimum_required(VERSION 3.20)
project(opencv_projects)

set(CMAKE_CXX_STANDARD 14)

# 直接使用原生find_package查找OpenCV，替换原有pkg-config代码
find_package(OpenCV REQUIRED)

add_executable(opencv_projects main.cpp)

target_link_libraries(opencv_projects ${OpenCV_LIBS})
target_include_directories(opencv_projects PUBLIC ${OpenCV_INCLUDE_DIRS})

如果CMake无法定位到OpenCV安装路径，可在CMake配置参数中添加前缀路径：

• Intel芯片Mac：-DCMAKE_PREFIX_PATH=/usr/local/opt/opencv
• Apple Silicon芯片Mac：-DCMAKE_PREFIX_PATH=/opt/homebrew/opt/opencv

内容的提问来源于stack exchange，提问作者Dirk