我正在开发一个软件,它包含一些带有python绑定的核心C代码. C代码已经使用了很多OpenCV,但现在我正在尝试将图像保存在两者之间,我似乎无法使用imwrite函数.在main.cpp中添加它并使用’Default’构建在eclipse中编译,但是为了将它与现有的Python代码一起使用,我需要使用CMake构建.这再次编译很好,但是当我从Python类调用代码时,我收到此错误：

ImportError: /.../pythonCPP.so: undefined symbol: _ZN2cv7imwriteERKNS_6StringERKNS_11_InputArrayERKSt6vectorIiSaIiEE

我搜索了这个,从我可以收集的内容来看,这通常似乎源于某种链接问题.我不知道从哪里开始查找或添加CMake文件中的任何标志.我在Ubuntu 16.04 64bit上使用OpenCV 3.2.0.

这是相应的CMakeLists.txt：

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)

project("blah")

#----------------------------CMAKE & GLOBAL PROPERTIES-------------------------#

list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")

###============= C++11 support====================================

include(CheckCXXCompilerFlag)

CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)

CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X)

if (COMPILER_SUPPORTS_CXX11)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -g0 -s -std=c++11")

elseif (COMPILER_SUPPORTS_CXX0X)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -g0 -s -std=c++0x")

else ()

message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")

endif ()

#=================================================================

# PYTHON option

set(PYTHON_OPTIONS "2.X" "3.X")

set(PYTHON_DESIRED_VERSION "3.X" CACHE STRING "Choose which python version to use, options are: ${PYTHON_OPTIONS}.")

set_property(CACHE PYTHON_DESIRED_VERSION PROPERTY STRINGS ${PYTHON_OPTIONS})

#=============== Find Packages

find_package(OpenCV 3 COMPONENTS core highgui imgproc REQUIRED)

message("Open CV version is ${OpenCV_VERSION}")

include("DetectPython")

if (${PYTHON_DESIRED_VERSION} STREQUAL "2.X")

set(Python_ADDITIONAL_VERSIONS ${PYTHON2_VERSION_MAJOR}.${PYTHON2_VERSION_MINOR})

find_package(Boost COMPONENTS python-py${PYTHON2_VERSION_MAJOR}${PYTHON2_VERSION_MINOR} REQUIRED)

else ()

set(Python_ADDITIONAL_VERSIONS ${PYTHON3_VERSION_MAJOR}.${PYTHON3_VERSION_MINOR})

find_package(Boost COMPONENTS python-py${PYTHON3_VERSION_MAJOR}${PYTHON3_VERSION_MINOR} REQUIRED)

endif ()

#========pick python stuff========================================

if (${PYTHON_DESIRED_VERSION} STREQUAL "2.X")

SET(PYTHON_INCLUDE_DIRS ${PYTHON2_INCLUDE_DIR} ${PYTHON2_INCLUDE_DIR2} ${PYTHON2_NUMPY_INCLUDE_DIRS})

SET(PYTHON_LIBRARIES ${PYTHON2_LIBRARY})

SET(PYTHON_EXECUTABLE ${PYTHON2_EXECUTABLE})

SET(PYTHON_PACKAGES_PATH ${PYTHON2_PACKAGES_PATH})

SET(ARCHIVE_OUTPUT_NAME py2)

else ()

SET(PYTHON_INCLUDE_DIRS ${PYTHON3_INCLUDE_DIR} ${PYTHON3_INCLUDE_DIR2} ${PYTHON3_NUMPY_INCLUDE_DIRS})

SET(PYTHON_LIBRARIES ${PYTHON3_LIBRARY})

SET(PYTHON_EXECUTABLE ${PYTHON3_EXECUTABLE})

SET(PYTHON_PACKAGES_PATH ${PYTHON3_PACKAGES_PATH})

SET(ARCHIVE_OUTPUT_NAME py3)

endif ()

file(GLOB project_sources ${CMAKE_CURRENT_SOURCE_DIR}/src/*.cpp)

add_library(${PROJECT_NAME} SHARED ${project_sources} ${CMAKE_CURRENT_SOURCE_DIR}/include/pyboostcvconverter/pyboostcvconverter.hpp)

target_include_directories(${PROJECT_NAME} PUBLIC

"${CMAKE_CURRENT_SOURCE_DIR}/include"

${Boost_INCLUDE_DIRS}

${OpenCV_INCLUDE_DIRS}

${PYTHON_INCLUDE_DIRS}

)

target_link_libraries(${PROJECT_NAME}

${Boost_LIBRARIES}

${OpenCV_LIBRARIES}

${PYTHON_LIBRARIES}

)

#--------------------------- INSTALLATION -----------------------------------------------------

#-get proper extension for python binary shared object on this platform

execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "import distutils.sysconfig; print(distutils.sysconfig.get_config_var('SO'))"

RESULT_VARIABLE PYTHON_${PROJECT_NAME}_PY_PROCESS

OUTPUT_VARIABLE ${PROJECT_NAME}_PY_SUFFIX

OUTPUT_STRIP_TRAILING_WHITESPACE)

set_target_properties(${PROJECT_NAME} PROPERTIES

ARCHIVE_OUTPUT_NAME ${ARCHIVE_OUTPUT_NAME} # prevent name conflict for python2/3 outputs

PREFIX ""

OUTPUT_NAME py

SUFFIX ${${PROJECT_NAME}_PY_SUFFIX})

if (MSVC AND NOT PYTHON_DEBUG_LIBRARIES)

set(PYTHON_INSTALL_CONFIGURATIONS CONFIGURATIONS Release)

else ()

set(PYTHON_INSTALL_CONFIGURATIONS "")

endif ()

if (WIN32)

set(PYTHON_INSTALL_ARCHIVE "")

else ()

set(PYTHON_INSTALL_ARCHIVE ARCHIVE DESTINATION ${PYTHON_PACKAGES_PATH} COMPONENT python)

endif ()

install(TARGETS ${PROJECT_NAME}

${PYTHON_INSTALL_CONFIGURATIONS}

RUNTIME DESTINATION ${PYTHON_PACKAGES_PATH} COMPONENT python

LIBRARY DESTINATION ${PYTHON_PACKAGES_PATH} COMPONENT python

${PYTHON_INSTALL_ARCHIVE}

)

解决方法:

我不是最好的cmake,但你似乎无法链接imwrite()函数.

我在Mac上,所以如果你在其他地方会有所不同,但如果你查看OpenCV库目录,特别是在libopencv_imgcodecs.dylib中,如下所示：

nm -gUP libopencv_imgcodecs.dylib | grep -i write

你会看到类似的东西：

__ZN2cv7imwriteERKNS_6StringERKNS_11_InputArrayERKNSt3__16vector...

这意味着imgcodecs提供了您需要的功能.

我希望(感谢@ Ptaq666),可靠地告知添加此库的最佳方法是使用：

find_package(OpenCV 3 REQUIRED)

其次是：

target_link_libraries( ${OpenCV_LIBRARIES})

原始建议

这意味着imgcodecs提供了你需要的功能,所以我认为你需要在你的CMakeLists.txt中添加它到这一行：

find_package(OpenCV 3 COMPONENTS core highgui imgproc REQUIRED)

我猜这将是这样的：

find_package(OpenCV 3 COMPONENTS core highgui imgproc imgcodecs REQUIRED)

标签：python,c,opencv

来源： https://codeday.me/bug/20191002/1844822.html