opencv - CMake:无法设置变量以关闭 OpenCV

Question

我有以下CMake代码段

#OpenCV
option(USE_OPENCV "Use OpenCV data sources" ON)

这里我默认打开 OpenCV 的使用，然后我有:

if(USE_OPENCV)
    find_package( OpenCV REQUIRED )
    if(OpenCV_FOUND)
        include_directories(${OpenCV_INCLUDE_DIRS})
    else(OpenCV_FOUND)
        set(USE_OPENCV OFF)
        message("OpenCV could not be found. Turning OPENCV OFF.")        
    endif(OpenCV_FOUND)
endif(USE_OPENCV)

所以我在没有 OpenCV 的配置上运行它，我从 CMake 收到消息:“找不到 OpenCV。关闭 OPENCV”。但是，退出屏幕后，我看到 CMake USE_OPENCV 变量仍处于打开状态。我期待它被设置为关闭。

我做错了什么吗？

[编辑]可以产生该行为的完整 CMakeLists 文件是:

project(Test)
cmake_minimum_required(VERSION 2.8)

#OpenCV
option(USE_OPENCV "Use OpenCV data sources" ON)

if(USE_OPENCV)
    find_package( OpenCV REQUIRED )
    if(OpenCV_FOUND)
        include_directories(${OpenCV_INCLUDE_DIRS})
    else(OpenCV_FOUND)
        set(USE_OPENCV OFF)
        message(FATAL_ERROR "OpenCV could not be found. Turning OpenCV OFF.")        
    endif(OpenCV_FOUND)
endif(USE_OPENCV)

做一些简单而毫无意义的事情，比如:

project(Test2)
cmake_minimum_required(VERSION 2.8)

#OpenCV
option(USE_OPENCV "Use OpenCV data sources" ON)

if(USE_OPENCV)
    message("Turn it OFF!")
    set(USE_OPENCV OFF)
endif(USE_OPENCV)

即使这样也行不通...

Answer 1

好的，所以必须缓存值。所以，我做了类似的事情:

set(USE_OPENCV OFF CACHE BOOL "ON OFF" FORCE)

这似乎有效。如果有人有更好的解决方案，请更新线程。