如何在没有无限循环的情况下使用 CMake 的add_subdirectory

How do I use CMake's add_subdirectory without endless loops

本文关键字：CMake add subdirectory 情况下 无限循环      更新时间：2023-10-16

我有一个要使用OpenCV和googletest构建的应用程序。有了我得到的cmakelists.txt，我得到了一个无尽的循环，cmake不断将googletest目录添加到build dir。

我添加了GoogleTest作为一个子目录（即使它不在实际项目树中），因为我阅读了为每个项目重新编译的，这会防止各种麻烦。当我删除add_subdirectory线时，不再有无尽的循环。

我的cmake文件：

cmake_minimum_required(VERSION 2.8.4)
project(imageprocessing)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
IF(NOT DEFINED ENV{OpenCV_DIR})
set(ENV{OpenCV_DIR} "/usr/local/opencv")
ENDIF(NOT DEFINED ENV{OpenCV_DIR})
MESSAGE("Using OpenCV from location: " $ENV{OpenCV_DIR} " (Override by exporting OpenCV_DIR)")
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
file(GLOB SOURCE_FILES "src/main/cpp/*.cpp")
add_executable(imageprocessing ${SOURCE_FILES})
target_link_libraries(imageprocessing ${OpenCV_LIBS} ) # <-- Line 16.
##########
# TESTING
##########
enable_testing()
IF(NOT DEFINED ENV{GOOGLETEST_DIR})
    set(ENV{GOOGLETEST_DIR} "/usr/local/googletest/gtest-1.7.0")
ENDIF(NOT DEFINED ENV{GOOGLETEST_DIR})
MESSAGE("Using Google Test from location: " $ENV{GOOGLETEST_DIR} " (Override by exporting GOOGLETEST_DIR)")
add_subdirectory("${GOOGLETEST_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/lib_googletest") # <-- EXCLUDE_FROM_ALL does not make a difference.
include_directories(${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})
##############
# Unit Tests
##############
file(GLOB TEST_SOURCE_FILES "src/test/cpp/*.cpp")
add_executable(runUnitTests ${TEST_SOURCE_FILES})
target_link_libraries(runUnitTests gtest gtest_main)
add_test(NAME test_images COMMAND runUnitTests)

弹出的错误消息：

CMake Error at CMakeLists.txt:16 (target_link_libraries):
  Attempt to add link library "opencv_core" to target "imageprocessing" which is not built in this directory.

我的环境：

$ cmake -version
cmake version 2.8.12.2

有助于使用正确的变量。

摘要来自问题：

IF(NOT DEFINED ENV{GOOGLETEST_DIR})
    set(ENV{GOOGLETEST_DIR} "/usr/local/googletest/gtest-1.7.0")
ENDIF(NOT DEFINED ENV{GOOGLETEST_DIR})
MESSAGE("Using Google Test from location: " $ENV{GOOGLETEST_DIR} " (Override by exporting GOOGLETEST_DIR)")
add_subdirectory("${GOOGLETEST_DIR}" # <-- THIS SHOULD READ $ENV{GOOGLETEST_DIR}!
"${CMAKE_CURRENT_BINARY_DIR}/lib_googletest") # <-- EXCLUDE_FROM_ALL does not make a difference.
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