快速了解如何编写CMakeLists.txt文件

 

 

本文以linux平台下CMakeLists.txt文件书写方法总结。

一 开头通用模块

 

1.1 cmake版本要求

cmake_minimum_required( VERSION 2.8 )

#工程文件名loop_closure,可任取

project( loop_closure )

1.2 编译模式

IF(NOT CMAKE_BUILD_TYPE)  SET(CMAKE_BUILD_TYPE Release)ENDIF()

MESSAGE("Build type: " ${CMAKE_BUILD_TYPE})

当然如果此处在前面加上语句：

set(CMAKE_BUILD_TYPE debug)

即表示设置为debug模式编译。

1.3 检查C++版本

检查C++的版本

# Check C++11 or C++0x supportinclude(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 "${CMAKE_CXX_FLAGS} -std=c++11")   add_definitions(-DCOMPILEDWITHC11)   message(STATUS "Using flag -std=c++11.")elseif(COMPILER_SUPPORTS_CXX0X)   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")   add_definitions(-DCOMPILEDWITHC0X)   message(STATUS "Using flag -std=c++0x.")else()   message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")endif()

 

二 项目文件配置模块

接下来，便开始配置各个库模块。

2.1 如果仅包含OpenCV库时

set(OpenCV_DIR "/usr/local/include/opencv3.2.0/share/OpenCV") find_package(OpenCV REQUIRED)

include_directories( ${OpenCV_INCLUDE_DIRS} )

 

#生成可执行文件

add_executable(${PROJECT_NAME} src/loop_closure.cpp )

target_link_libraries(${PROJECT_NAME} ${OpenCV_LIBS})

 

备注：这里的OpenCV包含目录为含有OpenCVConfig.cmake的路径。

如下图：

 

 

 

2.2 如果包含第三方库，该库为源码形式（.h和.cpp），非动态链接库

 

 

此处以在工程中添加词袋库DBoW2为例，这里的DBoW2是以源码形式包含，也即未编译成.so文件。

 

 

 

2.2.1 包含第三库的头文件

#设置.h文件对应的路径

set( DBoW2_INCLUDE_DIRS ${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/include/)

 

#包含.h文件路径

include_directories( ${OpenCV_INCLUDE_DIRS}         ${DBoW2_INCLUDE_DIRS} ${DBoW2_INCLUDE_DIRS}/DBoW2/)

 

注：上述为啥要用两条路径${DBoW2_INCLUDE_DIRS}和${DBoW2_INCLUDE_DIRS}/DBoW2/？

 

 

 

 

为了防止在include层找不到，继续往下一层路径include/DBoW2/路径下查找，这是为了防止某些文件的包含路径不一致导致头文件查找错误。

2.2.2 包含第三方库的cpp文件

 

 

 

 

set(DBoW2_SRCS "${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/src")

#生成可执行文件

add_executable(${PROJECT_NAME} src/loop_closure.cpp  src/run_main.cpp        ${DBoW2_SRCS}/BowVector.cpp ${DBoW2_SRCS}/FBrief.cpp ${DBoW2_SRCS}/FeatureVector.cpp        ${DBoW2_SRCS}/FORB.cpp ${DBoW2_SRCS}/FSurf64.cpp ${DBoW2_SRCS}/QueryResults.cpp ${DBoW2_SRCS}/ScoringObject.cpp)

其中，src/loop_closure.cpp  src/run_main.cpp 为本工程中我自己实现的，而对于其他的cpp文件，则直接添加路径即可。

另一种方式，添加cpp文件路径更为简洁方便。

file(GLOB DBoW2_SRCS ${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/src/*.cpp)

add_executable(${PROJECT_NAME} src/loop_closure.cpp  src/run_main.cpp ${DBoW2_SRCS})

 

2.3 如果包含第三方库，为库形式（此处以静态库为例(.a后缀)）

 

在上述工程下，同时还包含有DBoW3库，此库已经按默认路径编译安装到计算机内存中。我们可以按如下方式添加DBoW3库。

1）包含头文件

set( DBoW3_INCLUDE_DIRS "/usr/local/include")

2）添加库

set( DBoW3_LIBS "/usr/local/lib/libDBoW3.a")

target_link_libraries(${PROJECT_NAME}${OpenCV_LIBS}${DBoW3_LIBS})

通过上述方式，即可调用。

三 一个简单的CMakeLists.txt文件demo

该demo中相较于上述总结添加的库，还额外包含了DLib库。

cmake_minimum_required( VERSION 2.8 )project( loop_closure )#set(CMAKE_BUILD_TYPE  Debug)IF(NOT CMAKE_BUILD_TYPE)  SET(CMAKE_BUILD_TYPE Release)ENDIF()MESSAGE("Build type: " ${CMAKE_BUILD_TYPE})# Check C++11 or C++0x supportinclude(CheckCXXCompilerFlag)CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X)if(COMPILER_SUPPORTS_CXX11)   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")   add_definitions(-DCOMPILEDWITHC11)   message(STATUS "Using flag -std=c++11.")elseif(COMPILER_SUPPORTS_CXX0X)   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")   add_definitions(-DCOMPILEDWITHC0X)   message(STATUS "Using flag -std=c++0x.")else()   message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")endif()#opencv#set(OpenCV_DIR "/usr/local/include/opencv3.2.0/share/OpenCV")set(OpenCV_DIR "/opt/ros/kinetic/share/OpenCV-3.3.1-dev")find_package(OpenCV REQUIRED)set( DBoW3_INCLUDE_DIRS "/usr/local/include")set( DBoW2_INCLUDE_DIRS ${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/include/)message(${DBoW2_INCLUDE_DIRS})#important#file(GLOB DBoW2_SRCS ${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/src/*.cpp)#message(${DBoW2_SRCS})set(DBoW2_SRCS "${PROJECT_SOURCE_DIR}/ThirdParty/DBow-master/src")message(${DBoW2_SRCS})

find_package(DLib QUIET        PATHS ${DEPENDENCY_INSTALL_DIR})if(${DLib_FOUND})   message("DLib library found, using it from the system")   include_directories(${DLib_INCLUDE_DIRS})   add_custom_target(Dependencies)else(${DLib_FOUND})   message("DLib library not found in the system, it will be downloaded on build")   option(DOWNLOAD_DLib_dependency "Download DLib dependency" ON)   if(${DOWNLOAD_DLib_dependency})      ExternalProject_Add(DLib              PREFIX ${DEPENDENCY_DIR}              GIT_REPOSITORY http://github.com/dorian3d/DLib              GIT_TAG master              INSTALL_DIR ${DEPENDENCY_INSTALL_DIR}              CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>)      add_custom_target(Dependencies ${CMAKE_COMMAND} ${CMAKE_SOURCE_DIR} DEPENDS DLib)   else()      message(SEND_ERROR "Please, activate DOWNLOAD_DLib_dependency option or download manually")   endif(${DOWNLOAD_DLib_dependency})endif(${DLib_FOUND})

include_directories( ${OpenCV_INCLUDE_DIRS}        ${DBoW3_INCLUDE_DIRS} ${DBoW2_INCLUDE_DIRS} ${DBoW2_INCLUDE_DIRS}/DBoW2/)message("DBoW3_INCLUDE_DIRS ${DBoW3_INCLUDE_DIRS}")message("DBoW2_INCLUDE_DIRS ${DBoW2_INCLUDE_DIRS}")message("opencv ${OpenCV_VERSION}")# dbow3 # dbow3 is a simple lib so I assume you installed it in default directoryset( DBoW3_LIBS "/usr/local/lib/libDBoW3.a")add_executable(${PROJECT_NAME} src/loop_closure.cpp  src/run_main.cpp        ${DBoW2_SRCS}/BowVector.cpp ${DBoW2_SRCS}/FBrief.cpp ${DBoW2_SRCS}/FeatureVector.cpp        ${DBoW2_SRCS}/FORB.cpp ${DBoW2_SRCS}/FSurf64.cpp ${DBoW2_SRCS}/QueryResults.cpp ${DBoW2_SRCS}/ScoringObject.cpp        )message(${DBoW2_SRCS}/BowVector.cpp)target_link_libraries(${PROJECT_NAME}${OpenCV_LIBS}

${DLib_LIBS}${DBoW3_LIBS})

四 

以上仅仅为CMakeLists.txt的一个简单用法梳理，如有不到之处，还请批评指正。