github上算法库的CMakeLists如何理解

Question

cmake_minimum_required(VERSION 3.9)
project(Algorithms_in_C++
 LANGUAGES CXX VERSION 1.0.0 DESCRIPTION "Set of algorithms implemented in C++."
)
# set(CMAKE_CXX_CPPLINT "~/anaconda3/bin/cpplint --filter=-legal/copyright --std=c++11")
# find_program(CLANG_FORMAT "clang-format")
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
if(MSVC)
    # set(CMAKE_CXX_STANDARD 14)
 add_compile_definitions(_CRT_SECURE_NO_WARNINGS)
endif(MSVC)
option(USE_OPENMP "flag to use OpenMP for multithreading" ON)
if(USE_OPENMP)
    find_package(OpenMP 3.0 COMPONENTS CXX)
    if (OpenMP_CXX_FOUND)
        message(STATUS "Building with OpenMP Multithreading.")
    else()
        message(STATUS "No OpenMP found, no multithreading.")
    endif()
endif()
    
add_subdirectory(math)
add_subdirectory(others)
add_subdirectory(search)
add_subdirectory(ciphers)
add_subdirectory(hashing)
add_subdirectory(strings)
add_subdirectory(sorting)
add_subdirectory(geometry)
add_subdirectory(graphics)
add_subdirectory(probability)
add_subdirectory(backtracking)
add_subdirectory(data_structures)
add_subdirectory(machine_learning)
add_subdirectory(numerical_methods)
add_subdirectory(graph)
cmake_policy(SET CMP0054 NEW)
cmake_policy(SET CMP0057 NEW)
find_package(Doxygen OPTIONAL_COMPONENTS dot dia)
if(DOXYGEN_FOUND)
    set(DOXYGEN_GENERATE_MAN NO)
    set(DOXYGEN_USE_MATHJAX YES)
    set(DOXYGEN_GENERATE_HTML YES)
    # set(DOXYGEN_HTML_TIMESTAMP YES)
 set(DOXYGEN_EXTRACT_STATIC YES)
    set(DOXYGEN_INLINE_SOURCES YES)
    set(DOXYGEN_CREATE_SUBDIRS YES)
    set(DOXYGEN_EXTRACT_PRIVATE YES)
    set(DOXYGEN_GENERATE_TREEVIEW YES)
    set(DOXYGEN_STRIP_CODE_COMMENTS NO)
    set(DOXYGEN_EXT_LINKS_IN_WINDOW YES)
    set(DOXYGEN_BUILTIN_STL_SUPPORT YES)
    set(DOXYGEN_EXCLUDE_PATTERNS */build/*)
    set(DOXYGEN_ENABLE_PREPROCESSING YES)
    set(DOXYGEN_CLANG_ASSISTED_PARSING YES)
    set(DOXYGEN_FILE_PATTERNS *.cpp *.h *.hpp *.md)
    set(DOXYGEN_MATHJAX_EXTENSIONS  TeX/AMSmath TeX/AMSsymbols)
    set(DOXYGEN_TAGFILES "doc/cppreference-doxygen-web.tag.xml=http://en.cppreference.com/w/")
    if(MSVC)
        set(DOXYGEN_CPP_CLI_SUPPORT YES)
    endif()
    set(DOXYGEN_MATHJAX_RELPATH "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML")
    if(Doxygen_dot_FOUND)
        set(DOXYGEN_HAVE_DOT YES)
        set(DOXYGEN_CALL_GRAPH YES)
        set(DOXYGEN_INTERACTIVE_SVG YES)
        set(DOXYGEN_DOT_IMAGE_FORMAT "svg")
    endif()
    if(OPENMP_FOUND)
        set(DOXYGEN_PREDEFINED "_OPENMP=1")
    endif()
    if(GLUT_FOUND)
        set(DOXYGEN_PREDEFINED ${DOXYGEN_PREDEFINED} "GLUT_FOUND=1")
    endif()
    doxygen_add_docs(
        doc
 ${PROJECT_SOURCE_DIR}
 COMMENT "Generate documentation"
    )
endif()
set(CPACK_PROJECT_NAME ${PROJECT_NAME})
set(CPACK_PROJECT_VERSION ${PROJECT_VERSION})
include(CPack)

其中一个目录下的cmakelists.txt

# If necessary, use the RELATIVE flag, otherwise each source file may be listed
# with full pathname. RELATIVE may makes it easier to extract an executable name
# automatically.
file( GLOB APP_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp )
# file( GLOB APP_SOURCES ${CMAKE_SOURCE_DIR}/*.c )
# AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} APP_SOURCES)
foreach( testsourcefile ${APP_SOURCES} )
    # I used a simple string replace, to cut off .cpp.
 string( REPLACE ".cpp" "" testname ${testsourcefile} )
    add_executable( ${testname} ${testsourcefile} )
    set_target_properties(${testname} PROPERTIES LINKER_LANGUAGE CXX)
    if(OpenMP_CXX_FOUND)
        target_link_libraries(${testname} OpenMP::OpenMP_CXX)
    endif()
    install(TARGETS ${testname} DESTINATION "bin/data_structures")
endforeach( testsourcefile ${APP_SOURCES} )
add_subdirectory(cll)

想要达到一个项目下边多个main他这段,我需要如何精简,cpp小白求指教..

Answer 1

这是cmake构建工具的文件，你需要先跟着文档或者其他人的教程学习cmake的基本语法与使用，然后写较为简单的构建规则，这个目前对你来说太难了。
参考：(1条消息) 超详细的cmake教程_zhuiyunzhugang的博客-CSDN博客_cmake

Answer 2

cmake_minimum_required(VERSION 3.13)
project(demo)

# 获取目录下全部 *.cpp 文件，保存到 APP_SOURCES 变量
file(GLOB APP_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp)

# 遍历 APP_SOURCES 里的每一个文件
foreach( inputfile ${APP_SOURCES} )

  # 替换掉文件名的 .cpp 得到输出的可执行文件名字 output
  string(REPLACE ".cpp" "" output ${inputfile} )

  # 添加一个可执行文件 output，从 inputfile 编译得到
  add_executable( ${output} ${inputfile})

endforeach( inputfile ${APP_SOURCES} )

效果这样的：

λ cmake ..
-- The C compiler identification is GNU 10.2.0
.....
-- Build files have been written to: /...

λ make
Scanning dependencies of target b
[ 25%] Building CXX object CMakeFiles/b.dir/b.cpp.o
[ 50%] Linking CXX executable b
[ 50%] Built target b
Scanning dependencies of target a
[ 75%] Building CXX object CMakeFiles/a.dir/a.cpp.o
[100%] Linking CXX executable a
[100%] Built target a

λ ./a
A
λ ./b
B

语法和函数还是要看教程和文档。