Skip to content

cpp-build-system.md

Latest commit

 

History

History
296 lines (179 loc) · 7.49 KB

cpp-build-system.md

File metadata and controls

296 lines (179 loc) · 7.49 KB
Raw

make

概念

Make (or rather a Makefile) is a buildsystem - it drives the compiler and other build tools to build your code. But cmake is a generator of buildsystems.

几个关键指令

  1. configure

    • 概念

      • 是一个shell script

    • 作用

      make sure all of the dependencies

      produces a customised Makefile specific to your system from a template file called Makefile.in

    • configure script file来源

      run autoconf to turn configure.ac into a configure script

  2. make

    This runs a series of tasks defined in a Makefile to build the finished program from its source code.

    • MakeFile.in来源

      Run automake to turn Makefile.am into a Makefile.in

  3. make install

    The make install command will copy the built program, and its libraries and documentation, to the correct locations.

    It does do nothing less than running the install function/task in MakeFile

cmake

概念

  • 解释

    CMake is a generator of buildsystems. It can produce Makefiles, it can produce Ninja build files, it can produce KDEvelop or Xcode projects, it can produce Visual Studio solutions.

  • cmake和make的区别

    Make (or rather a Makefile) is a buildsystem - it drives the compiler and other build tools to build your code. But cmake is a generator of buildsystems.

    即make由cmake构建而来，cmake是构建工具的构建工具。make和nija是平级关系

使用

  • 经常使用的两个命令

    cmake -S . -B ./build
# -S <path-to-source> = Explicitly specify a source directory.
# -B <path-to-build>  = Explicitly specify a build directory.
cmake --build ./build
# --build <dir> = Build a CMake-generated project binary tree.
# path = the path to be built
cmake --install ./build
# --install <dir> = Install a CMake-generated project binary tree.
# path = the path to be installed

语法

  1. include_directories(/opt/homebrew/Cellar/glfw/3.4/include)

    • 标准格式

      include_directories([AFTER|BEFORE] [SYSTEM] dir1 [dir2 ...])

    • 标准解释

      Add the given directories to those the compiler uses to search for include files. Relative paths are interpreted as relative to the current source directory.

    • 通俗示例

      • 在CmakeLists.txt中加这样一句

        include_directories(/opt/homebrew/Cellar/glfw/3.4/include)

      • 等于如下效果

        clang -cc1  -I /opt/homebrew/Cellar/glfw/3.4/include

  2. add_execuable(main.out main.cpp other.cpp)

    • 标准格式

      add_executable(<name> [WIN32] [MACOSX_BUNDLE]
               [EXCLUDE_FROM_ALL]
               [source1] [source2 ...])

      • 标准解释

        Add an executable to the project using the specified source files.

      • 示范

        add_executable(3_hello_triangle main.cpp ~/Environment/glad/src/glad.c)
# glad.c文件不是链接库，不能用link_libraries
# 这种方式本质是将glad.c编译成glad.o，最后链接

# 所以也可以执行下面两条执行
add_library(glad STATIC ~/Environment/glad/src/glad.c)
link_libraries(glad)
add_executable(3_hello_triangle main.cpp)

  3. add_library(mainlib SHARED main.cpp other.cpp)

    • 标准格式

      add_library(<name> [STATIC | SHARED | MODULE]
            [EXCLUDE_FROM_ALL]
            [<source>...])

      • 标准解释

        Add a library to the project using the specified source files.

      • 通俗解释

        将mian.cpp和other.cpp源文件编译成一个命名为mainlib的共享库

  4. link_libraries(/opt/homebrew/Cellar/glfw/3.4/lib/libglfw.3.dylib)

    • 标准格式

      link_libraries([item1 [item2 [...]]]
               [[debug|optimized|general] <item>] ...)

    • 标准解释

      Specify libraries or flags to use when linking any targets created later in the current directory or below by commands such as add_executable() or add_library().

    • 通俗示例

      • 在CmakeLists.txt中加这样一句

        link_libraries(/opt/homebrew/Cellar/glfw/3.4/lib/libglfw.3.dylib)

      • 等于如下效果

        ld -o 1_create_a_window CMakeFiles/1_create_a_window.dir/main.cpp.o /opt/homebrew/Cellar/glfw/3.4/lib/libglfw.3.dylib

  5. target_link_libraries(main.out PUBLIC hellolib)

    • 标准格式

      target_link_libraries(<target>
                      <PRIVATE|PUBLIC|INTERFACE> <item>...
                     [<PRIVATE|PUBLIC|INTERFACE> <item>...]...)

      • 标准解释

        Specify libraries or flags to use when linking a given target and/or its dependents.

      • 示范

        add_library(glad STATIC ~/Environment/glad/src/glad.c)
add_executable(3_hello_triangle main.cpp)
target_link_libraries(3_hello_triangle PUBLIC glad)

  6. add_subdirectory(fmt)

    • 标准格式

      add_subdirectory(source_dir [binary_dir] [EXCLUDE_FROM_ALL])

    • 标准解释

      Add a subdirectory to the build.

  7. target_include_directories(hellolib PUBLIC .)

    • 标准格式

      target_include_directories(<target> [SYSTEM] [AFTER|BEFORE]
  <INTERFACE|PUBLIC|PRIVATE> [items1...]
  [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

    • 标准解释

      Add include directories to a target.

    • 通俗解释

      在构建hellolib搜索头文件时，将当前目录纳入头文件搜索目录，并且可以向下传递

其他

  • [PRIVATE|PUBLIC]区别

    • 是否link、include等操作时进行传染
    • 如target_link_libraries(myexec PRIVATE hellolib)表示另一个library在链接时需要myexec库时会自动可以添加hellolib进行链接，否则不能进行链接

  • C++声明的必要性

    • 声明即引入头文件或在顶部做一个函数等声明如void hello();
    • 不声明编译器无法知道名称的含义。如vector<MyClass> a可能会把vector、MyClass看作是变量，把<、>看作时运算符

  • 递归引入头文件

    • 当递归引入头文件时会报错无法通过编译

    • 防止递归引入的两种办法

      • #pragma once

      • 宏定义

        #ifndef INC_01_HEADER_NAME_H
#define INC_01_HEADER_NAME_H

#endif //INC_01_HEADER_NAME_H

  • 第三方库引入

    • 纯头文件引入
      • 直接target_include_directories()时将包含头文件的文件夹填入即可
      • 通常#include <xxx.h>时需要定义一个xxx.h定义的宏，因为要防止重复引入
    • 子模块引入
      • 即作为cmake的子模块引入，通过add_subdirectories()和target_link_libraries()即可
    • 引用系统中预安装的第三方库
      • 最麻烦，通常通过find_package()
      • 不推荐使用

  • 包管理器

    • C++没有包管理器，vcpkg太多问题简直没法用

编译

参数

  1. CMAKE_CXX_FLAGS

    • 含义: 编译器执行时加的参数

    • 用法:

      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v") # 输出详细的编译日志

  2. CMAKE_EXPORT_COMPILE_COMMANDS

    • 将编译指令输出到compile_commands.json文件

  3. CMAKE_VERBOSE_MAKEFILE

    • 让编译日志尽可能详细