【Make编译控制 06】CMake初步使用

目录

一、概述与安装

二、编译源文件

三、无关文件管理

---

一、概述与安装

CMake是一个跨平台的项目构建工具，相比于Makefile，CMake更加高级，因为CMake代码在执行的时候是会先翻译生成Makefile文件，再调用Makefile文件完成项目构建，这就像是高级语言和低级语言之间的关系。

Makefile虽然也支持在不同的平台上运行，但是不同平台上进行项目构建的Makefile代码是不一样的，也就是说不具备Makefile代码不具备跨平台性，所以CMake的出现便是帮Makefile解决了这个问题，因为CMake可以根据不同的平台生成不同的Makefile文件。

Linux系统CMake直接命令行安装：yum install -y cmake

Windows系统CMake安装地址：https://cmake.org/files/

选择对应版本的 x86_64.msi 文件下载运行，安装的时候选择添加系统环境变量：

# 在PowerShell上检查是否安装成功

PS C:\Users\pheonixFly> cmake --version
cmake version 3.28.0-rc1

CMake suite maintained and supported by Kitware (kitware.com/cmake).
PS C:\Users\pheonixFly>

二、编译源文件

// add.h

#pragma once
int add(int a, int b);

// sub.h

#pragma once
int sub(int a, int b);

// add.cpp

#include "add.h"

int add(int a, int b) {
    return a + b;
}

// add.cpp

#include "sub.h"

int sub(int a, int b) {
    return a - b;
}

# CMakeLists.txt 文件代码

cmake_minimum_required(VERSION 2.8)
# 指定使用的 cmake 的最低版本
# 可选，非必须，如果不加可能会有警告

project(MATH)
# 定义工程名称，
# 并可指定工程的版本、工程描述、web主页地址、支持的语言（默认情况支持所有语言），
# 如果不需要这些都是可以忽略的，只需要指定出工程名字即可。

add_executable(math.exe add.cpp sub.cpp main.cpp)
# add_executable(可执行程序名 源文件名称)
# 定义工程会生成一个可执行程序
# 源文件名可以是一个也可以是多个，如有多个可用空格或分号间隔

# 执行 cmake . 命令，生成 Makefile 文件
# 执行新生成的 Makefile 文件

(base) [root@localhost 10_test]# tree .
.
├── add.cpp
├── add.h
├── CMakeLists.txt
├── main.cpp
├── sub.cpp
└── sub.h

0 directories, 6 files
(base) [root@localhost 10_test]# cmake .
-- The C compiler identification is GNU 4.8.5
-- The CXX compiler identification is GNU 4.8.5
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /root/gitee/Test/Make_Learn/10_test
(base) [root@localhost 10_test]# tree .
.
├── add.cpp
├── add.h
├── CMakeCache.txt
├── CMakeFiles
│   ├── 2.8.12.2
│   │   ├── CMakeCCompiler.cmake
│   │   ├── CMakeCXXCompiler.cmake
│   │   ├── CMakeDetermineCompilerABI_C.bin
│   │   ├── CMakeDetermineCompilerABI_CXX.bin
│   │   ├── CMakeSystem.cmake
│   │   ├── CompilerIdC
│   │   │   ├── a.out
│   │   │   └── CMakeCCompilerId.c
│   │   └── CompilerIdCXX
│   │       ├── a.out
│   │       └── CMakeCXXCompilerId.cpp
│   ├── cmake.check_cache
│   ├── CMakeDirectoryInformation.cmake
│   ├── CMakeOutput.log
│   ├── CMakeTmp
│   ├── Makefile2
│   ├── Makefile.cmake
│   ├── math.exe.dir
│   │   ├── build.make
│   │   ├── cmake_clean.cmake
│   │   ├── DependInfo.cmake
│   │   ├── depend.make
│   │   ├── flags.make
│   │   ├── link.txt
│   │   └── progress.make
│   ├── progress.marks
│   └── TargetDirectories.txt
├── cmake_install.cmake
├── CMakeLists.txt
├── main.cpp
├── Makefile         ################ 新生成的 Makefile 文件       
├── sub.cpp
└── sub.h

6 directories, 32 files
(base) [root@localhost 10_test]# make
Scanning dependencies of target math.exe
[ 33%] Building CXX object CMakeFiles/math.exe.dir/add.cpp.o
[ 66%] Building CXX object CMakeFiles/math.exe.dir/sub.cpp.o
[100%] Building CXX object CMakeFiles/math.exe.dir/main.cpp.o
Linking CXX executable math.exe
[100%] Built target math.exe
(base) [root@localhost 10_test]# tree .
.
├── add.cpp
├── add.h
├── CMakeCache.txt
├── CMakeFiles
│   ├── 2.8.12.2
│   │   ├── CMakeCCompiler.cmake
│   │   ├── CMakeCXXCompiler.cmake
│   │   ├── CMakeDetermineCompilerABI_C.bin
│   │   ├── CMakeDetermineCompilerABI_CXX.bin
│   │   ├── CMakeSystem.cmake
│   │   ├── CompilerIdC
│   │   │   ├── a.out
│   │   │   └── CMakeCCompilerId.c
│   │   └── CompilerIdCXX
│   │       ├── a.out
│   │       └── CMakeCXXCompilerId.cpp
│   ├── cmake.check_cache
│   ├── CMakeDirectoryInformation.cmake
│   ├── CMakeOutput.log
│   ├── CMakeTmp
│   ├── Makefile2
│   ├── Makefile.cmake
│   ├── math.exe.dir
│   │   ├── add.cpp.o
│   │   ├── build.make
│   │   ├── cmake_clean.cmake
│   │   ├── CXX.includecache
│   │   ├── DependInfo.cmake
│   │   ├── depend.internal
│   │   ├── depend.make
│   │   ├── flags.make
│   │   ├── link.txt
│   │   ├── main.cpp.o
│   │   ├── progress.make
│   │   └── sub.cpp.o
│   ├── progress.marks
│   └── TargetDirectories.txt
├── cmake_install.cmake
├── CMakeLists.txt
├── main.cpp
├── Makefile         ################ 新生成的 Makefile 文件
├── math.exe         ################ 新生成的 math.exe 文件
├── sub.cpp
└── sub.h

6 directories, 38 files
(base) [root@localhost 10_test]# ./math.exe
10 + 5 = 15
10 - 5 = 5
(base) [root@localhost 10_test]# 

# CMake 生成的 Makefile 文件代码

# CMAKE generated file: DO NOT EDIT!
# Generated by "Unix Makefiles" Generator, CMake Version 2.8

# Default target executed when no arguments are given to make.
default_target: all
.PHONY : default_target

#=============================================================================
# Special targets provided by cmake.

# Disable implicit rules so canonical targets will work.
.SUFFIXES:

# Remove some rules from gmake that .SUFFIXES does not remove.
SUFFIXES =

.SUFFIXES: .hpux_make_needs_suffix_list

# Suppress display of executed commands.
$(VERBOSE).SILENT:

# A target that is always out of date.
cmake_force:
.PHONY : cmake_force

#=============================================================================
# Set environment variables for the build.

# The shell in which to execute make rules.
SHELL = /bin/sh

# The CMake executable.
CMAKE_COMMAND = /usr/bin/cmake

# The command to remove a file.
RM = /usr/bin/cmake -E remove -f

# Escaping for special characters.
EQUALS = =

# The program to use to edit the cache.
CMAKE_EDIT_COMMAND = /usr/bin/ccmake

# The top-level source directory on which CMake was run.
CMAKE_SOURCE_DIR = /root/gitee/Test/Make_Learn/10_test

# The top-level build directory on which CMake was run.
CMAKE_BINARY_DIR = /root/gitee/Test/Make_Learn/10_test

#=============================================================================
# Targets provided globally by CMake.

# Special rule for the target edit_cache
edit_cache:
	@$(CMAKE_COMMAND) -E cmake_echo_color --switch=$(COLOR) --cyan "Running CMake cache editor..."
	/usr/bin/ccmake -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR)
.PHONY : edit_cache

# Special rule for the target edit_cache
edit_cache/fast: edit_cache
.PHONY : edit_cache/fast

# Special rule for the target rebuild_cache
rebuild_cache:
	@$(CMAKE_COMMAND) -E cmake_echo_color --switch=$(COLOR) --cyan "Running CMake to regenerate build system..."
	/usr/bin/cmake -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR)
.PHONY : rebuild_cache

# Special rule for the target rebuild_cache
rebuild_cache/fast: rebuild_cache
.PHONY : rebuild_cache/fast

# The main all target
all: cmake_check_build_system
	$(CMAKE_COMMAND) -E cmake_progress_start /root/gitee/Test/Make_Learn/10_test/CMakeFiles /root/gitee/Test/Make_Learn/10_test/CMakeFiles/progress.marks
	$(MAKE) -f CMakeFiles/Makefile2 all
	$(CMAKE_COMMAND) -E cmake_progress_start /root/gitee/Test/Make_Learn/10_test/CMakeFiles 0
.PHONY : all

# The main clean target
clean:
	$(MAKE) -f CMakeFiles/Makefile2 clean
.PHONY : clean

# The main clean target
clean/fast: clean
.PHONY : clean/fast

# Prepare targets for installation.
preinstall: all
	$(MAKE) -f CMakeFiles/Makefile2 preinstall
.PHONY : preinstall

# Prepare targets for installation.
preinstall/fast:
	$(MAKE) -f CMakeFiles/Makefile2 preinstall
.PHONY : preinstall/fast

# clear depends
depend:
	$(CMAKE_COMMAND) -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake 1
.PHONY : depend

#=============================================================================
# Target rules for targets named math.exe

# Build rule for target.
math.exe: cmake_check_build_system
	$(MAKE) -f CMakeFiles/Makefile2 math.exe
.PHONY : math.exe

# fast build rule for target.
math.exe/fast:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/build
.PHONY : math.exe/fast

add.o: add.cpp.o
.PHONY : add.o

# target to build an object file
add.cpp.o:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/add.cpp.o
.PHONY : add.cpp.o

add.i: add.cpp.i
.PHONY : add.i

# target to preprocess a source file
add.cpp.i:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/add.cpp.i
.PHONY : add.cpp.i

add.s: add.cpp.s
.PHONY : add.s

# target to generate assembly for a file
add.cpp.s:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/add.cpp.s
.PHONY : add.cpp.s

main.o: main.cpp.o
.PHONY : main.o

# target to build an object file
main.cpp.o:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/main.cpp.o
.PHONY : main.cpp.o

main.i: main.cpp.i
.PHONY : main.i

# target to preprocess a source file
main.cpp.i:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/main.cpp.i
.PHONY : main.cpp.i

main.s: main.cpp.s
.PHONY : main.s

# target to generate assembly for a file
main.cpp.s:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/main.cpp.s
.PHONY : main.cpp.s

sub.o: sub.cpp.o
.PHONY : sub.o

# target to build an object file
sub.cpp.o:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/sub.cpp.o
.PHONY : sub.cpp.o

sub.i: sub.cpp.i
.PHONY : sub.i

# target to preprocess a source file
sub.cpp.i:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/sub.cpp.i
.PHONY : sub.cpp.i

sub.s: sub.cpp.s
.PHONY : sub.s

# target to generate assembly for a file
sub.cpp.s:
	$(MAKE) -f CMakeFiles/math.exe.dir/build.make CMakeFiles/math.exe.dir/sub.cpp.s
.PHONY : sub.cpp.s

# Help Target
help:
	@echo "The following are some of the valid targets for this Makefile:"
	@echo "... all (the default if no target is provided)"
	@echo "... clean"
	@echo "... depend"
	@echo "... edit_cache"
	@echo "... math.exe"
	@echo "... rebuild_cache"
	@echo "... add.o"
	@echo "... add.i"
	@echo "... add.s"
	@echo "... main.o"
	@echo "... main.i"
	@echo "... main.s"
	@echo "... sub.o"
	@echo "... sub.i"
	@echo "... sub.s"
.PHONY : help



#=============================================================================
# Special targets to cleanup operation of make.

# Special rule to run CMake to check the build system integrity.
# No rule that depends on this can have commands that come from listfiles
# because they might be regenerated.
cmake_check_build_system:
	$(CMAKE_COMMAND) -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake 0
.PHONY : cmake_check_build_system

三、无关文件管理

通过上面的例子可以看出，在执行 cmake 命令的时候，会在当前目录生成一些与项目执行无关的目录和文件，如果再基于 Makefile 执行 make，还会生成更过的中间件文件，这样会导致整个项目变得混乱和难以管理，所以我们需要将通过 cmake 生成的新文件都统一放到一个目录里面进行管理，这个目录通常叫做 build。

(base) [root@localhost 10_test]# mkdir build
(base) [root@localhost 10_test]# cd build
(base) [root@localhost build]# cmake ..
-- The C compiler identification is GNU 4.8.5
-- The CXX compiler identification is GNU 4.8.5
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /root/gitee/Test/Make_Learn/10_test/build
(base) [root@localhost build]# tree .
.
├── CMakeCache.txt
├── CMakeFiles
│   ├── 2.8.12.2
│   │   ├── CMakeCCompiler.cmake
│   │   ├── CMakeCXXCompiler.cmake
│   │   ├── CMakeDetermineCompilerABI_C.bin
│   │   ├── CMakeDetermineCompilerABI_CXX.bin
│   │   ├── CMakeSystem.cmake
│   │   ├── CompilerIdC
│   │   │   ├── a.out
│   │   │   └── CMakeCCompilerId.c
│   │   └── CompilerIdCXX
│   │       ├── a.out
│   │       └── CMakeCXXCompilerId.cpp
│   ├── cmake.check_cache
│   ├── CMakeDirectoryInformation.cmake
│   ├── CMakeOutput.log
│   ├── CMakeTmp
│   ├── Makefile2
│   ├── Makefile.cmake
│   ├── math.exe.dir
│   │   ├── build.make
│   │   ├── cmake_clean.cmake
│   │   ├── DependInfo.cmake
│   │   ├── depend.make
│   │   ├── flags.make
│   │   ├── link.txt
│   │   └── progress.make
│   ├── progress.marks
│   └── TargetDirectories.txt
├── cmake_install.cmake
└── Makefile    ####################### 在 build 目录下的 Makefile 文件             

6 directories, 26 files
(base) [root@localhost build]# cd ..
(base) [root@localhost 10_test]# ls
add.cpp  add.h  build  CMakeLists.txt  main.cpp  sub.cpp  sub.h
(base) [root@localhost 10_test]# cd build/
(base) [root@localhost build]# make
Scanning dependencies of target math.exe
[ 33%] Building CXX object CMakeFiles/math.exe.dir/add.cpp.o
[ 66%] Building CXX object CMakeFiles/math.exe.dir/sub.cpp.o
[100%] Building CXX object CMakeFiles/math.exe.dir/main.cpp.o
Linking CXX executable math.exe
[100%] Built target math.exe
(base) [root@localhost build]# tree ..
..
├── add.cpp
├── add.h
├── build
│   ├── CMakeCache.txt
│   ├── CMakeFiles
│   │   ├── 2.8.12.2
│   │   │   ├── CMakeCCompiler.cmake
│   │   │   ├── CMakeCXXCompiler.cmake
│   │   │   ├── CMakeDetermineCompilerABI_C.bin
│   │   │   ├── CMakeDetermineCompilerABI_CXX.bin
│   │   │   ├── CMakeSystem.cmake
│   │   │   ├── CompilerIdC
│   │   │   │   ├── a.out
│   │   │   │   └── CMakeCCompilerId.c
│   │   │   └── CompilerIdCXX
│   │   │       ├── a.out
│   │   │       └── CMakeCXXCompilerId.cpp
│   │   ├── cmake.check_cache
│   │   ├── CMakeDirectoryInformation.cmake
│   │   ├── CMakeOutput.log
│   │   ├── CMakeTmp
│   │   ├── Makefile2
│   │   ├── Makefile.cmake
│   │   ├── math.exe.dir
│   │   │   ├── add.cpp.o
│   │   │   ├── build.make
│   │   │   ├── cmake_clean.cmake
│   │   │   ├── CXX.includecache
│   │   │   ├── DependInfo.cmake
│   │   │   ├── depend.internal
│   │   │   ├── depend.make
│   │   │   ├── flags.make
│   │   │   ├── link.txt
│   │   │   ├── main.cpp.o
│   │   │   ├── progress.make
│   │   │   └── sub.cpp.o
│   │   ├── progress.marks
│   │   └── TargetDirectories.txt
│   ├── cmake_install.cmake
│   ├── Makefile    ####################### 在 build 目录下的 Makefile 文件  
│   └── math.exe    ####################### 在 build 目录下的 math.exe 文件  
├── CMakeLists.txt
├── main.cpp
├── sub.cpp
└── sub.h

7 directories, 38 files
(base) [root@localhost build]# ./math.exe
10 + 5 = 15
10 - 5 = 5
(base) [root@localhost build]# 

这样就可以在 build 目录中执行 make 命令编译项目，生成的相关文件自然也就被存储到 build 目录中了。这样通过 cmake 和 make 生成的所有文件就全部和项目源文件分离了。