cmake入门之内部构建

https://www.cnblogs.com/coderfenghc/tag/cmake/　　

https://cmake.org/cmake/help/v3.16/guide/tutorial/index.html#cmake-tutorial

https://www.ncnynl.com/category/ros-junior-tutorial/

https://blog.csdn.net/weixin_43455581/article/details/96306977#1_CPython_1

https://blog.csdn.net/wsc820508/article/details/81349675

最早的：https://www.ibm.com/developerworks/cn/linux/l-cn-cmake/

前言很多完全省略

1、编辑helloc.c文件：

 #include <stdio.h>

 int main(int argc, char **argv)
 {
     printf("Hello world from cMake pro1\n");

     return ;
 }

　　代码非常简单，不多罗嗦。

2、编辑CMakeList.txt文件，这个是cmake的指导性文件：

 cmake_minimum_required(VERSION 3.15)
 PROJECT(Pro1)
 SET(SRC_LIST helloc.c)
 MESSAGE(STATUS "This is BINARY_dir " ${PROJECT_BINARY_DIR})
 MESSAGE(STATUS "This is SOURCE_dir " ${PROJECT_SOURCE_DIR})
 ADD_EXECUTABLE(helloc ${SRC_LIST})

　　文件说明：对新手有用，老手请忽略

　　第1行：主要是不让camke时，工具出现警告，可以不加，建议加上

　　第2行：PROJECT指令指定项目名称为Rpo1，并暗含两个变量PROJECT_BINARY_DIR和PROJECT_SOURCE_DIR，前者是项目中可执行文件的目录名称，后者是项目的源代码目录名称；

　　第3行：SET指令相当与定义并设置变量SRC_LIST的值为helloc.c，如果有更多的源文件，以空格或分号分割即可

　　第4行：MESSAGE指令打印消息，STATUS表明正常消息，用${PROJECT_BINARY_DIR}获得PROJECT_BINARY_DIR的值，打印项目中可执行文件夹名称

　　第5行：打印项目中源代码文件夹名称

　　第6行：ADD_EXECUTABLE指令主要制定生成的可执行文件helloc和依赖列表，请务必使用 ${SRC_LIST}，以获取依赖列表中的所有文件，而不是依赖文件SRC_LIST

3、第一次构建，生成Makefile文件，返回信息如下：

 -- The C compiler identification is GNU 9.2.
 -- The CXX compiler identification is GNU 9.2.
 -- 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
 -- Detecting C compile features
 -- Detecting C compile features - 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
 -- Detecting CXX compile features
 -- Detecting CXX compile features - done
 -- This is BINARY_dir /home/nication/WORKM/studyCode/toolCode/cMake/pro1
 -- This is SOURCE_dir /home/nication/WORKM/studyCode/toolCode/cMake/pro1
 -- Configuring done
 -- Generating done
 -- Build files have been written to: /home/nication/WORKM/studyCode/toolCode/cMake/pro1

　　Makefile文件：

 # CMAKE generated file: DO NOT EDIT!
 # Generated by "Unix Makefiles" Generator, CMake Version 3.15

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

 .PHONY : default_target

 # Allow only one "make -f Makefile2" at a time, but pass parallelism.
 .NOTPARALLEL:

 #=============================================================================
 # 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 top-level source directory on which CMake was run.
 CMAKE_SOURCE_DIR = /home/nication/WORKM/studyCode/toolCode/cMake/pro1

 # The top-level build directory on which CMake was run.
 CMAKE_BINARY_DIR = /home/nication/WORKM/studyCode/toolCode/cMake/pro1

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

 # 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 -S$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR)
 .PHONY : rebuild_cache

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

 .PHONY : rebuild_cache/fast

 # 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 -S$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR)
 .PHONY : edit_cache

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

 .PHONY : edit_cache/fast

 # The main all target
 all: cmake_check_build_system
     $(CMAKE_COMMAND) -E cmake_progress_start /home/nication/WORKM/studyCode/toolCode/cMake/pro1/CMakeFiles /home/nication/WORKM/studyCode/toolCode/cMake/pro1/CMakeFiles/progress.marks
     $(MAKE) -f CMakeFiles/Makefile2 all
     $(CMAKE_COMMAND) -E cmake_progress_start /home/nication/WORKM/studyCode/toolCode/cMake/pro1/CMakeFiles
 .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:
     $(CMAKE_COMMAND) -S$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake
 .PHONY : depend

 #=============================================================================
 # Target rules for targets named helloc

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

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

 helloc.o: helloc.c.o

 .PHONY : helloc.o

 # target to build an object file
 helloc.c.o:
     $(MAKE) -f CMakeFiles/helloc.dir/build.make CMakeFiles/helloc.dir/helloc.c.o
 .PHONY : helloc.c.o

 helloc.i: helloc.c.i

 .PHONY : helloc.i

 # target to preprocess a source file
 helloc.c.i:
     $(MAKE) -f CMakeFiles/helloc.dir/build.make CMakeFiles/helloc.dir/helloc.c.i
 .PHONY : helloc.c.i

 helloc.s: helloc.c.s

 .PHONY : helloc.s

 # target to generate assembly for a file
 helloc.c.s:
     $(MAKE) -f CMakeFiles/helloc.dir/build.make CMakeFiles/helloc.dir/helloc.c.s
 .PHONY : helloc.c.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 "... rebuild_cache"
     @echo "... helloc"
     @echo "... edit_cache"
     @echo "... helloc.o"
     @echo "... helloc.i"
     @echo "... helloc.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:
     $(CMAKE_COMMAND) -S$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake
 .PHONY : cmake_check_build_system

4、二次构建并编译：

 make

　　返回信息：

 Scanning dependencies of target helloc
 [ %] Building C object CMakeFiles/helloc.dir/helloc.c.o
 [%] Linking C executable helloc
 [%] Built target helloc

　　自动生成可执行文件，helloc，文件列表：

 -rw-r--r--  nication nication  10月  : CMakeCache.txt
 drwxr-xr-x  nication nication   10月  : CMakeFiles
 -rw-r--r--  nication nication   10月  : cmake_install.cmake
 -rw-r--r--  nication nication    10月  : CMakeLists.txt
 -rwxr-xr-x  nication nication  10月  : helloc
 -rw-r--r--  nication nication    10月  : helloc.c
 -rw-r--r--  nication nication   10月  : Makefile

5、执行程序：

　　./helloc

　　执行结果：

　　Hello world from cMake pro1

到此为止，算是成功了。但是由于cmake过程中会产生很多中间文件，使用make clean只能清除可执行文件。清除临时文件不方便，因此，尽量使用cmake的外部构建。