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
");

    return 0;
}

　　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 9.2.0
-- The CXX compiler identification is GNU 9.2.0
-- 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 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:
    $(CMAKE_COMMAND) -S$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake 1
.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 0
.PHONY : cmake_check_build_system

4、二次构建并编译：

make

　　返回信息：

Scanning dependencies of target helloc
[ 50%] Building C object CMakeFiles/helloc.dir/helloc.c.o
[100%] Linking C executable helloc
[100%] Built target helloc

　　自动生成可执行文件，helloc，文件列表：

-rw-r--r-- 1 nication nication 13433 10月 30 09:16 CMakeCache.txt
drwxr-xr-x 5 nication nication  4096 10月 30 09:53 CMakeFiles
-rw-r--r-- 1 nication nication  1546 10月 30 09:16 cmake_install.cmake
-rw-r--r-- 1 nication nication   229 10月 30 09:15 CMakeLists.txt
-rwxr-xr-x 1 nication nication 16536 10月 30 09:53 helloc
-rw-r--r-- 1 nication nication   110 10月 30 08:56 helloc.c
-rw-r--r-- 1 nication nication  4839 10月 30 09:16 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。