sudo apt install gcc g++ make

hello: hello.cpp
    g++ hello.cpp -o hello # 开头必须为一个Tab，不能为空格

hello: hello.o
    g++ hello.o -o hello
hello.o: hello.cpp
    g++ -c hello.cpp

target … (目标): prerequisites …(依赖)
        recipe(方法)
        …
        …

target … (目标): prerequisites …(依赖); recipe(方法) ;…

snake.jar : C.class Main.class SnakeFrame.class SnakePanel.class
    jar -cvfe snake.jar Main *.class

C.class : C.java
    javac C.java

Main.class : Main.java
    javac Main.java

SnakeFrame.class : SnakeFrame.java
    javac SnakeFrame.java

SnakePanel.class : SnakePanel.java
    javac SnakePanel.java

.PHONY: clean
clean:
    rm *.class *.jar

make -f mkfile  # make -f <filename>
make --file=mkfile # make --file=<filename>

sudoku: block.o command.o input.o main.o scene.o test.o
    g++ -o sudoku block.o command.o input.o main.o scene.o test.o

block.o: block.cpp common.h block.h color.h
    g++ -c block.cpp

command.o: command.cpp scene.h common.h block.h command.h
    g++ -c command.cpp

input.o: input.cpp common.h utility.inl
    g++ -c input.cpp

main.o: main.cpp scene.h common.h block.h command.h input.h
    g++ -c main.cpp

scene.o: scene.cpp common.h scene.h block.h command.h utility.inl
    g++ -c scene.cpp

test.o: test.cpp test.h scene.h common.h block.h command.h
    g++ -c test.cpp

hello.o: hello.cpp
    g++ -c hello.cpp


clean:
    rm block.o command.o input.o main.o scene.o test.o
    rm sudoku.exe

target … (目标): prerequisites …(依赖)
        recipe(方法)
        …
        …

.PHONY: clean
clean:
    rm block.o command.o input.o main.o scene.o test.o
    rm sudoku.exe

test.o: test.cpp test.h
        g++ -c test.cpp

.PHONY: clean test.o

targets : normal-prerequisites | order-only-prerequisites

VPATH = <dir1>:<dir2>:<dir3>...
# 例如
VPATH = include:src

vpath <pattern> <directories>

vpath %.h include  # .h文件在include目录下查找
vpath %.h include:headers  # .h文件在include或headers文件下查找

vpath % src   # 所有文件都在src下查找

vpath hello.cpp src  # hello.cpp文件在src查找

target … (目标): prerequisites …(依赖)
        recipe(方法)
        …
        …

SHELL = C:/Windows/System32/WindowsPowerShell/v1.0/powershell.exe
SHELL = cmd.exe

.ONESHELL:

@echo hello
@g++ -o hello hello.cpp

.SILENT: main all

clean:
    rm main.o hello.o
    rm main.exe

clean:
    -rm main.o hello.o
    -rm main.exe

# <变量名> = <变量值>  <变量名> := <变量值>  <变量名> ::= <变量值>
files = main.cpp hello.cpp
objects := main.o hello.o
var3 ::= main.o

# $(<变量名>) 或者 ${<变量名>}
main.o : $(files) # 或者 ${files}
    ...

bar2 = ThisIsBar2No.1
foo = $(bar)
foo2 = $(bar2)

all:
    @echo $(foo)  # Huh?
    @echo $(foo2)  # ThisIsBar2No.2
    @echo $(ugh)   # Huh?

bar = $(ugh)
ugh = Huh?
bar2 = ThisIsBar2No.2

bar2 := ThisIsBar2No.1
foo := $(bar)
foo2 := $(bar2)

all:
    @echo $(foo)    # 空串，没有内容
    @echo $(foo2)    # ThisIsBar2No.1
    @echo $(ugh)    # 

bar := $(ugh)
ugh := Huh?
bar2 := ThisIsBar2No.2

var1 = 100
var1 ?= 200

all:
    @echo $(var1) # 100 注释var1 = 100之后为200

x = hello
y = world
a := $(x)$(y)

x = y
y = z
a := $($(x))

x = y
y = z
z = u
a := $($($(x)))

x = $(y)
y = z
z = Hello
a := $($(x))

files = main.cpp
files += hello.cpp

all:
    @echo $(files)

gcc_version != gcc --version
files != ls .

define <varable_name>  # 默认为 = 
# 变量内容
endef

define <varable_name> :=
# 变量内容
endef

define <varable_name> +=
# 变量内容
endef

echosomething = @echo This is the first line

define echosomething +=  

@echo hello
@echo world
@echo 3
endef


all:
    $(echosomething)

undefine <变量名>   如 undefine files,  undefine objs

all:
    @echo $(USERNAME)
    @echo $(JAVA_HOME)
    @echo $(SystemRoot)

files = main.cpp hello.cpp
objs := $(files:.cpp=.o) # main.o hello.o
# 另一种写法
objs := $(files:%.cpp=%.o)

OverridDemo := ThisIsInMakefile
all:
    @echo $(OverridDemo)

make

make OverridDemo=ThisIsFromOutShell # 等号两边不能有空格
# 如果变量值中有空格，需要用引号
make OverridDemo=“This Is From Out Shell”

override OverridDemo := ThisIsInMakefile
all:
    @echo $(OverridDemo)

make OverridDemo=ThisIsFromOutShell

target … : variable-assignment
target … : prerequisites
    recipes
    …

var1 = Global Var

first: all t2

all: var2 = Target All Var
all:
    @echo $(var1)
    @echo $(var2)

t2:
    @echo $(var1)
    @echo $(var2)

var1 = Global Var

first: all.v t2.v t3

%.v: var2 = Target %.v Var
all.v:
    @echo $@ -- $(var1)
    @echo $@ -- $(var2)

t2.v:
    @echo $@ -- $(var1)
    @echo $@ -- $(var2)
t3:
    @echo $@ -- $(var1)
    @echo $@ -- $(var2)

VAR1 = main.cpp
.SECONDEXPANSION:
all: $$(VAR1)
    @echo $^

VAR1 = hello.cpp

$(CC) $(CPPFLAGS) $(CFLAGS) -c

$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c

$(CC) $(LDFLAGS) *.o $(LOADLIBES) $(LDLIBS)

block.o input.o scene.o &: block.cpp input.cpp scene.cpp common.h
    g++ -c block.cpp
    g++ -c input.cpp
    g++ -c scene.cpp

input.o: input.cpp utility.inl
    g++ -c input.cpp
main.o: main.cpp scene.h input.h test.h
    g++ -c main.cpp
scene.o: scene.cpp scene.h utility.inl
    g++ -c scene.cpp

input.o main.o scene.o : common.h

targets …: target-pattern(目标模式): prereq-patterns(依赖模式) …
        recipe
        …

block.o : %.o : %.cpp %.h
    g++ -c $<

block.o : block.cpp block.h

block.o command.o input.o scene.o test.o: %.o : %.cpp %.h
    g++ -c $<
main.o: main.cpp scene.h input.h test.h
    g++ -c main.cpp

%.o : %.cpp %.h
    g++ -c $<

OS = Linux
ifdef Win
    OS = Windows
endif


OS = Linux
ifdef Win
    OS = Windows
else ifdef Mac
    OS= MacOS
endif


ifdef Win
    OS = Windows
else ifdef Mac
    OS= MacOS
else 
    OS = Linux
endif

ifndef FLAGS
    FLAGS = -finput-charset=utf-8
endif

version = 3.0

ifeq ($(version),1.0)            # ifeq后一定要一个空格
    msg := 版本太旧了，请更新版本
else ifeq ($(version), 3.0)
    msg := 版本太新了，也不行
else
    msg := 版本可以用
endif


# 另外的写法
msg = Other
ifeq "$(OS)" "Windows_NT"
    msg = This is a Windows Platform
endif

ifeq '$(OS)' 'Windows_NT'

ifeq '$(OS)' "Windows_NT"

$(function arguments) 或 ${function arguments}
$(function arg1,$(arg2),arg3 ...)  # 参数之间不要有空格

$(subst target,replacement,text)
        --- 用relacement替换text中的target
        --- target 需要替换的内容
        --- replacement 替换为的内容
        --- text 需要处理的内容，可以是任意字符串



objs = main.o hello.o
srcs = $(subst .o,.cpp,$(objs))
headers = $(subst .cpp,.h,$(srcs))

all:
    @echo $(srcs)
    @echo $(headers)

$(patsubst pattern,replacement,text)
        --- pattern 需要替换的模式
        --- replacement 需要替换为
        --- text 待处理内容，各项内容需要用空格隔开


objs = main.ohello.o
srcs = $(subst %.o,%.cpp,$(objs))
headers = $(subst %.cpp,%.h,$(srcs))  

$(strip string)
        --- string 需要去除空格的字符串


files = aa hello.cpp      main.cpp     test.cpp
files := $(subst aa,        ,$(files))
files2 = $(strip $(files))

$(findstring find,string)
        --- find 需要查找的字符串
        --- string 用来查找的内容

files = hello.cpp main.cpp test.cpp
find = $(findstring hel,$(files))
find = $(findstring HEL,$(files))

$(filter pattern…,text)
        --- pattern 模式，可以有多个，用空格隔开
        --- text 用来筛选的文本，多项内容需要用空格隔开，否则只会当一项来处理

files = hello.cpp main.cpp test.cpp main.o hello.o hello.h
files2 = $(filter %.o %.h,$(files))

$(filter-out pattern…,text)
        --- pattern 模式，可以有多个，用空格隔开
        --- text 用来筛选的文本，多项内容需要用空格隔开，否则只会当一项来处理


files = hello.cpp main.cpp test.cpp main.o hello.o hello.h
files2 = $(filter-out %.o %.cpp,$(files))

$(sort list)
        --- list 需要排序内容


files = hello.cpp main.cpp test.cpp main.o hello.o hello.h main.cpp hello.cpp
files2 = $(sort $(files))

$(word n,text)
        --- n 第n个单词，从1开始，如果n大于总单词数，则返回空串
        --- text 待处理文本

files = hello.cpp main.cpp test.cpp main.o hello.o hello.h main.cpp hello.cpp
files2 = $(word 3,$(files))

$(wordlist start,end,text)
        --- start 起始位置，如果大于单词总数，则返回空串
        --- end 结束位置，如果大于单词总数，则返回起始位置之后全部，如果start > end，什么都不返回

files = hello.cpp main.cpp test.cpp main.o hello.o hello.h main.cpp hello.cpp
files2 = $(wordlist 3,6,$(files))

$(words text)
        --- text 需要处理的文本


files = hello.cpp main.cpp test.cpp main.o hello.o hello.h main.cpp hello.cpp
nums = $(words $(files))

$(firstword text)

$(lastword text)

$(dir files)
        --- files 需要返回目录的文件名，可以有多个，用空格隔开

files = src/hello.cpp main.cpp

files2 = $(dir $(files))

$(notdir files)
        --- files 需要返回文件列表，可以有多个，用空格隔开

files = src/hello.cpp main.cpp
files2 = $(notdir $(files))

$(suffix files)
        --- files 需要返回后缀的文件名，可以有多个，用空格隔开


files = src/hello.cpp main.cpp hello.o hello.hpp hello
files2 = $(suffix $(files))

$(basename files)
        --- files 需要返回的文件名，可以有多个，用空格隔开


files = src/hello.cpp main.cpp hello.o hello.hpp hello
files2 = $(basename $(files))

$(addsuffix suffix,files)
        --- suffix 需要添加的后缀
        --- files 需要添加后缀的文件名，可以有多个，用空格隔开

files = src/hello.cpp main.cpp hello.o hello.hpp hello
files2 = $(addsuffix .exe,$(files))

$(addprefix prefix,files)
        --- prefix 需要添加的前缀
        --- files 需要添加前缀的文件名，可以有多个，用空格隔开

files = src/hello.cpp main.cpp hello.o hello.hpp hello
files2 = $(addprefix make/,$(files))

$(join list1,list2)
        --- list1 第一个列表
        --- list2 需要连接的第二个列表


f1 = hello main test
f2 = .cpp .hpp
files2 = $(join $(f1),$(f2))

$(wildcard pattern)
        --- pattern 通配符

files2 = $(wildcard *.cpp)
files2 = $(wildcard *)
files2 = $(wildcard src/*.cpp)

$(realpath files)
        --- files 需要返回绝对路径的文件，可以有多个，用空格隔开

f3 = $(wildcard src/*)
files2 = $(realpath $(f3))

$(abspath files)

$(if condition,then-part[,else-part])
        --- condition 条件部分
        --- then-part 条件为真时执行的部分
        --- else-part 条件为假时执行的部分，如果省略则为假时返回空串

files = src/hello.cpp main.cpp hello.o hello.hpp hello
files2 = $(if $(files),有文件,没有文件)

$(or condition1[,condition2[,condition3…]])

f1 = 
f2 = 
f3 = hello.cpp
f4 = main.cpp
files2 = $(or $(f1),$(f2),$(f3),$(f4))

$(and condition1[,condition2[,condition3…]])

f1 = 12
f2 = 34
f3 = hello.cpp
f4 = main.cpp
files2 = $(and $(f1),$(f2),$(f3),$(f4))

$(intcmp lhs,rhs[,lt-part[,eq-part[,gt-part]]]) 
        --- lhs 第一个数
        --- rhs 第二个数
        --- lt-part  lhs < rhs时执行
        --- eq-part  lhs = rhs时执行
        --- gt-part  lhs > rhs时执行
        --- 如果只提供前两个参数，则lhs == rhs时返回数值，否则返回空串
            参数为lhs,rhs,lt-part时，当lhs < rhs时返回lt-part结果，否则返回空
            参数为lhs,rhs,lt-part,eq-part，lhs < rhs返回lt-part结果，否则都返回eq-part结果
            参数全时，lhs < rhs返回lt-part，lhs == rhs返回eq-part, lhs > rhs返回gt-part



@echo $(intcmp 2,2,-1,0,1)

$(file op filename[,text])
        --- op 操作
                > 覆盖
                >> 追加
                < 读
        --- filename 需要操作的文件名
        --- text 写入的文本内容，读取是不需要这个参数


files = src/hello.cpp main.cpp hello.o hello.hpp hello
write = $(file > makewrite.txt,$(files))
read = $(file < makewrite.txt)

$(foreach each,list,process)
        --- each list中的每一项
        --- list 需要处理的字符串序列，用空格隔开
        --- process 需要对每一项进行的处理

list = 1 2 3 4 5
result = $(foreach each,$(list),$(addprefix cpp,$(addsuffix .cpp,$(each))))

int list[5] = {1, 2, 3, 4, 5};
int result[5];
int each;
for(int i = 0; i < 5; i++)
{
    each = list[i];
    result[i] = process(each);
}
// 此时result即为返回结果

$(call funcname,param1,param2,…)
        --- funcname 自定义函数（变量名）
        --- 参数至少一个，可以有多个，用逗号隔开

dirof =  $(dir $(realpath $(1))) $(dir $(realpath $(2)))
result = $(call dirof,main.cpp,src/hello.cpp)

$(value variable)

var = value function test
var2 = $(var)
var3 := $(var)
all:
    @echo $(value var2)
    @echo $(value var3)

$(origin variable)


var2 = origin function 
all:
    @echo $(origin var1)    # undefined 未定义
    @echo $(origin CC)        # default 默认变量
    @echo $(origin JAVA_HOME) # environment 环境变量
    @echo $(origin var2)    # file 在Makefile文件中定义的变量
    @echo $(origin @)        # automatic 自动变量

$(flavor variable)

var2 = flavor function
var3 := flavor funciton
all:
    @echo $(flavor var1)    # undefined 未定义
    @echo $(flavor var2)    # recursive 递归展开赋值
    @echo $(flavor var3)    # simple 简单赋值

$(eval text)

define eval_target = 
eval:
    @echo Target Eval Test
endef

$(eval $(eval_target))

files = $(shell ls *.cpp)
$(shell echo This is from shell function)

$(let var1 [var2 ...],[list],proc)
        --- var 变量，可以有多个，用空格隔开
        --- list 待处理字符串，各项之间空格隔开
        --- proc 对变量进行的操作，结果为let的返回值
            将list中的值依次一项一项放到var中，如果var的个数多于list项数，那多出来的var是空串。如果
            var的个数小于list项数，则先依次把前而的项放入var中，剩下的list所有项都放入最后一个var中


list = a b c d
letfirst = $(let first second rest,$(list),$(first))
letrest = $(let first second rest,$(list),$(rest))


# 结合call可以对所有项进行递归处理
reverse = $(let first rest,$(1),$(if $(rest),$(call reverse,$(rest)) )$(first))
all: ; @echo $(call reverse,d c b a)

$(error text)
        --- text 提示信息

EXIT_STATUS = -1
ifneq (0, $(EXIT_STATUS))
    $(error An error occured! make stopped!)
endif

$(warning text)

ifneq (0, $(EXIT_STATUS))
    $(warning This is a warning message)
endif

$(info text…)

$(info 编译开始.......)
$(info 编译结束)

include mkf1 mkf2 # 可以引入多个文件，用空格隔开
include *.mk    # 可以用通配符，表示引入所有以.mk结尾的文件

-include mkf1 mkf2

objs = block.o command.o input.o main.o scene.o test.o

sudoku: $(objs)
    g++ $(objs) -o sudoku

include $(objs:%.o=%.d)

%.d: %.cpp
    @-rm $@
    $(CXX) -MM  $< > $@.temp
    @sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.temp > $@
    @-rm $@.temp


%.o : %.cpp
    g++ -c $<
    @echo $^

vpath %.h ../include

CXXFLAGS += -I../include -fexec-charset=GBK -finput-charset=UTF-8

cpps := $(wildcard *.cpp)
objs := $(cpps:%.cpp=%.o)

libsudoku.a: $(objs)
    ar rcs $@ $^

$(objs): %.o : %.cpp %.h

CXXFLAGS += -I../include -fexec-charset=GBK -finput-charset=UTF-8
vpath %.h ../include
vpath %.a ../lib

../sudoku: main.o test.o -lsudoku
    $(CXX) -o $@ $^

.PHONY: all clean

all: subsrc

subsrc: sublib
    $(MAKE) -C src

sublib:
    $(MAKE) -C lib

clean:
    -rm *.exe src/*.o lib/*.o lib/*.a 

$(MAKE) -C subdir

export var  # 传递var
export         # 传递所有变量
unexport    # 取消传递