all:
    @echo "hello all"
test:
    @echo "hello test"

- make # hello all ，也就是make默认执行第一个
- make test # hello test , 指定目标

## 目标 ：依赖
simple: main.o foo.o 
    gcc -o simple main.o foo.o
main.o : main.c # 子目标
    gcc -o main.o -c main.c
foo.o : foo.c
    gcc -o foo.o -c foo.c
clean : 
    rm simple main.o foo.o
- make # 先执行依赖的内容，再执行simple

.PHONY: main clean # 假如这个不写，如果当前目录有clean这个文件，将会提示clean is up to date。
clean:
    rm simple main.o foo.o # 写了伪对象后即时存在同名文件，依然会执行这个。

.PHONY: clean
CC = gcc
RM = rm
EXE = simple
OBJS = main.o foo.o
DEBUG = -g
CFLAGS = $(DEBUG) -Wall -c
$(EXE) : $(OBJS)
    $(CC) -o $(EXE) $(OBJS)
main.o : main.c
    $(CC) $(CFLAGS) -o main.o -c main.c
foo.o : foo.c
    $(CC) $(CFLAGS) -o foo.o -c foo.c   
clean:
    $(RM) $(EXE) $(OBJS)

.PHONY all
all: first second third
    @echo "\$$@ = $@"
    @echo "$$^ = $^"
    @echo "$$< = $<"
first:
    @echo "1 first"
second:
    @echo "2 second"
third:
    @echo "3 third"
## 1 first
## 2 second
## 3 third
## $@ = all   $@表示目标本身
## $^ = first second third   $^表示所有的先决条件（依赖）
## $< = first   $<表示第一个先决条件（依赖）

.PHONY: clean
CC = gcc
RM = rm
EXE = simple
SRCS = $(wildcard *.c) # 通配符函数，得到所有.c文件组成的字符串
OBJS = $(patsubst %.c, %.o, $(SRCS)) # 字符串替换函数，将$(SRCS)的字符串中.c替换成.o

$(EXE): $(OBJS)
    $(CC) -o $@ $^
%.o: %.c
    $(CC) -o $@ -c $^
clean:
    $(RM) $(EXE) $(OBJS)

## 单个目录实现
## CMake 最低版本号要求
cmake_minimum_required (VERSION 2.8)
## 工程，他不是执行文件名
PROJECT(Darren)
## 手动加入文件 ${变量名}} ，比如${SRC_LIST}
SET(SRC_LIST main.c)
set(SRC_LIST2 main2.c)
## MESSAGE和echo类似 
MESSAGE(STATUS "PROJECT_BINARY_DIR DIR " ${PROJECT_BINARY_DIR})
MESSAGE(STATUS "PROJECT_SOURCE_DIR DIR " ${PROJECT_SOURCE_DIR})

## 生产执行文件名0voice  0voice2
ADD_EXECUTABLE(0voice ${SRC_LIST})
ADD_EXECUTABLE(0voice2 ${SRC_LIST2})

## CMake 最低版本号要求
cmake_minimum_required (VERSION 2.8)
PROJECT(0VOICE)

MESSAGE(STATUS "0voice top PROJECT_BINARY_DIR       " ${PROJECT_BINARY_DIR}) 
MESSAGE(STATUS "0voice top PROJECT_SOURCE_DIR       " ${PROJECT_SOURCE_DIR})
## CMAKE_CURRENT_SOURCE_DIR它的CMakeLists.txt所在的当前源目
MESSAGE(STATUS "0voice top CMAKE_CURRENT_SOURCE_DIR " ${CMAKE_CURRENT_SOURCE_DIR})

## 添加子目录
ADD_SUBDIRECTORY(src)

##INSTALL(FILES COPYRIGHT README DESTINATION share/doc/cmake/0voice)
## 安装doc到  share/doc/cmake/0voice目录
## 默认/usr/local/
##指定自定义目录，比如 cmake -DCMAKE_INSTALL_PREFIX=/tmp/usr ..
INSTALL(DIRECTORY doc/ DESTINATION share/doc/cmake/0voice)

cmake_minimum_required (VERSION 2.8)
SET(SRC_LIST main.c)
MESSAGE(STATUS "0voice sub PROJECT_BINARY_DIR       " ${PROJECT_BINARY_DIR}) 
MESSAGE(STATUS "0voice sub PROJECT_SOURCE_DIR       " ${PROJECT_SOURCE_DIR})
## CMAKE_CURRENT_SOURCE_DIR它的CMakeLists.txt所在的当前源目
MESSAGE(STATUS "0voice sub CMAKE_CURRENT_SOURCE_DIR " ${CMAKE_CURRENT_SOURCE_DIR})

ADD_EXECUTABLE(youzi ${SRC_LIST})
## 演示
ADD_EXECUTABLE(youzi2 ${SRC_LIST})
## 将执行文件安装到bin目录
## 默认/usr/local/
##指定自定义目录，比如 cmake -DCMAKE_INSTALL_PREFIX=/tmp/usr ..
INSTALL(TARGETS youzi RUNTIME DESTINATION bin)
INSTALL(TARGETS youzi2 RUNTIME DESTINATION bin)