make之PHONY浅析

单词释义

PHONY：假的

1.不存在依赖

clean:

rm *.o

all: hello (存在依赖)

hello: main.o factorial.o hello.o

    $(CC) main.o factorial.o hello.o -o hello

2.加.PHONY,忽略与clean同名的文件

.PHONY:clean

make clean  >> rm *.o

3.不加.PHONY

clean:

rm *.o

make clean  >> make: `clean' is up to date.