----伪目标----
target
：
commands
如果makefile
所在目录没有target
同名文件：make
target
则导致commands
总是被执行。
如果makefile
所在目录下存在target
同名文件：make
target
则commands
不被执行，认为target
总是最新的。
.PHONY:target
target:
commands
不论makefile
所在目录下存不存在与target
同名文件，make
target
导致commands
的执行，与上一种写法的区别是引用'.PHONY'
的意义所在。
-----强制目标-----
target:
因为没有命令，所以make
target
，与makefile
所在目录下是否存在与target
同名的文件没有直接关系。
-----双冒号规则-----
target::
commands
无论makefile
所在目录下存不存在与target
同名文件，make
target
导致commands
的执行，与使用'.PHONY'
定义的伪目标效果相同。
-----------------------------------------------------------------
----------1
.PHONY target
all:target
commands1
#
伪目标
target:
commands
----------2
all:target
commands1
#
伪目标
target:
commands
---------3
all:target
commands1
#
强制目标
target:
---------4
all:target
commands1
#
双冒号规则
target::
commands
1
和4make
all
执行情况相同，无论makefile
所在目录下存不存在与target
同名文件,commands1
和commands
都被执行。
2
和3make
all
执行情况在makefile
所在目录下存在与target
同名文件，commads
不被执行(
认为target
目标是最新的)
，commands1
将被执行；而如果不存在与target
同名的文件，则2
运行效果与1
和4
相同，3
运行将导致commands1
的执行。
>rm *
>vim
Makefile
>cat -n
Makefile
1 .PHONY:target1
2 all1:target1
3 echo
"all1_target1_.PHONY_command_all1"
4 target1:
5 echo
"all1_target1_.PHONY_command_target1"
6
7 all2:target2
8 echo
"all2_target2_command_all2"
9 target2:
10 echo
"all2_target2_command_target2"
11
12 all3:target3
13 echo
"all3_target3_force_command_all3"
14 target3:
15
16 all4:target4
17 echo
"all4_target4_::_command_all4"
18 target4::
19 echo
"all4_target4_::_command_target4"
20
>make all1
echo
"all1_target1_.PHONY_command_target1"
all1_target1_.PHONY_command_target1
echo
"all1_target1_.PHONY_command_all1"
all1_target1_.PHONY_command_all1
>make all2
echo
"all2_target2_command_target2"
all2_target2_command_target2
echo
"all2_target2_command_all2"
all2_target2_command_all2
>make all3
echo
"all3_target3_force_command_all3"
all3_target3_force_command_all3
>make all4
echo
"all4_target4_::_command_target4"
all4_target4_::_command_target4
echo
"all4_target4_::_command_all4"
all4_target4_::_command_all4
>touch
target{1,2,3,4}
>ls
>make all1
echo
"all1_target1_.PHONY_command_target1"
all1_target1_.PHONY_command_target1
echo
"all1_target1_.PHONY_command_all1"
all1_target1_.PHONY_command_all1
>make all2
echo
"all2_target2_command_all2"
all2_target2_command_all2
>make all3
echo
"all3_target3_force_command_all3"
all3_target3_force_command_all3
>make all4
echo
"all4_target4_::_command_target4"
all4_target4_::_command_target4
echo
"all4_target4_::_command_all4"
all4_target4_::_command_all4
-----------
以上测试在GNU
Make 3.81
版本进行