继续翻译
A phony target should not be a prerequisite of a real target file;if it is, its recipe will be run every time `make' goes to update that file. As long as a phony target is never a prerequisite of a real target, the phony target recipe will be executed only when the phony target is a specified goal (*note Arguments to Specify the Goals: Goals.). Phony targets can have prerequisites. When one directory contains multiple programs, it is most convenient to describe all of the programs in one makefile `./Makefile'. Since the target remade bydefault will be the first one in the makefile, it is common to make this a phony target named `all' and give it, as prerequisites, all the individual programs. For example: all : prog1 prog2 prog3 .PHONY : all prog1 : prog1.o utils.o cc -o prog1 prog1.o utils.o prog2 : prog2.o cc -o prog2 prog2.o prog3 : prog3.o sort.o utils.o cc -o prog3 prog3.o sort.o utils.o
一个伪目的不应当是一个真的目的的前提条件；如果是，它的片段将会在每次运行make 时被执行。正因为伪目的永远不会是一个真正的目的，所以伪目的的片段才能在仅当其为特殊终点时才获得运行。(*note Arguments to Specify the Goals:Goals)
伪目的自身可以有前提条件。当一个目录包含多个程序，把所有的程序均包含到一个 ./Makefile中是最为方便的。因为缺省的目的重建会针对第一个目的，把此目的命名为伪目的 all ,让它拥有所有其他单独的程序作为前提条件。例如:
all : prog1 prog2 prog3
.PHONY : all
prog1 : prog1.o utils.o
cc -o prog1 prog1.o utils.o
prog2 : prog2.o
cc -o prog2 prog2.o
prog3 : prog3.o sort.o utils.o
cc -o prog3 prog3.o sort.o utils.o
后文待续
本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/archive/2012/09/20/2695203.html，如需转载请自行联系原作者
