gnu make

模式替换

Another type of substitution reference lets you use the full power of the patsubst function. It has the same form ‘$(var:a=b)’ described above, except that now a must contain a single ‘%’ character. This case is equivalent to ‘$(patsubst a,b,$(var))’. See Functions for String Substitution and Analysis, for a description of the patsubst function.

For example:
foo := a.o b.o c.o
bar := $(foo:%.o=%.c)
sets ‘bar’ to ‘a.c b.c c.c’.

关于特殊符号变量

$<表示所有的依赖文件（：右侧的文件）

$@表示所有的目标文件（：左侧的文件）

下面是一个例子

Here is an example, which compiles each of foo.o and bar.o from the corresponding .c file:

objects = foo.o bar.o

all: $(objects)

$(objects): %.o: %.c
        $(CC) -c $(CFLAGS) $< -o $@