奇怪的表达式D_FILES := $(O_FILES:.o=

lbtianya

今天看到了一个奇怪的表达式

D_FILES := $(O_FILES:.o=.d)
include $(D_FILES)

不知道这两行式什么意识？？

mozilla

makefile里的？

lbtianya

是makefile里的


# Rule for compiling (always first)
%.o: %.c
        $(CC) $(CFLAGS) $< -c -o $@

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


# Rule for building dependencies from source (always second)
%.d: %.c
        $(CC) -M $(CFLAGS) $< > $@
%.d: %.cpp
        $(CC) -M $(CFLAGS) $< > $@

############################################################################
# Automatic source file dependencies
############################################################################

# include the dependencies (always third)
D_FILES := $(O_FILES:.o=.d)
include $(D_FILES)

all: $(EXEC)

# uses non LGPL librarys
$(EXEC): $(OBJS)
        $(CC) $(LDFLAGS) -o $@ $(OBJS) $(LIBHTTPCLIENT) $(LDLIBS) -lpthread -dHTTP0
        -$(STRIP) $@

kakuyou

6.3.1 Substitution References

A substitution reference substitutes the value of a variable with alterations that you specify. It has the form `$(var:a=b)' (or `${var:a=b}') and its meaning is to take the value of the variable var, replace every a at the end of a word with b in that value, and substitute the resulting string.

When we say "at the end of a word", we mean that a must appear either followed by whitespace or at the end of the value in order to be replaced; other occurrences of a in the value are unaltered. For example:

       

foo := a.o b.o c.o
bar := $(foo:.o=.c)

sets `bar' to `a.c b.c c.c'. See section Setting Variables.

A substitution reference is actually an abbreviation for use of the patsubst expansion function (see section Functions for String Substitution and Analysis). We provide substitution references as well as patsubst for compatibility with other implementations of make.

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 section 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'.

------------------------------------------------
gmake的字符替换

lbtianya

谢谢斑竹
  请问这篇完整的文章什么地方可以得到

kakuyou

见置顶贴

http://www.linuxfans.org/nuke/modules.php?name=Forums&file=viewtopic&t=151237