如何通过遍历子目录自动生成生成目标的列表? [英] How to generate list of make targets automatically by globbing subdirectories?
问题描述
我想使用一个Makefile在数百个子目录中生成目标.每个子目录都是这样的日期/时间戳:20120119_153957，它与以下模式????????_??????相匹配.没有其他子目录与此模式匹配.
I would like to use a single Makefile to generate targets in hundreds of subdirectories. Each subdirectory is a date/time stamp like this: 20120119_153957, which matches the following pattern ????????_??????. There are no other subdirectories that match this pattern.
我要生成的一个目标称为????????_??????/graph.pdf.我有一个名为make_graph的脚本，它将使图形具有子目录名称.但是我不确定如何编写一个Makefile，它将自动遍历所有子目录并以编程方式生成这些目标.
One target I would like to generate is called ????????_??????/graph.pdf. I have a script called make_graph that will make the graph given the subdirectory name. But I'm not sure how to write a Makefile that will automatically glob all of the subdirectores and generate these targets programmatically.
例如，代码SUBDIRS:=????????_??????似乎正确地遍历了所有子目录.我可以检查以下规则:
For example, the code SUBDIRS:=????????_?????? seems to correctly glob all of the subdirectories. I can check with this rule:
.PHONY: print
print:
echo $(SUBDIRS)
但是这个变量赋值
TARGETS:=$(SUBDIRS:%=%/graph.pdf)
似乎并没有达到我的期望，并分配了很多目标.相反，以下规则仅打印一个目标.
does not seem to do what I expect and assign lots and lots of targets. Instead the following rule just prints one target.
.PHONY: print
print:
echo $(TARGETS)
SUBDIRS应该具有正确的子目录，但是TARGET只有一个文件，这非常令人困惑.
It is very confusing that SUBDIRS should have the correct subdirectories but TARGET only has one file.
推荐答案
在您的示例中，全局匹配由外壳执行.
In your example glob matching is performed by the shell.
GNU Make具有内置的 wildcard函数，该函数您可以按如下方式使用:
GNU Make has the built-in wildcard function, which you can use as follows:
SUBDIRS := $(wildcard ????????_??????)
现在，您可以使用此变量来构建目标列表:
Now you can use this variable to construct a list of targets:
.PHONY : all
all : $(SUBDIRS:%=%/graph.pdf)
%/graph.pdf : # list prerequisites here.
# recipe to make '$@' in directory '$(@D)' from '$^'.
