Re: How to specify a dependence on a directory?

[Peng Yu]

On Sun, Jan 10, 2010 at 2:59 PM, Peng Yu <address@hidden> wrote:
> On Sun, Jan 10, 2010 at 11:02 AM, Paul Smith <address@hidden> wrote:
>> On Sun, 2010-01-10 at 10:22 -0600, Peng Yu wrote:
>>> The code that you suggested is not working properly, when make is
>>> called the second time. Would you please take a look at how to fix it?
>>
>>> $ cat Makefile
>>> TXT_FILES:=$(wildcard somedir/*.txt)
>>>
>>> ifeq ($(TXT_FILES),)
>>> .PHONY: all
>>> endif
>>>
>>> .PHONY: clean
>>>
>>> all: $(TXT_FILES)
>>>       ./command.sh
>>
>>> $make   # I do not expect command.sh should be called here, because
>>> all *.txt is newer than command.sh
>>
>> ?!?!  What does whether the text files are newer than command.sh have to
>> do with anything?
>
> I don't understand how to adapt your following code segment. Would you
> please be explicit on how to use your code in my problem?
>
>     FILES := $(wildcard somedir/*)
>       ifeq ($(FILES),)
>       .PHONY: target
>       endif
>       target: $(FILES)
>               somecommand

The solution that I found is the following. But there is a caveat that
if I stop 'make' (say be ctrl-C) at the first time when it is running
(not all txt files are generated). When I rerun 'make', it will not
call command.sh to generate all the txt files. You might have a more
concise and correct solution.

$ cat Makefile
TXT_FILES:=$(wildcard somedir/*.txt)

.PHONY: all

ifeq ($(TXT_FILES),)

all: ./command.sh
        ./command.sh

else

all: $(TXT_FILES)

$(TXT_FILES): ./command.sh
        ./command.sh

endif

.PHONY: clean

clean:
        @$(RM) -rf somedir

>> Your makefile shows that the target "all" depends on the text files, so
>> the only thing make cares about is whether any of the text files are
>> newer than "all".  Make doesn't know ANYTHING about command.sh.
>>
>>
>> If you don't want the command to be run when the text files haven't been
>> changed then you to be sure the file "all" exists with a timestamp newer
>> than the text files.  Or, change your rules.
>>
>> --
>> -------------------------------------------------------------------------------
>>  Paul D. Smith <address@hidden>          Find some GNU make tips at:
>>  http://www.gnu.org                      http://make.mad-scientist.net
>>  "Please remain calm...I may be mad, but I am a professional." --Mad 
>> Scientist
>>
>>
>>
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>>
>