make: computed & automatic variables in dependencies
ssad...@my-deja.com
I am having a problem with gnu make that I can't work out how to solve
with gnu make 3.79 and NT.
I define multiple sets of java classes:
LIB1_CLASSES=foo1.class
LIB2_CLASSES=foo2.class
And jar files into which they should go:
JAR_FILES=LIB1.jar LIB2.jar
now I want to make a single rule that determines for each jar whether
it must be rebuilt:
$(JAR_FILES): $($*_CLASSES)
jar -tvf $@ $($*_CLASSES)
The $($*_CLASSES) gets the right classes variable for the target being
made. Unfortunately, $* does not work in a dependency list - and I
find that the second one (in the command) works but the first doesn't.
As an alternative, I try using %. Eg,
$(JAR_FILES): %.jar: $(%_CLASSES)
jar -tvf $@ $($*_CLASSES)
But while % works generally in the dependency list, it fails when I try
to compute a variable from it.
Does anyone know how I could achieve what I want - either a solution to
the above or another approach to take?
Thanks for any suggestions!
Simon Sadedin.
Sent via Deja.com http://www.deja.com/
Before you buy.
Paul D. Smith
s> LIB1_CLASSES=foo1.class
s> LIB2_CLASSES=foo2.class
s> JAR_FILES=LIB1.jar LIB2.jar
s> now I want to make a single rule that determines for each jar whether
s> it must be rebuilt:
s> $(JAR_FILES): $($*_CLASSES)
s> jar -tvf $@ $($*_CLASSES)
You can't do this in make. Automatic variables are _ONLY_ valid within
the context of the command script, not the target or prerequisite lists.
s> As an alternative, I try using %. Eg,
s> $(JAR_FILES): %.jar: $(%_CLASSES)
s> jar -tvf $@ $($*_CLASSES)
s> But while % works generally in the dependency list, it fails when I try
s> to compute a variable from it.
Right. The command line must be expanded for variables _before_ the %'s
are replaced, the way make works.
s> Does anyone know how I could achieve what I want - either a solution to
s> the above or another approach to take?
The only way to do things like this now is via constructed makefiles.
You can create a makefile containing the dependencies you want, then
include them in your makefile. Due to GNU make's auto-re-exec feature,
they will be automatically kept up-to-date for you.
For example:
LIB1_CLASSES=foo1.class
LIB2_CLASSES=foo2.class
JAR_FILES=LIB1.jar LIB2.jar
$(JAR_FILES):
jar -tvf $@ $($*_CLASSES)
include jar_deps.mk
jar_deps.mk: Makefile
rm -f $@
for f in $(JAR_FILES:%.jar=); do \
echo "$$f.jar: \$$($$f_CLASSES)" >> $@; \
done
I didn't test this so the quoting might not be exact, but the
jar_deps.mk file should look like this after make builds it:
LIB1.jar: $(LIB1_CLASSES)
LIB2.jar: $(LIB2_CLASSES)
etc.
There is a feature I'm working on which will make this easier, but for
now this is the best you can do.
--
-------------------------------------------------------------------------------
Paul D. Smith <psm...@gnu.org> Find some GNU make tips at:
http://www.gnu.org http://www.ultranet.com/~pauld/gmake/
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist
ssad...@my-deja.com
> The only way to do things like this now is via constructed makefiles.
> You can create a makefile containing the dependencies you want, then
> include them in your makefile. Due to GNU make's auto-re-exec
feature,
> they will be automatically kept up-to-date for you.
>
Thanks for your excellent & detailed response - you've given me what I
needed to know, and I can probably work with your suggestion. My main
challenge is how to make it cross-platform
(yes, it has to work on windblows:-( )
>
> There is a feature I'm working on which will make this easier, but for
> now this is the best you can do.
Understanding that even answering my message is slowing it down :-),
any idea on the time frame/release it would appear in?
Cheers & thanks,
Paul D. Smith
s> Thanks for your excellent & detailed response - you've given me what I
s> needed to know, and I can probably work with your suggestion. My main
s> challenge is how to make it cross-platform
s> (yes, it has to work on windblows:-( )
Hmm. Doesn't GNU make on windows support auto-re-exec? I thought it
did.
--
-------------------------------------------------------------------------------
Paul D. Smith <psm...@baynetworks.com> Network Management Development
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist
-------------------------------------------------------------------------------
These are my opinions---Nortel Networks takes no responsibility for them.
Paul D. Smith
>> There is a feature I'm working on which will make this easier, but for
>> now this is the best you can do.
s> Understanding that even answering my message is slowing it down :-),
s> any idea on the time frame/release it would appear in?
Oops, forgot this one :)
I have no idea on the timeframe. Not within the next 3 months or so,
for sure.
My plan is to make this the next major feature, in the next version
3.80.
ssad...@my-deja.com
psm...@baynetworks.com wrote:
> %% ssad...@my-deja.com writes:
>
> s> Thanks for your excellent & detailed response - you've given me
what I
> s> needed to know, and I can probably work with your suggestion.
My main
> s> challenge is how to make it cross-platform
> s> (yes, it has to work on windblows:-( )
>
> Hmm. Doesn't GNU make on windows support auto-re-exec? I thought it
> did.
Actually I was referring to the "for" loop in your example. I can
probably get away with installing a real shell on the nt box - make has
some nice features to support that.
Cheers,
Simon.
Paul D. Smith
s> My main challenge is how to make it cross-platform (yes, it has to
s> work on windblows:-( )
>> Hmm. Doesn't GNU make on windows support auto-re-exec? I thought it
>> did.
s> Actually I was referring to the "for" loop in your example.
Hmm... doesn't command.com have any loop capabilities? I thought you
could loop in DOS batch files. You can use make functions to munge the
contents to exactly what you want, then the loop is very simple.
s> I can probably get away with installing a real shell on the nt box
That's definitely the best way to go, though :)