Date: Mon, 21 Jun 2010 04:00:12 GMT From: Garrett Cooper <gcooper@FreeBSD.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/148024: Some built-in AT&T/POSIX compat make variables are broken Message-ID: <201006210400.o5L40CYx093514@freefall.freebsd.org>
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The following reply was made to PR bin/148024; it has been noted by GNATS.
From: Garrett Cooper <gcooper@FreeBSD.org>
To: Garrett Wollman <wollman@hergotha.csail.mit.edu>
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: bin/148024: Some built-in AT&T/POSIX compat make variables are
broken
Date: Sun, 20 Jun 2010 20:56:23 -0700
On Sun, Jun 20, 2010 at 7:46 PM, Garrett Wollman
<wollman@hergotha.csail.mit.edu> wrote:
> In article
> <mit.lcs.mail.freebsd-bugs/201006210044.o5L0iPXK000857@www.freebsd.org>,
> gcooper@freebsd.org writes:
>
>>foo: bar
>> =A0 =A0 =A0 @echo target: $@ prereq: $<
>>$ make -f ~/Makefile.prereq foo
>>target: foo prereq:
>>
>>The above invocation should have printed out:
>>
>>target: foo prereq: bar
>
> No. =A0$< is only defined for pattern rules.
>
>>$<
>> =A0 =A0In an inference rule, the $< macro shall evaluate to the filename
>>whose existence allowed the inference rule to be chosen for the target.
>>In the .DEFAULT rule, the $< macro shall evaluate to the current target
>>name. The meaning of the $< macro shall be otherwise unspecified.
> =A0 =A0 =A0 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Ok.. this appears to be a GNU make `extension':
$ gmake -f ~/Makefile.prereq yadda.a
target: yadda.a prereq: bazinga.b
target: yadda.a prereq:
target: prereq:
$ make -f ~/Makefile.prereq yadda.a
target: yadda.a prereq:
target: yadda.a prereq: bazinga.b
target: yadda.a prereq: bazinga.b
$ bmake -f ~/Makefile.prereq yadda.a
target: yadda.a prereq:
target: yadda.a prereq: bazinga.b
target: yadda.a prereq: bazinga.b
$ cat ~/Makefile.prereq
.b.a:
echo target: $@ prereq: $<
bazinga.b:
yadda.a: bazinga.b
@echo target: $@ prereq: $<
@echo target: $@ prereq: $>
@echo target: ${.TARGET} prereq: ${.ALLSRC}
Is an inference rule the .b.a rule? POSIX doesn't properly define
what it is and assumes you know what's going on (lousy documentation)
:(...
Thanks,
-Garrett
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