Re: make -U
At 1:39 PM + 7/31/03, Christian Weisgerber wrote:
Juli Mallett <[EMAIL PROTECTED]> wrote:
> Why go thru those contortions? I sometimes use "make FOO=" to
> define things. -U obviously has a place, if it not existing
> means I have to have all these contortions to do a fairly
> obvious thing, yeah?
What are the exact semantics of -U supposed to be?
From the message in freebsd-hackers which first introduced
this patch:
- Date: Tue, 29 Jul 2003 09:09:17 -0700
- From: Faried Nawaz <[EMAIL PROTECTED]>
- Subject: patch to add make -U
While working around a port issue (ports/55013), I discovered
that make couldn't unset variables using make -U. I've written
a small patch that adds -U functionality, but I haven't tested
it extensively.
http://web.nilpotent.org/tmp/make.diff.bz2 (~ 3KB unpacked)
against yesterday's -CURRENT code.
A simple Makefile I used to test it:
-- cut here --
FOO = bar
.ifdef FOO
SAY = y
.else
SAY = n
.endif
all:
echo $(SAY)
-- cut here --
Try "make -U FOO".
Personally I think this is a reasonable option to implement.
An undefined variable is not the same as a variable which is
defined to be a null string.
--
Garance Alistair Drosehn= [EMAIL PROTECTED]
Senior Systems Programmer or [EMAIL PROTECTED]
Rensselaer Polytechnic Instituteor [EMAIL PROTECTED]
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Re: make -U
Juli Mallett <[EMAIL PROTECTED]> wrote: > Why go thru those contortions? I sometimes use "make FOO=" to define > things. -U obviously has a place, if it not existing means I have to > have all these contortions to do a fairly obvious thing, yeah? What are the exact semantics of -U supposed to be? -- Christian "naddy" Weisgerber [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: make -U
* Ruslan Ermilov <[EMAIL PROTECTED]> [ Date: 2003-07-30 ]
[ w.r.t. Re: make -U ]
> On Wed, Jul 30, 2003 at 04:23:20PM -0500, Juli Mallett wrote:
> > * Ruslan Ermilov <[EMAIL PROTECTED]> [ Date: 2003-07-30 ]
> > [ w.r.t. make -U ]
> > > Sorry, I've accidentally dropped an email about `make -U'.
> > >
> > > I think that it's not needed, since the functionality can
> > > easily be achieved by running "make FOO=", i.e., assigning
> > > an empty value. Remember that command line variables take
> > > precedence over globals, so the following makefile,
> > >
> > > FOO+= bar
> > >
> > > all:
> > > @echo ${FOO}
> > >
> > > when run as ``make FOO=foo'', will print just ``foo''.
> >
> > Does that work for the .if defined() case, too? Makefiles can grow
> > to be more complex than just that sort of stuff, after all :)
> >
> Not sure what do you mean. The "make -U FOO" was support to
> undefine the FOO variable, as it the ``.undef FOO'' was called
> at the end of makefile. Of course, setting FOO= on a command
> line still gets you a "defined" variable, but
>
> .if defined(FOO) && !empty(FOO)
>
> should do the trick. Try this out with "make FOO=":
>
> FOO= bar
>
> all:
> .if defined(FOO) && !empty(FOO)
> @echo FOO is set
> .endif
Why go thru those contortions? I sometimes use "make FOO=" to define
things. -U obviously has a place, if it not existing means I have to
have all these contortions to do a fairly obvious thing, yeah?
Thanx,
juli.
--
juli mallett. email: [EMAIL PROTECTED]; efnet: juli; aim: bsdflata;
i have lost my way home early - i don't care cause i won't stay there.
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Re: make -U
On Wed, Jul 30, 2003 at 04:23:20PM -0500, Juli Mallett wrote:
> * Ruslan Ermilov <[EMAIL PROTECTED]> [ Date: 2003-07-30 ]
> [ w.r.t. make -U ]
> > Sorry, I've accidentally dropped an email about `make -U'.
> >
> > I think that it's not needed, since the functionality can
> > easily be achieved by running "make FOO=", i.e., assigning
> > an empty value. Remember that command line variables take
> > precedence over globals, so the following makefile,
> >
> > FOO+= bar
> >
> > all:
> > @echo ${FOO}
> >
> > when run as ``make FOO=foo'', will print just ``foo''.
>
> Does that work for the .if defined() case, too? Makefiles can grow
> to be more complex than just that sort of stuff, after all :)
>
Not sure what do you mean. The "make -U FOO" was support to
undefine the FOO variable, as it the ``.undef FOO'' was called
at the end of makefile. Of course, setting FOO= on a command
line still gets you a "defined" variable, but
.if defined(FOO) && !empty(FOO)
should do the trick. Try this out with "make FOO=":
FOO=bar
all:
.if defined(FOO) && !empty(FOO)
@echo FOO is set
.endif
Cheers,
--
Ruslan Ermilov Sysadmin and DBA,
[EMAIL PROTECTED] Sunbay Software Ltd,
[EMAIL PROTECTED] FreeBSD committer
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Description: PGP signature
Re: make -U
* Ruslan Ermilov <[EMAIL PROTECTED]> [ Date: 2003-07-30 ]
[ w.r.t. make -U ]
> Sorry, I've accidentally dropped an email about `make -U'.
>
> I think that it's not needed, since the functionality can
> easily be achieved by running "make FOO=", i.e., assigning
> an empty value. Remember that command line variables take
> precedence over globals, so the following makefile,
>
> FOO+= bar
>
> all:
> @echo ${FOO}
>
> when run as ``make FOO=foo'', will print just ``foo''.
Does that work for the .if defined() case, too? Makefiles can grow
to be more complex than just that sort of stuff, after all :)
Thanx,
juli. (who admits she missed the rest of the conversation)
--
juli mallett. email: [EMAIL PROTECTED]; efnet: juli; aim: bsdflata;
i have lost my way home early - i don't care cause i won't stay there.
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make -U
Sorry, I've accidentally dropped an email about `make -U'.
I think that it's not needed, since the functionality can
easily be achieved by running "make FOO=", i.e., assigning
an empty value. Remember that command line variables take
precedence over globals, so the following makefile,
FOO+= bar
all:
@echo ${FOO}
when run as ``make FOO=foo'', will print just ``foo''.
Cheers,
--
Ruslan Ermilov Sysadmin and DBA,
[EMAIL PROTECTED] Sunbay Software Ltd,
[EMAIL PROTECTED] FreeBSD committer
pgp0.pgp
Description: PGP signature
