Is Makefile.inc1 in 6 wrong?

Jung-uk Kim jkim at FreeBSD.org
Tue Apr 4 21:52:35 UTC 2006


On Tuesday 04 April 2006 05:32 pm, Lars Eighner wrote:
> On Tue, 4 Apr 2006, Jung-uk Kim wrote:
> > On Tuesday 04 April 2006 05:14 pm, Lars Eighner wrote:
> >> It appears to me that either I have a wrong version of awk or
> >> this Makefile.inc1 is wrong:
> >>
> >> #
> >> # $FreeBSD: src/Makefile.inc1,v 1.499.2.11 2006/04/04 14:24:03
> >> glebius Exp $ #
> >>
> >> <Snippage>
> >>
> >> MAKEOBJDIRPREFIX?=	/usr/obj
> >> .if !defined(OSRELDATE)
> >> .if exists(/usr/include/osreldate.h)
> >> OSRELDATE!=	awk '/^\#define[[:space:]]*__FreeBSD_version/ {
> >> print $$3 }' \ /usr/include/osreldate.h
> >> .else
> >> OSRELDATE=	0
> >>
> >>
> >> In particular with the double dollar sign in the awk statement,
> >> I get no return, therefore OSRELDATE gets set to 0.  The awk
> >> statement also fails from the command line.  But if I use only
> >> one $, the awk statement succeeds.
> >>
> >> Is there a reason for the double dollar sign?
> >
> > Yes.  See make(1):
> >
> >    $   A single dollar sign `$', i.e. `$$' expands to a single
> > dollar sign.
>
> Then why does it get the wrong answer?

Because you ran it from command line. ;-)  You can copy and paste the
same lines to *Makefile* like this:

------------
.if !defined(OSRELDATE)
.if exists(/usr/include/osreldate.h)
OSRELDATE!=	awk '/^\#define[[:space:]]*__FreeBSD_version/ { print $$3 }' \
		/usr/include/osreldate.h
.else
OSRELDATE=	0
.endif
.endif

all:
	@echo "reldate = ${OSRELDATE}"
------------

and run make.  You will see something like this (depending on your
header file):

%make
reldate = 600034

> Also is there a difference when the accent mark is used in front
> instead of a real single quote?

Where do you see it?

Jung-uk Kim


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