testing the value of ${CXX} in ports Makefile

[Chris H]

On Thu, 29 Jan 2015 22:46:32 -0800 (PST) Don Lewis <truckman at FreeBSD.org> wrote

> On 29 Jan, Chris H wrote:
> > On Thu, 29 Jan 2015 19:43:38 -0800 (PST) Don Lewis <truckman at FreeBSD.org>
> > wrote 
> >> I need to test the value of ${CXX} in the Makefile for a port and am
> >> getting unexpected results.  Here is a simplified version of the
> >> Makefile:
> >> 
> >> PORTNAME=    junk
> >> PORTVERSION=    0.0.0
> >> CATEGORIES=    devel
> >> DISTFILES=
> >> 
> >> MAINTAINER=    truckman at FreeBSD.org
> >> COMMENT=    junk
> >> 
> >> USE_GCC=    4.9+
> >> 
> >> .include <bsd.port.pre.mk>
> >> 
> >> post-patch:
> >>     echo CXX=${CXX}
> >> .if ${CXX} == g++49
> >>     echo detected g++49
> >> .else
> >>     echo did not detect g++49
> >> .endif
> >> 
> >> .include <bsd.port.post.mk>
> >> 
> >> 
> >> If I run "make patch", this is what I get:
> >> 
> >> # make patch
> >> ===>   junk-0.0.0 depends on file: /usr/local/sbin/pkg - found
> >> ===> Fetching all distfiles required by junk-0.0.0 for building
> >> ===>  Extracting for junk-0.0.0
> >> ===>  Patching for junk-0.0.0
> >> echo CXX=g++49
> >> CXX=g++49
> >> echo did not detect g++49
> >> did not detect g++49
> >> 
> >> 
> >> If I run "make -dA patch" and look at the debug output, I observe
> >> bsd.gcc.mk getting processed after the .if is evaluated.  When the .if
> >> is processed, the value of ${CXX} is still c++.  It sort of looks like
> >> bsd.gcc.mk isn't getting included until bsd.port.post.mk and we are
> >> relying on lazy expansion to get the correct value of ${CXX} for the
> >> actions.
> >> 
> >> It sort of looks like I'll have to do something like:
> >> 
> >> post-patch:
> >>     [ ${CXX} = g++49 ] && echo detected g++49
> >> 
> >> but that just seems goofy.
> > I'm not attempting to come off as any sot of expert. But it
> > seems like you're going the long way around. Couldn't you
> > just as easily REQUIRE, or perhaps even better; simply reverse
> > the logic;
> > 
> > if ${CXX} != g++49
> > @VOMIT
> > endif
> > 
> > It'd be shorter, and still assures the results you require,
> > no? Just a thought.
> 
> gcc46, gcc47, gcc48, and probably gcc5 (haven't tested that one yet) all
> work.  gcc49 requires a source patch.  I just want to be able to set
> USE_GCC=yes and not have the port break when the default version of gcc
> gets changed to 4.9.
> 
> The way that the ports infrastructure is written, it looks like I can't
> do the test with a Makefile .if / .endif.  It looks like I have to do it
> in the shell code in actions for the target.
> 
> Instead of using [ condition ] && do something, I could also write it as
>     if [ ${CXX} = g++49 ]; then apply the patch; fi
Ahh. Sure. It's also shorter than the only alternative I can conceive
if ${CXX} <= g++48 || if ${CXX} >= g++50
@${PATCHME}
endif

--Chris

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