Re: [PATCH 1/2] config.mak.uname: Darwin: define HAVE_GETDELIM for modern OS X releases

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Jun 2, 2015, 19:57 UTC
Message-ID: <CAPig+cQLSF4=-4b1qOY4ChBj00=trvAO0qFEh0kOjLonJL4MBg@mail.gmail.com>
In-Reply-To: <20150602190403.GA12660@peff.net>

On Tue, Jun 2, 2015 at 3:04 PM, Jeff King <peff@peff.net> wrote:

Show 6 quoted lines

> On Tue, Jun 02, 2015 at 02:44:13PM -0400, Jeff King wrote:
>> > +   ifeq ($(shell expr $(shell expr "$(uname_R)" : '\([0-9][0-9]*\)\.') '>=' 11),1)
>>
>> Do you need to spawn two shells? It seems like:
>>
>>   $(shell expr `expr "$(uname_R)" : '\([0-9][0-9]*\)'` '>=' 11),1)

I considered that and waffled on it. Either approach uses an extra process, but I suppose `...` would likely be less expensive since it's just forking the shell rather than exec()ing a new one.

> Oops, I missed the trailing '.' in the regex there, and it probably
> needs double-quotes in case the inner expr fails to match anything.

Which is messy considering the double quotes already surrounding $(uname_R). Suggestions?

> We could also use "test -gt" instead of the outer expr, which is more
> idiomatic shell. But it reports via exit code, so you'd need "&& echo 1"
> at the end.

Yes, I messed around with that as well but didn't want to stray too far from existing practice.

I suppose the combination of `...` with built-in 'test' and built-in 'echo' would be the most efficient choice. Do you want it re-rolled?