From: Eric Sunshine Date: Tue, 02 Jun 2015 19:57:44 GMT Subject: Re: [PATCH 1/2] config.mak.uname: Darwin: define HAVE_GETDELIM for modern OS X releases Message-ID: In-Reply-To: <20150602190403.GA12660@peff.net> On Tue, Jun 2, 2015 at 3:04 PM, Jeff King wrote: > 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?