<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8"> <META NAME="GENERATOR" CONTENT="GtkHTML/3.26.0"> </HEAD> <BODY> On Thu, 2010-01-07 at 16:24 -0800, Alan Coopersmith wrote: <BLOCKQUOTE TYPE=CITE> <PRE> Dan Nicholson wrote: > On Thu, Jan 7, 2010 at 4:16 PM, Matt Turner <<A HREF="mailto:mattst88@gmail.com">mattst88@gmail.com</A>> wrote: >> On Thu, Jan 7, 2010 at 3:06 PM, Gaetan Nadon <<A HREF="mailto:memsize@videotron.ca">memsize@videotron.ca</A>> wrote: >>> This patch to xserver configure.ac is to increase code portability to >>> non POSIX system by using backticks rather than $() for command >>> substitution for BUILD_DATE and BUILD_TIME. >>> >> What kind of systems would these be? > > Older Solaris was definitely the common case where it would come up. Yes, /bin/sh on Solaris releases up to and including Solaris 10 and Solaris Express is a pre-POSIX bourne shell that only supports `` not $(). There are POSIX shells available, but then builders always have to remember to run /bin/bash ./configure or /bin/ksh ./configure instead of just ./configure. OpenSolaris and future Solaris releases make /bin/sh be ksh93 instead, so won't have this limitation, but it will be a long time before Solaris 10 and older variants die out in the wild. </PRE> </BLOCKQUOTE> For my part, not having extensive platform knowledge, I noticed that all autoconf/automake scripts use backticks. I searched all configure.ac files and there were only 2 cases, one with pkg-config (which I was unknowingly spreading) and the date/time. That reassured me it was the right thing to do. Finally I found this in Autoconf manual: <BLOCKQUOTE> Most notably, even recent releases of Solaris don't support it: <PRE> $ <TT>showrev -c /bin/sh | grep version</TT> Command version: SunOS 5.10 Generic 121005-03 Oct 2006 $ <TT>echo $(echo blah)</TT> syntax error: `(' unexpected </PRE> nor does irix 6.5's Bourne shell: <PRE> $ <TT>uname -a</TT> IRIX firebird-image 6.5 07151432 IP22 $ <TT>echo $(echo blah)</TT> $(echo blah) </PRE> </BLOCKQUOTE> I am glad Matt asked the question, this type of detailed information is hard to find. Gaetan </BODY> </HTML>