From owner-freebsd-questions  Tue Oct  2  3:29:12 2001
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Date: Tue, 2 Oct 2001 06:29:06 -0400
From: Chip Norkus <wd@arpa.com>
To: Wayne Pascoe <wayne.pascoe@ehsrealtime.com>
Cc: freebsd-questions@freebsd.org
Subject: Re: autoconf project problem - OS detection / definition
Message-ID: <20011002062906.A30146@anduril.org>
References: <86snd2wgay.fsf@pan.ehsrealtime.com>
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In-Reply-To: <86snd2wgay.fsf@pan.ehsrealtime.com>; from wayne.pascoe@ehsrealtime.com on Tue, Oct 02, 2001 at 10:18:45AM +0100
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On Tue Oct 02, 2001; 10:18AM +0100 Wayne Pascoe used 0.8K bytes of bandwidth to send the following:
> Hi all,
> 
> I'm trying to convert a project that I have to use autoconf. The main
> problem that I am having at the moment is OS detection. I see that I
> can use config.guess and that will make the os available as
> ${target_os} to my configure scripts.
> 
> My problem is that in my code I have several sections like
> 
> #ifdef HAVE_LINUX
> do stuff
> .
> .
> #endif
> 
> #ifdef HAVE_FREEBSD
> do other stuff
> .
> .
> #endif
> 
> How do I use the ${target_os} to define the OS in my config.h file ? I
> don't need it to be HAVE_FREEBSD or HAVE_LINUX, it just needs to be a
> unique def for each OS.
> 

In your configure.in script, add a line:
AC_CANONCIAL_HOST

then, later, you can do:
case "$target_os" in
	linux*)
		AC_DEFINE(HAVE_LINUX)
		;;
	freebsd*)
		AC_DEFINE(HAVE_FREEBSD)
		;;
	...
esac

Unless you're support cross compiling (which I bet you're not), you can use
"$host_os" as well as "$target_os"  The reason for the pattern instead of a
straight name (that is 'linux*' instead of 'linux') is that the version
number of the system is also supplised.  Obviously, if you're using
AC_DEFINE, your autoconf config header of choice will need to contain all
the necessary entries (that is, for each OS, you'll want to add an '#undef
HAVE_HOST')

> TIA,
> 
> -- 
> Wayne Pascoe <wayne.pascoe@ehsrealtime.com>
> 
> Things fall apart; the center cannot hold;
> Mere anarchy is loosed upon the world. - Yeats
> 
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-questions" in the body of the message

HTH,
-wd
-- 
chip norkus(rl); white_dragon('net');      wd@arpa.com
"That's Tron.  He fights for the users."   http://telekinesis.org

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