Path: utzoo!attcan!uunet!husc6!bloom-beacon!gatech!hubcap!ncrcae!ncr-sd!hp-sdd!hplabs!hpda!hpsemc!bd
From: bd@hpsemc.HP.COM (bob desinger)
Newsgroups: comp.sys.hp
Subject: Re: problems with make
Message-ID: <1250006@hpsemc.HP.COM>
Date: 16 May 88 07:43:59 GMT
References: <12407@sri-spam.istc.sri.com>
Organization: HP Technology Access Center, Cupertino, CA
Lines: 78

>   you can also get more refined by not looking at
>   the kernel, but rather:
> 	IFHP300 = test ! -f /bin/hp9000s300
> 	IFSUN3 = test ! -f /bin/sun3
> 	IFBSD = test ! -f /vmunix
> 	IFHPUX = test ! -f /hp-ux
>   and so on.

Yes, but be careful about merely checking the existence of the
programs in /bin/hp9000s*00; they're actually links to true(1) and
false(1) to return an exit status corresponding to the machine.

In other words, on the Series 300 and 800 both /bin/hp9000s300 and
/bin/hp9000s800 exist.  On the Series 300, /bin/hp9000s300 returns
true and /bin/hp9000s800 returns false.  On the Series 800,
/bin/hp9000s300 returns false and /bin/hp9000s800 returns true.

To get concrete about it, they're intended to be used in scripts as:

	/bin/hp9000s300 && echo "Here I am on my s300"
	/bin/hp9000s800 && echo "This executes on my s800"

The make command will complain about "Exit status 255" and stop
prematurely if the makefile uses them that way and the rule for the
`false' machine is executed.  (/bin/false is simply `exit 255'; cat
the file out and see.)  So you have to use them somewhat counter-
intuitively in the makefile, but it's nothing really strange for those
who have been following this newsgroup:

	# Which machine are we on?  (second version)
	IFHP300	= if hp9000s300 2>/dev/null; then
	IFHP800	= if hp9000s800 2>/dev/null; then
	IFSUN3	= if sun3 2>/dev/null; then
	
	target:
		$(IFHP300) echo Series 300; fi
		$(IFHP800) echo Series 800; fi
		$(IFSUN3) echo Sun 3; fi
		@echo Done

(The "2>/dev/null" keeps you from seeing complaints from the shell
about "sh: sun3: Command not found".)

As a matter of taste, you might prefer an extra makefile line of

	FI	= ; fi

with a cosmetic change to the target's rules:

	target:
		$(IFHP300) echo Series 300 $(FI)
		$(IFHP800) echo Series 800 $(FI)
		$(IFSUN3) echo Sun 3 $(FI)
		@echo Done

However you prefer the appearance, this solution gives you finer
control over your makes.  I like this solution better because it's the
cleanest so far.  (I wrote the earlier hack of peering at the kernels
because I didn't know that Sun offered /bin/sun3.  But since they do,
it's better to use the tools provided.)


>>By the way, your original makefile fragment works correctly on my
>>hp9000s800 (running 2.0).
>   because i bet you use ksh which knows about "]".  

Caught in the act!


>   since you're thinking about makefiles now, how would you accomplish
>   something like
>
> 							--bw

Could you repost that last fragment again?  The above four lines are
all I found on my machine.

-- bd