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Date: Wed, 7 Feb 2001 13:24:08 +0000 (GMT Standard Time)
From: Robert Bogomip <bob DOT bogo AT milohedge DOT com>
To: Scott Carter <scarter AT emware DOT com>
cc: <cygwin AT cygwin DOT com>
Subject: RE: make 3.79: core dump expanding target specific variables
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On Tue, 6 Feb 2001, Scott Carter wrote:
>
> I don't have a explanation/solution for the core dump, but here's a
> explanation of why you get [ 2] rather than [2]
>
> http://sources.redhat.com/ml/cygwin/2000-07/msg00816.html
> (summary: += inserts a space.)
>

No, I don't think so when this is the first time the variable is defined.
If we use the original Makefile without the target specific variables we
have:

  t+=2

  t:
	@echo "[${t}]"

giving:

  $ make all
  [2]
  $

on all versions of make I have (3.77, 3.78, 3.79 on Linux & cygwin). The
docs say

 "objects += another.o

  This takes the value of the variable objects, and adds the text
  `another.o' to it (preceded by a single space)."

and a little further down,

 "When the variable in question has not been defined before, `+=' acts
  just like normal `=': it defines a recursively-expanded variable."

A little ambiguous, but the tests above confirm that a space is only
inserted if ${t} already exists (even if it is empty).



BTW, the original core dump occurs on Linux make 3.79 too, so I suppose
it's a real make bug.
-- 
Robert Bogomip /// mailto:bob DOT bogo AT milohedge DOT com
Milo Hedge Ltd, OCFI, Mill Street, Oxford, OX2 0JX /// tel:+44 1865 799400


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