Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > One other idea would be to set CFLAGS to "" before including template,
> > and just test to see if it is still "" after --- that might be cleaner
> > than saving the original value and comparing.
>
> Yeah, that bothered me a bit too --- what if the template tries to set
> CFLAGS to its already-existing value? I was thinking that unsetting
> CFLAGS before running the template would be the best answer.
I assume he did it that way so if you do:
CFLAGS=
in the template file that it would be honored. I see lots of this in
configure:
ac_env_CFLAGS_set=${CFLAGS+set}
but that uses 'set' if the variable is null or unset:
${parameter:+word} Use Alternate Value. If parameter is null or unset, nothing is
substituted,otherwise the expan- sion of word is substituted.
However, I thought null meant "", but I now think null basically means
the same as unset in this manual page. Notice that '+' tests only for
unset, and knows when you have done VAR= and VAR="":$ echo ${Y+no}$ Y=$ echo ${Y+no}no$ Y=""$ echo ${Y+no}no$ unset Y$
echo${Y+no}$
so the proper test would be to unset the variable, then use ${var+val}
to test CFLAGS after the template file is included.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
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