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Re: please correct my ugly hack
From: |
Stepan Kasal |
Subject: |
Re: please correct my ugly hack |
Date: |
Fri, 3 Jun 2005 09:37:33 +0200 |
User-agent: |
Mutt/1.4.1i |
Hello again,
I'm sorry that I post a followup to my own mail:
On Thu, Jun 02, 2005 at 09:04:06PM +0200, Stepan Kasal wrote:
> On Wed, Jun 01, 2005 at 07:08:08PM +0200, Ralf Corsepius wrote:
> > No, caching had been invented for faster interaction of several
> > configure scripts (CONFIG_SUBDIRS) in large source trees.
So the subprojects can share the cache, even though their
configure.ac files might differ.
The consequences:
1) I proposed:
> Let's say that ac_cv_prog_FOO is an ``alias'' to FOO. [...]
> just before writing the cache, we'd do: ac_cv_prog_FOO=$FOO
This would be incorrect. The cache would be affected by the skew
which ca be added by each configure script.
2)
Two configure.ac files can contain AC_CHECK_PROGS([DUMP], ...),
with a totally different meanings.
Thus the general macros cannot use cache.
But the checks for particular programs (AC_PROG_AWK, AC_PROG_CC, etc.)
can cache their findings.
There is still one problem:
The variable itself has to have higher priority than its cache shadow.
Currently, AC_PROG_AWK is something like
AC_CACHE_VAL([ac_cv_prog_AWK], [if test "x$AWK" = x; then ... ; fi])
but it should be:
if test "x$AWK" = x; then
AC_CACHE_VAL([ac_cv_prog_AWK], [...])
fi
A plan:
The current caching scheme in programs.m4 has serious problems and has
to be removed. That will significantly improve correctness.
(I could get to that approx in July, I guess.)
Then the caching can be added back to the particular checks, if anyone
cares. (For specific setups, this will increase the speed again.)
Have a nice day,
Stepan Kasal
- Re: please correct my ugly hack, (continued)
- Re: please correct my ugly hack, Paul Eggert, 2005/06/01
- Re: please correct my ugly hack, Ralf Corsepius, 2005/06/01
- Re: please correct my ugly hack, Dan Manthey, 2005/06/01
- Re: please correct my ugly hack, Ralf Corsepius, 2005/06/02
- Re: please correct my ugly hack, Stepan Kasal, 2005/06/02
- unset variables, was Re: please correct my ugly hack, Dan Manthey, 2005/06/02
- Re: unset variables, was Re: please correct my ugly hack, Paul Eggert, 2005/06/03
- Re: unset variables, was Re: please correct my ugly hack, Stepan Kasal, 2005/06/03
- Re: unset variables, was Re: please correct my ugly hack, Dan Manthey, 2005/06/03
- Re: please correct my ugly hack, Stepan Kasal, 2005/06/02
- Re: please correct my ugly hack,
Stepan Kasal <=
- Re: please correct my ugly hack, Ralf Corsepius, 2005/06/03
- Re: please correct my ugly hack, Stepan Kasal, 2005/06/03
- Re: please correct my ugly hack, Ralf Corsepius, 2005/06/03
- Re: please correct my ugly hack, Bob Friesenhahn, 2005/06/03
- Re: please correct my ugly hack, Stepan Kasal, 2005/06/04
- Re: please correct my ugly hack, Ralf Wildenhues, 2005/06/05