Re: AS_TMPDIR in _AC_PATH_PROG_FEATURE_CHECK, $debug

[Stepan Kasal]

Hello Paul,

On Mon, Dec 06, 2004 at 12:01:29PM -0800, Paul Eggert wrote:
> But this whole area seems to be a bit of a mess.

Indeed.

There are only two users of AS_TMPDIR currently: _AC_OUTPUT_CONFIG_STATUS
in status.m4 and _AC_PATH_PROG_FEATURE_CHECK in programs.m4 .

As far as _AC_OUTPUT_CONFIG_STATUS is concerned, I'd simply move the
trap creation there.  AS_TMPDIR would not call trap at all.

Another problem is that there is prefix "confstat" while the documentation
to AS_TMPDIR says that the prefix should be at most 4 chars.

> > As far as the _AC_PATH_PROG_FEATURE_CHECK macro is concerned, perhaps it
> > could do without the tmp dir?  Why couldn't _AC_FEATURE_CHECK_LENGTH work
> > in current directory?  It uses the names conftest.*, which are removed
> > by the autoconf cleanup at the end of the standard trap.

> Another general issue is that /tmp is often a lot faster.

yes, I have thought about it.

"Rule 4 (for experts only): Don't optimize."

_AC_PATH_PROG_FEATURE_CHECK / _AC_FEATURE_CHECK_LENGTH have two problems:

1) _AC_PATH_PROG_FEATURE_CHECK creates the tmp dir, even though it pretends
to be a general macro.  _AC_FEATURE_CHECK_LENGTH needs tmp dir, but other
feature checks may not need it.

2) We have no clean way to register for cleanup, currently.

I suggest that we perform the _AC_FEATURE_CHECK_LENGTH in the current dir,
it's the easiest solution.

> > Perhaps we should set ``debug=false'' at the beginning of the configure
> > script.

I back out this suggestion; it's better to move the trap code out from
AS_TMPDIR.  The ``debug'' variable is used only in config.status, not in
configure.

If this makes sense, I'll write a patch eventually.

Stepan