Hi Paul, Paul Eggert wrote: > "Gary V. Vaughan" <[EMAIL PROTECTED]> writes: > > >> i) Let's just improve AC_CHECK_HEADERS (et al) to always make configure >> smaller and faster by despatching to (undocumented internal) >> _AC_CHECK_HEADERS_ONCE when it can. > > > Won't that break old scripts? If they do something like this: > > if test $ac_feature_foo = yes; then > AC_CHECK_HEADERS([sys/param.h]) > fi > > then we'd hoist the test for sys/param.h out of the then-part, which > is not what was intended.
Hmm. You're right :-( I was thinking that there might be a way to detect from the argument signature of the call which flavour the user wanted; but, looking at the implementation, the only way to do that would be either an optional fifth argument (ugly), or perhaps if the first argument does not end in `.h'. The latter is really a motter of picking between: AC_CHECK_HEADER_ONCE([sys/param.h]) and, for example: AC_CHECK_HEADER([1], [sys/param.h]) On balance, the former is clearer. Pity, as it adds just adds another function that has to be supported in later releases :-( >> ii) I would have thought that use of shell functions in generated >> configure scripts is safe enough by now > > > That's the direction I'd like to head too, but it's a big enough > change that it will cause problems. Let's wait until after 2.60 comes > out. Excellent. Yes, I think it is more important to get a release soon so that the huge improvements since 2.59 can begin to make their way to developers that don't want to risk a CVS snapshot. > It might make sense to have an "Autoconf 3" that has a lot of changes > along these lines (I'd like to assume at least C89 and POSIX-2.1992 > conformance, for example; sheesh, it's 2006 already!), and reserve > "Autoconf 2" for the current basic approach. That sounds like the best way forward to me! Cheers, Gary. -- Gary V. Vaughan ())_. [EMAIL PROTECTED],gnu.org} Research Scientist ( '/ http://tkd.kicks-ass.net GNU Hacker / )= http://www.gnu.org/software/libtool Technical Author `(_~)_ http://sources.redhat.com/autobook
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