* Benoit SIGOURE wrote on Mon, Oct 01, 2007 at 05:54:05PM CEST: > On Oct 1, 2007, at 2:22 PM, Ralf Wildenhues wrote: >>> On Oct 1, 2007, at 1:30 PM, Benoit SIGOURE wrote: >>> >>>> By the way, I have a question to the list, AC_CANONICAL_HOST implies >>>> AC_CANONICAL_BUILD, maybe this should be mentionned in the >>>> documentation? [...] >> But also, why do we want to document this at all? [...] > Because you can be surprised to see: > > checking build system type... i386-apple-darwin8.10.1 > checking host system type... i386-apple-darwin8.10.1 > checking build system type... (cached) i386-apple-darwin8.10.1 > > even though it doesn't harm. But if you want to keep this as an internal > detail, fair enough.
Ah, ok. Here's a different view to this: whenever you see cached checks or for that matter repeated tests at all on a configure run without sub configure scripts or a cache file, then either the macro ordering may be improved, or there is a certain redundancy in the tests. Sometimes the redundancy may be eliminated by having macros that call other macros instead AC_REQUIRE the latter ones. In Autoconf code, this is not always possible, for example due to semantic or backward compatibility reasons (e.g., a macro that should be expandable inside a shell conditional). So if you like, I would prefer that this principle be documented rather than every macro dependency; that's less work, too. ;-) Cheers, Ralf
