Bruno Haible wrote: > Paolo Bonzini wrote: >>> - macros defined with AC_DEFUN_IDEMPOTENT are *known* to be expandable >>> any number of times, hence they may be both invoked and required, >>> >>> - macros defined with AC_DEFUN_ONCE are *known* to be expandable only >>> once, hence the recommendation for them is to AC_REQUIRE them, >> Do we have any of these? I'd just change AC_DEFUN_ONCE to the meaning >> you suggest for AC_DEFUN_IDEMPOTENT > > It's too late for doing that: AC_DEFUN_ONCE was introduced on 2004-10-11.
I know. > Besides that, AC_DEFUN_ONCE and AC_DEFUN_IDEMPOTENT have really opposite > semantics. You cannot confuse people more than by using the same name for > two entities with opposite semantics. It looks to me like, in the wild, AC_DEFUN_ONCE is used for idempotent macros (and in Autoconf too, see AC_CANONICAL_*). The only correct use of AC_DEFUN_ONCE (where the warning *is* desired) is AC_NO_EXECUTABLES; and not even fully correct, as you'd want an error there. You can look at all of them at http://www.google.com/codesearch?hl=en&sa=N&q=AC_DEFUN_ONCE+-package:autoconf+-file:request+-package:automake+-file:traces*+-file:aclocal*++lang:m4&ct=rr&cs_r=lang:m4 Paolo
