Re: [PATCH 1/3] autoconf: prefer an unrolled loop for trivial AC_CHECK_FUNCS
Eric Blake <[email protected]>
| Newsgroups | gmane.comp.sysutils.autoconf.patches |
|---|---|
| Organization | Red Hat, Inc. |
| Message-ID | <[email protected]> |
On 10/31/2016 06:39 AM, Paolo Bonzini wrote: > An unrolled loop avoids the cost of spawning sed in AS_TR_SH and > AS_TR_CPP. Prefer it if there is nothing in the second and third > argument of AC_CHECK_FUNCS and the first argument is a literal. > Modify AC_CHECK_FUNCS_ONCE to avoid the variable indirection too. > > * lib/autoconf/functions.m4 (AC_CHECK_FUNCS): Unroll loop if safe. > (_AC_CHECK_FUNCS): Move basic implementation here. > (_AC_CHECK_FUNC_ONCE): Expand AC_CHECK_FUNCS here... > (_AC_FUNCS_EXPANSION): ... and not here, so remove. > - [$3])dnl]) > +[m4_if([$2$3]AS_LITERAL_IF([$1], [yes], [no]), []yes, Why []yes instead of the more typical [yes] ? If the user has (unwisely) defined yes as a macro, your version will compare against their expansion, instead of against the intended literal. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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