Re: Question about ac_lib and ac_res

[Sergio Belkin]

2012/10/17 Eric Blake <address@hidden>:
> On 10/17/2012 02:15 PM, Sergio Belkin wrote:
>> Hi folks,
>>
>> I've found in AC_SEARCH_LIBS functions ac_lib and ac_res what do they do?
>
> They aren't documented in the manual, so you can assume that they are
> used internally for implementing the actual search, and that you can
> (and should!) safely ignore them.  If you're still more curious than
> that, then read the source code: ac_lib is the shell variable that loops
> over the 2nd argument passed to the AC_SEARCH_LIBS macro, and ac_res is
> the shell variable that tracks which -l library, if any, was needed to
> make the link succeed.
>
> AC_DEFUN([AC_SEARCH_LIBS],
> [AS_VAR_PUSHDEF([ac_Search], [ac_cv_search_$1])dnl
> AC_CACHE_CHECK([for library containing $1], [ac_Search],
> [ac_func_search_save_LIBS=$LIBS
> AC_LANG_CONFTEST([AC_LANG_CALL([], [$1])])
> for ac_lib in '' $2; do
>   if test -z "$ac_lib"; then
>     ac_res="none required"
>   else
>     ac_res=-l$ac_lib
>     LIBS="-l$ac_lib $5 $ac_func_search_save_LIBS"
>   fi
>   AC_LINK_IFELSE([], [AS_VAR_SET([ac_Search], [$ac_res])])
>   AS_VAR_SET_IF([ac_Search], [break])
> done
>
> --
> Eric Blake   address@hidden    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>

Thanks for you explanation, I didn''t understand well what does "none
required".

I've found "The result of this test is cached in the
ac_cv_search_function variable as ‘none required’ if function is
already available" at
http://www.manpagez.com/info/autoconf/autoconf-2.69/autoconf_46.php

So I understand that function was found in the library searched on in
another in the system, wasn't it?

Thanks in advance!

-- 
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Sergio Belkin  http://www.sergiobelkin.com
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