Re: AC_SEARCH_LIBS directories on 32-bit and 64-bit

[Sergio Belkin]

2010/10/18 Eric Blake <address@hidden>:
> On 10/18/2010 04:54 PM, Sergio Belkin wrote:
>>
>> Hi,
>>
>> Let's say we have the check:
>>
>> AC_SEARCH_LIBS([ns_get16],[resolv])
>>
>> How can I do to detect library directory path based on host
>> architecture, I mean, I want that if is an x86_64 bit looks on
>> ${prefix}/lib64 and if is 32-bit look on /usr/lib. I'd want to avoid
>> that user has to provide manually LDFLAGS. Is that possible? If I am
>> thinking something wrong, correct me.
>
> Why should you want to offload the responsibility for the user setting up
> their system correctly in the first place?  And you can't blindly assume
> that ${prefix}/lib64 is the correct spelling, as there are 64-bit OSs that
> install their libraries directly in /usr/lib.  And, per the GNU Coding
> Standards, a user should feel free to install libraries in ~/lib (if they
> don't have write access to /usr) rather than /usr/local/lib (autoconf's
> default, good for installing optional packages above what the distro
> includes); as it is, libraries installed in /usr/lib64 is already a case of
> distros using the GCS-mandated ability to specify an alternate $prefix of
> /usr instead of the default /usr/local.
>
> In my opinion, the solution to the 32- vs. 64-bit library question SHOULD be
> answered by the user (and not by the configure author). Obviously, this can
> be done by setting LDFLAGS for every configure run of every package, but
> that gets tiresome.  But more efficiently, this can be done by installing an
> appropriate config.site to answer the question up front.  And the manual
> already mentions how to do that:
>
> http://www.gnu.org/software/autoconf/manual/autoconf.html#Site-Defaults
>
> If a distro wants to ship 64-bit libraries in /usr/lib64, then they should
> also ship a config.site that automatically uses that directory any time a
> configure script targets ${prefix} of /usr, so that users automatically get
> this default without having to set LDFLAGS themselves.  But that's in the
> realm of the distro, not of autoconf.
>
> As a package author, you shouldn't have to care about the distro's choice of
> spelling for preferred library location.
>
> --
> Eric Blake   address@hidden    +1-801-349-2682
> Libvirt virtualization library http://libvirt.org
>

Thanks Eric for your explanation

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