[libvirt] libvirt on x64

[Eric Blake]

On 07/26/2010 12:17 PM, Tavares, John wrote:
> I think I finally found such a system running RHEL 5.5 on x64 and it does have both a 32-bit and 64-bit version of libvirt installed (0.6.3).  Maybe this is just a SLES issue??

By default, 64-bit RHEL does not ship 32-bit versions of a library
unless it is necessary.  And yes, on my x86_64 Fedora 13 box, I have
only the 64-bit libvirt installed (my earlier suggestion to use 'yum
install libvirt-devel.i686' was exactly what I typed at my box, although
I then aborted that command rather than proceeding with the 32-bit
counterpart install).

One way to mark a 32-bit library as necessary is to list it as an rpm
dependency.  But why?  If you are building rpms, you might as well
distribute a source rpm, which can then be built for both i686 and
x86_64 (the i686 will depend on the 32-bit library, while the x86_64 can
take advantage of the 64-bit library rather than being crippled to the
32-bit version), rather than insisting that anyone who uses your package
must use the 32-bit pre-built version.

But if you are not distributing via rpms, then you must assume that your
customers will not have 32-bit libvirt already installed on their 64-bit
machines, since that's not how RHEL generally works (it is intentional
that RHEL does not install duplicate 32-bit libraries for every possible
.so).  So either you will have to build both versions of your software
against the two library versions on x86_64, or tell customers that they
need to install the 32-bit libraries on their own before using your
32-bit app.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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