[libvirt] virConnectClose() API function question

Eric Blake eblake at redhat.com
Wed Jun 22 15:41:57 UTC 2011


On 06/21/2011 09:53 AM, Matthias Bolte wrote:
>> [1] http://libvirt.org/html/libvirt-libvirt.html#virConnectClose
>>
> 
> In contrast to the documentation virConnectClose returns the remaining
> reference count of the connection after unref'ing it. This means
> virConnectClose returns -1 on error and returns 0 when there is no
> reference left and the connection is really closed. When it returns >
> 0 then the connection isn't closed yet, but is kept open because there
> are still objects alive that depend on it. For example when you open a
> connection and get a virDomainPtr from it then the refcount of the
> connection is increased, because the domain object depends on it. When
> the domain object is freed then the refcount of the connection is
> decreased again.
> 
> All objects in libvirt like connections, domains, networks etc are
> reference counted. But in contrast to virConnectClose other free
> functions like virDomainFree don't return the remaining reference
> count, they really just return -1 or 0. So the question is: do we
> change virConnectClose to really just return -1 or 0, or do we update
> the documentation, because someone might depend on virConnectClose
> allowing to detect via its return value whether the connection was
> really closed or not.

At this point, I worry that changing return values might break existing
code, so I would favor a documentation update, but I'd also like to hear
an opinion from DV or danpb.

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

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