[libvirt] [PATCH 3/3] Convert remainder of cgroups code to report errors

[Eric Blake]

On 07/19/2013 08:51 AM, Daniel P. Berrange wrote:

>>> +    if (virCgroupSetValueU64(group,
>>> +                             VIR_CGROUP_CONTROLLER_MEMORY,
>>> +                             filename, 1) < 0)
>>>          return -1;
>>> -    }
>>>  
>>>      return 0;
>>
>> Can code like this be simplified to:
>>
>> return virCgroupSetValueU64(group,
>>                             VIR_CGROUP_CONTROLLER_MEMORY,
>>                             filename, 1);
> 
> I'm not a fan of doing that, since it means it'll be re-arranged
> again if we ever put move code in this method.

Fair enough - don't change it.

>>> -        ignore_value(VIR_STRNDUP_QUIET(ret, group->controllers[i].mountPoint,
>>> -                                       tmp - group->controllers[i].mountPoint));
>>> +        if (VIR_STRNDUP(ret, group->controllers[i].mountPoint,
>>> +                        tmp - group->controllers[i].mountPoint) < 0)
>>> +            return NULL;
>>>          return ret;
>>
>> You can still use ignore_value() here rather than 'if', if desired,
>> since ret will be NULL if VIR_STRNDUP fails.
> 
> I don't like that kind of use of ignore_value(). It makes it really
> easy for someone else to screw things up later by adding in more
> code between the VIR_STRNDUP & the following 'return ret'. An
> explicit 'return NULL' is safe in that scenario.

Also a reasonable explanation.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 621 bytes
Desc: OpenPGP digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20130719/cc4cea85/attachment-0001.sig>