[libvirt-users] event handler

[Michal Privoznik]

On 14.10.2013 10:33, Alexandr wrote:
> Michal Privoznik писал 2013-10-14 08:48:
>> On 14.10.2013 02:42, Alexandr wrote:
>>> good day to all.
>>> i still have not solved my problem with event handling.
>>> currently i have following code
>>>
>>>
>>> void libvirt_eventloop_thr_func()
>>> {
>>>     while(true) //TODO: stop somehow on exit
>>>     {
>>>         if(virEventRunDefaultImpl() < 0)
>>>         {
>>>             virErrorPtr err = virGetLastError();
>>>             fprintf(stderr, "Failed to run event loop: %s\n", err &&
>>> err->message ? err->message : "Unknown error");
>>>         }
>>>     }
>>> }
>>>
>>>
>>>
>>> ...
>>>
>>>     virSetErrorFunc(NULL, libvirt_error_handler);
>>>     libvirt_connection = virConnectOpen("qemu:///system");
>>
>> Move this line ^^^ ...
>>
>>>     if (virEventRegisterDefaultImpl() < 0)
>>>     {
>>>         virErrorPtr err = virGetLastError();
>>>         fprintf(stderr, "Failed to register event implementation: %s\n",
>>> err && err->message ? err->message: "Unknown error");
>>>             return -1;
>>>     }
>>>     {
>>>         int callback =
>>> virConnectDomainEventRegisterAny(libvirt_connection, NULL,
>>> VIR_DOMAIN_EVENT_ID_LIFECYCLE,
>>> VIR_DOMAIN_EVENT_CALLBACK(domain_event_handler), NULL, NULL);
>>>         if(callback == -1)
>>>         {
>>>             std::cout<<"Error: failed to register domain event handle
>>> callback\n";
>>>             return -1;
>>>         }
>>>     }
>>>
>>>     boost::thread(boost::bind(&libvirt_eventloop_thr_func));
>>
>> ... over here. The virConnectOpen detects if there's an even loop
>> registered. And in your case you don't have any registered when
>> calling it.
>>
>> Michal
> 
> thank you very match, it now working as expected, but one thing are
> missed from documentations, current api docs says what i do not need to
> call virInitialize(), but if i call virEventRegisterDefaultImpl()
> without calling virInitialize() programm crashing (i have not used
> virInitialize() in my programm, just virConnectOpen() as docs said).
> problem solved now.

>From virInitialize documentation [1]:

"The only time it would be necessary to call virInitialize is if the
application did not invoke virConnectOpen as its first API call."

Which is your case. But if you believe this can be written better,
propose a patch and I'll review it.

Michal

1: http://libvirt.org/html/libvirt-libvirt.html#virInitialize