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Posted to user@zookeeper.apache.org by 李赫元 <li...@gmail.com> on 2012/05/14 11:04:12 UTC

How to know if connection to zk is successful in C API.

Hi All,

I encounter a problem in zookeeper 3.4.1 with C API.
The following is always show "success" even the zkserver is actually down.

    char* zk_server = "127.0.0.1:2181";
    zhandle_t* zh = zookeeper_init(zk_server, watcher_callback, 3000,
0, NULL, 0);
    if(!zh)
    {
        print_error(errno);
        return -1;
    }else
    {
        ::std::cout << "success" << ::std::endl;
    }

Even if the zookeeper is shutdown, the zh handle is still not NULL.
So, I don't know how to judge if connection to zookeeper is succful in C API.

Thanks all.

Heyuan Li

Re: How to know if connection to zk is successful in C API.

Posted by 李赫元 <li...@gmail.com>.

Thanks, I have found that a ZOO_SESSION_EVENT event with state
ZOO_CONNECTED_STATE will be recv after session is built.


2012/5/14 Martin Kou <bi...@gmail.com>:
> The connection API is asynchronous, you'll need to look for the session
> state changes in the watcher_callback.
>
> Best Regards,
> Martin Kou
>
> On Mon, May 14, 2012 at 2:04 AM, 李赫元 <li...@gmail.com> wrote:
>
>> Hi All,
>>
>> I encounter a problem in zookeeper 3.4.1 with C API.
>> The following is always show "success" even the zkserver is actually down.
>>
>>    char* zk_server = "127.0.0.1:2181";
>>    zhandle_t* zh = zookeeper_init(zk_server, watcher_callback, 3000,
>> 0, NULL, 0);
>>    if(!zh)
>>    {
>>        print_error(errno);
>>        return -1;
>>    }else
>>    {
>>        ::std::cout << "success" << ::std::endl;
>>    }
>>
>> Even if the zookeeper is shutdown, the zh handle is still not NULL.
>> So, I don't know how to judge if connection to zookeeper is succful in C
>> API.
>>
>> Thanks all.
>>
>> Heyuan Li
>>

Re: How to know if connection to zk is successful in C API.

Posted by Martin Kou <bi...@gmail.com>.

The connection API is asynchronous, you'll need to look for the session
state changes in the watcher_callback.

Best Regards,
Martin Kou

On Mon, May 14, 2012 at 2:04 AM, 李赫元 <li...@gmail.com> wrote:

> Hi All,
>
> I encounter a problem in zookeeper 3.4.1 with C API.
> The following is always show "success" even the zkserver is actually down.
>
>    char* zk_server = "127.0.0.1:2181";
>    zhandle_t* zh = zookeeper_init(zk_server, watcher_callback, 3000,
> 0, NULL, 0);
>    if(!zh)
>    {
>        print_error(errno);
>        return -1;
>    }else
>    {
>        ::std::cout << "success" << ::std::endl;
>    }
>
> Even if the zookeeper is shutdown, the zh handle is still not NULL.
> So, I don't know how to judge if connection to zookeeper is succful in C
> API.
>
> Thanks all.
>
> Heyuan Li
>