[visit-developers] VisIt and Qt signals
bjw at ilight.com
Tue Jun 16 16:39:03 EDT 2015
I made a change to RemoteProcess on the trunk that reinstalls the old
handler for SIGCHLD, if one exists.
On Tue, Jun 16, 2015 at 12:58 PM, Sveta <sveta at txcorp.com> wrote:
> Hi Brad,
> Not sure what you mean by reinstalling the old signal handler... I see
> one more type of the signal call: signal(SIGCHLD, DeadChildHandler).
> Should I use DeadChildHandler instead catch_dead_child and call it in Open
> after LaunchRemote?
> On 6/16/15 10:29 AM, Brad Whitlock wrote:
>> Okay, it seems like the next step would be for RemoteProcess to
>> reinstall the old signal handler after it has launched the remote
>> process. That would probably clear up launching the vis and getting the
>> finished signal.
>> On Tue, Jun 16, 2015 at 7:18 AM, sveta <sveta at txcorp.com
>> <mailto:sveta at txcorp.com>> wrote:
>> Very interesting. I commented out all signal() there and now the
>> viz does not open at all, but the "finished" signal gets delivered.
>> I will report more later. Thank you, Brad!
>> On 6/15/15 3:19 PM, Brad Whitlock wrote:
>> Hi Sveta,
>> DelayedMethods are queued up for later execution while the
>> object applies immediately. Calling DelayedMethods is useful
>> when you
>> want to queue up some work from a Qt slot that would take a long
>> time to
>> execute and would be best done from the main event loop. Both
>> ways will
>> get to the OpenDatabase action which will start the mdserver and
>> via the RemoteProcess class I mentioned last time. I would try
>> commenting out the calls to signal() in RemoteProcess to see if
>> class is the culprit.
>> On Mon, Jun 15, 2015 at 1:53 PM, Sveta <sveta at txcorp.com
>> <mailto:sveta at txcorp.com>
>> <mailto:sveta at txcorp.com <mailto:sveta at txcorp.com>>> wrote:
>> Hi Brad,
>> I investigated and the problem occurs when we call
>> VisItViewer::DelayedMethods::OpenDatabase... What is the
>> difference between DelayedMethods and Methods?
>> Thank you,
>> On Jun 12, 2015, at 4:52 PM, Brad Whitlock <bjw at ilight.com
>> <mailto:bjw at ilight.com>
>> <mailto:bjw at ilight.com <mailto:bjw at ilight.com>>> wrote:
>> Hi Sveta,
>> VisIt's src/common/comm/RemoteProcess class installs
>> a signal
>> handler for SIGCHLD that lets it detect when child
>> processes die.
>> This is so it can detect when VisIt programs die on
>> startup. It
>> looks like it does not restore any previously existing
>> handler. Maybe this is interfering with Qt's "finished"
>> On Fri, Jun 12, 2015 at 3:30 PM, Sveta
>> <sveta at txcorp.com <mailto:sveta at txcorp.com>
>> <mailto:sveta at txcorp.com <mailto:sveta at txcorp.com>>>
>> Hi everybody,
>> We have been having a strange problem. We have Qt
>> started by our application and we connect to it
>> "finished." All signals emit and all works before
>> we load
>> files into VisIt. Once we do this, the processes
>> do not emit
>> "finished" (looks like). Any ideas, suggestions
>> and opinions
>> are appreciated.
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