Hello! You are still using recursive event loop. Try not to use recursive event loop with WServer::post(). Use WDialog->show() instead of WDialog::exec(). Make sure to remove this WDialog, when it is closed.
On Sat, Nov 17, 2012 at 4:13 AM, Joseph VanAndel <vanan...@ucar.edu> wrote: > OK, I've modified my application to use wApp->bind() as shown below. > > Unfortunately, if a session dies, my application still crashes, as before: > ================== > terminate called after throwing an instance of 'Wt::WException' > what(): doRecursiveEventLoop(): session was killed > > #5 0x00b3a183 in std::terminate() () from /usr/lib/libstdc++.so.6 > #6 0x00b3a2c2 in __cxa_throw () from /usr/lib/libstdc++.so.6 > #7 0x01767af8 in Wt::WebSession::doRecursiveEventLoop ( > this=0xb5e3f850) > at /usr/local/src/wt-3.2.3/src/web/WebSession.C:1051 > #8 0x0143a7da in Wt::WDialog::exec (this=0x87fedb8, > animation=...) at /usr/local/src/wt-3.2.3/src/Wt/WDialog.C:292 > #9 0x08125562 in Login_GUI::confirm (this=0x87fed48, > message=..., info=..., id=..., passwd=..., name=..., > location=..., comment=...) at src/view/Login_GUI.cpp:75 > #10 0x0816e002 in UIServer::showLogin (this=0x876aeb8, > message=..., info=...) at src/view/UIServer.cpp:716 > #11 0x0816f107 in UIServer::processStatusEvent (this=0x876aeb8, > event=...) at src/view/UIServer.cpp:920 > #12 0x0816f01c in UIServer::notifyStatusEvent (this=0x876aeb8) > at src/view/UIServer.cpp:913 > #13 0x08150537 in boost::_mfi::mf0<void, UIServer>::operator() ( > this=0x87fed10, p=0x876aeb8) > ====================== > Although the session was killed, the WServer::post() call still invokes the > callback, which eventually tries to post a WDialog. > Wt::WebSession::doRecursiveEventLoop sees the session is dead, and throws an > error. > > What I don't understand is how this could happen. WServer::post() schedules > a call to > WebController::handleApplicationEvent(), which checks whether the session > corresponding to sessionID is alive before it invokes the session's callback. > > > On Nov 13, 2012, at 9:30 AM, Joseph VanAndel <vanan...@ucar.edu> wrote: > >> Yes, although the logic is more complex, I can have the bound function >> callback into the shared object to retrieve the data that I wanted to pass >> to the bound function. >> >> For my application, I have a UIServer object (1 per session) and a >> StatusServer (singleton), which relays status messages between sessions. >> UIServer ctor calls >> StatusServer::connect( this, >> wApp->bind( boost::bind( &UIServer::notifyStatusEvent, this) )) >> >> StatusServer::postStatusEvent() will save a copy of the event in a >> per-session queue. >> and calls WServer::post(sessionid, callback), which indirectly calls >> UIServer::notifyStatusEvent() >> >> UIServer::notifyStatusEvent() calls >> StatusServer::getEvent() to retrieve the event, and call >> UIServer::processStatusEvent() to handle the StatusEvent. >> >> >> It would be quite helpful if <Wt_src>/examples/simplechat used >> WApplication::bind(). >> >> I appreciate any examples, but examples that correctly handle real-world >> situations, like browser sessions being closed are MUCH more useful. As far >> as I can tell, because simplechat doesn't use WApplication::bind(), it may >> not safely handle browser sessions that are closed. >> >> If I get the chance, I'll submit a rewritten simplechat example that uses >> WApplication::bind(), but as they say "It won't be pretty!" >> >> >> On Nov 13, 2012, at 4:44 AM, Koen Deforche wrote: >> >>> Hey Joseph, Rob, >>> >>> I guess you are both indicating a limitation: WApplication::bind() >>> essentially returns a function without arguments, and thus all >>> arguments already have to be bound before the call, which makes it >>> useless when you want to pass on information from the external source. >>> >>> As a workaround, perhaps you can rather than 'push' new information, >>> make the bound function 'poll' the information from the shared object >>> ? >>> >>> I believe it should be possible to make WApplication::bind() work >>> properly with any kind of function, including functions with free >>> parameters -- although that requires a bit of digging into the >>> meta-function possiblities of boost-ified c++... >>> >>> In any case, using WApplication::bind() later on is not very useful -- >>> it needs to happen with the session lock and with the objects bound >>> guaranteed to be alive at the moment of calling WApplication::bind(). >>> >>> Regards, >>> koen >>> >>> ------------------------------------------------------------------------------ >>> Monitor your physical, virtual and cloud infrastructure from a single >>> web console. Get in-depth insight into apps, servers, databases, vmware, >>> SAP, cloud infrastructure, etc. Download 30-day Free Trial. >>> Pricing starts from $795 for 25 servers or applications! >>> http://p.sf.net/sfu/zoho_dev2dev_nov >>> _______________________________________________ >>> witty-interest mailing list >>> witty-interest@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/witty-interest >> >> >> ------------------------------------------------------------------------------ >> Monitor your physical, virtual and cloud infrastructure from a single >> web console. Get in-depth insight into apps, servers, databases, vmware, >> SAP, cloud infrastructure, etc. Download 30-day Free Trial. >> Pricing starts from $795 for 25 servers or applications! >> http://p.sf.net/sfu/zoho_dev2dev_nov >> _______________________________________________ >> witty-interest mailing list >> witty-interest@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/witty-interest > > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. 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