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  • Delphi: How to call a method when i click a control?

    - by Ian Boyd
    i have a method: procedure Frob(Sender: TObject); that i want to call when i click a menu item. The method comes to me though an interface: animal: IAnimal; IAnimal = interface procedure Frob(Sender: TObject); end; The question revolves around what to assign to the OnClick event handler of a menu item (i.e. control): var animal: IAnimal; ... begin ... menuItem := TMenuItem.Create(FileMenu) menuItem.Caption := 'Click me!'; menuItem.OnClick := <-------- what to do ... end; The obvious choice, my first attempt, and the wrong answer is: menuItem.OnClick := animal.Frob; So how can i call a method when user clicks a control? See also Why doesn't it work?

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  • Python - network buffer handling question...

    - by Patrick Moriarty
    Hi, I want to design a game server in python. The game will mostly just be passing small packets filled with ints, strings, and bytes stuffed into one message. As I'm using a different language to write the game, a normal packet would be sent like so: Writebyte(buffer, 5); // Delimit type of message Writestring(buffer, "Hello"); Sendmessage(buffer, socket); As you can see, it writes the bytes to the buffer, and sends the buffer. Is there any way to read something like this in python? I am aware of the struct module, and I've used it to pack things, but I've never used it to actually read something with mixed types stuck into one message. Thanks for the help.

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  • handling javaScript alerts when running a selenium test?

    - by Mo
    Hi I am am running some selenium tests(ruby) on my web page and as i enter an invalid characters in to a text box i have the JavaScript throw a alert like so if(isNaN($(this).val()) || Number($(this).val().valueOf() <=0)){ alert("Please Enter A Number"); } how can i handle this alert when its made and close the pop up? i tried to use the wait_for_pop_up() and close() but i think that's only for browser pop up's and not JavaScript alerts. any ideas? thanks

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  • C++ Storing variables and inheritance

    - by Kaa
    Hello Everyone, Here is my situation: I have an event driven system, where all my handlers are derived from IHandler class, and implement an onEvent(const Event &event) method. Now, Event is a base class for all events and contains only the enumerated event type. All actual events are derived from it, including the EventKey event, which has 2 fields: (uchar) keyCode and (bool)isDown. Here's the interesting part: I generate an EventKey event using the following syntax: Event evt = EventKey(15, true); and I ship it to the handlers: EventDispatch::sendEvent(evt); // void EventDispatch::sendEvent(const Event &event); (EventDispatch contains a linked list of IHandlers and calls their onEvent(const Event &event) method with the parameter containing the sent event. Now the actual question: Say I want my handlers to poll the events in a queue of type Event, how do I do that? x Dynamic pointers with reference counting sound like too big of a solution. x Making copies is more difficult than it sounds, since I'm only receiving a reference to a base type, therefore each time I would need to check the type of event, upcast to EventKey and then make a copy to store in a queue. Sounds like the only solution - but is unpleasant since I would need to know every single type of event and would have to check that for every event received - sounds like a bad plan. x I could allocate the events dynamically and then send around pointers to those events, enqueue them in the array if wanted - but other than having reference counting - how would I be able to keep track of that memory? Do you know any way to implement a very light reference counter that wouldn't interfere with the user? What do you think would be a good solution to this design? I thank everyone in advance for your time. Sincerely, Kaa

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  • Handling inheritance with overriding efficiently

    - by Fyodor Soikin
    I have the following two data structures. First, a list of properties applied to object triples: Object1 Object2 Object3 Property Value O1 O2 O3 P1 "abc" O1 O2 O3 P2 "xyz" O1 O3 O4 P1 "123" O2 O4 O5 P1 "098" Second, an inheritance tree: O1 O2 O4 O3 O5 Or viewed as a relation: Object Parent O2 O1 O4 O2 O3 O1 O5 O3 O1 null The semantics of this being that O2 inherits properties from O1; O4 - from O2 and O1; O3 - from O1; and O5 - from O3 and O1, in that order of precedence. NOTE 1: I have an efficient way to select all children or all parents of a given object. This is currently implemented with left and right indexes, but hierarchyid could also work. This does not seem important right now. NOTE 2: I have tiggers in place that make sure that the "Object" column always contains all possible objects, even when they do not really have to be there (i.e. have no parent or children defined). This makes it possible to use inner joins rather than severely less effiecient outer joins. The objective is: Given a pair of (Property, Value), return all object triples that have that property with that value either defined explicitly or inherited from a parent. NOTE 1: An object triple (X,Y,Z) is considered a "parent" of triple (A,B,C) when it is true that either X = A or X is a parent of A, and the same is true for (Y,B) and (Z,C). NOTE 2: A property defined on a closer parent "overrides" the same property defined on a more distant parent. NOTE 3: When (A,B,C) has two parents - (X1,Y1,Z1) and (X2,Y2,Z2), then (X1,Y1,Z1) is considered a "closer" parent when: (a) X2 is a parent of X1, or (b) X2 = X1 and Y2 is a parent of Y1, or (c) X2 = X1 and Y2 = Y1 and Z2 is a parent of Z1 In other words, the "closeness" in ancestry for triples is defined based on the first components of the triples first, then on the second components, then on the third components. This rule establishes an unambigous partial order for triples in terms of ancestry. For example, given the pair of (P1, "abc"), the result set of triples will be: O1, O2, O3 -- Defined explicitly O1, O2, O5 -- Because O5 inherits from O3 O1, O4, O3 -- Because O4 inherits from O2 O1, O4, O5 -- Because O4 inherits from O2 and O5 inherits from O3 O2, O2, O3 -- Because O2 inherits from O1 O2, O2, O5 -- Because O2 inherits from O1 and O5 inherits from O3 O2, O4, O3 -- Because O2 inherits from O1 and O4 inherits from O2 O3, O2, O3 -- Because O3 inherits from O1 O3, O2, O5 -- Because O3 inherits from O1 and O5 inherits from O3 O3, O4, O3 -- Because O3 inherits from O1 and O4 inherits from O2 O3, O4, O5 -- Because O3 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 O4, O2, O3 -- Because O4 inherits from O1 O4, O2, O5 -- Because O4 inherits from O1 and O5 inherits from O3 O4, O4, O3 -- Because O4 inherits from O1 and O4 inherits from O2 O5, O2, O3 -- Because O5 inherits from O1 O5, O2, O5 -- Because O5 inherits from O1 and O5 inherits from O3 O5, O4, O3 -- Because O5 inherits from O1 and O4 inherits from O2 O5, O4, O5 -- Because O5 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 Note that the triple (O2, O4, O5) is absent from this list. This is because property P1 is defined explicitly for the triple (O2, O4, O5) and this prevents that triple from inheriting that property from (O1, O2, O3). Also note that the triple (O4, O4, O5) is also absent. This is because that triple inherits its value of P1="098" from (O2, O4, O5), because it is a closer parent than (O1, O2, O3). The straightforward way to do it is the following. First, for every triple that a property is defined on, select all possible child triples: select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value from TriplesAndProperties tp -- Select corresponding objects of the triple inner join Objects as Objects1 on Objects1.Id = tp.O1 inner join Objects as Objects2 on Objects2.Id = tp.O2 inner join Objects as Objects3 on Objects3.Id = tp.O3 -- Then add all possible children of all those objects inner join Objects as Children1 on Objects1.Id [isparentof] Children1.Id inner join Objects as Children2 on Objects2.Id [isparentof] Children2.Id inner join Objects as Children3 on Objects3.Id [isparentof] Children3.Id But this is not the whole story: if some triple inherits the same property from several parents, this query will yield conflicting results. Therefore, second step is to select just one of those conflicting results: select * from ( select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value, row_number() over( partition by Children1.Id, Children2.Id, Children3.Id, tp.Property order by Objects1.[depthInTheTree] descending, Objects2.[depthInTheTree] descending, Objects3.[depthInTheTree] descending ) as InheritancePriority from ... (see above) ) where InheritancePriority = 1 The window function row_number() over( ... ) does the following: for every unique combination of objects triple and property, it sorts all values by the ancestral distance from the triple to the parents that the value is inherited from, and then I only select the very first of the resulting list of values. A similar effect can be achieved with a GROUP BY and ORDER BY statements, but I just find the window function semantically cleaner (the execution plans they yield are identical). The point is, I need to select the closest of contributing ancestors, and for that I need to group and then sort within the group. And finally, now I can simply filter the result set by Property and Value. This scheme works. Very reliably and predictably. It has proven to be very powerful for the business task it implements. The only trouble is, it is awfuly slow. One might point out the join of seven tables might be slowing things down, but that is actually not the bottleneck. According to the actual execution plan I'm getting from the SQL Management Studio (as well as SQL Profiler), the bottleneck is the sorting. The problem is, in order to satisfy my window function, the server has to sort by Children1.Id, Children2.Id, Children3.Id, tp.Property, Parents1.[depthInTheTree] descending, Parents2.[depthInTheTree] descending, Parents3.[depthInTheTree] descending, and there can be no indexes it can use, because the values come from a cross join of several tables. EDIT: Per Michael Buen's suggestion (thank you, Michael), I have posted the whole puzzle to sqlfiddle here. One can see in the execution plan that the Sort operation accounts for 32% of the whole query, and that is going to grow with the number of total rows, because all the other operations use indexes. Usually in such cases I would use an indexed view, but not in this case, because indexed views cannot contain self-joins, of which there are six. The only way that I can think of so far is to create six copies of the Objects table and then use them for the joins, thus enabling an indexed view. Did the time come that I shall be reduced to that kind of hacks? The despair sets in.

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  • what happens when two exceptions occur?

    - by ashish yadav
    what will the operating system and compiler behave when they have two exceptions. And none of them have been caught yet. what type of handler will be called . lets say both the exceptions were of different type. i apologize if i am not clear but i feel i have made myself clear enough. thank you!!!

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  • handling ImageList with windows hooks

    - by user337309
    Hi, I am programming an application that can catching the information about the screen items by Hooks Now I am trying to get the information of the ImageList when I pass them by mouse, "I want to know the name of the item" how can i do this? Thank you.

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  • Is there any real world reason to use throw ex?

    - by Michael Stum
    In C#, throw ex is almost always wrong, as it resets the stack trace. I just wonder, is there any real world use for this? The only reason I can think of is to hide internals of your closed library, but that's a really weak reason. Apart from that, I've never encountered in the real world. Edit: I do mean throw ex, as in throwing the exact same exception that was caught but with an empty stacktrace, as in doing it exactly wrong. I know that throw ex has to exist as a language construct to allow throwing a different exception (throw new DifferentException("ex as innerException", ex)) and was just wondering if there is ever a situration where a throw ex is not wrong.

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  • Consuming services that consume other services.

    - by phthomas
    What is the best way to confirm that these consumed services are actually up and running before I actually try to invoke its operation contracts? I want to do this so that I can gracefully display some message to the customer to give him/her a more pleasant user experience. Thanks.

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  • GWT: Getting events in a button in a panel used as a Table cell

    - by mjeffw
    I'm using GWT 1.6. I am creating a panel that contains a Button and a Label, which I then add to a FlexTable as one of its cells. The Button is not receiving any Click events. I see that the table supports determining which Cell is clicked on, but in this case, I want the Mouse events to propagate to the various widgets inside the cell. Any idea on how to do that?

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  • Php string handling tricks

    - by Dam
    Hi my question Need to get the 10 word before and 10 words after for the given text . i mean need to start the 10 words before the keyword and end with 10 word after the key word. Given text : "Twenty-three" The main trick : content having some html tags etc .. tags need to keep that tag with this content only . need to display the words from 10before - 10after content is bellow : removed Thank you

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  • Handling multiple async HTTP requests in Silverlight serially

    - by Jeb
    Due to the async nature of http access via WebClient or HttpWebRequest in Silverlight 4, when I want to do multiple http get/posts serially, I find myself writing code that looks like this: doFirstGet(someParams, () => { doSecondGet(someParams, () => { doThirdGet(... } }); Or something similar. I'll end up nesting subsequent calls within callbacks usually implemented using lambdas of some sort. Even if I break things out into Actions or separate methods, it still ends up being hard to read. Does anyone have a clean solution to executing multiple http requests in SL 4 serially? I don't need things to be synchronous, I just want serial execution.

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  • Hooking a synchronous event handler on a form submit button in JS

    - by Xzhsh
    Hi, I'm working on a security project in javascript (something I honestly have not used), and I'm having some trouble with EventListeners. My code looks something like this: function prevclick(evt) { evt.preventDefault(); document.loginform.submitbtn.removeEventListener('click',prevclick,false); var req = new XMLHttpRequest(); req.open("GET","testlog.php?submission=complete",false); req.send(); document.loginform.submitbtn.click(); //tried this and loginform.submit() } document.loginform.submitbtn.addEventListener('click',prevclick,false); But the problem is, the submit button doesn't submit the form on the first click (it does, however, send the http request on the first click), and on the second click of the submit button, it works as normal. I think there is a problem with the synchronization, but I do need to have the request processed before forwarding the user to the next page. Any ideas on this would be great. Thanks in advance.

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  • vc++ - static member is showing error

    - by prabhakaran
    I am using vc++(2010). I am trying to create a class for server side socket. Here is the header file #include<winsock.h> #include<string> #include<iostream> using namespace std; class AcceptSocket { // static SOCKET s; protected: SOCKET acceptSocket; public: AcceptSocket(){}; void setSocket(SOCKET socket); static void EstablishConnection(int portNo,string&); static void closeConnection(); static void StartAccepting(); virtual void threadDeal(); static DWORD WINAPI MyThreadFunction(LPVOID lpParam); }; SOCKET AcceptSocket::s; and the corresponding source file #include<NetWorking.h> #include<string> void AcceptSocket::setSocket(SOCKET s) { acceptSocket=s; } void AcceptSocket::EstablishConnection(int portno,string &failure) { WSAData w; int error = WSAStartup(0x0202,&w); if(error) failure=failure+"\nWSAStartupFailure"; if(w.wVersion != 0x0202) { WSACleanup(); failure=failure+"\nVersion is different"; } SOCKADDR_IN addr; addr.sin_family=AF_INET; addr.sin_port=htons(portno); addr.sin_addr.s_addr=htonl(INADDR_ANY); AcceptSocket::s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(AcceptSocket::s == INVALID_SOCKET) failure=failure+"\nsocket creating error"; if(bind(AcceptSocket::s,(LPSOCKADDR) &addr,sizeof(addr)) == SOCKET_ERROR) failure=failure+"\nbinding error"; listen(AcceptSocket::s,SOMAXCONN); } void AcceptSocket::closeConnection() { if(AcceptSocket::s) closesocket(AcceptSocket::s); WSACleanup(); } void AcceptSocket::StartAccepting() { sockaddr_in addrNew; int size=sizeof(addrNew); while(1) { SOCKET temp=accept(AcceptSocket::s,(sockaddr *)&addrNew,&size); AcceptSocket * tempAcceptSocket=new AcceptSocket(); tempAcceptSocket->setSocket(temp); DWORD threadId; HANDLE thread=CreateThread(NULL,0,MyThreadFunction,(LPVOID)tempAcceptSocket,0,&threadId); } } DWORD WINAPI AcceptSocket::MyThreadFunction(LPVOID lpParam) { AcceptSocket * acceptsocket=(AcceptSocket *) lpParam; acceptsocket->threadDeal(); return 1; } void AcceptSocket::threadDeal() { "You didn't define threadDeal in the derived class"; } Now the main.cpp is #include<Networking.h> int main() { } When I am compiling The error I got is Error 1 error LNK2005: "private: static unsigned int AcceptSocket::s" (?s@AcceptSocket@@0IA) already defined in NetWorking.obj C:\Documents and Settings\prabhakaran\Desktop\check\check\main.obj check Error 2 error LNK1169: one or more multiply defined symbols found C:\Documents and Settings\prabhakaran\Desktop\check\Debug\check.exe 1 1 check Now anybody please enlighten me about this issue

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  • task strategies for handling HardDeadlineExceededError

    - by Stevko
    I've got a number of tasks/servlets that are hitting the HardDeadlineExceededError which is leaving everything hanging in an 'still executing' state. The work being done can easily exceed the 29 second threshold. I try to catch the DeadlineExceededException and base Exception in order to save the exit state but neither of these exception handlers are being caught... Is there a way to determine which tasks are in the queue or currently executing? Are there any other strategies for dealing with this situation?

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  • Flex Drag & Drop: Detecting when all data has been moved from source to destination

    - by Adam Tuttle
    I have two mx:TileList controls that I'm using to allow editing of objects in batch. The first contains a collection of all available data, and the 2nd contains the current batch. Both are bound to ArrayCollections, and using the native drag-n-drop functionality of the TileList control the data is moved from one ArrayCollection to the other when an object is dragged between them. I need to change the currentState to show & reset the batch manipulation controls when the batch count goes from 0 to n or n to 0 items. Based on the documentation, I would have thought that I should listen to the dragComplete event, but my testing shows that instead of firing after the data has been removed from the source ArrayCollection and added to the destination ArrayCollection, it fires (consistently) between these two actions. Both lists are similar to this: <mx:TileList id="srcList" dragEnabled="true" dropEnabled="true" dragMoveEnabled="true" dataProvider="{images}" dragComplete="handleDragComplete(event)" allowMultipleSelection="true" /> And here's the source of the handleDragComplete function: private function handleDragComplete(e:DragEvent):void{ trace(e.dragInitiator.name + '.dragComplete: batch.length=' + batch.length.toString()); trace(e.dragInitiator.name + '.dragComplete: images.length=' + images.length.toString()); if (batch.length > 0){ currentState = 'show'; }else{ currentState = ''; } } And lastly, here's some example output from running the code. These are all run one after the other. Case 1: The application loads with 10 objects in the first list and the batch is empty. I dragged 1 object from the source list to the batch list. srcList.dragComplete: batch.length=1 srcList.dragComplete: images.length=10 (Expected: 1,9) Clearly, the object has been added to the batch ArrayCollection but not removed from the source. Case 2: Now, I'll drag a 2nd object into the batch. srcList.dragComplete: batch.length=2 srcList.dragComplete: images.length=9 (Expected: 2,8) Firstly, we can see that images.length has changed, showing that the object that I dragged from the source list to the batch list was removed AFTER the dragComplete event fired. The same thing happens this time: The new object is added to the batch ArrayCollection (batch.length=2), the dragComplete event fires (running these traces), and then the object is removed from the source ArrayCollection. Case 3: Now, I'll drag both images from the batch list back to their original location in the source list. batchList.dragComplete: batch.length=2 batchList.dragComplete: images.length=10 (Expected: 0,10) We can see that batch.length hasn't gone down, but the source images array is back at its original length of 10. QUESTION: Am I doing something wrong? Is there another event I could listen for? (Note: I tried both DragExit and DragDrop, just to be sure, and those behave as expected, but are not what I need.) Or is there another way to get the data that I want? Or... have I found a bug in the SDK?

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  • Handling Complex Rules in in GUI applciations (C++ or C#)

    - by Canacourse
    Im working on a dialog box in which several rules must be satisfied before the OK button is enabled. Currently any action on the page such as entering data or selecting an item from a drop down list (amongst other things) calls a single function called ProcessEvent() - this function handles all logic and either enables or disables the OK button. My problem is I finding it difficult making the rules concise and understandable. Some of the rules can be negated by another action on the dialog and I have now ended up with if else statements all over the place or which are difficult to read and follow & extend. The code below is a simplification of the problem but demonstrates it well. How do I handle this problem better (If its Possible) bool CWorkstation::ProcessEvent(void) { UpdateData(); CharCount = GetDlgItemInt(IDC_CharCount, NULL, FALSE); //get latest if ( IsDlgButtonChecked(IDC_USEDBNAME)) { if (!IsDlgButtonChecked(IDC_MAXDBNAME)) { EnableNext(TRUE); } } if (IsDlgButtonChecked(IDC_MAXDBNAME) && CharCount) { if (IsDlgButtonChecked(IDC_USEXMLNAME)) { if ( PrefixName.IsEmpty() ) { EnableNext(FALSE); } else { EnableNext(TRUE); } } } if (IsDlgButtonChecked(IDC_USEXMLNAME) && PrefixName.GetLength() > 1) { EnableNext(TRUE); } if ( IsDlgButtonChecked(IDC_WSAUTONAME) || IsDlgButtonChecked(IDC_RENAMEIFDUP)) { // TRACE("IDC_WSAUTONAME is Checked\n"); if ( IsDlgButtonChecked(IDC_USEXMLNAME) && PrefixName.GetLength() > 1 ) { if ( IsDlgButtonChecked(IDC_IDC_USESHORTNAME) ) { EnableNext(TRUE); } else if ( IsDlgButtonChecked(IDC_USELONGNAME) ) { EnableNext(TRUE); } else { EnableNext(FALSE); } } if ( !IsDlgButtonChecked(IDC_USEPREFIX) ) { if ( IsDlgButtonChecked(IDC_IDC_USESHORTNAME) || IsDlgButtonChecked(IDC_USELONGNAME) ) { EnableNext(TRUE); } } return false; } }

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  • What's a good way to throw and handle events in PHP?

    - by techexpert
    Hi everyone, I am just trying to get a general idea about the event prcessing mechanism in PHP5 in as neat way as possible. First of all I understand that a PHP application is not exactly a persistent type, so the events may not make a lot of sense, but from the OO perspective it might be a very elegant way to "communicate" between the objects. So I am thinking that it would make sense to separate the events on the external events, such as $_POST & $_GET and the internal ones, i.e. function callbacks. As far as the external ones, is it a good idea to process the $_GETs and $_POSTs directly, or is it better to wrap them into an event of some sort? Also, in order to process the internal events, do you have to pass the reference to the event handler/dispatcher to each class so they know how to throw them? I was thinking to use the PEAR EventDispatcher to do the work, but I am open to other suggestions. Thank you!

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  • How can I add an event handler to an event by name?

    - by cyclotis04
    I'm attempting to add an event handler for every control on my form. The form is a simple info box which pops up, and clicking anywhere on it does the same thing (sort of like Outlook's email notifier.) To do this, I've written a recursive method to add a MouseClick handler to each control, as follows: private void AddMouseClickHandler(Control control, MouseEventHandler handler) { control.MouseClick += handler; foreach (Control subControl in control.Controls) AddMouseClickHandler(subControl, handler); } However, if I wanted to add a handler for all of the MouseDown and MouseUp events, I'd have to write two more methods. I'm sure there's a way around this, but I can't find it. I want a method like: private void AddRecursiveHandler(Control control, Event event, EventHandler handler) { control.event += handler; foreach (Control subControl in control.Controls) AddRecursiveHandler(subControl, event, handler); }

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  • iphone - how to properly handle exceptional situations (signals ?)

    - by pmilosev
    Hi In my iphone app, I want to provide some sort of app termination handler that will do some final work (delete some sensitive data) before the application terminates. I want to handle as much of the termination situations as possible: 1) User terminates the app 2) The device runs out of battery 3) The system terminates the app due to some reason (e.g. out of memory or app freeze) 4) Application crashes (EXC_BAD_ACCESS or SIGSEGV) Any other exceptional situation ? What is the best way to achieve this (e.g. is applicationWillTerminate method called in situation 2) ? Is it possible to do the cleanup in a signal handler (includes iPhone Security framework calls) ? regards

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