Search Results

Search found 20211 results on 809 pages for 'language implementation'.

Page 696/809 | < Previous Page | 692 693 694 695 696 697 698 699 700 701 702 703  | Next Page >

• Why is Excel's 'Evaluate' method a general expression evaluator?

  - by jtolle

  A few questions have come up recently involving the Application.Evaluate method callable from Excel VBA. The old XLM macro language also exposes an EVALUATE() function. Both can be quite useful. Does anyone know why the evaluator that is exposed can handle general expressions, though? My own hunch is that Excel needed to give people a way to get ranges from string addresses, and to get the value of named formulas, and just opening a portal to the expression evaluator was the easiest way. (The help for the VBA version does say its purpose it to "convert a Microsoft Excel name to an object or a value".) But of course you don't need the ability to evaluate arbitrary expressions just to do that. (That is, Excel could provide a Name.Evaluate method or something instead.) Application.Evaluate seems kind of...unfinished. It's full behavior isn't very well documented, and there are quite a few quirks and limitations (as described by Charles Williams here: http://www.decisionmodels.com/calcsecretsh.htm) with what is exposed. I suppose the answer could be simply "why not expose it?", but I'd be interested to know what design decisions led to this feature taking the form that it does. Failing that, I'd be interested to hear other hunches.

  Read the article

• Added CAGradientLayer, getting this in my UIView dealloc: [CALayer release]: message sent to deallocated instance

  - by developerdoug

  Here there, I have a custom UIView. This view acts as a activity indicator but as label above the UIActivityIndicatorView. In the init, I add a CAGradientLayer. I allocate and initialize it and insert it at index 0 as a sublayer of the UIView layer property. In my dealloc method was called, I received a message in the console: - [CALayer release]: message sent to deallocated instance. My code: @interface LabelActivityIndicatorView () { UILabel *_label; UIActivityIndicatorView *_activityIndicatorView; CAGradientLayer *_gradientLayer; } @end @implementation LabelActivityIndicatorView //dealloc - (void) dealloc { [_label release]; [_activityIndicatorView release]; //even tried to remove the layer [_gradientLayer removeFromSuperLayer]; [_gradientLayer release]; [super dealloc]; } // init - (id) initWithFrame:(CGRect)frame { if ( (self = [super initWithFrame:frame]) ) { // init the label // init the gradient layer _gradientLayer = [[CAGradientLayer alloc] init]; [_gradientLayer setBounds:[self bounds]]; [_gradientLayer setPosition:CGPointMake(frame.size.width/2, frame.size.height/2)]; [[self layer] insertSublayer:_gradientLayer atIndex:0]; [[self layer] setNeedsDisplay]; } return self; } @end Anyone have any ideas. Since I'm allocating and initializing the gradient layer I'm responsible for releasing it. I should be able to alloc and init and assign to some ivar. Perhaps I should create a property with retain on it. Thanks,

  Read the article

• trying to reenter IT field after a break of over 5 years

  - by josephj1989

  Hello I have had some misfortune in life - I was unwell and had to stay out of work for an extended period of about 5 years.Before that I used to work as an Oracle/Oracle Ebusiness suite consultant (I was charging very good contract rates). But now I am fully recovered ,feeling sharper than ever. But there arent many opportunities in my areas of expertise in a small market like New Zealand and the long absence is no help either. So for the last 5 months I have been training myself in C# ,ASP .NET,WEB technologies like HTML,JQuery,CSS and also SQL Server.I had some previous experience with JAVA and VB .NET (few months). But I am fully confident of my abilities and believe I can hit the ground running given a chance.I used to be an expert with SQL and C language and these skills are portable to SQL Server and C#. Another problem I face is my age- I am over 50. What is your opinion - Am I doing the right thing. Can I get back into an IT career-I am willing to start all over again at a junior level, I am really facing a crisis in my life.

  Read the article

• Where to place interactive objects in JavaScript?

  - by Chris

  I'm creating a web based application (i.e. JavaScript with jQuery and lots of SVG) where the user interacts with "objects" on the screen (think of DIVs that can be draged around, resized and connected by arraows - like a vector drawing programm or a graphical programming language). As each "object" contains individual information but is allways belonging to a "class" of elements it's obvious that this application should be programmed by using an OOP approach. But where do I store the "objects" best? Should I create a global structure ("registry") with all (JS native) objects and tell them "draw yourself on the DOM"? Or should I avoid such a structure and think of the (relevant) DOM nodes as my objects and attach the relevant data as .data() to them? The first approach is very MVC - but I guess the attachment of all the event handlers will be non trivial. The second approach will handle the events in a trivial way and it doesn't create a duplicate structure, but I guess the usual OO stuff (like methods) will be more complex. What do you recomend? I think the answer will be JavaScript and SVG specific as "usual" programming languages don't have such a highly organized output "canvas".

  Read the article

• Many users, many cpus, no delays. Good for cloud?

  - by Eric

  I wish to set up a CPU-intensive time-important query service for users on the internet. A usage scenario is described below. Is cloud computing the right way to go for such an implementation? If so, what cloud vendor(s) cater to this type of application? I ask specifically, in terms of: 1) pricing 2) latency resulting from: - slow CPUs, instance creations, JIT compiles, etc.. - internal management and communication of processes inside the cloud (e.g. a queuing process and a calculation process) - communication between cloud and end user 3) ease of deployment A usage scenario I am expecting is: - A typical user sends a query (XML of size around 1K) once every 30 seconds on average. - Each query requires a numerical computation of average time 0.2 sec and max time 1 sec on a 1 GHz Pentium. The computation requires no data other than the query itself and is performed by the same piece of code each time. - The delay a user experiences between sending a query and receiving a response should be on average no more than 2 seconds and in general no more than 5 seconds. - A background save to a DB of the response should occur (not time critical) - There can be up to 30000 simultaneous users - i.e., on average 1000 queries a second, each requiring an average 0.2 sec calculation, so that would necessitate around 200 CPUs. Currently I'm look at GAE Java (for quicker deployment and less IT hassle) and EC2 (Speed and price optimization) as options. Where can I learn more about the right way to set ups such a system? past threads, different blogs, books, etc.. BTW, if my terminology is wrong or confusing, please let me know. I'd greatly appreciate any help.

  Read the article

• Using TXMLDocument to serialize form settings to XML and database.

  - by LukLed

  I have an interface: type IXMLSerializable = interface function SaveToXML : DOMString; function SaveToXMLDocument : IXMLDocument; procedure LoadFromXML(AXML : DOMString); end; It is used to serialize some settings of forms or frames to xml. Simple implementation: SaveToXMLDocument: function TSomething.SaveToXMLDocument: IXMLDocument; begin Result := TXMLDocument.Create(nil); with Result do begin Active := True; with AddChild(Self.Name) do begin AddChild(edSomeTextBox.Name).Attributes['Text'] := edSomeTextBox.Text; end; end; Result := XMLDoc; end; LoadFromXML: procedure TSomething.LoadFromXML(AXML: DOMString); var XMLDoc : IXMLDocument; I : Integer; begin XMLDoc := TXMLDocument.Create(nil); with XMLDoc do begin LoadFromXML(AXML); Active := True; with ChildNodes[0] do begin for I := 0 to ChildNodes.Count-1 do begin If ChildNodes[I].NodeName = 'edSomeTextBox' then edSomeTextBox.Text := ChildNodes[I].Attributes['Text']; end; end; end; end; SaveToXML: function TSomething.SaveToXML: DOMString; begin SaveToXMLDocument.SaveToXML(Result); end; DOMString result of SaveToXML is saved to database to blob field. I had some encoding issues with other implementations and this one works fine (right now). Do you see any dangers in this code? Can I have issues with different settings on various machines and systems?

  Read the article

• problems getting HTTPRiot working

  - by bwizzy

  I've got an iphone app where I'm trying to use HTTPRiot to make some API calls to a web app. Problem is I can't see that none of the HTTPRiot delegate methods are being called. I've got a log in all the delegate methods, and I'm also looking at the webserver log. I see that the URL is being hit. //API.h #import <Foundation/Foundation.h> #include <HTTPRiot/HTTPRiot.h> @interface API : HRRestModel { } +(void)runTest; @end //API.m #import "API.h" @implementation API + (void)initialize { NSLog(@"api initialize"); [self setDelegate:self]; [self setBaseURL:[NSURL URLWithString:@"http://localhost:3000/api"]]; [self setBasicAuthWithUsername:@"demo" password:@"123456"]; NSDictionary *params = [NSDictionary dictionaryWithObject:@"1234567" forKey:@"api_key"]; [self setDefaultParams:params]; }//end initialize +(void)runTest { NSLog(@"api run test"); // Would send a request to http://localhost:1234/api/people/1?api_key=1234567 [self getPath:@"/save_diet" withOptions:nil object:nil]; } +(void)restConnection:(NSURLConnection *)connection didReturnResource:(id)resource object:(id)object { NSLog(@"didReturnResource"); } +(void)restConnection:(NSURLConnection *)connection didReceiveResponse:(NSHTTPURLResponse *)response object:(id)object { NSLog(@"didReceiveResponse"); } +(void)restConnection:(NSURLConnection *)connection didReceiveParseError:(NSError *)error responseBody:(NSString *)body object:(id)object { NSLog(@"didReceiveParseError"); } +(void)restConnection:(NSURLConnection *)connection didReceiveError:(NSError *)error response:(NSHTTPURLResponse *)response object:(id)object { NSLog(@"didReceiveError"); } +(void)restConnection:(NSURLConnection *)connection didFailWithError:(NSError *)error object:(id)object { NSLog(@"didFailWithError"); } @end //test code [API runTest]; //log output

  Read the article

• Cannot redeclare class on a copy of a site

  - by Polity

  I've developed a small SMS utility for a customer in PHP. The details are of non-importance. This project is hosted in: http://project.example.com/customer1 Now a second customer requests almost the same functionality, one cheap way of providing this is to copy the project from the first customer and modify it slightly. So i made a direct copy of the project for customer1 to another folder for customer 2. This project is hosted in: http://project.example.com/customer2 Now when i try and run the project for customer2 (calling a single page), i get the error message: Fatal error: Cannot redeclare class SmsService in /var/www/html/project/customer1/application/service.class.php on line 3 Here, service.class.php is a simple interface with 3 methods: interface SmsService { public function SendSms($mobile, $customerId, $customerName, $message); public function QueryIncomingResponse(); public function CleanExpiredConfirmations($maxConfirmationDays); } printing the backtrace in service.class.php reveals something interresting: #0 require_once() called at [/var/www/html/project/customer2/endpoint/queryIncomingResponse.php:2] Fatal error: Cannot redeclare class SmsService in /var/www/html/project/customer1/application/service.class.php on line 3 Line 2 in queryIncomingResponses is the very first require line there is. Line 3 in service.class.php is the first statement there is in the file (Line 2 is an empty line and line 1 is the php file opening tag). Naturally, I only work with relative requires (double checked this) so there is no way one include/require from customer2 actually refers to a file for customer1. It seems to me that in some way SmsService and other classes gets cached by PHP. (I have little control over the server environment). One solution to this would be namespaces. Unfortunatly, we work with PHP 5.1.7 where namespaces are not a part of the language feature just yet. Another way would be to mimic namespaces by prefixing all classes but this approach just feels dirty. Does anyone have more information on this problem and possibly solutions? Many thanks in advance!

  Read the article

• How to use interfaces in exception handling

  - by vikp

  Hi, I'm working on the exception handling layer for my application. I have read few articles on interfaces and generics. I have used inheritance before quite a lot and I'm comfortable with in that area. I have a very brief design that I'm going to implement: public interface IMyExceptionLogger { public void LogException(); // Helper methods for writing into files,db, xml } I'm slightly confused what I should be doing next. public class FooClass: IMyExceptionLogger { // Fields // Constructors } Should I implement LogException() method within FooClass? If yes, than I'm struggling to see how I'm better of using an interface instead of the concrete class... I have a variety of classes that will make a use of that interface, but I don't want to write an implementation of that interface within each class. In the same time If I implement an interface in one class, and then use that class in different layers of the application I will be still using concrete classes instead of interfaces, which is a bad OO design... I hope this makes sense. Any feedback and suggestions are welcome. Please notice that I'm not interested in using net4log or its competitors because I'm doing this to learn. Thank you Edit: Wrote some more code. So I will implement variety of loggers with this interface, i.e. DBExceptionLogger, CSVExceptionLogger, XMLExceptionLogger etc. Than I will still end up with concrete classes that I will have to use in different layers of my application.

  Read the article

• Cast base class object to derived class

  - by Popgalop

  Lets say I have two classes, animal and dog like this. class Animal { }; class Dog : public Animal { }; And I have an animal object named animal, that is actually an instance of dog, how would I cast it back to dog? This may seem like an odd question, but I need it because I am writing a programming language interpreter, and on the stack everything is stored as a BaseObject, and all the other datatypes extend BaseObject. How would I cast the base object from the stack, to a specific data type? I have tried something like this Dog dog = static_cast<Dog>(animal); But it gives me an error 1>------ Build started: Project: StackTests, Configuration: Debug Win32 ------ 1> StackTests.cpp 1>c:\users\owner\documents\visual studio 2012\projects\stacktests\stacktests\stacktests.cpp(173): error C2440: 'static_cast' : cannot convert from 'Animal' to 'Dog' 1> No constructor could take the source type, or constructor overload resolution was ambiguous 1>c:\users\owner\documents\visual studio 2012\projects\stacktests\stacktests\stacktests.cpp(173): error C2512: 'Dog' : no appropriate default constructor available ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

  Read the article

• VB app to web service

  - by brandon

  I know very little about web service but I assumed it would be the solution I was looking for. Basically I made an application in VB that I want to be ubiquitous for a lack of a better word. I need it to receive requests from multiple users and respond all at once. I was told "technically if you write a webservice you can provide as many results back to users as are connected." Maybe there is another solution for me that will give me the results I want. Here is an example of what I'm trying to do. Lets say I make an application in VB that does math. I now make a website. My website allows for a person to input 1 + 1 they click submit and my website then connects to my VB application running on my server listening for a request. It accepts the request from my website, and then it solves the math problem and returns the answer back to the website "1 + 1 = 2" That is only an example of the type of thing I need. My problem is that I can't have multiple people visiting my website all connecting to that same application running on my server so somehow I need the application to be where it can be accessed by multiple users. I was told a web service would be the answer but if there is another solution I'd like to know. If the only solution is a web service, then how can I manage to either convert the VB app to a web service? Can I have to convert the app to asp.net or some other language? Is there an easier option?

  Read the article

• std::vector elements initializing

  - by Chameleon

  std::vector<int> v1(1000); std::vector<std::vector<int>> v2(1000); std::vector<std::vector<int>::const_iterator> v3(1000); How elements of these 3 vectors initialized? About int, I test it and I saw that all elements become 0. Is this standard? I believed that primitives remain undefined. I create a vector with 300000000 elements, give non-zero values, delete it and recreate it, to avoid OS memory clear for data safety. Elements of recreated vector were 0 too. What about iterator? Is there a initial value (0) for default constructor or initial value remains undefined? When I check this, iterators point to 0, but this can be OS When I create a special object to track constructors, I saw that for first object, vector run the default constructor and for all others it run the copy constructor. Is this standard? Is there a way to completely avoid initialization of elements? Or I must create my own vector? (Oh my God, I always say NOT ANOTHER VECTOR IMPLEMENTATION) I ask because I use ultra huge sparse matrices with parallel processing, so I cannot use push_back() and of course I don't want useless initialization, when later I will change the value.

  Read the article

• crash when using stl vector at instead of operator[]

  - by Jamie Cook

  I have a method as follows (from a class than implements TBB task interface - not currently multithreading though) My problem is that two ways of accessing a vector are causing quite different behaviour - one works and the other causes the entire program to bomb out quite spectacularly (this is a plugin and normally a crash will be caught by the host - but this one takes out the host program as well! As I said quite spectacular) void PtBranchAndBoundIterationOriginRunner::runOrigin(int origin, int time) const // NOTE: const method { BOOST_FOREACH(int accessMode, m_props->GetAccessModes()) { // get a const reference to appropriate vector from member variable // map<int, vector<double>> m_rowTotalsByAccessMode; const vector<double>& rowTotalsForAccessMode = m_rowTotalsByAccessMode.find(accessMode)->second; if (origin != 129) continue; // Additional debug constrain: I know that the vector only has one non-zero element at index 129 m_job->Write("size: " + ToString(rowTotalsForAccessMode.size())); try { // check for early return... i.e. nothing to do for this origin if (!rowTotalsForAccessMode[origin]) continue; // <- this works if (!rowTotalsForAccessMode.at(origin)) continue; // <- this crashes } catch (...) { m_job->Write("Caught an exception"); // but its not an exception } // do some other stuff } } I hate not putting in well defined questions but at the moment my best phrasing is : "WTF?" I'm compiling this with Intel C++ 11.0.074 [IA-32] using Microsoft (R) Visual Studio Version 9.0.21022.8 and my implementation of vector has const_reference operator[](size_type _Pos) const { // subscript nonmutable sequence #if _HAS_ITERATOR_DEBUGGING if (size() <= _Pos) { _DEBUG_ERROR("vector subscript out of range"); _SCL_SECURE_OUT_OF_RANGE; } #endif /* _HAS_ITERATOR_DEBUGGING */ _SCL_SECURE_VALIDATE_RANGE(_Pos < size()); return (*(_Myfirst + _Pos)); } (Iterator debugging is off - I'm pretty sure) and const_reference at(size_type _Pos) const { // subscript nonmutable sequence with checking if (size() <= _Pos) _Xran(); return (*(begin() + _Pos)); } So the only difference I can see is that at calls begin instead of simply using _Myfirst - but how could that possibly be causing such a huge difference in behaviour?

  Read the article

• Best (Java) book for understanding 'under the bonnet' for programming?

  - by Ben

  What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

  Read the article

• Uniquely identify files/folders in NTFS, even after move/rename

  - by Felix Dombek

  I haven't found a backup (synchronization) program which does what I want so I'm thinking about writing my own. What I have now does the following: It goes through the data in the source and for every file which has its archive bit set OR does not exist in the destination, copies it to the destination, overwriting a possibly existing file. When done, it checks for all files in the destination if it exists in the source, and if it doesn't, deletes it. The problem is that if I move or rename a large folder, it first gets copied to the destination even though it is in principle already there, just has a different path. Then the folder which was already there is deleted afterwards. Apart from the unnecessary copying, I frequently run into space problems because my backup drive isn't large enough to hold the original data twice. Is there a way to programmatically identify such moved/renamed files or folders, i.e. by NTFS ID or physical location on media or something else? Are there solutions to this problem? I do not care about the programming language, but hints for doing this with Python, C++, C#, Java or Prolog are appreciated.

  Read the article

• Accessing red5 server outside the localhost

  - by user1039290

  I am new on red5 server so I stuck in. I am trying to record videos from webcam and save them in to my server. To do this, I installed red5 to my server. In addition, I also downloaded red5recorder and put it into my webapps folder. But there is any information about its implementation details. Whatever. So I go on with Red5 SimpleRecorder tutorial. Everything works fine when I tried in my server, but there is a problem when I try to connect to server from other computer to record a video. Actually, video recording is handled but the recorded video is not uploaded to the server. When I work in localhost it works fine, but from outside I couldn't be able to record or upload the video. I change the red5-web.properties document, and set virtual host to my server's IP but it again only works in localhost. What could be the reason? Is it about file permissions? or what could it be? Kind regards, Can

  Read the article

• NSMutableArray for Object which has NSString property causes memory leak

  - by user262325

  Hello everyone I hope to add objects to a NSMutableArray "myArray", The NSMutableArray is the array for FileObj which has a NSString property "fileName" #import <UIKit/UIKit.h> @interface FileObj : NSObject { NSString *fileName; } -(void) setfileName:(NSString *)s ; -(NSString *) getfileName ; @end // // File.m// #import "File.h" @implementation FileObj -(void) setfileName:(NSString *)s ; { fileName=s; } -(NSString *) getfileName ; { return fileName; } @end I initialize the myArray here: NSMutableArray *temarray; temarray=[[NSMutableArray alloc] init]; self.myArray=temarray; [temarray release]; the codes to add object to myArray FileObj *newobj=[[FileObj alloc]init ]; NSString *fieldValue2 = [[NSString alloc] initWithUTF8String:@"aaaa"]; [newobj setfileName:fieldValue2]; [myArray addObject:newobj]; [fieldValue2 release]; //**if I enabled the line, it will cause crash** //**if I disable the line, it will cause memory leak** [newobj release]; Welcome any comment Thanks interdev

  Read the article

• Reverse engineering and redistributing code from .NET Framework

  - by ToxicAvenger

  Once or twice I have been running into the following issue: Classes I want to reuse in my applications (and possibly redistribute) exist in the .NET Framework assemblies, but are marked internal or private. So it is impossible to reuse them directly. One way is to disassemble them, pick the pieces you need, put them in a different namespace, recompile (this can be some effort, but usually works quite well). My question is: Is this legal? Is this only legal for the classes of the Framework which are available as source code anyway? Is it illegal? I think that Microsoft marks them internal or private primarily so that they don't have to support them or can change the interfaces later. But some pieces - be it SharePoint or WCF - are almost impossible to properly extend by only using public classes from the apis. And rewriting everything from scratch generates a huge amount of effort, before you even start solving the problem you intended to solve. This is in my eyes not a "dirty" approach per se. The classes Microsoft ships are obviously well tested, if I reuse them under a different namespace I have "control" over them. If Microsoft changes the original implementation, my code won't be affected (some internals in WCF changed quite a bit with v4). It is not a super-clean approach. I would much prefer Microsoft making several classes public, because there are some nice classes hidden inside the framework.

  Read the article

• Computing, storing, and retrieving values to and from an N-Dimensional matrix

  - by Adam S

  This question is probably quite different from what you are used to reading here - I hope it can provide a fun challenge. Essentially I have an algorithm that uses 5(or more) variables to compute a single value, called outcome. Now I have to implement this algorithm on an embedded device which has no memory limitations, but has very harsh processing constraints. Because of this, I would like to run a calculation engine which computes outcome for, say, 20 different values of each variable and stores this information in a file. You may think of this as a 5(or more)-dimensional matrix or 5(or more)-dimensional array, each dimension being 20 entries long. In any modern language, filling this array is as simple as having 5(or more) nested for loops. The tricky part is that I need to dump these values into a file that can then be placed onto the embedded device so that the device can use it as a lookup table. The questions now, are: What format(s) might be acceptable for storing the data? What programs (MATLAB, C#, etc) might be best suited to compute the data? C# must be used to import the data on the device - is this possible given your answer to #1?

  Read the article

• Esper generating episodes

  - by Jasonojh

  I would like to use Esper to generate episodes of events. I am trying to detect the changes in robot movement during each time period and was wondering what would be the best way of implementation. The rules for generation of episodes from the events would be If the new event time(eg. 7sec, robot A) of a robot is more than 3 sec than the latest event(eg. 3 sec, robot A) of the same robot, the new event belongs to a new episode. Each episode should represent only one robot (eg. 2sec, robotA and 3sec, robotB should output 2 episodes) Input data: Event Time Robot Position 1 1 A 0 2 2 A 1 3 6 A 2 Output data should be: Array[0]={Event 1,Event 2} Array[1]={Event 3} //more than 3 sec Input data: Event Time Robot Position 1 1 A 0 2 2 A 1 3 4 B 0 4 6 A 2 Output data should be: Array[0]={Event 1,Event 2} Array[1]={Event 3} //different robot Array[2]={Event 4} Please help provide suggestions. I have tried using mulitple listeners, one for each robot, to create episodes and it works but I am trying to use a single EPL statement to do it. I have tried win:time_accum(3sec) group by robot but the second example output: Array[0]={Event 1,Event 2, Event 4} Array[1]={Event 3} as the time window is shifted everytime an event comes in, the system still thinks that event 4 is less than 3 sec due to event 3. how do I create a unique time window for each robot? Thank you for your suggestions and any help is greatly appreciated.

  Read the article

• C++ private inheritance and static members/types

  - by WearyMonkey

  I am trying to stop a class from being able to convert its 'this' pointer into a pointer of one of its interfaces. I do this by using private inheritance via a middle proxy class. The problem is that I find private inheritance makes all public static members and types of the base class inaccessible to all classes under the inheriting class in the hierarchy. class Base { public: enum Enum { value }; }; class Middle : private Base { }; class Child : public Middle { public: void Method() { Base::Enum e = Base::value; // doesn't compile BAD! Base* base = this; // doesn't compile GOOD! } }; I've tried this in both VS2008 (the required version) and VS2010, neither work. Can anyone think of a workaround? Or a different approach to stopping the conversion? Also I am curios of the behavior, is it just a side effect of the compiler implementation, or is it by design? If by design, then why? I always thought of private inheritance to mean that nobody knows Middle inherits from Base. However, the exhibited behavior implies private inheritance means a lot more than that, in-fact Child has less access to Base than any namespace not in the class hierarchy!

  Read the article

• WPF bound object update notification

  - by Carlo

  I have a TreeView with a few objects bound to it, let's say something like this: public class House { public List<Room> Rooms { get; set; } public List<Person> People { get; set; } public House() { this.Rooms = new List<Room>(); this.People = new List<Person>(); } public void BuildRoom(string name) { this.Rooms.Add(new Room() { Name = name }); } public void DestroyRoom(string name) { this.Rooms.Remove(new Room() { Name = name }); } public void PersonEnter(string name) { this.People.Add(new Person() { Name = name }); } public void PersonLeave(string name) { this.People.Remove(new Person() { Name = name }); } } public class Room { public string Name { get; set; } } public class Person { public string Name { get; set; } } The TreeView is watching over the House object, whenever a room is built / destroyed or a person enters / leaves, my tree view updates itself to show the new state of the house (I omitted some implementation details for simplicity). What I want is to know the exact moment when this update finishes, so I can do something right there, the thing is that I created an indicator of the selected item, and when something moves, I need to update said indicator's position, that's the reason I need it exactly when the tree view updates. Let me know if you know a solution to this. Also, the code is not perfect (DestroyRoom and PersonLeave), but you get the idea. Thanks!

  Read the article

• Adding new records in Access without wrecking the form

  - by Matt Parker

  I'm working on a simple Access 2003 application to keep track of things that need to be done for clients for some colleagues. Each colleague has a set of clients, and each client has a set of actions that need to be taken by a certain date. I've set up a form that consists of a combobox for client ID (indexed), a drop-down for the person who is handling that client's case, and a button for adding new clients (a standard Access-created Add Record button). The actions are listed in a subform below these three elements. The problem I've run into is that the first person I tested this on clicked the button to add a new record, then didn't fill it out and tried to select another client from the drop-down list. Access interprets this as an attempt to set the selected Client ID as the ID for the new record and rightfully throws an error for duplicate primary keys. I can think of a couple of ways around this problem, but I'd much rather hear your elegant solutions than kludge together some junk in a language I don't know. Let me know if you have any questions. Thank you.

  Read the article

• Subquery with multiple results combined into a single field?

  - by Todd

  Assume I have these tables, from which i need to display search results in a browser: Table: Containers id | name 1 Big Box 2 Grocery Bag 3 Envelope 4 Zip Lock Table: Sale id | date | containerid 1 20100101 1 2 20100102 2 3 20091201 3 4 20091115 4 Table: Items id | name | saleid 1 Barbie Doll 1 2 Coin 3 3 Pop-Top 4 4 Barbie Doll 2 5 Coin 4 I need output that looks like this: itemid itemname saleids saledates containerids containertypes 1 Barbie Doll 1,2 20100101,20100102 1,2 Big Box, Grocery Bag 2 Coin 3,4 20091201,20091115 3,4 Envelope, Zip Lock 3 Pop-Top 4 20091115 4 Zip Lock The important part is that each item type only gets one record/row in the return on the screen. I accomplished this in the past by returning multiple rows of the same item and using a scripting language to limit the output. However, this makes the ui overly complicated and loopy. So, I'm hoping I can get the database to spit out only as many records as there are rows to display. This example may be a bit extreme because of the 2 joins needed to get to the container from the item (through the sale table). I'd be happy for just an example query that outputs this: itemid itemname saleids saledates 1 Barbie Doll 1,2 20100101,20100102 2 Coin 3,4 20091201,20091115 3 Pop-Top 4 20091115 I can only return a single result in a subquery, so I'm not sure how to do this.

  Read the article

• how to emulate thread local storage at user space in C++ ?

  - by vprajan

  I am working on a mobile platform over Nucleus RTOS. It uses Nucleus Threading system but it doesn't have support for explicit thread local storage i.e, TlsAlloc, TlsSetValue, TlsGetValue, TlsFree APIs. The platform doesn't have user space pthreads as well. I found that __thread storage modifier is present in most of the C++ compilers. But i don't know how to make it work for my kind of usage. How does __thread keyword can be mapped with explicit thread local storage? I read many articles but nothing is so clear for giving me the following basic information will __thread variable different for each thread ? How to write to that and read from it ? does each thread has exactly one copy of the variable ? following is the pthread based implementation: pthread_key_t m_key; struct Data : Noncopyable { Data(T* value, void* owner) : value(value), owner(owner) {} int* value; }; inline ThreadSpecific() { int error = pthread_key_create(&m_key, destroy); if (error) CRASH(); } inline ~ThreadSpecific() { pthread_key_delete(m_key); // Does not invoke destructor functions. } inline T* get() { Data* data = static_cast<Data*>(pthread_getspecific(m_key)); return data ? data->value : 0; } inline void set(T* ptr) { ASSERT(!get()); pthread_setspecific(m_key, new Data(ptr, this)); } How to make the above code use __thread way to set & get specific value ? where/when does the create & delete happen? If this is not possible, how to write custom pthread_setspecific, pthread_getspecific kind of APIs. I tried using a C++ global map and index it uniquely for each thread and retrieved data from it. But it didn't work well.

  Read the article

< Previous Page | 692 693 694 695 696 697 698 699 700 701 702 703  | Next Page >