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  • GWT PagingScrollTable ( set a style on a particular cell of the header table )

    - by Mario
    I have a column Definition for each colume that extends AbstractColumnDefinition these columns are put in a DefaultTableDefinition PART OF a PagingScrollTable example: NAME | SIZE | RES | DELETE | this style (AT THE END OF THE PAGE ) is added to the column names if you notice all of them are with a cursor pointer , meaning a hand shows up when i hover above each one. I want to remove the cursor for some cells in the header like delete. HOW DO YOU set/add/remove a style on a particular cell of the header table of a PagingScrollTable? THANK YOU .gwt-ScrollTable .headerTable td { border-left: 1px solid #CCCCCC; border-right: 1px solid #CCCCCC; border-bottom: 1px solid black; vertical-align: bottom; cursor: pointer; }

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  • classes and static variables in shared libraries

    - by abel
    I am trying to write something in c++ with an architecture like: App -- Core (.so) <-- Plugins (.so's) for linux, mac and windows. The Core is implicitly linked to App and Plugins are explicitly linked with dlopen/LoadLibrary to App. The problem I have: static variables in Core are duplicated at run-time -- Plugins and App have different copys of them. at least on mac, when a Plugin returns a pointer to App, dynamic casting that pointer in App always result in NULL. Can anyone give me some explanations and instructions for different platforms please? I know this may seem lazy to ask them all here but I really cannot find a systematic answer to this question.

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  • Objective-C getter/ setter question

    - by pic-o-matic
    Hi, im trying to works my way trough an Objective-C tutorial. In the book there is this example: @interface { int width; int height; XYPoint *origin; } @property int width, height; I though, hey there's no getter/setter for the XYPoint object. The code does work though. Now i'm going maybe to answer my own question :). I thinks its because "origin" is a pointer already, and whats happening under the hood with "width" and "height", is that there is going te be created a pointer to them.. Am i right, or am i talking BS :) ??

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  • Any Win32 APIs to get the screenshots?

    - by Microkernel
    Hi all, I am writing an app, which needs to take the screen shots automatically (just like pressing PrintScreen button). So please suggest me how to get this done. A raw 24 bit BMP image would suffice. PLEASE NOTE: My app is in C, so any win32 APIs that can be called from my code is what I am looking for. (Sometimes back I had got an example code from codeproject which used to get the screen shots but the mouse pointer user to blink when the screen shot is taken. As multiple shots are taken this looks irritating to the user, so I don't want the mouse pointer to blink!) Regards, Chethan KR

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  • Memory cleanup on returned array from static method (objective-c)

    - by Michael Bordelon
    In objective-c, I have a utility class with a bunch of static methods that I call for various tasks. As an example, I have one method that returns an NSArray that I allocate in the static method. If I set the NSArray to autorelease, then some time later, the NSArray in my calling method (that is assigned to the returned pointer) losses it's reference because the original form the static method is cleaned up. I can't release the NSArray object in the static method because it needs to be around for the return and assignment. What is the right way to return an object (like the NSArray) from a static class, and have it hang around for the calling class, but then get cleaned up later when it is no longer needed? Do I have to create the object first in the caller and pass in a pointer to the object and then return that same object form the static method? I know this is a basic O-O problem, I just never had this issue in Java and I do not do much C/C++. Thanks for your help.

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  • How to achieve Bing maps like InfoWindow in Google Maps?

    - by BillB
    I'm using Google Maps v3. I really like the InfoWindows found in Bing, as opposed to Google. Screenshots & functionality found here comparing the two: http://www.axismaps.com/blog/2009/07/data-probing-and-info-window-design-on-web-based-maps/ Question: How can I replicate Bing like InfoWindows while using Google Maps v3? UPDATE: To be more specific, what I like about Bing's InfoWindows include: - The pointer dynamically changes sides from left/right/bottom/top, as opposed to Google limited to only have the InfoWindow pointer on the bottom - Bing's InfoWindows use less space - You can configure Bing's InfoWindows to pop up outside of the map bounders so that you don't have to autopan the map to display the marker's InfoWindow

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  • Smart pointers and polymorphism

    - by qwerty
    hello. I implemented reference counting pointers (called SP in the example) and im having problems with polymorphism which i think i shouldn't have. In the following code: SP<BaseClass> foo() { // Some logic... SP<DerivedClass> retPtr = new DerivedClass(); return retPtr; } DerivedClass inherits from BaseClass. With normal pointers this should have worked, but with the smart pointers it says "cannot convert from 'SP<T>' to 'const SP<T>&" and i think it refers to the copy constructor of the smart pointer. How to i allow this kind of polymorphism with reference counting pointer? I'd appreciate code samples cause obviously im doing something wrong here if im having this problem. Thanks! :) [p.s., plz don't tell me to use standart liberary with smart pointers cuz that's impossible at this moment.]

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  • ASP.NET MVC and ApplicationPath

    - by user93422
    Question is about paths and domains: I have an out-of-the box ASP.NET MVC project (generated by "File-New Project"). On LogOn page it does: return Redirect("~/Account/LogOn");. I have a domain name: mycompany.com, and following file structure on the server: /Root /MyApp (this is where my app goes into) Default.aspx ... I have set up following domain pointer: mycompany.com -> \MyApp When I go to mycompany.com I get an error, something about can't find mycompany.com/MyApp/MyApp/Account/LogOn Question: Where does second /MyApp path element comes from? Note: If I don't use domain pointer and deploy the site to the root - everything works just fine. Note: My hosting provider is webhost4life.com.

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  • May volatile be in user defined types to help writing thread-safe code

    - by David Rodríguez - dribeas
    I know, it has been made quite clear in a couple of questions/answers before, that volatile is related to the visible state of the c++ memory model and not to multithreading. On the other hand, this article by Alexandrescu uses the volatile keyword not as a runtime feature but rather as a compile time check to force the compiler into failing to accept code that could be not thread safe. In the article the keyword is used more like a required_thread_safety tag than the actual intended use of volatile. Is this (ab)use of volatile appropriate? What possible gotchas may be hidden in the approach? The first thing that comes to mind is added confusion: volatile is not related to thread safety, but by lack of a better tool I could accept it. Basic simplification of the article: If you declare a variable volatile, only volatile member methods can be called on it, so the compiler will block calling code to other methods. Declaring an std::vector instance as volatile will block all uses of the class. Adding a wrapper in the shape of a locking pointer that performs a const_cast to release the volatile requirement, any access through the locking pointer will be allowed. Stealing from the article: template <typename T> class LockingPtr { public: // Constructors/destructors LockingPtr(volatile T& obj, Mutex& mtx) : pObj_(const_cast<T*>(&obj)), pMtx_(&mtx) { mtx.Lock(); } ~LockingPtr() { pMtx_->Unlock(); } // Pointer behavior T& operator*() { return *pObj_; } T* operator->() { return pObj_; } private: T* pObj_; Mutex* pMtx_; LockingPtr(const LockingPtr&); LockingPtr& operator=(const LockingPtr&); }; class SyncBuf { public: void Thread1() { LockingPtr<BufT> lpBuf(buffer_, mtx_); BufT::iterator i = lpBuf->begin(); for (; i != lpBuf->end(); ++i) { // ... use *i ... } } void Thread2(); private: typedef vector<char> BufT; volatile BufT buffer_; Mutex mtx_; // controls access to buffer_ };

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  • How do I specify the block object / predicate required by NSDictionary's keysOfEntriesPassingTest ?

    - by Todd
    For learning (not practical -- yet) purposes, I'd like to use the following method on an NSDictionary to give me back a set of keys that have values using a test I've defined. Unfortunately have no idea how to specify the predicate. NSDictionary keysOfEntriesPassingTest: - (NSSet *)keysOfEntriesPassingTest:(BOOL (^)(id key, id obj, BOOL *stop))predicate Let's say for example all my values are NSURLs, and I'd like to get back all the URLs that are on port 8080. Here's my stab at coding that -- though it doesn't really make sense to me that it'd be correct: NSSet * mySet = [myDict keysOfEntriesPassingTest:^(id key, id obj, BOOL *stop) { if( [[obj port] isEqual: [NSNumber numberWithInt: 8080]]) { return key; }] And that's because I get back the following compiler error: incompatible block pointer types initializing 'void (^)(struct objc_object *, struct objc_object *, BOOL *)', expected 'BOOL (^)(struct objc_object *, struct objc_object *, BOOL *)' What am I missing? I'd appreciate a pointer at some docs that go into more detail about the "Block object" that the predicate is supposed to be. Thanks!

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  • Objective-C : Member variable is losing reference between method calls.

    - by Winston
    Hello, I've been having with an objective-c class which appears to be losing its pointer reference between methods of the same class. In the MyTableViewController.h file, I declare: @interface SettingsTableViewController : UITableViewController <UITextFieldDelegate>{ OCRAppDelegate *delegate; } MyTableViewController.m file - (id) init { self = [ super initWithStyle: UITableViewStyleGrouped ]; delegate = [(OCRAppDelegate *)[[UIApplication sharedApplication] delegate] retain]; } The problem is when the "MyTableViewController" view appears again and a different method is executed within that same class, the delegate pointer (which was assigned during the init method) is no longer there. I tried to retain, but to no avail. Would anyone know why this is, it seems like perhaps it is a fundamental Objective-C issue which I am missing. Appreciate your help. Thanks, Winston

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  • How to improve this piece of code

    - by user303518
    Can anyone help me on this. It may be very frustrating for you all. But I want you guys to take a moment to look at the code below and please tell me all the things that are wrong in the below piece of code. You can copy it into your visual studio to analyze this better. You don’t have to make this code compile. My task is to get the following things: Most obvious mistakes with this code All the things that are wrong/bad practices with the code below Modify/Write an optimized version of this code. Keep in mind, the code DOES NOT need to compile. Reduce the number of lines of code You should NEVER try to implement something like below: public List<ValidationErrorDto> ProcessEQuote(string eQuoteXml, long programUniversalID) { // Get Program Info. DataTable programs = GetAllPrograms(); DataRow[] programRows = programs.Select(string.Format("ProgramUniversalID = {0}", programUniversalID)); long programID = (long)programRows[0]["ProgramID"]; string programName = (string)programRows[0]["Description"]; // Get Config file values. string fromEmail = ConfigurationManager.AppSettings["eQuotesFromEmail"]; string technicalSupportPhone = ConfigurationManager.AppSettings["TechnicalSupportPhone"]; string fromEmailDisplayName = string.IsNullOrEmpty(ConfigurationManager.AppSettings["eQuotesFromDisplayName"]) ? null : string.Format(ConfigurationManager.AppSettings["eQuotesFromDisplayName"], programName); string itEmail = !string.IsNullOrEmpty(ConfigurationManager.AppSettings["ITEmail"]) ? ConfigurationManager.AppSettings["ITEmail"] : string.Empty; string itName = !string.IsNullOrEmpty(ConfigurationManager.AppSettings["ITName"]) ? ConfigurationManager.AppSettings["ITName"] : "IT"; try { List<ValidationErrorDto> allValidationErrors = new List<ValidationErrorDto>(); List<ValidationErrorDto> validationErrors = new List<ValidationErrorDto>(); if (validationErrors.Count == 0) { validationErrors.AddRange(ValidateEQuoteXmlAgainstSchema(eQuoteXml)); if (validationErrors.Count == 0) { XmlDocument eQuoteXmlDoc = new XmlDocument(); eQuoteXmlDoc.LoadXml(eQuoteXml); XmlElement rootElement = eQuoteXmlDoc.DocumentElement; XmlNodeList quotesList = rootElement.SelectNodes("Quote"); foreach (XmlNode node in quotesList) { // Each node should be a quote node but to be safe, check if (node.Name == "Quote") { string groupName = node.SelectSingleNode("Group/GroupName").InnerText; string groupCity = node.SelectSingleNode("Group/GroupCity").InnerText; string groupPostalCode = node.SelectSingleNode("Group/GroupZipCode").InnerText; string groupSicCode = node.SelectSingleNode("Group/GroupSIC").InnerText; string generalAgencyLicenseNumber = node.SelectSingleNode("Group/GALicenseNbr").InnerText; string brokerName = node.SelectSingleNode("Group/BrokerName").InnerText; string deliverToEmailAddress = node.SelectSingleNode("Group/ReturnEmailAddress").InnerText; string brokerEmail = node.SelectSingleNode("Group/BrokerEmail").InnerText; string groupEligibleEmployeeCountString = node.SelectSingleNode("Group/GroupNbrEmployees").InnerText; string quoteEffectiveDateString = node.SelectSingleNode("Group/QuoteEffectiveDate").InnerText; string salesRepName = node.SelectSingleNode("Group/SalesRepName").InnerText; string salesRepPhone = node.SelectSingleNode("Group/SalesRepPhone").InnerText; string salesRepEmail = node.SelectSingleNode("Group/SalesRepEmail").InnerText; string brokerLicenseNumber = node.SelectSingleNode("Group/BrokerLicenseNbr").InnerText; DateTime? quoteEffectiveDate = null; int eligibleEmployeeCount = int.Parse(groupEligibleEmployeeCountString); DateTime quoteEffectiveDateOut; if (!DateTime.TryParse(quoteEffectiveDateString, out quoteEffectiveDateOut)) validationErrors.Add(ValidationHelper.CreateValidationError((long)QuoteField.EffectiveDate, "Quote Effective Date", ValidationErrorDto.ValueOutOfRange, false, ValidationHelper.CreateValidationContext(Entity.QuoteDetail, "Quote"))); else quoteEffectiveDate = quoteEffectiveDateOut; Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); if (string.IsNullOrEmpty(Resources.ParameterMessageKeys.ResourceManager.GetString("GroupName"))) throw new InvalidOperationException("GroupName key is not configured"); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, groupName); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepName, salesRepName); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepPhone, salesRepPhone); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepEmail, salesRepEmail); replacementCodeValues.Add(Resources.ParameterMessageKeys.TechnicalSupportPhone, technicalSupportPhone); replacementCodeValues.Add(Resources.ParameterMessageKeys.EligibleEmployeCount, eligibleEmployeeCount.ToString()); // Retrieve the CityID and StateID long? cityID = null; long? stateID = null; DataSet citiesAndStates = Addresses.GetCitiesAndStatesFromPostalCode(groupPostalCode); DataTable cities = citiesAndStates.Tables[0]; DataTable states = citiesAndStates.Tables[1]; DataRow[] cityRows = cities.Select(string.Format("Name = '{0}'", groupCity)); if (cityRows.Length > 0) { cityID = (long)cityRows[0]["CityID"]; DataRow[] stateRows = states.Select(string.Format("CityID = {0}", cityID)); if (stateRows.Length > 0) stateID = (long)stateRows[0]["StateID"]; } // If the StateID does not exist, then we cannot get the GeneralAgency, so set a validation error and do not contine. // Else, Continue and look for an General Agency. If a GA was found, look for or create a Broker. Then look for or create a Prospect Group // Then using the info, create a quote. if (!stateID.HasValue) validationErrors.Add(ValidationHelper.CreateValidationError((long)ProspectGroupField.State, "Prospect Group State", ValidationErrorDto.RequiredFieldMissing, false, ValidationHelper.CreateValidationContext(Entity.ProspectGroup, "Prospect Group"))); bool brokerValidationError = false; SalesRepDto salesRep = GetSalesRepByEmail(salesRepEmail, ref validationErrors); if (salesRep == null) { string exceptionMessage = "Sales Rep Not found in Opportunity System. Please make sure Sales Rep is present in the system by adding the sales rep in AWP SR Add Screen." + Environment.NewLine; exceptionMessage = exceptionMessage + " Sales Rep Name: " + salesRepName + Environment.NewLine; exceptionMessage = exceptionMessage + " Sales Rep Email: " + salesRepEmail + Environment.NewLine; exceptionMessage = exceptionMessage + " Module : E-Quote Service" + Environment.NewLine; throw new Exception(exceptionMessage); } if (validationErrors.Count == 0) { // Note that StateID and EffectiveDate should be valid at this point. If it weren't there would be validation errors. // Find General Agency long? generalAgencyID; validationErrors.AddRange(GetEQuoteGeneralAgency(generalAgencyLicenseNumber, stateID.Value, out generalAgencyID)); // If GA was found, check for Broker. if (validationErrors.Count == 0 && generalAgencyID.HasValue) { Dictionary<string, string> brokerNameParts = ContactHelper.GetNamePartsFromFullName(brokerName); long? brokerID; validationErrors.AddRange(CreateEQuoteBroker(brokerNameParts["FirstName"], brokerNameParts["LastName"], brokerEmail, brokerLicenseNumber, stateID.Value, generalAgencyID.Value, salesRep, programID, out brokerID)); // If Broker was found but had validation errors if (validationErrors.Count > 0) { DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteBrokerValidationFailureMessageEmail, replacementCodeValues); brokerValidationError = true; } // If Broker was found, check for Prospect Group if (validationErrors.Count == 0 && brokerID.HasValue) { long? prospectGroupID; validationErrors.AddRange(CreateEQuoteProspectGroup(groupName, cityID, stateID, groupPostalCode, groupSicCode, brokerID.Value, out prospectGroupID)); if (validationErrors.Count == 0 && prospectGroupID.HasValue) { if (validationErrors.Count == 0) { long? quoteID; validationErrors.AddRange(CreateEQuote(programID, prospectGroupID.Value, generalAgencyID.Value, quoteEffectiveDate.Value, eligibleEmployeeCount, deliverToEmailAddress, node.SelectNodes("Employees/Employee"), deliverToEmailAddress, out quoteID)); if (validationErrors.Count == 0 && quoteID.HasValue) { QuoteFromServiceDto quoteFromService = GetQuoteByQuoteID(quoteID.Value); // Generate Pre-Message replacementCodeValues.Add(Resources.ParameterMessageKeys.QuoteNumber, string.Format("{0}.{1}", quoteFromService.QuoteNumber, quoteFromService.QuoteVersion)); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); replacementCodeValues.Add(Resources.ParameterMessageKeys.LicenseNumbers, brokerLicenseNumber); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, deliverToEmailAddress, DocumentType.EQuotePreMessageEmail, replacementCodeValues); bool quoteGenerated = false; try { quoteGenerated = GenerateAndDeliverInitialQuote(quoteID.Value); } catch (Exception exception) { TraceLogger.LogException(exception, LoggingCategory); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = itName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Errors)) replacementCodeValues[Resources.ParameterMessageKeys.Errors] = string.Format("Errors:\r\n:{0}", exception); else replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("Errors:\r\n:{0}", exception)); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); } if (!quoteGenerated) { // Generate System Failure Message if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = brokerName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Errors)) replacementCodeValues[Resources.ParameterMessageKeys.Errors] = string.Empty; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Empty); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); } } } } } } } //if (validationErrors.Count > 0) // Per spec, if Broker Validation returned an error we already sent an email, don't send another generic one if (validationErrors.Count > 0 && (!brokerValidationError)) { StringBuilder errorString = new StringBuilder(); foreach (ValidationErrorDto validationError in validationErrors) errorString = errorString.AppendLine(string.Format(" - {0}", ValidationHelper.GetValidationErrorReason(validationError, true))); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, errorString.ToString()); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = brokerName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); // HACK: If there is no effective date, then use Today's date. Do we care about the effecitve dat on validation message? if (quoteEffectiveDate.HasValue) DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteValidationFailureMessageEmail, replacementCodeValues); else DeliverEmailMessage(programID, DateTime.Now, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteValidationFailureMessageEmail, replacementCodeValues); } allValidationErrors.AddRange(validationErrors); validationErrors.Clear(); } } } else { // Use todays date as the effective date. Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); StringBuilder errorString = new StringBuilder(); foreach (ValidationErrorDto validationError in validationErrors) errorString = errorString.AppendLine(string.Format(" - {0}", ValidationHelper.GetValidationErrorReason(validationError, true))); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("The following validation errors occurred: \r\n{0}", errorString)); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, "Group"); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); DeliverEmailMessage(programID, DateTime.Now, fromEmail, null, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); allValidationErrors.AddRange(validationErrors); validationErrors.Clear(); } } return allValidationErrors; } catch (Exception exception) { TraceLogger.LogException(exception, LoggingCategory); // Use todays date as the effective date. Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, "Group"); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("Errors:\r\n:{0}", exception)); DeliverEmailMessage(programID, DateTime.Now, fromEmail, null, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); throw new FaultException(exception.ToString()); } }

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  • How to create a container that holds different types of function pointers in C++?

    - by Alex
    I'm doing a linear genetic programming project, where programs are bred and evolved by means of natural evolution mechanisms. Their "DNA" is basically a container (I've used arrays and vectors successfully) which contain function pointers to a set of functions available. Now, for simple problems, such as mathematical problems, I could use one type-defined function pointer which could point to functions that all return a double and all take as parameters two doubles. Unfortunately this is not very practical. I need to be able to have a container which can have different sorts of function pointers, say a function pointer to a function which takes no arguments, or a function which takes one argument, or a function which returns something, etc (you get the idea)... Is there any way to do this using any kind of container ? Could I do that using a container which contains polymorphic classes, which in their turn have various kinds of function pointers? I hope someone can direct me towards a solution because redesigning everything I've done so far is going to be painful.

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  • How does void QTableWidget::setItemPrototype ( const QTableWidgetItem * item ) clones objects?

    - by chappar
    QTableWidget::setItemPrototype says following. "The table widget will use the item prototype clone function when it needs to create a new table item. For example when the user is editing in an empty cell. This is useful when you have a QTableWidgetItem subclass and want to make sure that QTableWidget creates instances of your subclass." How does this actually work as you can pass any of the QTableWidgetItem subclass pointer to setItemPrototype and at run time there is no way you can get the size of an object having just pointer to it?

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  • Exception_Record in python2.5 problem

    - by amir
    I'm using Python2.5 & the following code produce 2 errors. Can any body help me? class EXCEPTION_RECORD(Structure): _fields_ = [ ("ExceptionCode", DWORD), ("ExceptionFlags", DWORD), ("ExceptionRecord", POINTER(EXCEPTION_RECORD)), ("ExceptionAddress", LPVOID), ("NumberParameters", DWORD), ("ExceptionInformation", ULONG_PTR * EXCEPTION_MAXIMUM_PARAMETERS)] Python Error: Traceback (most recent call last): File "E:\Python25\my_debugger_defines.py", line 70, in <module> class EXCEPTION_RECORD(Structure): File "E:\Python25\my_debugger_defines.py", line 74, in EXCEPTION_RECORD ("ExceptionRecord", POINTER(EXCEPTION_RECORD)), NameError: name 'EXCEPTION_RECORD' is not defined Microsoft Document: The EXCEPTION_RECORD structure describes an exception. typedef struct _EXCEPTION_RECORD { // exr DWORD ExceptionCode; DWORD ExceptionFlags; struct _EXCEPTION_RECORD *ExceptionRecord; PVOID ExceptionAddress; DWORD NumberParameters; DWORD ExceptionInformation[EXCEPTION_MAXIMUM_PARAMETERS]; } EXCEPTION_RECORD; Thanks in advance

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  • VIrtual class problem

    - by ugur
    What i think about virtual class is, if a derived class has a public base, let's say, class base, then a pointer to derived can be assigned to a variable of type pointer to base without use of any explicit type conversion. But what if, we are inside of base class then how can we call derived class's functions. I will give an example: class Graph{ public: Graph(string); virtual bool addEdge(string,string); } class Direct:public Graph{ public: Direct(string); bool addEdge(string,string); } Direct::Direct(string filename):Graph(filename){}; When i call constructor of Direct class then it calls Graph. Now lets think Graph function calls addedge. Graph(string str){ addedge(str,str); } When it calls addedge, even if the function is virtual, it calls Graph::edge. What i want is, to call Direct::addedge. How can it be done?

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  • Virtual class problem

    - by ugur
    What i think about virtual class is, if a derived class has a public base, let's say, class base, then a pointer to derived can be assigned to a variable of type pointer to base without use of any explicit type conversion. But what if, we are inside of base class then how can we call derived class's functions. I will give an example: class Graph{ public: Graph(string); virtual bool addEdge(string,string); } class Direct:public Graph{ public: Direct(string); bool addEdge(string,string); } Direct::Direct(string filename):Graph(filename){}; When i call constructor of Direct class then it calls Graph. Now lets think Graph function calls addedge. Graph(string str){ addedge(str,str); } When it calls addedge, even if the function is virtual, it calls Graph::edge. What i want is, to call Direct::addedge. How can it be done?

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  • While loop in IL - why stloc.0 and ldloc.0?

    - by Michael Stum
    I'm trying to understand how a while loop looks in IL. I have written this C# function: static void Brackets() { while (memory[pointer] > 0) { // Snipped body of the while loop, as it's not important } } The IL looks like this: .method private hidebysig static void Brackets() cil managed { // Code size 37 (0x25) .maxstack 2 .locals init ([0] bool CS$4$0000) IL_0000: nop IL_0001: br.s IL_0012 IL_0003: nop // Snipped body of the while loop, as it's not important IL_0011: nop IL_0012: ldsfld uint8[] BFHelloWorldCSharp.Program::memory IL_0017: ldsfld int16 BFHelloWorldCSharp.Program::pointer IL_001c: ldelem.u1 IL_001d: ldc.i4.0 IL_001e: cgt IL_0020: stloc.0 IL_0021: ldloc.0 IL_0022: brtrue.s IL_0003 IL_0024: ret } // end of method Program::Brackets For the most part this is really simple, except for the part after cgt. What I don't understand is the local [0] and the stloc.0/ldloc.0. As far as I see it, cgt pushes the result to the stack, stloc.0 gets the result from the stack into the local variable, ldloc.0 pushes the result to the stack again and brtrue.s reads from the stack. What is the purpose of doing this? Couldn't this be shortened to just cgt followed by brtrue.s?

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  • Objective-C member variable assignment?

    - by Alex
    I have an objective-c class with member variables. I am creating getters and setters for each one. Mostly for learning purposes. My setter looks like the following: - (void) setSomething:(NSString *)input { something = input; } However, in C++ and other languages I have worked with in the past, you can reference the member variable by using the this pointer like this->something = input. In objective-c this is known as self. So I was wondering if something like that is possible in objective-c? Something like this: - (void) setSomething:(NSString *)input { [self something] = input; } But that would call the getter for something. So I'm not sure. So my question is: Is there a way I can do assignment utilizing the self pointer? If so, how? Is this good practice or is it evil? Thanks!

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  • C++: How to build an events / messaging system without void pointers?

    - by Jarx
    I'd like to have a dynamic messaging system in my C++ project, one where there is a fixed list of existing events, events can be triggered anywhere during runtime, and where you can subscribe callback functions to certain events. There should be an option for arguments passed around in those events. For example, one event might not need any arguments (EVENT_EXIT), and some may need multiple ones (EVENT_PLAYER_CHAT: Player object pointer, String with message) The first option for making this possible is allowing to pass a void pointer as argument to the event manager when triggering an event, and receiving it in the callback function. Although: I was told that void pointers are unsafe and I shouldn't use them. How can I keep (semi) dynamic argument types and counts for my events whilst not using void pointers?

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  • const correctness

    - by ra170
    I was going through: C++ FAQs about inheritance and decided to implement it (just to learn it) #include "Shape.h" void Shape::print() const { float a = this->area(); // area() is pure virtual ... } now, everything (well, almost) works as described in item: faq:23.1 except that print() is const and so it can't access the "this" pointer, as soon as you take out const, it works. Now, C++ FAQs have been around for a while and are usually pretty good. Is this a mistake? Do they have typo or am I wrong? If I'm wrong, I would like to know how is it possible to access the "this" pointer in a const function.

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  • C: How come an array's address is equal to its value?

    - by Alexandre
    In the following bit of code, pointer values and pointer addresses differ as expected. But array values and addresses don't! How can this be? Output my_array = 0022FF00 &my_array = 0022FF00 pointer_to_array = 0022FF00 &pointer_to_array = 0022FEFC ... #include <stdio.h> int main() { char my_array[100] = "some cool string"; printf("my_array = %p\n", my_array); printf("&my_array = %p\n", &my_array); char *pointer_to_array = my_array; printf("pointer_to_array = %p\n", pointer_to_array); printf("&pointer_to_array = %p\n", &pointer_to_array); printf("Press ENTER to continue...\n"); getchar(); return 0; }

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  • Question about member function pointers in a heirarchy

    - by Jesse Beder
    I'm using a library that defines an interface: template<class desttype> void connect(desttype* pclass, void (desttype::*pmemfun)()); and I have a small heirarchy class base { void foo(); }; class derived: public base { ... }; In a member function of derived, I want to call connect(this, &derived::foo); but it seems that &derived::foo is actually a member function pointer of base; gcc spits out error: no matching function for call to ‘connect(derived* const&, void (base::* const&)())’ I can get around this by explicitly casting this to base *; but why can't the compiler match the call with desttype = base (since derived * can be implicitly cast to base *)? Also, why is &derived::foo not a member function pointer of derived?

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  • C++: set of C-strings

    - by Nicholas
    I want to create one so that I could check whether a certain word is in the set using set::find However, C-strings are pointers, so the set would compare them by the pointer values by default. To function correctly, it would have to dereference them and compare the strings. I could just pass the constructor a pointer to the strcmp() function as a comparator, but this is not exactly how I want it to work. The word I might want to check could be part of a longer string, and I don't want to create a new string due to performance concerns. If there weren't for the set, I would use strncmp(a1, a2, 3) to check the first 3 letters. In fact, 3 is probably the longest it could go, so I'm fine with having the third argument constant. Is there a way to construct a set that would compare its elements by calling strncmp()? Code samples would be greatly appreciated.

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  • Virtual Function Implementation

    - by Gokul
    Hi, I have kept hearing this statement. Switch..Case is Evil for code maintenance, but it provides better performance(since compiler can inline stuffs etc..). Virtual functions are very good for code maintenance, but they incur a performance penalty of two pointer indirections. Say i have a base class with 2 subclasses(X and Y) and one virtual function, so there will be two virtual tables. The object has a pointer, based on which it will choose a virtual table. So for the compiler, it is more like switch( object's function ptr ) { case 0x....: X->call(); break; case 0x....: Y->call(); }; So why should virtual function cost more, if it can get implemented this way, as the compiler can do the same in-lining and other stuff here. Or explain me, why is it decided not to implement the virtual function execution in this way? Thanks, Gokul.

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