Search Results

Search found 8397 results on 336 pages for 'implementation'.

Page 202/336 | < Previous Page | 198 199 200 201 202 203 204 205 206 207 208 209  | Next Page >

  • Why do C++ streams use char instead of unsigned char?

    - by Johannes Schaub - litb
    I've always wondered why the C++ Standard library has instantiated basic_[io]stream and all its variants using the char type instead of the unsigned char type. char means (depending on whether it is signed or not) you can have overflow and underflow for operations like get(), which will lead to implementation-defined value of the variables involved. Another example is when you want to output a byte, unformatted, to an ostream using its put function. Any ideas? Note: I'm still not really convinced. So if you know the definitive answer, you can still post it indeed.

    Read the article

  • How to give a timeout to an FTP connection

    - by dierre
    The story behind: Old script written in ruby 1.8.6 that opens a connection to a ftp and download a configuration file. For a specific client with a windows ftp server the script just hangs. The log stops writing after it opens the connection to the ftp. It's an old script, it's in ruby and I'm not an expert on it. What I tried: So I tried this implementation of a timeout to check if an ftp connection hangs out with this code Timeout::timeout(5) { ftp = Net::FTP.new(host,pass,host) } The problem is that this isn't working. My guess is that the interpreter stops on opening the connection and the timeout doesn't kill the connection because the interpreter is stuck. Is it possible that that's the problem? Could you tell me if there is maybe an alternative solution or if I'm doing something wrong?

    Read the article

  • CUDA small kernel 2d convolution - how to do it

    - by paulAl
    I've been experimenting with CUDA kernels for days to perform a fast 2D convolution between a 500x500 image (but I could also vary the dimensions) and a very small 2D kernel (a laplacian 2d kernel, so it's a 3x3 kernel.. too small to take a huge advantage with all the cuda threads). I created a CPU classic implementation (two for loops, as easy as you would think) and then I started creating CUDA kernels. After a few disappointing attempts to perform a faster convolution I ended up with this code: http://www.evl.uic.edu/sjames/cs525/final.html (see the Shared Memory section), it basically lets a 16x16 threads block load all the convolution data he needs in the shared memory and then performs the convolution. Nothing, the CPU is still a lot faster. I didn't try the FFT approach because the CUDA SDK states that it is efficient with large kernel sizes. Whether or not you read everything I wrote, my question is: how can I perform a fast 2D convolution between a relatively large image and a very small kernel (3x3) with CUDA?

    Read the article

  • Standard Workflow when working with JPA

    - by jschoen
    I am currently trying to wrap my head around working with JPA. I can't help but feel like I am missing something or doing it the wrong way. It just seems forced so far. What I think I know so far is that their are couple of ways to work with JPA and tools to support this. You can do everything in Java using annotations, and let JPA (whatever implementation you decide to use) create your schema and update it when changes are made. You can use a tool to reverse engineer you database and generate the entity classes for you. When the schema is updated you have to regenerate these classes, or manually update them. There seems to be drawbacks to both, and benefits to both (as with all things). My question is in an ideal situation what is the standard workflow with JPA? Most schemas will require updates during the maintenance phase and especially during the development phase, so how is this handled?

    Read the article

  • How to handle splitting a file under source control?

    - by sharptooth
    I have a .cpp file and .h file containing a class. Class.cpp contains the implementation and Class.h contains the definition. The class is overcomplicated so I want to separate some code and move it into a separate class. So I create NewClass.cpp and NewClass.h and move the code there. How do I handle this when the files are under SVN? I can simply "svn add" the two new files, but then they will appear as new and will have no history. I could instead "svn copy and rename" the two initial files and edit the the two old files and the two new files - then the two new files will have common history. Which approach is better from the point of version control? Should the new files share history with the old files or should they appear as new?

    Read the article

  • Implementing DRY Forms

    - by virtualeyes
    Getting into Play 2.0, overall, blown away, great stuff. Anyway, wondering how one can achieve DRY forms in Play? If you look at the create & edit examples in the Computer Database Sample, you'll see that the form elements are repeated. With just 4 fields (in the sample form), no big deal, but when you're dealing with large, complex forms and/or handling many CRUD models, the duplication becomes a bigger maintenance issue. On the binding end ( form.bindFromRequest and form.fill(Foo) ), the implementation is so elegant for create/edit operations; is there a corresponding solution in the template layer?

    Read the article

  • How can I require an attribute on a class definition?

    - by spoulson
    Is there a way to enforce a compile requirement for certain attributes on a class or interface implementation? For example, let's say my application uses a series of static classes that contain const int resource values. I'd like to decorate the class in a Description attribute to describe its contents. In concept, I'd like to apply this attribute requirement to an interface, then each static class would implement it with its required Description. I could write a run-time check or a unit test to check compliance. But really a compile-time check would be best. Is there such a thing?

    Read the article

  • save and play recorded sound

    - by blacksheep
    i'd like to save and play again this recorded sounds: @interface Recorder : NSObject { NSMutableArray *times; NSMutableArray *samples; } @end @implementation Recorder – (id) init { [super init]; times = [[NSMutableArray alloc] init]; samples = [[NSMutableArray alloc] init]; return self; } – (void) recordSound: (id) someSound { CFAbsoluteTime now = CFAbsoluteTimeGetCurrent(); NSNumber *wrappedTime = [NSNumber numberWithDouble:now]; [times addObject:wrappedTime]; [samples addObject:someSound]; } @end thanx blacksheep

    Read the article

  • Choosing the non-empty Monoid

    - by Nikita Volkov
    I need a function which will choose a non-empty monoid. For a list this will mean the following behaviour: > [1] `mor` [] [1] > [1] `mor` [2] [1] > [] `mor` [2] [2] Now, I've actually implemented it but am wondering wether there exists some standard alternative, because it seems to be a kind of a common case. Unfortunately Hoogle doesn't help. Here's my implementation: mor :: (Eq a, Monoid a) => a -> a -> a mor a b = if a /= mempty then a else b

    Read the article

  • How to handle failure to release a resource which is contained in a smart pointer?

    - by cj
    How should an error during resource deallocation be handled, when the object representing the resource is contained in a shared pointer? Smart pointers are a useful tool to manage resources safely. Examples of such resources are memory, disk files, database connections, or network connections. // open a connection to the local HTTP port boost::shared_ptr<Socket> socket = Socket::connect("localhost:80"); In a typical scenario, the class encapsulating the resource should be noncopyable and polymorphic. A good way to support this is to provide a factory method returning a shared pointer, and declare all constructors non-public. The shared pointers can now be copied from and assigned to freely. The object is automatically destroyed when no reference to it remains, and the destructor then releases the resource. /** A TCP/IP connection. */ class Socket { public: static boost::shared_ptr<Socket> connect(const std::string& address); virtual ~Socket(); protected: Socket(const std::string& address); private: // not implemented Socket(const Socket&); Socket& operator=(const Socket&); }; But there is a problem with this approach. The destructor must not throw, so a failure to release the resource will remain undetected. A common way out of this problem is to add a public method to release the resource. class Socket { public: virtual void close(); // may throw // ... }; Unfortunately, this approach introduces another problem: Our objects may now contain resources which have already been released. This complicates the implementation of the resource class. Even worse, it makes it possible for clients of the class to use it incorrectly. The following example may seem far-fetched, but it is a common pitfall in multi-threaded code. socket->close(); // ... size_t nread = socket->read(&buffer[0], buffer.size()); // wrong use! Either we ensure that the resource is not released before the object is destroyed, thereby losing any way to deal with a failed resource deallocation. Or we provide a way to release the resource explicitly during the object's lifetime, thereby making it possible to use the resource class incorrectly. There is a way out of this dilemma. But the solution involves using a modified shared pointer class. These modifications are likely to be controversial. Typical shared pointer implementations, such as boost::shared_ptr, require that no exception be thrown when their object's destructor is called. Generally, no destructor should ever throw, so this is a reasonable requirement. These implementations also allow a custom deleter function to be specified, which is called in lieu of the destructor when no reference to the object remains. The no-throw requirement is extended to this custom deleter function. The rationale for this requirement is clear: The shared pointer's destructor must not throw. If the deleter function does not throw, nor will the shared pointer's destructor. However, the same holds for other member functions of the shared pointer which lead to resource deallocation, e.g. reset(): If resource deallocation fails, no exception can be thrown. The solution proposed here is to allow custom deleter functions to throw. This means that the modified shared pointer's destructor must catch exceptions thrown by the deleter function. On the other hand, member functions other than the destructor, e.g. reset(), shall not catch exceptions of the deleter function (and their implementation becomes somewhat more complicated). Here is the original example, using a throwing deleter function: /** A TCP/IP connection. */ class Socket { public: static SharedPtr<Socket> connect(const std::string& address); protected: Socket(const std::string& address); virtual Socket() { } private: struct Deleter; // not implemented Socket(const Socket&); Socket& operator=(const Socket&); }; struct Socket::Deleter { void operator()(Socket* socket) { // Close the connection. If an error occurs, delete the socket // and throw an exception. delete socket; } }; SharedPtr<Socket> Socket::connect(const std::string& address) { return SharedPtr<Socket>(new Socket(address), Deleter()); } We can now use reset() to free the resource explicitly. If there is still a reference to the resource in another thread or another part of the program, calling reset() will only decrement the reference count. If this is the last reference to the resource, the resource is released. If resource deallocation fails, an exception is thrown. SharedPtr<Socket> socket = Socket::connect("localhost:80"); // ... socket.reset();

    Read the article

  • ICOmmand - canexecute can not disable Button with image content.

    - by Anish
    Hi , I have a button control in my wpf-mvvm application. I use an ICommand property (defined in viewmodel) to bind the button click event to viewmodel. I have - execute and canexecute parameters for my ICommand implementation (RelayCommand). Even if CanExecute is false...button is not disabled...WHEN button CONTENT is IMAGE But, when button content is text..enable/disable works fine. <Button DockPanel.Dock="Top" Command="{Binding Path=MoveUpCommand}"> <Button.Content> <Image Source="/Resources/MoveUpArrow.png"></Image> </Button.Content> <Style> <Style.Triggers> <Trigger Property="IsEnabled" Value="False"> <Setter Property="Opacity" Value=".5" /> </Trigger> </Style.Triggers> </Style> </Button>

    Read the article

  • Multi-Threaded Application - Help with some pseudo code!!

    - by HonorGod
    I am working on a multi-threaded application and need help with some pseudo-code. To make it simpler for implementation I will try to explain that in simple terms / test case. Here is the scenario - I have an array list of strings (say 100 strings) I have a Reader Class that reads the strings and passes them to a Writer Class that prints the strings to the console. Right now this runs in a Single Thread Model. I wanted to make this multi-threaded but with the following features - Ability to set MAX_READERS Ability to set MAX_WRITERS Ability to set BATCH_SIZE So basically the code should instantiate those many Readers and Writers and do the work in parallel. Any pseudo code will really be helpful to keep me going!

    Read the article

  • How to get at ResourceDictionary style when it is loaded from external xap and assemblies are MEF-fe

    - by user158503
    I've got the following setup: The main application loads a XAP with an IPlugin implementation. The Plugin contains a 'DisplayPanel' that contains a referenced Control with other controls. The DisplayPanel here is simply a container control to show referenced Control. This referenced Control, from an assembly, uses a Style from a ResourceDictionary xaml in this assembly. At least that's what I want to have. The problem is that the referenced Control throws an error: Cannot find a Resource with the Name/Key PlayerPanelGrad [Line: 1500 Position: 127] I've tried to get at the style by referencing the ResourceDictionary through a Merged Resource dictionary reference: <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="TableControls;component/ControlsStyle.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> But that doesn't work. How would you approch this?

    Read the article

  • How do I implement a Google Latitude check-in feature on Windows Mobile?

    - by Carnotaurus
    I hope this is the correct forum. I wish to write a mobile application (MVC 4 mobile app) that extends Google Latitude for Windows Mobile 7 (or version 8 when launched in November). However, according to Google's own website (see http://www.google.com/mobile/latitude/), the check-in feature is not supported on Windows Mobile. So, how would I implement such a feature (not so interested in the UI here) using the technologies that I have mentioned? EDIT The implementation needs to store check-in data against a Google Latitude account.

    Read the article

  • fluent nhibernate not caching queries in asp.net mvc

    - by AWC
    I'm using a fluent nhibernate with asp.net mvc and I not seeing anything been cached when making queries against the database. I'm not currently using an L2 cache implementation. Should I see queries being cached without configuring an out of process L2 cache? Mapping are like this: Table("ApplicationCategories"); Not.LazyLoad(); Cache.ReadWrite().IncludeAll(); Id(x => x.Id); Map(x => x.Name).Not.Nullable(); Map(x => x.Description).Nullable(); Example Criteria: return session .CreateCriteria<ApplicationCategory>() .Add(Restrictions.Eq("Name", _name)) .SetCacheable(true); Everytime I make a request for an application cateogry by name it is hitting the database is this expected behaviour?

    Read the article

  • Build a decision tree for classification of large amount data,using python?

    - by kaushik
    Hi,i am working for speech synthesis.In this i have a large number of pronunciation for each phone i.e alphabet and need to classify them according to few feature such as segment size(int) and alphabet itself(string) into a smaller set suitable for that particular context. For this purpose,i have decided to use decision tree for classification.the data to be parsed is in the S expression format.eg:((question)(LEFTNODE)(RIGHTNODE)). i hav idea for building decision tree for normal buit in type such as list..looking for suggestion for implementation for S expression.. kindly help.. Thanks in advance.. Note:this question may look similar to my prev post,srry if cant giv multiple post.already edited it many times so though of wirting new question instead of editing again

    Read the article

  • How to apply Abstract Factory Pattern ???

    - by Amit
    I am new to Design Pattern and I have a scenario here... and not sure as how to implement the pattern ... We have multiple vendors Philips, Onida... Each vendor (philips, onida...) may have different type of product i.e. Plasma or Normal TV I want specific product of each vendor using Abstract Factory Pattern... Thanks in advance for any help... My implementation so far... public enum TvType { Samsung = 0,LG = 1,Philips = 2, Sony = 3 } public enum Product { Plasma = 0,NormalTV = 1 } concrete class of each vendor.... that returns each product and also the interface that contains ProductInfo i.e. if Vendor is ... then it must have this product....

    Read the article

  • Doxygen comments on declarations or on definitions?

    - by Arkaitz Jimenez
    Just started using Doxygen for documenting my code here and can't decide where to put them. At first look it seems better to put them in the declaration files as it is there where you actually declare what you receive, what you are going to return and stuff like that, apart from that things like data members that are only in the declaration files can obviously only documented there. But often I find handier to comment methods in the implementation files as they are more accessible to me and the declaration file doesn't get cluttered with dozens of lines of comments making it harder to find what you look for when developing. What is your experience with that?

    Read the article

  • Integrating WebSockets with Rails using Rack and Event Machine

    - by Toby Hede
    I have created an Asynchronous version of Rails 3 that I would like to integrate with a WebSocket implementation. I am using EventMachine, Ruby 1.9, Fibers and various em-flavoured libraries as documented by the wickedly good Ilya Grigorik. I have been looking at em-websocket as the handler for WebSocket connections but unsure of the best approach for hooking this into a Rails app. Ideally, this would work in a similar fashion to node.js with Express and Socket.io - incoming connections should be detected and dispatched to the WebSocket handler or the regular rails stack as indicated by the HTTP headers & etc. TL;DR WebSocket handler that plugs into an existing Rails application Transparently dispatch incoming WebSocket requests to endpoints in the app

    Read the article

  • Why should I use MVVM when it breaks built in functionality

    - by Jakob
    I'm struggling to grasp why MVVM is really a good pattern to implement in riaserivces, To me there's nothing but trouble to it, it just add's another tier that I have to code. I Get that I could change the UI, but really I don't need to. Instead i won't be able to user out of the box functionality with riaservices, datagrid, dataform all controls require some implementation. Why can't it just be simple? Is there really no way to get MVVM to automatically set "IsBusy" and all the dataform edit functionality. It's like reinventing the wheel to me, and it seems that I'd be able to write code much faster just using riaservices

    Read the article

  • I'm new to C++. Please Help me with the Linked List (What functions to add)?

    - by Igal
    DEAR All; Hi, I'm just beginner to C++; Please help me to understand: What functions should be in the Linked list class ? I think there should be overloaded operators << and ; Please help me to improve the code (style, errors, etc,) Thanks for advance. Igal. Please review the small code for the integer List (enclosed MyNODE.h and ListDriver1.cpp); MyNODE.h // This is my first attempt to write linked list. Igal Spector, June 2010. #include <iostream.h> #include <assert.h> //Forward Declaration of the classes: class ListNode; class TheLinkedlist; // Definition of the node (WITH IMPLEMENTATION !!!, without test drive): class ListNode{ friend class TheLinkedlist; public: // constructor: ListNode(const int& value, ListNode *next= 0); // note: no destructor, as this handled by TheLinkedList class. // accessor: return data in the node. // int Show() const {return theData;} private: int theData; //the Data ListNode* theNext; //points to the next node in the list. }; //Implementations: //constructor: inline ListNode::ListNode(const int &value,ListNode *next) :theData(value),theNext(next){} //end of ListNode class, now for the LL class: class TheLinkedlist { public: //constructors: TheLinkedlist(); virtual ~TheLinkedlist(); // Accessors: void InsertAtFront(const &); void AppendAtBack(const &); // void InOrderInsert(const &); bool IsEmpty()const;//predicate function void Print() const; private: ListNode * Head; //pointer to first node ListNode * Tail; //pointer to last node. }; //Implementation: //Default constructor inline TheLinkedlist::TheLinkedlist():Head(0),Tail(0) {} //Destructor inline TheLinkedlist::~TheLinkedlist(){ if(!IsEmpty()){ //list is not empty cout<<"\n\tDestroying Nodes"<<endl; ListNode *currentPointer=Head, *tempPtr; while(currentPointer != 0){ //Delete remaining Nodes. tempPtr=currentPointer; cout<<"The node: "<<tempPtr->theData <<" is Destroyed."<<endl<<endl; currentPointer=currentPointer->theNext; delete tempPtr; } Head=Tail = 0; //don't forget this, as it may be checked one day. } } //Insert the Node to the beginning of the list: void TheLinkedlist::InsertAtFront(const int& value){ ListNode *newPtr = new ListNode(value,Head); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty newPtr->theNext = Head; Head = newPtr; } } //Insert the Node to the beginning of the list: void TheLinkedlist::AppendAtBack(const int& value){ ListNode *newPtr = new ListNode(value, NULL); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty Tail->theNext = newPtr; Tail = newPtr; } } //is the list empty? inline bool TheLinkedlist::IsEmpty() const { return (Head == 0); } // Display the contents of the list void TheLinkedlist::Print()const{ if ( IsEmpty() ){ cout << "\n\t The list is empty!!"<<endl; return; } ListNode *tempPTR = Head; cout<<"\n\t The List is: "; while ( tempPTR != 0 ){ cout<< tempPTR->theData <<" "; tempPTR = tempPTR->theNext; } cout<<endl<<endl; } ////////////////////////////////////// The test Driver: //Driver test for integer Linked List. #include <iostream.h> #include "MyNODE.h" // main Driver int main(){ cout<< "\n\t This is the test for integer LinkedList."<<endl; const int arraySize=11, ARRAY[arraySize]={44,77,88,99,11,2,22,204,50,58,12}; cout << "\n\tThe array is: "; //print the numbers. for (int i=0;i<arraySize; i++) cout<<ARRAY[i]<<", "; TheLinkedlist list; //declare the list for(int index=0;index<arraySize;index++) list.AppendAtBack( ARRAY[index] );//create the list cout<<endl<<endl; list.Print(); //print the list return 0; //end of the program. }

    Read the article

  • Does isolation frameworks (Moq, RhinoMock, etc) lead to test overspecification?

    - by Marius
    In Osherove's great book "The Art of Unit Testing" one of the test anti-patterns is over-specification which is basically the same as testing the internal state of the object instead of some expected output. To my experience, using Isolation frameworks can cause the same unwanted side effects as testing internal behavior because one tends to only implement the behavior necessary to make your stub interact with the object under test. Now if your implementation changes later on (but the contract remains the same), your test will suddenly break because you are expecting some data from the stub which was not implemented. So what do you think is the best approach to counter this? 1) Implement your stubs/mocks fully, this has the negative side-effect of potentially making your test less readable and also specifying more than necessary to make your test pass. 2) Favor manual, fully implemented fakes. 3) Implement your stubs/fakes so that they make your test just pass, and then deal with the brittleness that this might introduce.

    Read the article

  • Legality Of Re-Implementing An Existing API (e.g. GNU implementing the UNIX APIs)

    - by splicer
    I've often wondered about this. I'm not looking for legal advice, just casual opinions ;) If some company publishes an API on the web for their closed-source library, would it be legal for another party to release an open-source implementation of that API? Are function declarations considered source code? Take GNU implementing the UNIX APIs, for example. The UNIX standard gives the following function declaration and defines its required behaviour in English: char * mktemp(char *template); Now, consider an API that lists and declares and describes several thousand (more much complex) functions, enums, etc.; an API which defines a solution to a non-trival set of problems. If an open-source project publishes C headers that copy (verbatim) the function definitions contained in the closed-source company's published API, doesn't that violate some sort copyright law?

    Read the article

  • MEMORY(HEAP) vs. InnoDB in a Read and Write Environment

    - by Johannes
    I want to program a real-time application using MySQL. It needs a small table (less than 10000 rows) that will be under heavy read (scan) and write (update and some insert/delete) load. I am really speaking of 10000 updates or selects per second. These statements will be executed on only a few (less than 10) open mysql connections. The table is small and does not contain any data that needs to be stored on disk. So I ask which is faster: InnoDB or MEMORY (HEAP)? My thoughts are: Both engines will probably serve SELECTs directly from memory, as even InnoDB will cache the whole table. What about the UPDATEs? (innodb_flush_log_at_trx_commit?) My main concern is the locking behavior: InnoDB row lock vs. MEMORY table lock. Will this present the bottleneck in the MEMORY implementation? Thanks for your thoughts!

    Read the article

  • Converting between unsigned and signed int safely

    - by polemic
    I have an interface between a client and a server where a client sends (1) an unsigned value, and (2) a flag which indicates if value is signed/unsigned. Server would then static cast unsigned value to appropriate type. I later found out that this is implementation defined behavior and I've been reading about it but I couldn't seem to find an appropriate solution that's completely safe? I've read about type punning, pointer conversions, and memcpy. Would simply using a union type work? A UnionType containing signed and unsigned int, along with the signed/unsigned flag. For signed values, client sets the signed part of the union, and server reads the signed part. Same for the unsigned part. Or am I completely misunderstanding something? Side question: how do I know the specific behavior in this case for a specific scenario, e.g. windriver diab on PPC? I'm a bit lost on how to find such documentation.

    Read the article

< Previous Page | 198 199 200 201 202 203 204 205 206 207 208 209  | Next Page >