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  • Which character is first among 4 characters in c++

    - by Ashiqur Rahman
    In my project I take a string from user and then I need to check if vowels a, e, I, O, U are present. If so, I have to find out which one comes first in the string and which one comes next after that. For example, if a user gave input something like this: char expr[] = "this is for something real"; I comes first, then I again, then O and so on. I checked whether the characters are in the string or not using strchr(expr,'character here'). To find which character comes first, I find the index of each character using const char *ptr = strchr(expr, characters here); if(ptr) { int index = ptr - expr; } After that I check which index is bigger. But this is very long process. Is there a smarter way to do this?

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  • What is better: to delete pointer or set it with a new value?

    - by user63898
    Hi simple question in c++ , say i have a loop and i have function that returns pointer to item so i have to define inner loop pointer so my question is what to do with the pointer inside the loop , delete it ? or to set it with new value is good for example: for(int i =0;i<count();i++) { ptrTmp* ptr = getItemPtr(); // do somthing with the ptr ... // what to do here ? to delete the poinetr or not? delete ptr; // ?? }

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  • function declaration

    - by robUK
    Hello, gcc 4.1.2 c89 I am reviewing some code and I have come across the following function. I have never seen a function declared like this before. There are no data types for the paraemeters. My best guess is that the function is using a list of data types separated by semi-colons. The return type seems to be returning a function with those parameters. However, the read function is not defined anywhere. What is the advantage and purpose of declaring a function like this? Many thanks for any advice, int my_read(fd, ptr, cnt) int fd; char *ptr; unsigned cnt; { printf("Read\n"); return(read(fd, ptr, cnt)); }

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  • Use of Shl in assembly

    - by user3097712
    I have the following piece of lines and I do not understand that. Hope that someone can help me: ..... MOV EAX, DWORD PTR SS:[EBP-0x4] SHL EAX, 0x2 ADD EAX, DWORD PTR SS:[EBP-0x8] PUSH EAX .... Normally, it helps me to translate that into C language. But somehow I cant find a way to do it in that case. So, I only know that in the second line with SHL the register is multiplied by 4. And that the DWORD PTR SS:[EBP-0x4] looks like an array representation but i am not sure. I also find the following link x86 Assembler: shl and other instructions But I dont understand the answer there. So my question would be: What it is going on there? Thx...

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  • in c++ what is bettr to delete poiner or set it with new value?

    - by user63898
    Hi simple question in c++ , say i have a loop and i have function that returns pointer to item so i have to define inner loop pointer so my question is what to do with the pointer inside the loop , delete it ? or to set it with new value is good for example: for(int i =0;i<count();i++) { ptrTmp* ptr = getItemPtr(); // do somthing with the ptr ... // what to do here ? to delete the poinetr or not? delete ptr; // ?? }

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  • JSF 2.0: Preserving component state across multiple views

    - by tlind
    The web application I am developing using MyFaces 2.0.3 / PrimeFaces 2.2RC2 is divided into a content and a navigation area. In the navigation area, which is included into multiple pages using templating (i.e. <ui:define>), there are some widgets (e.g. a navigation tree, collapsible panels etc.) of which I want to preserve the component state across views. For example, let's say I am on the home page. When I navigate to a product details page by clicking on a product in the navigation tree, my Java code triggers a redirect using navigationHandler.handleNavigation(context, null, "/detailspage.jsf?faces-redirect=true") Another way of getting to that details page would be by directly clicking on a product teaser that is shown on the home page. The corresponding <h:link> would lead us to the details page. In both cases, the expansion state of my navigation tree (a PrimeFaces tree component) and my collapsible panels is lost. I understand this is because the redirect / h:link results in the creation of a new view. What is the best way of dealing with this? I am already using MyFaces Orchestra in my project along with its conversation scope, but I am not sure if this is of any help here (since I'd have to bind the expansion/collapsed state of the widgets to a backing bean... but as far as I know, this is not possible). Is there a way of telling JSF which component states to propagate to the next view, assuming that the same component exists in that view? I guess I could need a pointer into the right direction here. Thanks! Update 1: I just tried binding the panels and the tree to a session-scoped bean, but this seems to have no effect. Also, I guess I would have to bind all child components (if any) manually, so this doesn't seem like the way to go. Update 2: Binding UI components to non-request scoped beans is not a good idea (see link I posted in a comment below). If there is no easier approach, I might have to proceed as follows: When a panel is collapsed or the tree is expanded, save the current state in a session-scoped backing bean (!= the UI component itself) The components' states are stored in a map. The map key is the component's (hopefully) unique, relative ID. I cannot use the whole absolute component path here, since the IDs of the parent naming containers might change if the view changes, assuming these IDs are generated programmatically. As soon as a new view gets constructed, retrieve the components' states from the map and apply them to the components. For example, in case of the panels, I can set the collapsed attribute to a value retrieved from my session-scoped backing bean.

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  • Trying to figure out SDL pixel manipulation?

    - by NoobScratcher
    Hello so I've found code that plots a pixel in an SDL Screen Surface : void putpixels(int x, int y, int color) { unsigned int *ptr = (unsigned int*)Screen->pixels; int lineoffset = y * (Screen->pitch / 4 ); ptr[lineoffset + x ] = color; } But I have no idea what its actually doing here this is my thoughts. You make an unsigned integer to hold the unsigned int version of pixels then you make another integer to hold the line offset and it equals to multiply by pitch which is then divided by 4 ... Now why am I dividing it by 4 and what is the pitch and why do I multiply it?? Why must I change the lineoffset and add it to the x value then equal it to colors? I'm soo confused.. ;/ I found this function here - http://sol.gfxile.net/gp/ch02.html

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  • How do I create a curved line or filled circle or generally a circle using C++/SDL?

    - by NoobScratcher
    Hello I've been trying for ages to make a pixel circle using the putpixel function provided by SDL main website here is that function : void putpixel(int x,int y , int color , SDL_Surface* surface) { unsigned int *ptr = static_cast <unsigned int *> (surface->pixels); int offset = y * (surface->pitch/sizeof(unsigned int)); ptr[offset + x] = color; } and my question is how do I curve a line or create an circle arc of pixels or any other curved shape then a rectangle or singular pixel or line. for example here are some pictures filled pixel circle below enter link description here now my idea was too change the x and y value of the pixel position using + and - to create the curves but in practice didn't provide the correct results what my results are in this is to be able to create a circle that is made out of pixels only nothing else. thank you for anyone who takes the time to read this question thanks! :D

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  • What is upcasting/downcasting?

    - by acidzombie24
    When learning about polymorphism you commonly see something like this class Base { int prv_member; virtual void fn(){} } class Derived : Base { int more_data; virtual void fn(){} } What is upcasting or downcasting? Is (Derived*)base_ptr; an upcast or downcast? I call it upcast because you are going away from the base into something more specific. Other people told me it is a downcast because you are going down a hierarchy into something specific with the top being the root. But other people seem to call it what i call it. When converting a base ptr to a derived ptr is it called upcasting or downcasting? and if someone can link to an official source or explain why its called that than great.

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  • C++ unmanaged inside winform

    - by Gosso
    First: I am using C# and C++ on windows 7. I have created a basic rendering engine in c++ with directx 10. It works good as a stand alone application. But, when I sending the Form.Handle of a WinForm I want to render inside to the engine it crashes during D3D10CreateDeviceAndSwapChain with the following error: HRESULT: 0x887a0001 (2289696769) Name: DXGI_ERROR_INVALID_CALL I get the handle from the winform during loading of the form. unsafe { void *ptr=m_view.Handle.ToPointer(); uint v = (uint)ptr; lhandle = v.ToString(); };

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  • Unable to launch onscreen keyboard (osk.exe) from a 32-bit process on Win7 x64

    - by Steven Robbins
    90% of the time I am unable to launch osk.exe from a 32bit process on Win7 x64. Originally the code was just using: Process.Launch("osk.exe"); Which won't work on x64 because of the directory virtualization. Not a problem I thought, I'll just disable virtualization, launch the app, and enable it again, which I thought was the correct way to do things. I also added some code to bring the keyboard back up if it has been minimized (which works fine) - the code (in a sample WPF app) now looks as follows: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation;using System.Diagnostics; using System.Runtime.InteropServices; namespace KeyboardTest { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { [DllImport("kernel32.dll", SetLastError = true)] private static extern bool Wow64DisableWow64FsRedirection(ref IntPtr ptr); [DllImport("kernel32.dll", SetLastError = true)] public static extern bool Wow64RevertWow64FsRedirection(IntPtr ptr); private const UInt32 WM_SYSCOMMAND = 0x112; private const UInt32 SC_RESTORE = 0xf120; [DllImport("user32.dll", CharSet = CharSet.Auto)] static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam); private string OnScreenKeyboadApplication = "osk.exe"; public MainWindow() { InitializeComponent(); } private void KeyboardButton_Click(object sender, RoutedEventArgs e) { // Get the name of the On screen keyboard string processName = System.IO.Path.GetFileNameWithoutExtension(OnScreenKeyboadApplication); // Check whether the application is not running var query = from process in Process.GetProcesses() where process.ProcessName == processName select process; var keyboardProcess = query.FirstOrDefault(); // launch it if it doesn't exist if (keyboardProcess == null) { IntPtr ptr = new IntPtr(); ; bool sucessfullyDisabledWow64Redirect = false; // Disable x64 directory virtualization if we're on x64, // otherwise keyboard launch will fail. if (System.Environment.Is64BitOperatingSystem) { sucessfullyDisabledWow64Redirect = Wow64DisableWow64FsRedirection(ref ptr); } // osk.exe is in windows/system folder. So we can directky call it without path using (Process osk = new Process()) { osk.StartInfo.FileName = OnScreenKeyboadApplication; osk.Start(); osk.WaitForInputIdle(2000); } // Re-enable directory virtualisation if it was disabled. if (System.Environment.Is64BitOperatingSystem) if (sucessfullyDisabledWow64Redirect) Wow64RevertWow64FsRedirection(ptr); } else { // Bring keyboard to the front if it's already running var windowHandle = keyboardProcess.MainWindowHandle; SendMessage(windowHandle, WM_SYSCOMMAND, new IntPtr(SC_RESTORE), new IntPtr(0)); } } } } But this code, most of the time, throws the following exception on osk.Start(): The specified procedure could not be found at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo) I've tried putting long Thread.Sleep commands in around the osk.Start line, just to make sure it wasn't a race condition, but the same problem persists. Can anyone spot where I'm doing something wrong, or provide an alternative solution for this? It seems to work fine launching Notepad, it just won't play ball with the onscreen keyboard.

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  • C++ template function specialization using TCHAR on Visual Studio 2005

    - by Eli
    I'm writing a logging class that uses a templatized operator<< function. I'm specializing the template function on wide-character string so that I can do some wide-to-narrow translation before writing the log message. I can't get TCHAR to work properly - it doesn't use the specialization. Ideas? Here's the pertinent code: // Log.h header class Log { public: template <typename T> Log& operator<<( const T& x ); template <typename T> Log& operator<<( const T* x ); template <typename T> Log& operator<<( const T*& x ); ... } template <typename T> Log& Log::operator<<( const T& input ) { printf("ref"); } template <typename T> Log& Log::operator<<( const T* input ) { printf("ptr"); } template <> Log& Log::operator<<( const std::wstring& input ); template <> Log& Log::operator<<( const wchar_t* input ); And the source file // Log.cpp template <> Log& Log::operator<<( const std::wstring& input ) { printf("wstring ref"); } template <> Log& Log::operator<<( const wchar_t* input ) { printf("wchar_t ptr"); } template <> Log& Log::operator<<( const TCHAR*& input ) { printf("tchar ptr ref"); } Now, I use the following test program to exercise these functions // main.cpp - test program int main() { Log log; log << "test 1"; log << L"test 2"; std::string test3( "test3" ); log << test3; std::wstring test4( L"test4" ); log << test4; TCHAR* test5 = L"test5"; log << test4; } Running the above tests reveals the following: // Test results ptr wchar_t ptr ref wstring ref ref Unfortunately, that's not quite right. I'd really like the last one to be "TCHAR", so that I can convert it. According to Visual Studio's debugger, the when I step in to the function being called in test 5, the type is wchar_t*& - but it's not calling the appropriate specialization. Ideas? I'm not sure if it's pertinent or not, but this is on a Windows CE 5.0 device.

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  • 5 Best Practices - Laying the Foundation for WebCenter Projects

    - by Kellsey Ruppel
    Today’s guest post comes from Oracle WebCenter expert John Brunswick. John specializes in enterprise portal and content management solutions and actively contributes to the enterprise software business community and has authored a series of articles about optimal business involvement in portal, business process management and SOA development, examining ways of helping organizations move away from monolithic application development. We’re happy to have John join us today! Maximizing success with Oracle WebCenter portal requires a strategic understanding of Oracle WebCenter capabilities.  The following best practices enable the creation of portal solutions with minimal resource overhead, while offering the greatest flexibility for progressive elaboration. They are inherently project agnostic, enabling a strong foundation for future growth and an expedient return on your investment in the platform.  If you are able to embrace even only a few of these practices, you will materially improve your deployment capability with WebCenter. 1. Segment Duties Around 3Cs - Content, Collaboration and Contextual Data "Agility" is one of the most common business benefits touted by modern web platforms.  It sounds good - who doesn't want to be Agile, right?  How exactly IT organizations go about supplying agility to their business counterparts often lacks definition - hamstrung by ambiguity. Ultimately, businesses want to benefit from reduced development time to deliver a solution to a particular constituent, which is augmented by as much self-service as possible to develop and manage the solution directly. All done in the absence of direct IT involvement. With Oracle WebCenter's depth in the areas of content management, pallet of native collaborative services, enterprise mashup capability and delegated administration, it is very possible to execute on this business vision at a technical level. To realize the benefits of the platform depth we can think of Oracle WebCenter's segmentation of duties along the lines of the 3 Cs - Content, Collaboration and Contextual Data.  All three of which can have their foundations developed by IT, then provisioned to the business on a per role basis. Content – Oracle WebCenter benefits from an extremely mature content repository.  Work flow, audit, notification, office integration and conversion capabilities for documents (HTML & PDF) make this a haven for business users to take control of content within external and internal portals, custom applications and web sites.  When deploying WebCenter portal take time to think of areas in which IT can provide the "harness" for content to reside, then allow the business to manage any content items within the site, using the content foundation to ensure compliance with business rules and process.  This frees IT to work on more mission critical challenges and allows the business to respond in short order to emerging market needs. Collaboration – Native collaborative services and WebCenter spaces are a perfect match for business users who are looking to enable document sharing, discussions and social networking.  The ability to deploy the services is granular and on the basis of roles scoped to given areas of the system - much like the first C “content”.  This enables business analysts to design the roles required and IT to provision with peace of mind that users leveraging the collaborative services are only able to do so in explicitly designated areas of a site. Bottom line - business will not need to wait for IT, but cannot go outside of the scope that has been defined based on their roles. Contextual Data – Collaborative capabilities are most powerful when included within the context of business data.  The ability to supply business users with decision shaping data that they can include in various parts of a portal or portals, just as they would with content items, is one of the most powerful aspects of Oracle WebCenter.  Imagine a discussion about new store selection for a retail chain that re-purposes existing information from business intelligence services about various potential locations and or custom backend systems - presenting it directly in the context of the discussion.  If there are some data sources that are preexisting in your enterprise take a look at how they can be made into discrete offerings within the portal, then scoped to given business user roles for inclusion within collaborative activities. 2. Think Generically, Execute Specifically Constructs.  Anyone who has spent much time around me knows that I am obsessed with this word.  Why? Because Constructs offer immense power - more than APIs, Web Services or other technical capability. Constructs offer organizations the ability to leverage a platform's native characteristics to offer substantial business functionality - without writing code.  This concept becomes more powerful with the additional understanding of the concepts from the platform that an organization learns over time.  Let's take a look at an example of where an Oracle WebCenter construct can substantially reduce the time to get a subscription-based site out the door and into the hands of the end consumer. Imagine a site that allows members to subscribe to specific disciplines to access information and application data around that various discipline.  A space is a collection of secured pages within Oracle WebCenter.  Spaces are not only secured, but also default content stored within it to be scoped automatically to that space. Taking this a step further, Oracle WebCenter’s Activity Stream surfaces events, discussions and other activities that are scoped to the given user on the basis of their space affiliations.  In order to have a portal that would allow users to "subscribe" to information around various disciplines - spaces could be used out of the box to achieve this capability and without using any APIs or low level technical work to achieve this. 3. Make Governance Work for You Imagine driving down the street without the painted lines on the road.  The rules of the road are so ingrained in our minds, we often do not think about the process, but seemingly mundane lane markers are critical enablers. Lane markers allow us to travel at speeds that would be impossible if not for the agreed upon direction of flow. Additionally and more importantly, it allows people to act autonomously - going where they please at any given time. The return on the investment for mobility is high enough for people to buy into globally agreed up governance processes. In Oracle WebCenter we can use similar enablers to lane markers.  Our goal should be to enable the flow of information and provide end users with the ability to arrive at business solutions as needed, not on the basis of cumbersome processes that cannot meet the business needs in a timely fashion. How do we do this? Just as with "Segmentation of Duties" Oracle WebCenter technologies offer the opportunity to compartmentalize various business initiatives from each other within the system due to constructs and security that are available to use within the platform. For instance, when a WebCenter space is created, any content added within that space by default will be secured to that particular space and inherits meta data that is associated with a folder created for the space. Oracle WebCenter content uses meta data to support a broad range of rich ECM functionality and can automatically impart retention, workflow and other policies automatically on the basis of what has been defaulted for that space. Depending on your business needs, this paradigm will also extend to sub sections of a space, offering some interesting possibilities to enable automated management around content. An example may be press releases within a particular area of an extranet that require a five year retention period and need to the reviewed by marketing and legal before release.  The underlying content system will transparently take care of this process on the basis of the above rules, enabling peace of mind over unstructured data - which could otherwise become overwhelming. 4. Make Your First Project Your Second Imagine if Michael Phelps was competing in a swimming championship, but told right before his race that he had to use a brand new stroke.  There is no doubt that Michael is an outstanding swimmer, but chances are that he would like to have some time to get acquainted with the new stroke. New technologies should not be treated any differently.  Before jumping into the deep end it helps to take time to get to know the new approach - even though you may have been swimming thousands of times before. To quickly get a handle on Oracle WebCenter capabilities it can be helpful to deploy a sandbox for the team to use to share project documents, discussions and announcements in an effort to help the actual deployment get under way, while increasing everyone’s knowledge of the platform and its functionality that may be helpful down the road. Oracle Technology Network has made a pre-configured virtual machine available for download that can be a great starting point for this exercise. 5. Get to Know the Community If you are reading this blog post you have most certainly faced a software decision or challenge that was solved on the basis of a small piece of missing critical information - which took substantial research to discover.  Chances were also good that somewhere, someone had already come across this information and would have been excited to share it. There is no denying the power of passionate, connected users, sharing key tips around technology.  The Oracle WebCenter brand has a rich heritage that includes industry-leading technology and practitioners.  With the new Oracle WebCenter brand, opportunities to connect with these experts has become easier. Oracle WebCenter Blog Oracle Social Enterprise LinkedIn WebCenter Group Oracle WebCenter Twitter Oracle WebCenter Facebook Oracle User Groups Additionally, there are various Oracle WebCenter related blogs by an excellent grouping of services partners.

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  • Introduction to WebCenter Personalization: &ldquo;The Conductor&rdquo;

    - by Steve Pepper
    There are some new faces in the town of WebCenter with the latest 11g PS3 release.  A new component has introduced itself as "Oracle WebCenter Personalization", a.k.a WCP, to simplify delivery of a personalized experience and content to end users.  This posting reviews one of the primary components within WCP: "The Conductor". The Conductor: This ain't just an ordinary cloud... One of the founding principals behind WebCenter Personalization was to provide an open client-side API that remains independent of the technology invoking it, in addition to independence from the architecture running it.  The Conductor delivers this, and much, much more. The Conductor is the engine behind WebCenter Personalization that allows flow-based documents, called "Scenarios", to be managed and executed on the server-side through a well published and RESTful api.      The Conductor also supports an extensible model for custom provider integration that can be easily invoked within a Scenario to promote seamless integration with existing business assets. Introducing the Scenario Conductor Scenarios are declarative offline-authored documents using the custom Personalization JDeveloper bundle included with WebCenter.  A Scenario contains one (or more) statements that can: Create variables that are scoped to the current execution context Iterate over collections, or loop until a specific condition is met Execute one or more statements when a condition is met Invoke other scenarios that exist within the same namespace Invoke a data provider that integrates with custom applications Once a variable is assigned within the Scenario's execution context, it can be referenced anywhere within the same Scenario using the common Expression Language syntax used in J2EE web containers. Scenarios are then published and tested to the Integrated WebLogic Server domain, or published remotely to other domains running WebCenter Personalization. Various Client-side Models The Conductor server API is built upon RESTful services that support a wide variety of clients able to communicate over HTTP.  The Conductor supports the following client-side models: REST:  Popular browser-based languages can be used to manage and execute Conductor Scenarios.  There are other public methods to retrieve configured provider metadata that can be used by custom applications. The Conductor currently supports XML and JSON for it's API syntax. Java: WebCenter Personalization delivers a robust and light-weight java client with the popular Jersey framework as it's foundation.  It has never been easier to write a remote java client to manage remote RESTful services. Expression Language (EL): Allow the results of Scenario execution to control your user interface or embed personalized content using the session-scoped managed bean.  The EL client can also be used in straight JSP pages with minimal configuration. Extensible Provider Framework The Conductor supports a pluggable provider framework for integrating custom code with Scenario execution.  There are two types of providers supported by the Conductor: Function Provider: Function Providers are simple java annotated classes with static methods that are meant to be served as utilities.  Some common uses would include: object creation or instantiation, data transformation, and the like.  Function Providers can be invoked using the common EL syntax from variable assignments, conditions, and loops. For example:  ${myUtilityClass:doStuff(arg1,arg2))} If you are familiar with EL Functions, Function Providers are based on the same concept. Data Provider: Like Function Providers, Data Providers are annotated java classes, but they must adhere to a much more strict object model.  Data Providers have access to a wealth of Conductor services, such as: Access to namespace-scoped configuration API that can be managed by Oracle Enterprise Manager, Scenario execution context for expression resolution, and more.  Oracle ships with three out-of-the-box data providers that supports integration with: Standardized Content Servers(CMIS),  Federated Profile Properties through the Properties Service, and WebCenter Activity Graph. Useful References If you are looking to immediately get started writing your own application using WebCenter Personalization Services, you will find the following references helpful in getting you on your way: Personalizing WebCenter Applications Authoring Personalized Scenarios in JDeveloper Using Personalization APIs Externally Implementing and Calling Function Providers Implementing and Calling Data Providers

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  • cannot evaluate expression because a native frame is on top of the call stack and system.accessviolationexception

    - by Joseph
    I have this code using c#. public partial class MainForm : Form { private CvCapture VideoCapture; private IplImage frame; private IplImage imgMain; public MainForm() { InitializeComponent(); } private void btnVideo_Click(object sender, EventArgs e) { double vidWidth, vidHeight; try { VideoCapture = highgui.CvCreateCameraCapture(0); } catch (Exception except) { MessageBox.Show(except.Message); } if (btnVideo.Text.CompareTo("Start Video") == 0) { if (VideoCapture.ptr == IntPtr.Zero) { MessageBox.Show("badtrip ah!!!"); return; } btnVideo.Text = "Stop Video"; highgui.CvSetCaptureProperty(ref VideoCapture, highgui.CV_CAP_PROP_FRAME_WIDTH, 640); highgui.CvSetCaptureProperty(ref VideoCapture, highgui.CV_CAP_PROP_FRAME_HEIGHT, 480); highgui.CvQueryFrame(ref VideoCapture); vidWidth = highgui.cvGetCaptureProperty(VideoCapture, highgui.CV_CAP_PROP_FRAME_WIDTH); vidHeight = highgui.cvGetCaptureProperty(VideoCapture, highgui.CV_CAP_PROP_FRAME_HEIGHT); picBoxMain.Width = (int)vidWidth; picBoxMain.Height = (int)vidHeight; timerGrab.Enabled = true; timerGrab.Interval = 42; timerGrab.Start(); } else { btnVideo.Text = "Start Video"; timerGrab.Enabled = false; if (VideoCapture.ptr == IntPtr.Zero) { highgui.CvReleaseCapture(ref VideoCapture); VideoCapture.ptr = IntPtr.Zero; } } } private void timerGrab_Tick(object sender, EventArgs e) { try { frame = highgui.CvQueryFrame(ref VideoCapture); if (frame.ptr == IntPtr.Zero) { timerGrab.Stop(); MessageBox.Show("??"); return; } imgMain = cxcore.CvCreateImage(cxcore.CvGetSize(ref frame), 8, 3); picBoxMain.Image = highgui.ToBitmap(imgMain, false); cxcore.CvReleaseImage(ref imgMain); //cxcore.CvReleaseImage(ref frame); } catch (Exception excpt) { MessageBox.Show(excpt.Message); } } } The problem is after i break all and step through the debugger the program stops at a certain code. the code where it stops is here: frame = highgui.CvQueryFrame(ref VideoCapture); the error is that it says that cannot evaluate expression because a native frame is on top of the call stack. and then when i try to shift+F11 it. there is another error saying that system.accessviolationexception. the stack trace says that: at System.Runtime.InteropServices.Marshal.CopyToManaged(IntPtr source, Object destination, Int32 startIndex, Int32 length) at CxCore.IplImage.get_ImageDataDb()

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  • How to use mmap to point to STL type?

    - by srikfreak
    I have a mmap typecast to a char pointer char *ptr; ptr = (char *)mmap(0, FILESIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); This was my earlier code. But now I want to use a map instead of char * as the requirements changed. Now, my map is declared as map i_s_map; How do I change my mmap call to point to the map?

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  • Windows32 API: "mov edi,edi" on function entry?

    - by Ira Baxter
    I'm stepping through Structured Error Handling recovery code in Windows 7 (e.g, what happens after SEH handler is done and passes back "CONTINUE" code). Here's a function which is called: 7783BD9F mov edi,edi 7783BDA1 push ebp 7783BDA2 mov ebp,esp 7783BDA4 push 1 7783BDA6 push dword ptr [ebp+0Ch] 7783BDA9 push dword ptr [ebp+8] 7783BDAC call 778692DF 7783BDB1 pop ebp 7783BDB2 ret 8 I'm used to the function prolog of "push ebp/mov ebp,esp". What's the purpose of the "mov edi,edi"?

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  • Does operator new allocate on THREAD heap?

    - by Jonas Byström
    My problem seems to be this: heap data allocated by one thread (that later dies) seems to die as well. As so: Thread X: starts Thread Y: starts Thread X: ptr = new some bytes Thread X: dies Thread Y: tries to use ptr - and crashes! So far, I've only seen this problem on Darwin (Mac OS 10.5 and 10.6), but haven't tried more other platforms than Windows and Linux (Ubuntu) where it works as expected. I've had this problem for some time, so any know-how or more information about this is highly appreciated!

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  • How can I get valgrind to tell me the address of each non-freed block of memory?

    - by James
    Valgrind tells me function xxx allocated memory which was not freed. Fine. It's proving more difficult than usual to trace however. To this end I have created numerous: #ifdef DEBUG fprintf(stderr, "something happening:%lx\n", (unsigned long)ptr); #endif So I just need to match these ptr addresses that are displayed with the addresses of non-freed memory. How can I get valgrind to tell me the address of each non-freed block of memory?

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  • How can I prevent segmentation faults in my program?

    - by worlds-apart89
    I have a C assignment. It is a lot longer than the code shown below, and we are given the function prototypes and instructions only. I have done my best at writing code, but I am stuck with segmentation faults. When I compile and run the program below on Linux, at "735 NaN" it will terminate, indicating a segfault occurred. Why? What am I doing wrong? Basically, the program does not let me access table-list_array[735]-value and table-list_array[735]-key. This is of course the first segfault. There might be more following index 735. #include <stdio.h> #include <stdlib.h> typedef struct list_node list_node_t; struct list_node { char *key; int value; list_node_t *next; }; typedef struct count_table count_table_t; struct count_table { int size; list_node_t **list_array; }; count_table_t* table_allocate(int size) { count_table_t *ptr = malloc(sizeof(count_table_t)); ptr->size = size; list_node_t *nodes[size]; int k; for(k=0; k<size; k++){ nodes[k] = NULL; } ptr->list_array = nodes; return ptr; } void table_addvalue(count_table_t *table) { int i; for(i=0; i<table->size; i++) { table->list_array[i] = malloc(sizeof(list_node_t)); table->list_array[i]->value = i; table->list_array[i]->key = "NaN"; table->list_array[i]->next = NULL; } } int main() { count_table_t *table = table_allocate(1000); table_addvalue(table); int i; for(i=0; i<table->size; i++) printf("%d %s\n", table->list_array[i]->value, table->list_array[i]->key); return 0; }

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  • Split string in C every white space

    - by redsolja
    I want to write a program in C that displays each word of a whole sentence (taken as input) at a seperate line. This is what i have done so far: void manipulate(char *buffer); int get_words(char *buffer); int main(){ char buff[100]; printf("sizeof %d\nstrlen %d\n", sizeof(buff), strlen(buff)); // Debugging reasons bzero(buff, sizeof(buff)); printf("Give me the text:\n"); fgets(buff, sizeof(buff), stdin); manipulate(buff); return 0; } int get_words(char *buffer){ // Function that gets the word count, by counting the spaces. int count; int wordcount = 0; char ch; for (count = 0; count < strlen(buffer); count ++){ ch = buffer[count]; if((isblank(ch)) || (buffer[count] == '\0')){ // if the character is blank, or null byte add 1 to the wordcounter wordcount += 1; } } printf("%d\n\n", wordcount); return wordcount; } void manipulate(char *buffer){ int words = get_words(buffer); char *newbuff[words]; char *ptr; int count = 0; int count2 = 0; char ch = '\n'; ptr = buffer; bzero(newbuff, sizeof(newbuff)); for (count = 0; count < 100; count ++){ ch = buffer[count]; if (isblank(ch) || buffer[count] == '\0'){ buffer[count] = '\0'; if((newbuff[count2] = (char *)malloc(strlen(buffer))) == NULL) { printf("MALLOC ERROR!\n"); exit(-1); } strcpy(newbuff[count2], ptr); printf("\n%s\n",newbuff[count2]); ptr = &buffer[count + 1]; count2 ++; } } } Although the output is what i want, i have really many black spaces after the final word displayed, and the malloc() returns NULL so the MALLOC ERROR! is displayed in the end. I can understand that there is a mistake at my malloc() implementation but i do not know what it is. Is there another more elegant - generally better way to do it? Thanks in advance.

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  • A few questions about char pointers.

    - by m4design
    1- How does this work: char *ptr = "hi"; Now the compiler will put this string in the memory (I'm guessing the stack), and create a pointer to it? Is this is how it works? 2- Also if it is created locally in a function, when the function returns will the memory occupied by the string be freed? 3- Last but not least, why is this not allowed: ptr[0] = 'H'; ?

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