Search Results

Search found 6587 results on 264 pages for 'double dispatch'.

Page 10/264 | < Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >

  • Screensaver + lock double login problem after Maverick upgrade

    - by dr Hannibal Lecter
    Just found something strange after updating from 10.04 to 10.10. I've set up my screensaver to lock the account when activated. When I log back in, I see my desktop for a second and then the screensaver starts again and I have to re-login. I checked my process list in gnome system monitor, and I have two gnome-screensaver processes(!?), one started as /usr/bin/gnome-screensaver and other simply as gnome-screensaver. And no, I did not start one manually. Where do I look for a way to switch off one of those (supposing that's the problem)? I did not find anything in my startup applications.

    Read the article

  • double vision screen after installing ubuntu

    - by Heather Torgensen
    I'm not much of a techie but my friend who is a software engineer suggested I download ubuntu after my Windows computer was not connecting to certain Wi-Fi networks ( including the one at my house). He said it may be because of the drivers. I did download ubuntu but now the home screen is totally off center.Any ideas? Step by step instructions would be awesome since I'm not super great at this! Thank you!!

    Read the article

  • Unity3D - Android pause screen - double click issue

    - by user3666251
    I made a pause script for the game im developing for android. I added the script to the GUITexture I created and placed on the top right side of the screen.The issue stands at the part where if the player clicks the pause button then clicks resume then he wants to pause the game again.When he clicks pause the second time the buttons dont show up unless he clicks again. This is the script : #pragma strict var paused = false; var isButtonVisible : boolean = true; function OnMouseDown(){ this.paused = !this.paused; Time.timeScale = 0; isButtonVisible = true; } function OnGUI(){ if ( isButtonVisible ) { if(this.paused){ if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2+3,200,50),"Restart")){ Application.LoadLevel(Application.loadedLevel); Time.timeScale = 1; isButtonVisible = false; } if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2-50,200,50),"Resume")){ Time.timeScale = 1; isButtonVisible = false; } // Insert the rest of the pause menu logic if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2+56,200,50),"Main Menu")){ Application.LoadLevel ("MainMenu"); isButtonVisible = false; Time.timeScale = 1; } } } } Thank you.

    Read the article

  • Double lock screen Ubuntu 14.04

    - by Adam
    So I've got a brandynew System 76 laptop running Ubuntu 14.04, and if I close the lid, putting it to sleep, and reopen it, I am presented with the very nice new Unity lock screen. However, when I enter my password, and it succeeds, it then presents me with a second lock screen. Where I have to enter my password again, before finally being let into the desktop. Hash anyone else seen this sort of behavior?

    Read the article

  • Double entries in the gnome 3 task bar

    - by Mark
    I am running Ubuntu 12.04 with Gnome 3. All was working well except that graphics were slow and even moving a window on the screen seemed slow. I installed the fglrx ati driver. Which seems to have improved matters. But on first login I had all gnome items duplicated. That is my task bar has the ubuntu sign, then says Applications, then places then the ubuntu sign then Aplications and then places. Any application I run produces two icons at the bottom of the screen. This was after a reboot. I rebooted again. Now I have 3!! On the right each set of icons such as printer is also trippled!! See screenshot at http://jetmark.co.uk/Screenshot.png See Dmesg at http://jetmark.co.uk/dmesg.txt Any suggestions welcome. Reboot - now I have 4!! So one set gets added on each reboot. Help!! I am going to be task barred out before long!!

    Read the article

  • Avoiding "double" subscriptions

    - by john smith
    I am working on a website that requires a bit of marketing; let me explain. This website is offering a single, say, iTunes 50$ voucher to a lucky winner. To be entered in the draw, you need to invite (and has to join) at least one friend to the website. Pretty straightforward. Now, of course it would be easy for anyone to just create a fake account and invite that account so, I was thinking of some other way to somehow find out of possible cheating. I was thinking of an IP check on the newly subscribed (invited) user, and if there is the same IP logged in the last 24 hours, and if that's the case, investigate more about it. But I was thinking that maybe there is a more clever way around this issue. Has anyone ever though about this? What other solutions did you try? Thanks in advance.

    Read the article

  • Double launchers and mouse captured between screens in Twinview configuration

    - by Numpty
    Just upgraded to 12.04 and noticed an extremely annoying issue. While using twinview, there now appears to be a launcher on each screen. Moving the mouse between monitors and over the launcher "captures" the mouse for half a second or so, creating the perception of lag. According to some bug reports I've read it appears that a launcher on every screen is a new "feature". Is there any way I can get rid of the 2nd launcher? It's driving my crazy.

    Read the article

  • Objective C message dispatch mechanism

    - by Dolphin
    I am just staring to play around with Objective C (writing toy iPhone apps) and I am curious about the underlying mechanism used to dispatch messages. I have a good understanding of how virtual functions in C++ are generally implemented and what the costs are relative to a static or non-virtual method call, but I don't have any background with Obj-C to know how messages are sent. Browsing around I found this loose benchmark and it mentions IMP cached messages being faster than virtual function calls, which are in turn faster than a standard message send. I am not trying to optimize anything, just get deeper understanding of how exactly the messages get dispatched. How are Obj-C messages dispatched? How do Instance Method Pointers get cached and can you (in general) tell by reading the code if a message will get cached? Are class methods essentially the same as a C function (or static class method in C++), or is there something more to them? I know some of these questions may be 'implementation dependent' but there is only one implementation that really counts.

    Read the article

  • Double type returns -1.#IND/NaN error when calculating pi iteratively

    - by Draak
    I am working through a problem for my MCTS certification. The program has to calculate pi until the user presses a key, at which point the thread is aborted, the result returned to the main thread and printed in the console. Simple enough, right? This exercise is really meant to be about threading, but I'm running into another problem. The procedure that calculates pi returns -1.#IND. I've read some of the material on the web about this error, but I'm still not sure how to fix it. When I change double to Decimal type, I unsurprisingly get Overflow Exception very quickly. So, the question is how do I store the numbers correctly? Do I have to create a class to somehow store parts of the number when it gets too big to be contained in a Decimal? Class PiCalculator Dim a As Double = 1 Dim b As Double = 1 / Math.Sqrt(2) Dim t As Double = 1 / 4 Dim p As Double = 1 Dim pi As Double Dim callback As DelegateResult Sub New(ByVal _callback As DelegateResult) callback = _callback End Sub Sub Calculate() Try Do While True Dim a1 = (a + b) / 2 Dim b1 = Math.Sqrt(a * b) Dim t1 = t - p * (a - a1) ^ 2 Dim p1 = 2 * p a = a1 b = b1 t = t1 p = p1 pi = ((a + b) ^ 2) / (4 * t) Loop Catch ex As ThreadAbortException Finally callback(pi) End Try End Sub End Class

    Read the article

  • What is the benefit of triple buffering?

    - by user782220
    I read everything written in a previous question. From what I understand in double buffering the program must wait until the finished drawing is copied or swapped before starting the next drawing. In triple buffering the program has two back buffers and can immediately start drawing in the one that is not involved in such copying. But with triple buffering if you're in a situation where you can take advantage of the third buffer doesn't that suggest that you are drawing frames faster than the monitor can refresh. So then you don't actually get a higher frame rate. So what is the benefit of triple buffering then?

    Read the article

  • double-click to run .sh file

    - by Delirium tremens
    GUI: I changed the permissions of an sh file, so that I can read, write and execute it. I double-clicked it, selected run in Terminal, but it didn't run. I double-clicked it, selected run, but it didn't run. Command-Line: bash *filename* runs it sh *filename* runs it The file content is: #!/bin/bash # get dirsyncpro home DIRSYNCPRO_HOME="$(dirname $0)" # start programm and pass any parameters java -Xmx512M -jar "$DIRSYNCPRO_HOME/dirsyncpro.jar" $* Works in this person's computer: http://www.knowliz.com/2008/08/how-to-installrun-sh-file-in-linux.html What's going on?

    Read the article

  • Memory allocation problem C/Cpp Windows critical error

    - by Andrew
    Hi! I have a code that need to be "translated" from C to Cpp, and i cant understand, where's a problem. There is the part, where it crashes (windows critical error send/dontSend): nDim = sizeMax*(sizeMax+1)/2; printf("nDim = %d sizeMax = %d\n",nDim,sizeMax); hamilt = (double*)malloc(nDim*sizeof(double)); printf("End hamilt alloc. %d allocated\n",(nDim*sizeof(double))); transProb = (double*)malloc(sizeMax*sizeMax*sizeof(double)); printf("End transProb alloc. %d allocated\n",(sizeMax*sizeMax*sizeof(double))); eValues = (double*)malloc(sizeMax*sizeof(double)); printf("eValues allocated. %d allocated\n",(sizeMax*sizeof(double))); eVectors = (double**)malloc(sizeMax*sizeof(double*)); printf("eVectors allocated. %d allocated\n",(sizeMax*sizeof(double*))); if(eVectors) for(i=0;i<sizeMax;i++) { eVectors[i] = (double*)malloc(sizeMax*sizeof(double)); printf("eVectors %d-th element allocated. %d allocated\n",i,(sizeMax*sizeof(double))); } eValuesPrev = (double*)malloc(sizeMax*sizeof(double)); printf("eValuesPrev allocated. %d allocated\n",(sizeMax*sizeof(double))); eVectorsPrev = (double**)malloc(sizeMax*sizeof(double*)); printf("eVectorsPrev allocated. %d allocated\n",(sizeMax*sizeof(double*))); if(eVectorsPrev) for(i=0;i<sizeMax;i++) { eVectorsPrev[i] = (double*)malloc(sizeMax*sizeof(double)); printf("eVectorsPrev %d-th element allocated. %d allocated\n",i,(sizeMax*sizeof(double))); } Log: nDim = 2485 sizeMax = 70 End hamilt alloc. 19880 allocated End transProb alloc. 39200 allocated eValues allocated. 560 allocated eVectors allocated. 280 allocated So it crashes at the start of the loop of allocation. If i delete this loop it crashes at the next line of allocation. Does it mean that with the numbers like this i have not enough memory?? Thank you.

    Read the article

  • Dispatch request to an Async Servlet from managed bean generate exception

    - by Thang Pham
    when a button click, I need to have stuff running in my background, so I have a async Servlet. From my managed bean, if I do redirect, it works great (meaning that it execute my run() method inside my class that extends Runnable correctly). Like this String url = externalContext.getRequestContextPath() + "/ReportExecutionServlet"; externalContext.redirect(url); But if I switch to dispatch, like this externalContext.redirect("/ReportExecutionServlet"); it fail when I try to obtain the AsyncContext AsyncContext aCtx = request.startAsync(request, response); The error is below Caused By: java.lang.IllegalStateException: The async-support is disabled on this request: weblogic.servlet.internal.ServletRequestImpl Any idea how to fix this please? NOTE: This is how to execute my async servlet, just in case: AsyncContext aCtx = request.startAsync(request, response); //delegate long running process to an "async" thread aCtx.addListener(new AsyncListener() { @Override public void onComplete(AsyncEvent event) throws IOException { logger.log(Level.INFO, "ReportExecutionServlet handle async request - onComplete"); } @Override public void onTimeout(AsyncEvent event) throws IOException { logger.log(Level.WARNING, "ReportExecutionServlet handle async request - onTimeout"); } @Override public void onError(AsyncEvent event) throws IOException { logger.log(Level.SEVERE, "ReportExecutionServlet handle async request - onError"); } @Override public void onStartAsync(AsyncEvent event) throws IOException { logger.log(Level.INFO, "ReportExecutionServlet handle async request - onStartAsync"); } }); // Start another service ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(10); executor.execute(new AsyncRequestReportProcessor(aCtx));

    Read the article

  • A "Trig" Calculating Class

    - by Clinton Scott
    I have been trying to create a gui that calculates trigonometric functions based off of the user's input. I have had success in the GUI part, but my class that I wrote to hold information using inheritance seems to be messed up, because when I run it gives an error saying: Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - constructor ArcTrigCalcCon in class TrigCalc.ArcTrigCalcCon cannot be applied to given types; required: double,double,double,double,double,double found: java.lang.Double,java.lang.Double,java.lang.Double reason: actual and formal argument lists differ in length at TrigCalc.TrigCalcGUI.(TrigCalcGUI.java:31) at TrigCalc.TrigCalcGUI.main(TrigCalcGUI.java:87) Java Result: 1 and says it is the object causing the problem. Below Will be my code. First I will put up my inheritance class with cosecant secant and cotangent and then my original class with the original 3 trig functions: { public ArcTrigCalcCon(double s, double cs, double t, double csc, double sc, double ct) { // Inherit from the Trig Calc class super(s, cs, t); cosecant = 1/s; secant = 1/cs; cotangent = 1/t; } public void setCsc(double csc) { cosecant = csc; } public void setSec(double sc) { secant = sc; } public void setCot(double ct) { cotangent = ct; } } Here is the first Trigonometric class: public class TrigCalcCon { public double sine; public double cosine; public double tangent; public TrigCalcCon(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public void setSin(double s) { sine = s; } public void setCos(double cs) { cosine = cs; } public void setTan(double t) { tangent = t; } public void set(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public double getSin() { return Math.sin(sine); } public double getCos() { return Math.cos(cosine); } public double getTan() { return Math.tan(tangent); } } and here is the demo class to run the gui: public class TrigCalcGUI extends JFrame implements ActionListener { // Instance Variables private String input; private Double s, cs, t, csc, sc, ct; private JPanel mainPanel, sinPanel, cosPanel, tanPanel, cscPanel, secPanel, cotPanel, buttonPanel, inputPanel, displayPanel; // Panel Display private JLabel sinLabel, cosLabel, tanLabel, secLabel, cscLabel, cotLabel, inputLabel; private JTextField sinTF, cosTF, tanTF, secTF, cscTF, cotTF, inputTF; //Text Fields for sin, cos, and tan, and inverse private JButton calcButton, clearButton; // Calculate and Exit Buttons // Object ArcTrigCalcCon trC = new ArcTrigCalcCon(s, cs, t); public TrigCalcGUI() { // title bar text. super("Trig Calculator"); // Corner exit button action. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Create main panel to add each panel to mainPanel = new JPanel(); mainPanel.setLayout(new GridLayout(3,2)); displayPanel = new JPanel(); displayPanel.setLayout(new GridLayout(3,2)); // Assign Panel to each variable inputPanel = new JPanel(); sinPanel = new JPanel(); cosPanel = new JPanel(); tanPanel = new JPanel(); cscPanel = new JPanel(); secPanel = new JPanel(); cotPanel = new JPanel(); buttonPanel = new JPanel(); // Call each constructor buildInputPanel(); buildSinCosTanPanels(); buildCscSecCotPanels(); buildButtonPanel(); // Add each panel to content pane displayPanel.add(sinPanel); displayPanel.add(cscPanel); displayPanel.add(cosPanel); displayPanel.add(secPanel); displayPanel.add(tanPanel); displayPanel.add(cotPanel); // Add three content panes to GUI mainPanel.add(inputPanel, BorderLayout.NORTH); mainPanel.add(displayPanel, BorderLayout.CENTER); mainPanel.add(buttonPanel, BorderLayout.SOUTH); //add mainPanel this.add(mainPanel); // size of window to content this.pack(); // display window setVisible(true); } public static void main(String[] args) { new TrigCalcGUI(); } private void buildInputPanel() { inputLabel = new JLabel("Enter a Value: "); inputTF = new JTextField(5); inputPanel.add(inputLabel); inputPanel.add(inputTF); } // Building Constructor for sinPanel cosPanel, and tanPanel private void buildSinCosTanPanels() { // Set layout and border for sinPanel sinPanel.setLayout(new GridLayout(2,2)); sinPanel.setBorder(BorderFactory.createTitledBorder("Sine")); // sinTF = new JTextField(5); sinTF.setEditable(false); sinPanel.add(sinTF); // Set layout and border for cosPanel cosPanel.setLayout(new GridLayout(2,2)); cosPanel.setBorder(BorderFactory.createTitledBorder("Cosine")); cosTF = new JTextField(5); cosTF.setEditable(false); cosPanel.add(cosTF); // Set layout and border for tanPanel tanPanel.setLayout(new GridLayout(2,2)); tanPanel.setBorder(BorderFactory.createTitledBorder("Tangent")); tanTF = new JTextField(5); tanTF.setEditable(false); tanPanel.add(tanTF); } // Building Constructor for cscPanel secPanel, and cotPanel private void buildCscSecCotPanels() { // Set layout and border for cscPanel cscPanel.setLayout(new GridLayout(2,2)); cscPanel.setBorder(BorderFactory.createTitledBorder("Cosecant")); // cscTF = new JTextField(5); cscTF.setEditable(false); cscPanel.add(cscTF); // Set layout and border for secPanel secPanel.setLayout(new GridLayout(2,2)); secPanel.setBorder(BorderFactory.createTitledBorder("Secant")); secTF = new JTextField(5); secTF.setEditable(false); secPanel.add(secTF); // Set layout and border for cotPanel cotPanel.setLayout(new GridLayout(2,2)); cotPanel.setBorder(BorderFactory.createTitledBorder("Cotangent")); cotTF = new JTextField(5); cotTF.setEditable(false); cotPanel.add(cotTF); } private void buildButtonPanel() { // Create buttons and add events calcButton = new JButton("Calculate"); calcButton.addActionListener(new CalcButtonListener()); clearButton = new JButton("Clear"); clearButton.addActionListener(new ClearButtonListener()); buttonPanel.add(calcButton); buttonPanel.add(clearButton); } @Override public void actionPerformed(ActionEvent e) { } private class CalcButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Declare boolean variable boolean incorrect = true; // Set input variable to input text field text input = inputTF.getText(); ImageIcon newIcon; ImageIcon frowny = new ImageIcon(TrigCalcGUI.class.getResource("/Sad_Face.png")); Image gm = frowny.getImage(); Image newFrowny = gm.getScaledInstance(100, 100, java.awt.Image.SCALE_FAST); newIcon = new ImageIcon(newFrowny); // If boolean is true, throw exception if(incorrect) { try{Double.parseDouble(input); incorrect = false;} catch(NumberFormatException nfe) { String s = "Invalid Input " + "/n Input Must Be a Numerical value." + "/nPlease Press Ok and Try Again"; JOptionPane.showMessageDialog(null, s, "Invalid", JOptionPane.ERROR_MESSAGE, newIcon); inputTF.setText(""); inputTF.requestFocus(); } } // If boolean is not true, proceed with output if (incorrect != true) { /* Set each text field's output to the String double value * of inputTF */ sinTF.setText(input); cosTF.setText(input); tanTF.setText(input); cscTF.setText(input); secTF.setText(input); cotTF.setText(input); } } } /** * Private inner class that handles the event when * the user clicks the Exit button. */ private class ClearButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Clear field sinTF.setText(""); cosTF.setText(""); tanTF.setText(""); cscTF.setText(""); secTF.setText(""); cotTF.setText(""); // Clear textfield and set cursor focus to field inputTF.setText(""); inputTF.requestFocus(); } } }

    Read the article

  • Why does double dispatch not work in C++?

    - by Bruce
    #include<iostream.h> #include<conio.h> using namespace std; class SpaceShip {}; class GiantSpaceShip : public SpaceShip {}; class Asteroid { public: virtual void CollideWith(SpaceShip *) { cout << "Asteroid hit a SpaceShip" << endl; } virtual void CollideWith(GiantSpaceShip *) { cout << "Asteroid hit a GiantSpaceShip" << endl; } }; class ExplodingAsteroid : public Asteroid { public: virtual void CollideWith(SpaceShip *) { cout << "ExplodingAsteroid hit a SpaceShip" << endl; } virtual void CollideWith(GiantSpaceShip *) { cout << "ExplodingAsteroid hit a GiantSpaceShip" << endl; } }; int main() { SpaceShip * s = new GiantSpaceShip(); Asteroid * a = new ExplodingAsteroid(); a->CollideWith(s); getch(); return 0; } How can I enable double dispatch in C++?

    Read the article

  • Is there a 128 or 256 bit double class in .net?

    - by AKRamkumar
    I have an application that I want to be able to use large numbers and very precise numbers. For this, I needed a precision interpretation and IntX only works for integers. Is there a class in .net framework or even third party(preferably free) that would do this? Is there another way to do this?

    Read the article

  • singledispatch in class, how to dispatch self type

    - by yanxinyou
    Using python3.4. Here I want use singledispatch to dispatch different type in __mul__ method . The code like this : class Vector(object): ## some code not paste @functools.singledispatch def __mul__(self, other): raise NotImplementedError("can't mul these type") @__mul__.register(int) @__mul__.register(object) # Becasue can't use Vector , I have to use object def _(self, other): result = Vector(len(self)) # start with vector of zeros for j in range(len(self)): result[j] = self[j]*other return result @__mul__.register(Vector) # how can I use the self't type @__mul__.register(object) # def _(self, other): pass # need impl As you can see the code , I want support Vector*Vertor , This has Name error Traceback (most recent call last): File "p_algorithms\vector.py", line 6, in <module> class Vector(object): File "p_algorithms\vector.py", line 84, in Vector @__mul__.register(Vector) # how can I use the self't type NameError: name 'Vector' is not defined The question may be How Can I use class Name a Type in the class's method ? I know c++ have font class statement . How python solve my problem ? And it is strange to see result = Vector(len(self)) where the Vector can be used in method body .

    Read the article

  • Properly force SSL with .htaccess, no double authentication

    - by cwd
    I'm trying to force SSL with .htaccess on a shared host. This means there I only have access to .htaccess and not the vhosts config. I know you can put a rule in the VirtualHost config file to force SSL which will be picked up there (and acted upon first), preventing double authentication, but I can't get to that. Here's the progress I've made: Config 1 This works pretty well but it does force double authentication if you visit http://site.com - once for http and then once for https. Once you are logged in, it automatically redirects http://site.com/page1.html to the https coutnerpart just fine: RewriteEngine On RewriteCond %{HTTPS} !=on RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301] RewriteEngine on RewriteCond %{HTTP_HOST} !(^www\.site\.com*)$ RewriteRule (.*) https://www.site.com$1 [R=301,L] AuthName "Locked" AuthUserFile "/home/.htpasswd" AuthType Basic require valid-user Config 2 If I add this to the top of the file, it works a lot better in that it will switch to SSL before prompting for the password: SSLOptions +StrictRequire SSLRequireSSL SSLRequire %{HTTP_HOST} eq "site.com" ErrorDocument 403 https://site.com It's clever how it will use the SSLRequireSSL option and the ErrorDocument403 to redirect to the secure version of the site. My only complaint is that if you try and access http://site.com/page1.html it will redirect to https://site.com/ So it is forcing SSL without a double-login, but it is not properly forwarding non-SSL resources to their SSL counterparts. Regarding the first config, Insyte mentioned "using mod_rewrite to perform a simple redirect is a bit of overkill. Use the Redirect directive instead. It's possible this may even fix your problem, as I believe mod_rewrite rules are some of the last directives to be processed, just before the file is actually grabbed from the filesystem" I have not had no such luck on finding a force-ssl config option with the redirect directive and so have been unable to test this theory.

    Read the article

  • Dynamic Dispatch without Virtual Functions

    - by Kristopher Johnson
    I've got some legacy code that, instead of virtual functions, uses a kind field to do dynamic dispatch. It looks something like this: // Base struct shared by all subtypes // Plain-old data; can't use virtual functions struct POD { int kind; int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); }; enum Kind { Kind_Derived1, Kind_Derived2, Kind_Derived3 }; struct Derived1: POD { Derived1(): kind(Kind_Derived1) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; struct Derived2: POD { Derived2(): kind(Kind_Derived2) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; struct Derived3: POD { Derived3(): kind(Kind_Derived3) {} int GetFoo(); int GetBar(); int GetBaz(); int GetXyzzy(); // plus other type-specific data and function members }; and then the POD class's function members are implemented like this: int POD::GetFoo() { // Call kind-specific function switch (kind) { case Kind_Derived1: { Derived1 *pDerived1 = static_cast<Derived1*>(this); return pDerived1->GetFoo(); } case Kind_Derived2: { Derived2 *pDerived2 = static_cast<Derived2*>(this); return pDerived2->GetFoo(); } case Kind_Derived3: { Derived3 *pDerived3 = static_cast<Derived3*>(this); return pDerived3->GetFoo(); } default: throw UnknownKindException(kind, "GetFoo"); } } POD::GetBar(), POD::GetBaz(), POD::GetXyzzy(), and other members are implemented similarly. This example is simplified. The actual code has about a dozen different subtypes of POD, and a couple dozen methods. New subtypes of POD and new methods are added pretty frequently, and so every time we do that, we have to update all these switch statements. The typical way to handle this would be to declare the function members virtual in the POD class, but we can't do that because the objects reside in shared memory. There is a lot of code that depends on these structs being plain-old-data, so even if I could figure out some way to have virtual functions in shared-memory objects, I wouldn't want to do that. So, I'm looking for suggestions as to the best way to clean this up so that all the knowledge of how to call the subtype methods is centralized in one place, rather than scattered among a couple dozen switch statements in a couple dozen functions. What occurs to me is that I can create some sort of adapter class that wraps a POD and uses templates to minimize the redundancy. But before I start down that path, I'd like to know how others have dealt with this.

    Read the article

  • Thread scheduling Round Robin / scheduling dispatch

    - by MRP
    #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <semaphore.h> #define NUM_THREADS 4 #define COUNT_LIMIT 13 int done = 0; int count = 0; int quantum = 2; int thread_ids[4] = {0,1,2,3}; int thread_runtime[4] = {0,5,4,7}; pthread_mutex_t count_mutex; pthread_cond_t count_threshold_cv; void * inc_count(void * arg); static sem_t count_sem; int quit = 0; ///////// Inc_Count//////////////// void *inc_count(void *t) { long my_id = (long)t; int i; sem_wait(&count_sem); /////////////CRIT SECTION////////////////////////////////// printf("run_thread = %d\n",my_id); printf("%d \n",thread_runtime[my_id]); for( i=0; i < thread_runtime[my_id];i++) { printf("runtime= %d\n",thread_runtime[my_id]); pthread_mutex_lock(&count_mutex); count++; if (count == COUNT_LIMIT) { pthread_cond_signal(&count_threshold_cv); printf("inc_count(): thread %ld, count = %d Threshold reached.\n", my_id, count); } printf("inc_count(): thread %ld, count = %d, unlocking mutex\n",my_id, count); pthread_mutex_unlock(&count_mutex); sleep(1) ; }//End For sem_post(&count_sem); // Next Thread Enters Crit Section pthread_exit(NULL); } /////////// Count_Watch //////////////// void *watch_count(void *t) { long my_id = (long)t; printf("Starting watch_count(): thread %ld\n", my_id); pthread_mutex_lock(&count_mutex); if (count<COUNT_LIMIT) { pthread_cond_wait(&count_threshold_cv, &count_mutex); printf("watch_count(): thread %ld Condition signal received.\n", my_id); printf("watch_count(): thread %ld count now = %d.\n", my_id, count); } pthread_mutex_unlock(&count_mutex); pthread_exit(NULL); } ////////////////// Main //////////////// int main (int argc, char *argv[]) { int i; long t1=0, t2=1, t3=2, t4=3; pthread_t threads[4]; pthread_attr_t attr; sem_init(&count_sem, 0, 1); /* Initialize mutex and condition variable objects */ pthread_mutex_init(&count_mutex, NULL); pthread_cond_init (&count_threshold_cv, NULL); /* For portability, explicitly create threads in a joinable state */ pthread_attr_init(&attr); pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE); pthread_create(&threads[0], &attr, watch_count, (void *)t1); pthread_create(&threads[1], &attr, inc_count, (void *)t2); pthread_create(&threads[2], &attr, inc_count, (void *)t3); pthread_create(&threads[3], &attr, inc_count, (void *)t4); /* Wait for all threads to complete */ for (i=0; i<NUM_THREADS; i++) { pthread_join(threads[i], NULL); } printf ("Main(): Waited on %d threads. Done.\n", NUM_THREADS); /* Clean up and exit */ pthread_attr_destroy(&attr); pthread_mutex_destroy(&count_mutex); pthread_cond_destroy(&count_threshold_cv); pthread_exit(NULL); } I am trying to learn thread scheduling, there is a lot of technical coding that I don't know. I do know in theory how it should work, but having trouble getting started in code... I know, at least I think, this program is not real time and its not meant to be. Some how I need to create a scheduler dispatch to control the threads in the order they should run... RR FCFS SJF ect. Right now I don't have a dispatcher. What I do have is semaphores/ mutex to control the threads. This code does run FCFS... and I have been trying to use semaphores to create a RR.. but having a lot of trouble. I believe it would be easier to create a dispatcher but I dont know how. I need help, I am not looking for answers just direction.. some sample code will help to understand a bit more. Thank you.

    Read the article

< Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >