Search Results

Search found 1638 results on 66 pages for 'multithreading'.

Page 58/66 | < Previous Page | 54 55 56 57 58 59 60 61 62 63 64 65  | Next Page >

• New to threading in C#, can you make thread methods generic and what are the dangers?

  - by ibarczewski

  Hey all, I'm just now starting to get into the idea of threading, and wanted to know if I could make this more abstract. Both foo and bar derive methods from a base class, so I'd like to pass in one or the other and be able to do work using a method that was derived. I'd also like to know how you properly name threads and the methods inside threads. if (ChkFoo.Checked) { Thread fooThread = new Thread(new ThreadStart(this.ThreadedFooMethod)); fooThread.Start(); } if (ChkBar.Checked) { Thread barThread = new Thread(new ThreadStart(this.ThreadedBarMethod)); barThread.Start(); } . . . public void ThreadedFooMethod() { Foo newFoo = new Foo(); //Do work on newFoo } public void ThreadedBarMethod() { Bar newBar = new Bar(); //Do similar work } Thanks all!

  Read the article

• How to use CriticalSection - MFC?

  - by mapples

  I' am working on a small example and am a bit of curious using criticalsection in my example. What I'am doing is,I have a CStringArray(which has 10 elements added to it).I want to copy these 10 elements(string) to another CStringArray(am doing this to understand threading and Critical section),I have created 2 threads,Thread1 will copy the first 5 element to another CStringArray and Thread2 will copy the rest.Here two CStringArray are being used,I know only 1 thread can access it at a time.I wanted to know how this can be solved by using criticalsection or any other method. void CThreadingEx4Dlg::OnBnClickedOk() { // TODO: Add your control notification handler code here thread1 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction1,this); thread2 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction2,this); } UINT MyThreadFunction1(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyFunction(0,5); return 0; } UINT MyThreadFunction2(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyFunction(6,10); return 0; } void CThreadingEx4Dlg::MyFunction(int minCount,int maxCount) { for(int i=minCount;i<=maxCount;i++) { CString temp; temp = myArray.GetAt(i); myShiftArray.Add(temp); } }

  Read the article

• C# thread safety for class instances

  - by Steveng

  I am learning C# and I am confused with the thread safety of the copies of the class instances as below: eg: classA objA; classA objB = objA; objA.field1 = value2; //do I need lock around modification of field1? //let say we pass the objB to another thread objB.field1 = value1 //do I need a lock for objB because of the modification of field1? I am confused because coming from the background of C++, the class in C# is the reference type. If both objA and objB refer to the same memory underlying, then I would need a lock to protect the simultaneous writing to the field1. Could someone confirm with this or am I missing something? Thanks.

  Read the article

• How to insert into data base using multi threading programming [closed]

  - by user1196650

  I am having a method and that method needs to do the following thing: It has to insert records into a database. No insert is done for the same table again. All inserts are into different tables. I need a multi threading logic which inserts the details into db using different threads. I am using oracle db and driver configuration and remaining stuff are perfect. Please help me with an efficient answer. Can anyone could provide me with a skeleton logic of the program.

  Read the article

• Java Socket - how to catch Exception of BufferedReader.readline()

  - by Hasan Tahsin

  I have a Thread (let's say T1) which reads data from socket: public void run() { while (running) { try { BufferedReader reader = new BufferedReader( new InputStreamReader(socket.getInputStream()) ); String input = reader.readLine(); } catch (IOException e) { e.printStackTrace(); } } } Another Thread (lets say T2) try to finish the program in one of its method. Therefore T2 does the following: T1.running = false; socket.close(); Here is this scenario for which i couldn't find a solution: T1 is active and waiting for some input to read i.e. blocking. context switching T2 is active and sets running to false, closes the socket context switching because T1 was blocking and T2 closed the socket, T1 throws an Exception. What i want is to catch this SocketException. i can't put a try/catch(SocketException) in T1.run(). So how can i catch it in T1's running-method? If it's not possible to catch it in T1's running, then how can i catch it elsewhere? PS: "Another question about the Thread Debugging" Normally when i debug the code step by step, i lose the 'active running line' on a context switch. Let's say i'm in line 20 of T1, context switch happens, let's assume the program continues from the 30.line of T2, but the debugger does not go/show to the 30.line of T2, instead the 'active running line' vanishes. So i lose the control over the code. I use Eclipse for Java and Visual Studio for C#. So what is the best way to track the code while debugging on a context switch ?

  Read the article

• How do I make this Java code operate properly? [Multi-threaded, race condition]

  - by Fixee

  I got this code from a student, and it does not work properly because of a race condition involving x++ and x--. He added synchronized to the run() method trying to get rid of this bug, but obviously this only excludes threads from entering run() on the same object (which was never a problem in the first place) but doesn't prevent independent objects from updating the same static variable x at the same time. public class DataRace implements Runnable { static volatile int x; public synchronized void run() { for (int i = 0; i < 10000; i++) { x++; x--; } } public static void main(String[] args) throws Exception { Thread [] threads = new Thread[100]; for (int i = 0; i < threads.length; i++) threads[i] = new Thread(new DataRace()); for (int i = 0; i < threads.length; i++) threads[i].start(); for (int i = 0; i < threads.length; i++) threads[i].join(); System.out.println(x); // x not always 0! } } Since we cannot synchronize on x (because it is primitive), the best solution I can think of is to create a new static object like static String lock = ""; and enclose the x++ and x-- within a synchronized block, locking on lock. But this seems really awkward. Is there a better way?

  Read the article

• C# Anyway to detect if an object is locked.

  - by scope-creep

  Hi, Is their anyway to determine if a object is locked in c#. I have the unenviable position, through design where i'm reading from a queue inside a class, and I need to dump the contents into a collection in the class. But that collection is also read/write from an interface outside the class. So obviously their may be a case when the collection is being written to, as the same time i want to write to it. I could program round it, say using delegate but it would be ugly. Bob.

  Read the article

• What is the performance cost of calling Thread.isInterrupted()?

  - by Michael Barker

  From the java sources, it look like to drops into native code. Is the cost roughly equivalent to a volatile read or does it need to acquire a lock of some type?

  Read the article

• Is PThread a good choice for multi-platorm C/C++ multi-threading program?

  - by RogerV

  Been doing mostly Java and smattering of .NET for last five years and haven't written any significant C or C++ during that time. So have been away from that scene for a while. If I want to write a C or C++ program today that does some multi-threading and is source code portable across Windows, Mac OS X, and Linux/Unix - is PThread a good choice? The C or C++ code won't be doing any GUI, so won't need to worry with any of that. For the Windows platform, I don't want to bring a lot of Unix baggage, though, in terms of unix emulation runtime libraries. Would prefer a PThread API for Windows that is a thin-as-possible wrapper over existing Windows threading APIs. ADDENDUM EDIT: Am leaning toward going with boost:thread - I also want to be able to use C++ try/catch exception handling too. And even though my program will be rather minimal and not particularly OOPish, I like to encapsulate using class and namespace - as opposed to C disembodied functions.

  Read the article

• Is there a timeout for threads waiting on a synchronised method in Java?

  - by MalcomTucker

  Is there a default timeout for threads waiting on a synchronised method in Java? Some threads in my app are not completing as expected. Is there anyway to check whether threads have died as a result of timeouts?

  Read the article

• Easy Threading in WPF

  - by Sandeep Bansal

  Hi everyone, I've been reading a lot about threading in C#, WPF and Silverlight but can't get it to work. My main problem is I have the _load (_Initialized) action and it has a lot of object creation and along with that I have timers working doing different things, this causes the startup time of the program to be very slow and obviously causes the UI to hang and it isn't a good thing for deploying to a lot of users. My timers change values of labels and textfields but having them do that on another thread is an obvious no go. So can someone give me some examples on how to achieve what I need to do? Thanks

  Read the article

• "Multi-threading" w/ NSTimers in an iPhone app

  - by MrDatabase

  Say I have two NSTimers in my iPhone app: timer1 and timer2. timer1 calls function1 30 times per second and timer2 calls function2 30 times per second. Assume these two functions are reading and updating the same integer variables. Are there any "multi-threading" issues here? If not how does iPhone OS handle the execution of the two functions (in general)?

  Read the article

• Thread too slow. Better way to execute code (Android AndEngine)?

  - by rphello101

  I'm developing a game where the user creates sprites with every touch. I then have a thread run to check to see if those sprites collide with any others. The problem is, if I tap too quickly, I cause a null pointer exception error. I believe it's because I'm tapping faster than my thread is running. This is the thread I have: public class grow implements Runnable{ public grow(Sprite sprite){ } @Override public void run() { float radf, rads; //fill radius/stationary radius float fx=0, fy=0, sx, sy; while(down){ if(spriteC[spriteNum].active){ spriteC[spriteNum].sprite.setScale(spriteC[spriteNum].scale += 0.001); if(spriteC[spriteNum].sprite.collidesWith(ground)||spriteC[spriteNum].sprite.collidesWith(roof)|| spriteC[spriteNum].sprite.collidesWith(left)||spriteC[spriteNum].sprite.collidesWith(right)){ down = false; spriteC[spriteNum].active=false; yourScene.unregisterTouchArea(spriteC[spriteNum].sprite); } fx = spriteC[spriteNum].sprite.getX(); fy = spriteC[spriteNum].sprite.getY(); radf=spriteC[spriteNum].sprite.getHeightScaled()/2; Log.e("F"+Float.toString(fx),Float.toString(fy)); if(spriteNum>0) for(int x=0;x<spriteNum;x++){ rads=spriteC[x].sprite.getHeightScaled()/2; sx = spriteC[x].body.getWorldCenter().x * 32; sy = spriteC[x].body.getWorldCenter().y * 32; Log.e("S"+Float.toString(sx),Float.toString(sy)); Log.e(Float.toString((float) Math.sqrt(Math.pow((fx-sx),2)+Math.pow((fy-sy),2))),Float.toString((radf+rads))); if(Math.sqrt(Math.pow((fx-sx),2)+Math.pow((fy-sy),2))<(radf+rads)){ down = false; spriteC[spriteNum].active=false; yourScene.unregisterTouchArea(spriteC[spriteNum].sprite); Log.e("Collided",Boolean.toString(down)); } } } } spriteC[spriteNum].body = PhysicsFactory.createCircleBody(mPhysicsWorld, spriteC[spriteNum].sprite, BodyType.DynamicBody, FIXTURE_DEF); mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(spriteC[spriteNum].sprite, spriteC[spriteNum].body, true, true)); } } Better solution anyone? I know there is something to do with a handler, but I don't exactly know what that is or how to use one.

  Read the article

• Running 2 threads simultaneously

  - by lamsaitat

  In the case of an IM client. I have made 2 separate threads to handle sending packets (by std io) and receiving packets. The question is how to make these 2 threads run simultaneously so that I can keep prompting for input while at the same time be ready to receive packets at any time? I have already tried setting a timer but the data is always lost receiving.

  Read the article

• How to address thread-safety of service data used for maintaining static local variables in C++?

  - by sharptooth

  Consider the following scenario. We have a C++ function with a static local variable: void function() { static int variable = obtain(); //blahblablah } the function needs to be called from multiple threads concurrently, so we add a critical section to avoid concurrent access to the static local: void functionThreadSafe() { CriticalSectionLockClass lock( criticalSection ); static int variable = obtain(); //blahblablah } but will this be enough? I mean there's some magic that makes the variable being initialized no more than once. So there's some service data maintained by the runtime that indicates whether each static local has already been initialized. Will the critical section in the above code protect that service data as well? Is any extra protection required for this scenario?

  Read the article

• Should I use multiple threads in this situation? [Ruby]

  - by mr popo

  I'm opening multiple files and processing them, one line at a time. The files contain tokens separating the data, such that sometimes the processing of one file may have to wait for others to catch up to that same token. I was doing this initially with only one thread and an array indicating with true/false if the file should be read in the current iteration or if it should wait for some of the others to catch up. Would using threads make this simpler? More efficient? Does Ruby have a mechanism for this?

  Read the article

• Does SetThreadPriority cause thread reschedulling?

  - by Suma

  Consider following situation, assuming single CPU system: thread A is running with a priority THREAD_PRIORITY_NORMAL, signals event E thread B with a priority THREAD_PRIORITY_LOWEST is waiting for an event E (Note: at this point the thread is not scheduled because it is runnable, but A is higher priority and runnable as well) thread A calls SetThreadPriority(B, THREAD_PRIORITY_ABOVE_NORMAL) Is thread B re-scheduled immediately to run, or is thread A allowed to continue until current time-slice is over, and B is scheduled only once a new time-slice has begun? I would be interested to know the answer for WinXP, Vista and Win7, if possible. Note: the scenario above is simplified from my real world code, where multiple threads are running on multiple cores, but the main object of the question stays: does SetThreadPriority cause thread scheduling to happen?

  Read the article

• Multithreaded SDL error in C++

  - by wyatt

  I'm building a program in C++, using SDL, and am occasionally receiving this error: * glibc detected * ./assistant: double free or corruption (!prev) It's difficult to replicate, so I can't find exactly what's causing it, but I just added a second thread to the program, and neither thread run on its own seems to cause the error. The threads don't share any variables, though they both run the functions SDL_BlitSurface and SDL_Flip. Could running these concurrently throw up such an error, or am I barking up the wrong tree? If this is the cause, should I simply throw a mutex around all SDL calls? Thanks

  Read the article

• Have main thread wait for a boost thread complete a task (but not finish).

  - by JAKE6459

  I have found plenty on making one thread wait for another to finish executing before continuing, but that is not what I wanted to do. I am not very familiar with using any multi-threading apis but right now I'm trying to learn boost. My situation is that I am using my main thread (the starting one from int main()) to create an instance of a class that is in charge of interacting with the main GUI. A class function is then called that creates a boost thread which in turn creates the GUI and runs the message pump. The thing I want to do is when my main thread calls the classes member function to create the GUI, I don't want that function to return until I tell it to from the newly created thread. This way my main thread can't continue and call more functions from the GUI class that interact with the GUI thread until that thread has completed GUI creation and entered the message loop. I think I may be able to figure it out if it was multiple boost thread objects interacting with each other, but when it is the main thread (non-boost object) interacting with a boost thread object, I get lost. Eventually I want a loop in my main thread to call a class function (among other tasks) to check if the user as entered any new input into the GUI (buy any changes detected by the message loop being updated into a struct and changing a bool to tell the main thread in the class function a change has occurred). Any suggestions for any of this would be greatly appreciated. This is the member function called by the main thread. int ANNGUI::CreateGUI() { GUIMain = new Main(); GUIThread = new boost::thread(boost::bind(&Main::MainThreadFunc, GUIMain)); return 0; }; This is the boost thread starting function. void Main::MainThreadFunc() { ANNVariables = new GUIVariables; WndProc = new WindowProcedure; ANNWindowsClass = new WindowsClass(ANNVariables, WndProc); ANNWindow = new MainWindow(ANNVariables); GUIMessagePump = new MessagePump; ANNWindow-ShowWindows(); while(true) { GUIMessagePump-ProcessMessage(); } }; BTW, everything compiles fine and when I run it, it works I just put a sleep() in the main thread so I can play with the GUI a little.

  Read the article

• OpenGL multiple threads, variable handling [closed]

  - by toeplitz

  I have written an OpenGL program which runs in the following way: Main: - Initialize SDL - Create thread which has the OpenGL context: - Renderloop - Set camera (view) matrix with glUniform. - glDrawElements() .... etc. - Swapbuffers(); - Main SDL loop handling input events and such. - Update camera matrix of type glm::mat4. This is how I pass my camera object to the class that handles opengl. Camera *cam = new Camera(); gl.setCam(cam); where void setCam(Camera *camera) { this->camera = camera; } For rendering in the opengl context thread, this happens: glm::mat4 modelView = camera->view * model; glUniformMatrix4fv(shader->bindUniform("modelView"), 1, GL_FALSE, glm::value_ptr(modelView)); In the main program where my SDL and other things are handles I then recompute the view matrix. This his working fine without me using any mutex locks. Is this correct? On the other hand, I add objects to my scene by an "upload queue" and in this case I have to mutex lock my upload queue vector (vector class type) when adding items to it or else the program crashes. In summary: I recompute my matrix in a different thread and then use it in the opengl thread without any mutex lock. Why is this working? Edit: I think my question is similar to what was asked here: Should I lock a variable in one thread if I only need it's value in other threads, and why does it work if I don't?, only in my case it is even more simple with only one matrix being changed.

  Read the article

• Difference between Locks, Mutex and Critical Sections

  - by viswanathan

  There is an existing question regarding difference between Mutex and Critical section but it does not deal with Locks also. So i want to know whether Critical sections can be used for thread synchronisation between processes. Also what is meant by signalled states and non-signalled states

  Read the article

• Using two threads and controlling one from the other in java?

  - by sidra

  Can someone please help me out. I need to use two threads in a way that one thread will run permanently while(true) and will keep track of a positioning pointer (some random value coming in form a method). This thread has a logic, if the value equals something, it should start the new thread. And if the value does not equal it should stop the other thread. Can someone give me some code snippet (block level) about how to realize this?

  Read the article

• how do I repaint an applet while moving a sprite?

  - by Nagrom_17

  I have a little java applet where I create 2 threads, one thread repaints and the other moves an image from a point to where the user clicks. The problem is that when I call the move function it loops until the image is where the user clicks but it wont repaint until I break out of the loop even though the thread doing the moving and the thread doing the painting are separate. shortened version of key points: my program is an applet using the paint() method I have 2 threads one moves an image and the other paints that image when I am moving the image it is in a while loop the painting thread is still calling repaint() but that is as far as the call goes, it never repaints thank you for your time.

  Read the article

• Threading in C#

  - by j-t-s

  Hi All Just looking for something ultra simple. I need to spawn a method off to a new thread. I don't care when or how it ends. Can somebody please help me with this? Thank you

  Read the article

• How to handle error on other thread?

  - by markattwood

  Hi, I'm trying to handle errors that have occurred on other threads the .NET CF program is like below: static void Main() { Thread t = new Thread(Start); t.Start(); ... } void Start() { ... Exception here } In my situation, putting try catch in the Start method is impossible. How can I handle it in the global code?

  Read the article

< Previous Page | 54 55 56 57 58 59 60 61 62 63 64 65  | Next Page >