I need to run 5 algorithms parallely each takes an image as input and gives image as output. After each of these is done, I need to display the 5 output images. I'm using Asynchronous Callback using delegates for this task. So, I created 5 delegates for these 5 algos and calling them like algo1Delegate.BeginInvoke(). Algorithms are run...
On Linux pwrite operation (which is seek+write) is atomic, meaning doing pwrite-s in multiple threads with one file descriptor is safe. I want to create file descriptor duplicate, using dup(). Now, having fd1 and fd2 - will pwrite-s work as expected, or there's danger of race condition? ...
The idomatic way to start a new side-effect-only task (that is: a task that returns no result) using the TPL in .NET 4.0 is using the following API: Task Task.Factory.StartNew(Action<object>, object) But why doesn't the signature of this API look like this Task Task.Factory.StartNew<T>(Action<T>, T) or like this Task Task.Factor...
I have a WinForms app (c#) that has a background thread that periodically grabs data from a data source, does some manipulation of it, and puts it in a DataTable. There are 1 or more components in the app that periodically poll this common data to do stuff with it. I'm wondering, what's the "right" way to synchronize this, so e.g. the co...
Hey I have run into a rather weird little problem. In the following code I can not understand how e can be null; try { //Some Code here } catch (Exception e) { //Here e is null } As far as I know, throw null will be converted to throw new NullReferenceException(). The problem seems to be related to multithreading, as removi...
So I'm working on a speed contest in Java. I have (number of processors) threads doing work, and they all need to add to a B-Tree. Originally I just used a synchronized add method, but I wanted to make it so threads could follow each other through the tree (each thread only has the lock on the object it's accessing). Unfortunately, even ...
I have a java applet. A class inside that applet is creating a thread to do some work, waiting 30 seconds for that work to complete, if its not completed in 30 secs it sets a Boolean to stop the thread. The wait and Boolean change are in a synchronized block, Is this necessary considering there is no other thread running aside from these...
I'm writing a project at the moment that involves running two parallel threads to pull data from different sources at regular intervals. I am using the Threads functionality in ruby 1.9 to do this but am unfortunately running up against deadlock problems. Also I have a feeling that the Thread.join method is causing the threads to queue r...
i have a process ta take long time and i want a window to show the progresse but i can't figure how to display the progress here the code: if (procced) { // the wpf windows : myLectureFichierEnCour = new LectureFichierEnCour(_myTandemLTEclass); myLectureFichierEnCour.Show(); ...
In Spring, is there a way to execute a task after returning a view or I need to create a ThreadPool and do it ? Ex: public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { Map<Object, Object> data = new HashMap<Object, Object>(); //do some stuff exe...
Is std::list thread safe? I'm assuming its not so I added my own synchronization mechanisms (I think i have the right term). But I am still running into problems Each function is called by a separate thread. Thread1 can not wait, it has to be as fast as possible std::list<CFoo> g_buffer; bool g_buffer_lock; void thread1( CFoo fram...
This is on a Redhat EL5 machine w/ a 2.6.18-164.2.1.el5 x86_64 kernel using gcc 4.1.2 and gdb 7.0. When I run my application with gdb and break in while it's running, several of my threads show the following call stack when I do a backtrace: #0 0x000000000051d7da in pthread_cond_wait () #1 0x0000000100000000 in ?? () #2 0x0000000000...
I'm running 40-or-so threads with the following subroutine: my $app = shift; my $ua = LWP::UserAgent->new(); $ua->timeout(5); my $response = $ua->get($$app{'watch_url'}); my $new_md5; if ($response->is_success()) { $new_md5 = md5_hex($response->content()); } return ($$app{'short_name'}, $$app{'watch_md5'}, $new_md5); Core dumps en...
What are the effects of calling SetThreadUILanguage in an applicaton? Will it cause captions like "OK" and "CANCEL" on a MessageBox to appear in the language set through this API? If the captions do appear in the set language, do they require a localized version of the OS in that language or is it sufficient to have an MUI (Multilinguis...
I'm looking for the simplest, most straightforward way to implement the following: main starts and launches 3 threads all 3 tasks process and end in a resulting value (which I need to return somehow?) main waits (.join?) on each thread to ensure they have all 3 completed their task main somehow gets the value from each thread (3 values...
How can I know if the running code is executed in the main thread (UI thread). With Swing I use the isEventDispatchThread method... ...
We used Apache with JBOSS for hosting our Application, but we found some issues related to thread handling of mod_jk. Our website comes under low traffic websites and has maximum 200-300 concurrent users during our website's peak activity time. As the traffic grows (not in terms of concurrent users, but in terms of cumulative requests ...
I have a std::map that I use to map values (field ID's) to a human readable string. This map is initialised once when my program starts before any other threads are started, and after that it is never modified again. Right now, I give every thread its own copy of this (rather large) map but this is obviously inefficient use of memory and...
As the subject is self explainatory, I need help. I'm writing a small tool that displays a splash screen when starting. The splash screen is a Form. When there was only a Button control on it it was working fine. But when I removed it and placed a WebBrowser control on it, it throws the above exception. Thanks in advance. ...
Good day, How I can use QWebView with method load() in threads? I have create QWebView in main(!) thread, but I can't use load() with QWebView (used signals/slots from other threads to do it): QWebView wv = new QWebView(); //ok QUrl url = new QUrl("http://somesite.com/"); //ok wv.load(url); //ERROR: QObject: Cannot create children for...