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• What could cause these Apache crash errors ?

  - by jacobanderssen

  Hello guys. I had a server crash several days ago. I use Cacti to keep stats: at the time when the server crashed, a huge spike from Load 1 to Load 200 occurred, with over 800 processes in the run queue ( from 300 average). Upon checking /var/log/httpd I notice this: * glibc detected /usr/sbin/httpd: double free or corruption (out): 0x00002b8f3142c2f0 ** Followed by alot of these: [Sat Mar 13 19:20:20 2010] [warn] child process 3090 still did not exit, sending a SIGTERM [Sat Mar 13 19:20:20 2010] [warn] child process 3091 still did not exit, sending a SIGTERM Followed by this: ======= Backtrace: ========= /lib64/libc.so.6[0x2b8f1463c2ef] /lib64/libc.so.6(cfree+0x4b)[0x2b8f1463c73b] /usr/lib64/libapr-1.so.0(apr_pool_destroy+0x131)[0x2b8f13f98821] /usr/sbin/httpd[0x2b8f126df47e] /usr/sbin/httpd[0x2b8f126df4ab] /lib64/libpthread.so.0[0x2b8f141b87c0] /etc/httpd/modules/mod_file_cache.so[0x2b8f1cdf00fb] ======= Memory map: ======== And finally a lot of these: [Sat Mar 13 19:20:27 2010] [error] could not make child process 733 exit, attempting to continue anyway [Sat Mar 13 19:20:27 2010] [error] could not make child process 24560 exit, attempting to continue anyway [Sat Mar 13 19:20:27 2010] [error] could not make child process 31384 exit, attempting to continue anyway I am also noticing one or two lines like this: [Mon Mar 15 01:17:26 2010] [notice] child pid 20765 exit signal Segmentation fault (11) Please help me shed some light on this. Thanks !

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• how to assign value to EIP with C language in ubuntu

  - by user353573

  where is wrong? how to assign value to eip to change the location of running in program? Please help !!!! error: cannot convert ‘mcontext_t*’ to ‘sigcontext*’ in assignment struct ucontext { unsigned long uc_flags; struct ucontext *uc_link; stack_t uc_stack; struct sigcontext uc_mcontext; sigset_t uc_sigmask; /* mask last for extensibility */ }; #include <stdio.h> #include <signal.h> #include <asm/ucontext.h> void handler(int signum, siginfo_t *siginfo, void *uc0){ struct ucontext *uc; struct sigcontext *sc; uc = (struct ucontext *)uc0; sc = &uc->uc_mcontext; sc->eip = target; //uc->uc_mcontext.gregs[REG_EIP] } int main (int argc, char** argv){ struct sigaction act; act.sa_sigaction = handler; act.sa_flags = SA_SIGINFO; sigaction(SIGTRAP, &act, NULL); asm("movl $skipped, %0" : : "m" (target)); asm("int3"); // cause SIGTRAP printf("to be skipped.\n"); asm("skipped:"); printf("Done.\n"); }

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• Best practices for encrypting continuous/small UDP data

  - by temp

  Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (no waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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• Using sigprocmask to implement locks

  - by EpsilonVector

  I'm implementing user threads in Linux kernel 2.4, and I'm using ualarm to invoke context switches between the threads. We have a requirement that our thread library's functions should be uninterruptable, so I looked into blocking signals and learned that using sigprocmask is the standard way to do this. However, it looks like I need to do quite a lot to implement this: sigset_t new_set, old_set; sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); This blocks SIGALARM but it does this with 3 function invocations! A lot can happen in the time it takes for these functions to run, including the signal being sent. The best idea I had to mitigate this was temporarily disabling ualarm, like this: sigset_t new_set, old_set; time=ualarm(0,0); sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); ualarm(time, 0); Which is fine except that this feels verbose. Isn't there a better way to do this?

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• In ArrayBlockingQueue, why copy into ReentrantLock field into local final variable?

  - by mjlee

  In ArrayBlockingQueue, any method that requires lock will get set 'final' local variable before calling 'lock()'. public boolean offer(E e) { if (e == null) throw new NullPointerException(); final ReentrantLock lock = this.lock; lock.lock(); try { if (count == items.length) return false; else { insert(e); return true; } } finally { lock.unlock(); } } Is there any reason to set a local variable 'lock' from 'this.lock' when field 'this.lock' is final also. Additionally, it also set local variable of E[] before acting on. private E extract() { final E[] items = this.items; E x = items[takeIndex]; items[takeIndex] = null; takeIndex = inc(takeIndex); --count; notFull.signal(); return x; } Is there any reason for copying to local final variable?

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• Displaying modal view in Objective-C

  - by kpower

  I'm trying to display Modal View in my app. I have subclass of UIViewController that has only the "Done" button (UIButton created with IB and linked with XCode). .h @interface myModalVC : UIViewController { UIButton *bDone; } @property (nonatomic, retain) IBOutlet UIButton *bDone; - (IBAction)bDoneTouchDown:(id)sender; @end .m #import "myModalVC.h" @implementation myModalVC @synthesize bDone; - (void)dealloc { [bDone release]; [super dealloc]; } - (void)viewDidLoad { [super viewDidLoad]; } - (void)viewDidUnload { } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (UIInterfaceOrientationLandscapeLeft == interfaceOrientation || UIInterfaceOrientationLandscapeRight == interfaceOrientation); } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; } - (IBAction)bDoneTouchDown:(id)sender { [self.parentViewController dismissModalViewControllerAnimated:YES]; } @end I'm trying to display modal view with this code (from my main view): myModalVC *temp = [[[myModalVC alloc] initWithNibName:@"myModalVC" bundle:[NSBundle mainBundle]] autorelease]; [self presentModalViewController:temp animated:YES]; If this code is placed in some method, that responds to button touches - everything is fine. But when I place it to some other method (called during some processes in my app) - modal view is displayed without problems, but when I press (touch) "Done" button, application crashes with "Program received signal: “EXC_BAD_ACCESS”." What am I doing wrong?

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• Why does using the Asynchronous Programming Model in .Net not lead to StackOverflow exceptions?

  - by uriDium

  For example, we call BeginReceive and have the callback method that BeginReceive executes when it has completed. If that callback method once again calls BeginReceive in my mind it would be very similar to recursion. How is that this does not cause a stackoverflow exception. Example code from MSDN: private static void Receive(Socket client) { try { // Create the state object. StateObject state = new StateObject(); state.workSocket = client; // Begin receiving the data from the remote device. client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void ReceiveCallback( IAsyncResult ar ) { try { // Retrieve the state object and the client socket // from the asynchronous state object. StateObject state = (StateObject) ar.AsyncState; Socket client = state.workSocket; // Read data from the remote device. int bytesRead = client.EndReceive(ar); if (bytesRead > 0) { // There might be more data, so store the data received so far. state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead)); // Get the rest of the data. client.BeginReceive(state.buffer,0,StateObject.BufferSize,0, new AsyncCallback(ReceiveCallback), state); } else { // All the data has arrived; put it in response. if (state.sb.Length > 1) { response = state.sb.ToString(); } // Signal that all bytes have been received. receiveDone.Set(); } } catch (Exception e) { Console.WriteLine(e.ToString()); } }

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• C++ Initialize array in constructor EXC_BAD_ACCESS

  - by user890395

  I'm creating a simple constructor and initializing an array: // Construtor Cinema::Cinema(){ // Initalize reservations for(int i = 0; i < 18; i++){ for(int j = 0; j < 12; j++){ setReservation(i, j, 0); } } // Set default name setMovieName("N/A"); // Set default price setPrice(8); } The setReservation function: void Cinema::setReservation(int row, int column, int reservation){ this->reservations[row][column] = reservation; } The setMovieName function: void Cinema::setMovieName(std::string movieName){ this->movieName = movieName; } For some odd reason when I run the program, the setMovieName function gives the following error: "Program Received Signal: EXC_BAD_ACCESS" If I take out the for-loop that initializes the array of reservations, the problem goes away and the movie name is set without any problems. Any idea what I'm doing wrong? This is the Cinema.h file: #ifndef Cinema_h #define Cinema_h class Cinema{ private: int reservations[17][11]; std::string movieName; float price; public: // Construtor Cinema(); // getters/setters int getReservation(int row, int column); int getNumReservations(); std::string getMovieName(); float getPrice(); void setReservation(int row, int column, int reservation); void setMovieName(std::string movieName); void setPrice(float price); }; #endif

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• How to update a Widget dynamically (Not waiting 30 min for onUpdate to be called)?

  - by Donal Rafferty

  I am currently learning about widgets in Android. I want to create a WIFI widget that will display the SSID, the RSSI (Signal) level. But I also want to be able to send it data from a service I am running that calculates the Quality of Sound over wifi. Here is what I have after some reading and a quick tutorial: public class WlanWidget extends AppWidgetProvider{ RemoteViews remoteViews; AppWidgetManager appWidgetManager; ComponentName thisWidget; WifiManager wifiManager; public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { Timer timer = new Timer(); timer.scheduleAtFixedRate(new WlanTimer(context, appWidgetManager), 1, 10000); } private class WlanTimer extends TimerTask{ RemoteViews remoteViews; AppWidgetManager appWidgetManager; ComponentName thisWidget; public WlanTimer(Context context, AppWidgetManager appWidgetManager) { this.appWidgetManager = appWidgetManager; remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget); thisWidget = new ComponentName(context, WlanWidget.class); wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE); } @Override public void run() { remoteViews.setTextViewText(R.id.widget_textview, wifiManager.getConnectionInfo().getSSID()); appWidgetManager.updateAppWidget(thisWidget, remoteViews); } } The above seems to work ok, it updates the SSID on the widget every 10 seconds. However what is the most efficent way to get the information from my service that will be already running to update periodically on my widget? Also is there a better approach to updating the the widget rather than using a timer and timertask? (Avoid polling) UPDATE As per Karan's suggestion I have added the following code in my Service: RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget); ComponentName thisWidget = new ComponentName( context, WlanWidget.class ); remoteViews.setTextViewText(R.id.widget_QCLevel, " " + qcPercentage); AppWidgetManager.getInstance( context ).updateAppWidget( thisWidget, remoteViews ); This gets run everytime the RSSI level changes but it still never updates the TextView on my widget, any ideas why?

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• Communication between lexer and parser

  - by FredOverflow

  Every time I write a simple lexer and parser, I stumble upon the same question: how should the lexer and the parser communicate? I see four different approaches: The lexer eagerly converts the entire input string into a vector of tokens. Once this is done, the vector is fed to the parser which converts it into a tree. This is by far the simplest solution to implement, but since all tokens are stored in memory, it wastes a lot of space. Each time the lexer finds a token, it invokes a function on the parser, passing the current token. In my experience, this only works if the parser can naturally be implemented as a state machine like LALR parsers. By contrast, I don't think it would work at all for recursive descent parsers. Each time the parser needs a token, it asks the lexer for the next one. This is very easy to implement in C# due to the yield keyword, but quite hard in C++ which doesn't have it. The lexer and parser communicate through an asynchronous queue. This is commonly known under the title "producer/consumer", and it should simplify the communication between the lexer and the parser a lot. Does it also outperform the other solutions on multicores? Or is lexing too trivial? Is my analysis sound? Are there other approaches I haven't thought of? What is used in real-world compilers? It would be really cool if compiler writers like Eric Lippert could shed some light on this issue.

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• Distributed Cache with Serialized File as DataStore in Oracle Coherence

  - by user226295

  Weired but I am investigating the Oracle Coherence as a substitue for distribute cache. My primarr problem is that we dont have distribituted cache as such as of now in our app. Thats my major concern. And thats what I want to implement. So, lets say if I take up a machine and start a new (3rd) reading process, it will be able to connect to the cache and listen to the cache and will have a full set of cache triplicated (as of now its duplicated) Now thats waste from a common person stanpoint too. The size of the cache is 2 GB and without going distibuted its limiting us. Thats bring me to Coheremce. But now, we dont have database as persistent store too. we have the archival processes as our persistent store. (90 days worth of data) Ok now multiply that with soem where around 2 GB * 90 (thats the bare minimum we want to keep). Preliminary/Intermediate analysis of Coherence as a solution. And a (supposedly) brilliant thought crossed my mind. Why not have this as persistant storage with my distributed cache. Does Oracle Coherence support that. I will get rid of archiving infrastructure too (i hate daemon archiving processes). For some starnge reasons, I dont wanna go to the DB to replace those flat files. What say?, can Coherence be my savior? Any other stable alternate too. (Coherence is imposed on me by big guys, FYI)

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• Syncing two AS3 NetStreams

  - by Lowgain

  I'm writing an app that requires an audio stream to be recording while a backing track is played. I have this working, but there is an inconsistent gap in between playback and record starting. I don't know if I can do anything to make the sync perfect every time, so I've been trying to track what time each stream starts so I can calculate the delay and trim it server-side. This also has proved to be a challenge as no events seem to be sent when a connection starts (as far as I know). I've tried using various properties like the streams' buffer sizes, etc. I'm thinking now that as my recorded audio is only mono, I may be able to put some kind of 'control signal' on the second stereo track which I could use to determine exactly when a sound starts recording (or stick the whole backing track in that channel so I can sync them that way). This leaves me with the new problem of properly injecting this sound into the NetStream. If anyone has any idea whether or not any of these ideas will work, how to execute them, or some alternatives, that would be extremely helpful! Been working on this issue for awhile

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• fix needed for bug in TextField/Text

  - by Mark

  Sort of a complicated scenario - just curious if anyone else could come up with something: I have a Text control and when I scroll it and stop the scroll with the cursor over some text that has a url, the cursor doesn't revert to a hand, and also flash player starts acting as if a selection is being made from the last cursor position. So IOW a bonafide bug in flash as far as I can determine. The above probably wasn't completely clear so let me elaborate. If you grab a scrollbar thumb and start moving it up and down, you don't actually have to keep the mouse pointer on the thumb while doing so. When you stop the scroll, the mouse pointer could be outside the browser window, inside your flash application, but not currently on the scroll bar thumb, or wherever. The previously mentioned bug occurs when you stop the scroll with the mouse pointer positioned over text with an html anchor (a hyperlink). At that point the cursor enters into some state of limbo, and doesn't show the url hand pointer, and furthermore acts as if some text selection is taking place from the last cursor position prior to the scroll. So the question would be, what sort of event could I simulate in code to jolt flash out of this erroneous state it is in. And furthermore in what event could I perform this simulated event (given that for example there is no AS3 event to signal the end of a scroll.) To be clear, the Text control in question is on a canvas, and that canvas (call it A) is on another canvas which actually owns the scrollbar, and scrolling takes place by changing the scrollRect of canvas A.

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• Common "truisms" needing correction the most

  - by Charles Bretana

  In addition to "I never met a man I didn't like", Will Rogers had another great little ditty I've always remembered. It went: "It's not what you don't know that'll hurt you, it's what you do know that ain't so." We all know or subscribe to many IT "truisms" that mostly have a strong basis in fact, in something in our professional careers, something we learned from others, lessons learned the hard way by ourselves, or by others who came before us. Unfortuntely, as these truisms spread throughout the community, the details—why they came about and the caveats that affect when they apply—tend to not spread along with them. We all have a tendency to look for, and latch on to, small "rules" or principles that we can use to avoid doing a complete exhaustive analysis for every decision. But even though they are correct much of the time, when we sometimes misapply them, we pay a penalty that could be avoided by understooding the details behind them. For example, when user-defined functions were first introduced in SQL Server it became "common knowledge" within a year or so that they had extremely bad performance (because it required a re-compilation for each use) and should be avoided. This "trusim" still increases many database developers' aversion to using UDFs, even though Microsoft's introduction of InLine UDFs, which do not suffer from this issue at all, mitigates this issue substantially. In recent years I have run into numerous DBAs who still believe you should "never" use UDFs, because of this. What other common not-so-"trusims" do you know, which many developers believe, that are not quite as universally true as is commonly understood, and which the developer community would benefit from being better educated about? Please include why it was "true" to start off with, and under what circumstances it's not true. Limit responses to issues that are technical, where the "common" application of a "rule or principle" is in fact correct most of the time, or was correct back when it was first elucidated, but—in the edge cases, or because of not understanding the principle thoroughly, because technology has changed since it first spread, or applying the rule today without understanding the details behind the rule—can easily backfire or cause the opposite of the intended effect.

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• WSDL first for existing service layer

  - by Jurgen H

  I am working on an existing Java project with a typical services - dao setup for which only a webapplication was available. My job is to add webservices on top of the services layer, but the webservices have their own functional analysis and datamodel. The functional analyses ofcource focuses on what is possible in the different service methods. As good practice demands, we used the WSDL first strategy and generated JAXB bound Java classes and a SEI for the webservices. After having implemented the webservices partially, we noticed a 70% match between the datamodel. This resulted in writing converters which take the webservice JAXB classes and map them with the service layer classes. Customer customer = new Customer(); customer.setName(wsCustomer.getName()); customer.setFirstName(wsCustomer.getFirstName(); .. This is a very obvious example, some other mappings where little more complicated. Can anyone give his best practices, experiences, solutions to this kind of situations? Are any of these frameworks usefull? http://transmorph.sourceforge.net/wiki/index.php/Main_Page http://ezmorph.sourceforge.net/ Please don't start a discussion about WSDL first vs code first.

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• problem with implementing a simple work queue

  - by John Deerikio

  Hi all, I am having troubles with implementing a simple work queue. Doing some analysis, I am facing a subtle problem. The work queue is backed by a regular linked list. The code looks like this (simplified): 0. while (true) 1. while (enabled == true) 2. acquire lock on the list and get the next action to be executed (blocking operation) (store it in a local variable) 3. execute the action (outside the lock on the list on previous line) 4. get lock on this work queue 5. wait until this work queue has been notified (triggered when setEnabled(true) has been callled) The setEnabled(e) operation looks like this (simplified): enabled = e if (enabled == true) acquire lock on this work queue and do notify() Although this works, there is a condition in which a deadlock occurs. It happens in the following rare situation: while an action is being executed, setEnabled(false) is called just before step (4) is entered, setEnabled(true) is called now step (5) keeps waiting forever, because this work queue has already been notified How do I solve this? I have been looking at this for some time, but I cannot come up with a solution. Please note I am fairly new to thread synchronization. Thanks a lot.

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• Organising UI code in .NET forms

  - by sb3700

  Hi I'm someone who has taught myself programming, and haven't had any formal training in .NET programming. A while back, I started C# in order to develop a GUI program to control sensors, and the project has blossomed. I was just wondering how best to organise the code, particularly UI code, in my forms. My forms currently are a mess, or at least seem a mess to me. I have a constructor which initialises all the parameters and creates events. I have a giant State property, which updates the Enabled state of all my form control as users progress through the application (ie: disconnected, connected, setup, scanning) controlled by a States enum. I have 3-10 private variables accessed through properties, some of which have side-effects in changing the values of form elements. I have a lot of "UpdateXXX" functions to handle UI elements that depend on other UI elements - ie: if a sensor is changed, then change the baud rate drop down list. They are separated into regions I have a lot of events calling these Update functions I have a background worker which does all the scanning and analysis. My problem is this seems like a mess, particularly the State property, and is getting unmaintainable. Also, my application logic code and UI code are in the same file and to some degree, intermingled which seems wrong and means I need to do a lot of scrolling to find what I need. How do you structure your .net forms? Thanks

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• Accurately and securely measure the time spent viewing a web page

  - by balpha

  Suppose the following: You have a web page that presents a simple game to a user (e.g. a quiz, a puzzle, etc). The user solves the puzzle, submits the result, and you want to measure as precisely as possible how long they took to solve it. Assume it's quite simple, so we're talking seconds, not hours. Also assume JavaScript is required anyway, so there's no need to think of JS-disabled browsers. Finally, assume we don't want to use anything like Flash, Silverlight, or the like. I can think of several techniques: Simply take the time between the points when the data was sent from the server and when the submission arrives. Since this is exclusively server-side, there's no chance for cheating. However, issues like network latency and page rendering time might make this unfair for users with slow computers / browsers / internet connections. On the first request, just send the page without the actual game data. When everything is loaded so far, retrieve the game data through an AJAX call and populate it into the page. This is similar to 1., but reduces some of the caveats introduced through time spent on overhead. Have the time measured on the client side using JavaScript and submitted alongside with the solution. This would theoretically be the most accurate, but it introduces the possibility of cheating, because you're relying on client data. Use the request time headers of a "ready to play" AJAX call and the result submission request. Same caveat as 3., as it is still client data. A combination of server side and client side measuring with some kind of plausibility analysis. I can't think of a good way, but maybe you can. Thoughts? Other ideas?

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• How can I build a generic dataset-handling Perl library?

  - by Pep.

  Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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• How to properly handle signals when using the worker thread pattern?

  - by ipartola

  I have a simple server that looks something like this: void *run_thread(void *arg) { // Communicate via a blocking socket } int main() { // Initialization happens here... // Main event loop while (1) { new_client = accept(socket, ...); pthread_create(&thread, NULL, &run_thread, *thread_data*); pthread_detach(thread); } // Do cleanup stuff: close(socket); // Wait for existing threads to finish exit(0); ) Thus when a SIGINT or SIGTERM is received I need to break out of the main event loop to get to the clean up code. Moreover most likely the master thread is waiting on the accept() call so it's not able to check some other variable to see if it should break;. Most of the advice I found was along the lines of this: http://devcry.blogspot.com/2009/05/pthreads-and-unix-signals.html (creating a special signal handling thread to catch all the signals and do processing on those). However, it's the processing portion that I can't really wrap my head around: how can I possibly tell the main thread to return from the accept() call and check on an external variable to see if it should break;?

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• TCP Message Structure with XML

  - by metdos

  Hello Everybody, I'm sending messages over TCP/IP and on the other side I parse TCP message.For example this is one of the sent messages. $DKMSG(requestType=REQUEST_LOGIN&requestId=123&username=metdos&password=123)$EDKMSG Clarification: $DKMSG( //Start )$EDKMSG //End requestType //Parameter REQUEST_LOGIN //Parameter Value Now I also want to add an Xml file to my message. I'm considering this option: $DKMSG(requestType=REQUEST_LOGIN&xmlData= <Item id="56D@MIT" type="SIGNAL"> <Label> <Text>56D</Text> <X1>10</X1> <Y1>40</Y1> <RotateAngle>90</RotateAngle> </Label> <X1>0</X1> <Y1>20</Y1> <Width>35</Width> <Height>10</Height> <Source>sgs3lr</Source> </Item> )$EDKMSG There are problems with this way: 1-)It doesn't seem right to me. 2-)I have to handle delimeter "=" with much more care or I need to change it in parameters. What are your suggestions, thanks.

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• Typical SVN repo structure seems to be sub-optimal for continuous integration...

  - by Dave

  I've set up our SVN repository like the Subversion book suggests, and this is also how my previous companies have done it. It looks something like this: /trunk /branches /tags /extlibs /docs where the first three are pretty obvious, and extlibs is for 3rd party assemblies that we wouldn't typically recompile ourselves. All of this works great for the daily development stuff. Now I've installed TeamCity and have builds, unit tests, code coverage, and code analysis running. Everything is great, except for the fact that this code structure results in too much code getting downloaded. So here's the catch 22, in my opinion: it's silly to download all of aforementioned folders from the SVN repo when I only need /trunk and /extlibs. But I can only specify one repo folder to download in the TeamCity VCS settings. So then the other possibility is to put the /extlibs folder into /trunk, but in order to compile branches, /extlibs would have to go into all of those as well (since I usually branch the trunk, and not individual subfolders... and this would seem infinitely more evil since /extlibs could actually be larger than /trunk and /branches, with all of the binaries stored there... Do you guys have any suggestions for me? Thanks!

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• google maps api keys to be set webserver-wide, (as env var? inside apache?)

  - by ~knb

  I have a web site with many virtual hosts and each registered with several domain names (ending in .org, .de), site1.mysite.de, site2.mysite.org Then I have different templating systems based on several programming languages (perl and php) in use on the web server. The Google Maps Api requires a unique Google Maps api key for each vhost. I want to have something like a web-server wide variable $goomapkey that I can call from inside my code. In PHP code, Now I have a kludgy case-analysis solution like $domain = substr($_SERVER['SERVER_NAME'], -3); if (".de" == $domain){ //if ("xxxxxx" eq substr($ENV{SERVER_NAME}, 0, 5)){ // $gookey = "ABQIAAA..."; //} else { //site1.de $gookey = "ABQIAAAA1Js..."; //} } elseif ("dev" == substr($_SERVER['SERVER_NAME'], 0, 3)){ //dev.mysite.org $gookey = "ABQIAAAA1JsSb..."; } else { //www.mysite.org $gookey = "ABQIAAAA1JsS..."; //TODO: Add more keys for each virtual host, for my.machinename.de, IP-address based URL, ... } ... inside my php-based CMS. A non-ideal solution, because it is, php-only, and I still have to set it at several html templates inside the CMS, and there are too many cases. I want the google maps api key to be set by the apache web server who examines the request *early in the request loop before any php page template code is constructed and evaluated. is an environment variable a good solution? which technology should be used to set the $goomapkey variable? I'd prefer mod_perl2 Apache request handler, but the documentation is confusing (many API changes in the past ). Which Apache module could I use? Is there a built-in Apache module that does the same thing?

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• What are salesforce.com and Apex like as an application development platform?

  - by mhollers

  I have recently discovered that salesforce.com is much more than an online CRM after coming across a Morrison's Case Study in which they develop a works management application. I've been trying it out with a view to recreating our own Works Management system on the platform. My background is in Microsoft and .Net, and the obvious 1st choice would be asp.net. However, there's only really myself with .net experience and my manager with a more legacy Synergy programming background, and I am self taught and am looking at evaluating other RAD options (eg Ironspeed). the nature of the business is in the main 2-5 concurrent construction type contracts that run for 3-5 yrs each, each requiring 15-50 system users. Traditionally we have used our character based Works Mangement system for everything and tweaked it for each contract. The Salesforce licensing model on the face of it suits this sort of flexibilty, but I'm worried about the development flexibilty/learning curve and all the issues that surround lock-in. There doesn't seem to be much neutral sober analysis of the platform on the web that isn't salesforce's own material/blogs Has anyone any experience of developing an application on salesforce as compared to the more 'traditional' .Net route?

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• Execute a block of database querys

  - by Nightmare

  I have the following task to complete: In my program a have a block of database querys or questions. I want to execute these questions and wait for the result of all questions or catch an error if one question fails! My Question object looks like this (simplified): public class DbQuestion(String sql) { [...] } [...] //The answer is just a holder for custom data... public void SetAnswer(DbAnswer answer) { //Store the answer in the question and fire a event to the listeners this.OnAnswered(EventArgs.Empty); } [...] public void SetError() { //Signal an Error in this query! this.OnError(EventArgs.Empty); } So every question fired to the database has a listener that waits for the parsed result. Now I want to fire some questions asynchronous to the database (max. 5 or so) and fire an event with the data from all questions or an error if only one question throws one! Which is the best or a good way to accomplish this task? Can I really execute more then one question parallel and stop all my work when one question throws an error? I think I need some inspiration on this... Just a note: I´m working with .NET framework 2.0

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