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  • What are the right questions to ask when deciding whether to use Chef or Puppet?

    - by John Feminella
    I am about to start a new project which will, in part, require deploying many identical nodes of approximately three different classes: Data nodes, which will run sharded instances of MongoDB. Application nodes, which will run instances of a Ruby on Rails application and an older ASP.NET MVC application. Processing nodes, which will run jobs requested by the application nodes. ALl the nodes will run on instances of Ubuntu 10.04, though they will have different packages installed. I have some familiarity with Chef from previous projects, though I don't consider myself an expert. In an effort to do due diligence, I have been investigating alternative possibilities. We have a number of folks in-house who are long-time Puppet users, and they have encouraged me to take a look. I am having trouble evaluating both choices, though. Chef and Puppet share many of the same domain terminology -- packages, resources, attributes, and so on, and they have a common history that stems from taking different approaches to the same problem. So in some sense they are very similar. But much of the comparison information I've found, like this article, is a little outdated. If you were starting this project today, what questions would you ask yourself to decide whether you should use Chef or Puppet for configuration management? (Note: I don't want answer to the question "Should I use Chef or Puppet?")

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  • How many iptables block rules is too many

    - by mhost
    We have a server with a Quad-Core AMD Opteron Processor 2378. It acts as our firewall for several servers. I've been asked to block all IPs from China. In a separate network, we have some small VPS machines (256MB and 512MB). I've been asked to block china on those VPS's as well. I've looked online and found lists which requires 4500 block rules. My question is will putting in all 4500 rules be a problem? I know iptables can handle far more rules than that, what I am concerned about is since these are blocks that I don't want to have access to any port, I need to put these rules before any allow. This means all legitimate traffic needs to be compared to all those rules before getting through. Will the traffic be noticeably slower after implementing this? Will those small VPS's be able to handle processing that many rules for every new packet (I'll put an established allow before the blocks)? My question is not How many rules can iptables support?, its about the effect that these rules will have on load and speed. Thanks.

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  • Strange 3-second tcp connection latencies (Linux, HTTP)

    - by user25417
    Our webservers with static content are experiencing strange 3 second latencies occasionally. Typically, an ApacheBench run ( 10000 requests, concurrency 1 or 40, no difference, but keepalive off) looks like this: Connection Times (ms) min mean[+/-sd] median max Connect: 2 10 152.8 3 3015 Processing: 2 8 34.7 3 663 Waiting: 2 8 34.7 3 663 Total: 4 19 157.2 6 3222 Percentage of the requests served within a certain time (ms) 50% 6 66% 7 75% 7 80% 7 90% 9 95% 11 98% 223 99% 225 100% 3222 (longest request) I have tried many things: - Apache2 2.2.9 with worker or prefork MPM, no difference (with KeepAliveTimeout 10-15) - Nginx 0.6.32 - various tcp parameters (net.core.somaxconn=3000, net.ipv4.tcp_sack=0, net.ipv4.tcp_dsack=0) - putting the files/DocumentRoot on tmpfs - shorewall on or off (i.e. empty iptables or not) - AllowOverride None is on for /, so no .htaccess checks (verified with strace) - the problem persists whether the webservers are accessed directly or through a Foundry load balancer Kernel is 2.6.32 (Debian Lenny backports), but it occurred with 2.6.26 also. IPv6 is enabled, but not used. Does the issue look familiar to anyone? Help/suggestions are much appreciated. It sounds a bit like a SYN,ACK packet getting lost or ignored.

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  • Vim: How to join multiples lines based on a pattern?

    - by ryz
    I want to join multiple lines in a file based on a pattern that both lines share. This is my example: {101}{}{Apples} {102}{}{Eggs} {103}{}{Beans} {104}... ... {1101}{}{This is a fruit.} {1102}{}{These things are oval.} {1103}{}{You have to roast them.} {1104}... ... I want to join the lines {101}{}{Apples} and {1101}{}{This is a fruit.} to one line {101}{}{Apples}{1101}{}{This is a fruit.} for further processing. Same goes for the other lines. As you can see, both lines share the number 101, but I have no idea how to pull this off. Any Ideas? /EDIT: I found a "workaround": First, delete all preceding "{1" characters from group two in VISUAL BLOCK mode with C-V (or similar shortcut), then sort all lines by number with :%sort n, then join every second line with :let @q = "Jj" followed by 500@q. This works, but leaves me with {101}{}{Apples} 101}{}{This is a fruit.}. I would then need to add the missing characters "{1" in each line, not quite what I want. Any help appreciated.

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  • PDF rendering crashes app Core Graphics

    - by Felixyz
    EDIT: The memory leaks turned out to be unrelated to the crashes. Leaks are fixed but crashes remain, still mysterious. My (iPhone) app does lots of PDF loading and rendering, some of it threaded. Sometime, it seems always after I flush a page cash after getting a memory warning, the app crashes with a bad access when trying to draw a pdf page stored in an NSData object. Here is one example trace: #0 0x3016d564 in CGPDFResourcesGetResource () #1 0x3016d58a in CGPDFResourcesGetResource () #2 0x3016d94e in CGPDFResourcesGetExtGState () #3 0x3015fac4 in CGPDFContentStreamGetExtGState () #4 0x301629a8 in op_gs () #5 0x3016df12 in handle_xname () #6 0x3016dd9e in read_objects () #7 0x3016de6c in CGPDFScannerScan () #8 0x30161e34 in CGPDFDrawingContextDraw () #9 0x3016a9dc in CGContextDrawPDFPage () But sometimes I get this instead: Program received signal: “EXC_BAD_ACCESS”. (gdb) bt #0 0x335625fa in objc_msgSend () #1 0x32c04eba in CFDictionaryGetValue () #2 0x3016d500 in get_value () #3 0x3016d5d6 in CGPDFResourcesGetFont () #4 0x3015fbb4 in CGPDFContentStreamGetFont () #5 0x30163480 in op_Tf () #6 0x3016df12 in handle_xname () #7 0x3016dd9e in read_objects () #8 0x3016de6c in CGPDFScannerScan () #9 0x30161e34 in CGPDFDrawingContextDraw () #10 0x3016a9dc in CGContextDrawPDFPage () Is this an indication that I've mistakenly deallocated an object? It's hard for me to decode what's happening here. This is how I create and retain the various objects involved: // Some data was just loaded from the network and is pointed to by "data" self.pdfData = data; _dataProviderRef = CGDataProviderCreateWithData( NULL, [_pdfData bytes], [_pdfData length], NULL ); _documentRef = CGPDFDocumentCreateWithProvider(_dataProviderRef); _pageRef = CGPDFDocumentGetPage(_documentRef, 1); CGPDFPageRetain(_pageRef); _pdfFrame = CGPDFPageGetBoxRect(_pageRef, kCGPDFArtBox); So the NSData object is retained, and I explicitly retain the page reference. The data provider and the document are already retained by the create-functions. And here is my dealloc method: -(void)dealloc { if (_pageRef) CGPDFPageRelease(_pageRef); if (_documentRef) CGPDFDocumentRelease(_documentRef); if (_dataProviderRef) CGDataProviderRelease(_dataProviderRef); self.pdfData = nil; [super dealloc]; } Am I doing anything wrong? Even an assurance that I'm not, with explanation, would be a help.

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  • How to use Tor control protocol in C#?

    - by Ed
    I'm trying to send commands to the Tor control port programmatically to make it refresh the chain. I haven't been able to find any examples in C#, and my solution's not working. The request times out. I have the service running, and I can see it listening on the control port. public string Refresh() { TcpClient client = new TcpClient("localhost", 9051); string response = string.Empty; string authenticate = MakeTcpRequest("AUTHENTICATE", client); if (authenticate.Equals("250")) response = MakeTcpRequest("SIGNAL NEWNYM", client); client.Close(); return response; } public string MakeTcpRequest(string message, TcpClient client) { client.ReceiveTimeout = 20000; client.SendTimeout = 20000; string proxyResponse = string.Empty; try { // Send message StreamWriter streamWriter = new StreamWriter(client.GetStream()); streamWriter.Write(message); streamWriter.Flush(); // Read response StreamReader streamReader = new StreamReader(client.GetStream()); proxyResponse = streamReader.ReadToEnd(); } catch (Exception ex) { // Ignore } return proxyResponse; } Can anyone spot what I'm doing wrong?

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  • Label in PyQt4 GUI not updating with every loop of FOR loop

    - by user297920
    I'm having a problem, where I wish to run several command line functions from a python program using a GUI. I don't know if my problem is specific to PyQt4 or if it has to do with my bad use of python code. What I wish to do is have a label on my GUI change its text value to inform the user which command is being executed. My problem however, arises when I run several commands using a for loop. I would like the label to update itself with every loop, however, the program is not updating the GUI label with every loop, instead, it only updates itself once the entire loop is completed, and displays only the last command that was executed. I am using PyQt4 for my GUI environment. And I have established that the text variable for the label is indeed being updated with every loop, but, it is not actually showing up visually in the GUI. Is there a way for me to force the label to update itself? I have tried the update() and repaint() methods within the loop, but they don't make any difference. I would really appreciate any help. Thank you. Ronny. Here is the code I am using: # -*- coding: utf-8 -*- import sys, os from PyQt4 import QtGui, QtCore Gui = QtGui Core = QtCore # ================================================== CREATE WINDOW OBJECT CLASS class Win(Gui.QWidget): def __init__(self, parent = None): Gui.QWidget.__init__(self, parent) # --------------------------------------------------- SETUP PLAY BUTTON self.but1 = Gui.QPushButton("Run Commands",self) self.but1.setGeometry(10,10, 200, 100) # -------------------------------------------------------- SETUP LABELS self.label1 = Gui.QLabel("No Commands running", self) self.label1.move(10, 120) # ------------------------------------------------------- SETUP ACTIONS self.connect(self.but1, Core.SIGNAL("clicked()"), runCommands) # ======================================================= RUN COMMAND FUNCTION def runCommands(): for i in commands: win.label1.setText(i) # Make label display the command being run print win.label1.text() # This shows that the value is actually # changing with every loop, but its just not # being reflected in the GUI label os.system(i) # ======================================================================== MAIN # ------------------------------------------------------ THE TERMINAL COMMANDS com1 = "espeak 'senntence 1'" com2 = "espeak 'senntence 2'" com3 = "espeak 'senntence 3'" com4 = "espeak 'senntence 4'" com5 = "espeak 'senntence 5'" commands = (com1, com2, com3, com4, com5) # --------------------------------------------------- SETUP THE GUI ENVIRONMENT app = Gui.QApplication(sys.argv) win = Win() win.show() sys.exit(app.exec_())

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  • Objective C - displaying data in NSTextView

    - by Leo
    Hi, I'm having difficulties displaying data in a TextView in iPhone programming. I'm analyzing incoming audio data (from the microphone). In order to do that, I create an object "analyzer" from my SignalAnalyzer class which performs analysis of the incoming data. What I would like to do is to display each new incoming data in a TextView in realtime. So when I push a button, I create the object "analyzer" whiwh analyze the incoming data. Each time there is new data, I need to display it on the screen in a TextView. My problem is that I'm getting an error because (I think) I'm trying to send a message to the parent class (the one taking care of displaying stuff in my TextView : it has a TexView instance variable linked in Interface Builder). What should I do in order to tell my parent class what it needs to display ? Or how sohould I design my classes to display automaticlally something ? Thank you for your help. PS : Here is my error : 2010-04-19 14:59:39.360 MyApp[1421:5003] void WebThreadLockFromAnyThread(), 0x14a890: Obtaining the web lock from a thread other than the main thread or the web thread. UIKit should not be called from a secondary thread. 2010-04-19 14:59:39.369 MyApp[1421:5003] bool _WebTryThreadLock(bool), 0x14a890: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now... Program received signal: “EXC_BAD_ACCESS”.

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  • iPhone crashing when presenting modal view controller

    - by Michael Waterfall
    Hi there, I'm trying to display a modal view straight after another view has been presented modally (the second is a loading view that appears). - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; // Show load LoadViewController *loader = [[LoadViewController alloc] init]; [self presentModalViewController: loader animated:NO]; [loader release]; } But when I do this I get a "Program received signal: "EXC_BAD_ACCESS"." error. The stack trace is: 0 0x30b43234 in -[UIWindowController transitionViewDidComplete:fromView:toView:] 1 0x3095828e in -[UITransitionView notifyDidCompleteTransition:] 2 0x3091af0d in -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] 3 0x3091ad7c in -[UIViewAnimationState animationDidStop:finished:] 4 0x0051e331 in run_animation_callbacks 5 0x0051e109 in CA::timer_callback 6 0x302454a0 in CFRunLoopRunSpecific 7 0x30244628 in CFRunLoopRunInMode 8 0x32044c31 in GSEventRunModal 9 0x32044cf6 in GSEventRun 10 0x309021ee in UIApplicationMain 11 0x00002154 in main at main.m:14 Any ideas? I'm totally stumped! The loading view is empty so there's definitely nothing going on in there that's causing the error. Is it something to do with launching 2 views modally in the same event loop or something? Thanks, Mike Edit: Very strange... I have modified it slightly so that the loading view is shown after a tiny delay, and this works fine! So it appears to be something within the same event loop! - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; // Show load [self performSelector:@selector(doit) withObject:nil afterDelay:0.1]; } - (void)doit { [self presentModalViewController:loader animated:YES]; }

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  • Segmentation fault on MPI, runs properly on OpenMP

    - by Bellman
    Hi, I am trying to run a program on a computer cluster. The structure of the program is the following: PROGRAM something ... CALL subroutine1(...) ... END PROGRAM SUBROUTINE subroutine1(...) ... DO i=1,n CALL subroutine2(...) ENDDO ... END SUBROUTINE SUBROUTINE subroutine2(...) ... CALL subroutine3(...) CALL subroutine4(...) ... END SUBROUTINE The idea is to parallelize the loop that calls subroutine2. Main program basically only makes the call to subroutine1 and only its arguments are declared. I use two alternatives. On the one hand, I write OpenMP clauses arround the loop. On the other hand, I add an IF conditional branch arround the call and I use MPI to share the results. In the OpenMP case, I add CALL KMP_SET_STACKSIZE(402653184) at the beginning of the main program and I can run it with 8 threads on an 8 core machine. When I run it (on the same 8 core machine) with MPI (either using 8 or 1 processors) it crashes just when makes the call to subroutine3 with a segmentation fault (signal 11) error. If I comment subroutine4, then it doesn't crash (notice that it crashed just when calling subroutine3 and it works when commenting subroutine4). I compile with mpif90 using MPICH2 libraries and the following flags: -O3 -fpscomp logicals -openmp -threads -m64 -xS. The machine has EM64T architecture and I use a Debian Linux distribution. I set ulimit -s hard before running the program. Any ideas on what is going on? Has it something to do with stack size? Thanks in advance

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  • django+uploadify - don't working

    - by Erico
    Hi, I'm trying to use an example posted on the "github" the link is http://github.com/tstone/django-uploadify. And I'm having trouble getting work. can you help me? I followed step by step, but does not work. Accessing the "URL" / upload / the only thing is that returns "True" part of settings.py import os PROJECT_ROOT_PATH = os.path.dirname(os.path.abspath(file)) MEDIA_ROOT = os.path.join(PROJECT_ROOT_PATH, 'media') TEMPLATE_DIRS = ( os.path.join(PROJECT_ROOT_PATH, 'templates')) urls.py from django.conf.urls.defaults import * from django.conf import settings from teste.uploadify.views import * from django.contrib import admin admin.autodiscover() urlpatterns = patterns('', (r'^admin/', include(admin.site.urls)), url(r'upload/$', upload, name='uploadify_upload'), ) views.py from django.http import HttpResponse import django.dispatch upload_received = django.dispatch.Signal(providing_args=['data']) def upload(request, *args, **kwargs): if request.method == 'POST': if request.FILES: upload_received.send(sender='uploadify', data=request.FILES['Filedata']) return HttpResponse('True') models.py from django.db import models def upload_received_handler(sender, data, **kwargs): if file: new_media = Media.objects.create( file = data, new_upload = True, ) new_media.save() upload_received.connect(upload_received_handler, dispatch_uid='uploadify.media.upload_received') class Media(models.Model): file = models.FileField(upload_to='images/upload/', null=True, blank=True) new_upload = models.BooleanField() uploadify_tags.py from django import template from teste import settings register = template.Library() @register.inclusion_tag('uploadify/multi_file_upload.html', takes_context=True) def multi_file_upload(context, upload_complete_url): """ * filesUploaded - The total number of files uploaded * errors - The total number of errors while uploading * allBytesLoaded - The total number of bytes uploaded * speed - The average speed of all uploaded files """ return { 'upload_complete_url' : upload_complete_url, 'uploadify_path' : settings.UPLOADIFY_PATH, # checar essa linha 'upload_path' : settings.UPLOADIFY_UPLOAD_PATH, } template - uploadify/multi_file_upload.html {% load uploadify_tags }{ multi_file_upload '/media/images/upload/' %} <script type="text/javascript" src="{{ MEDIA_URL }}js/swfobject.js"></script> <script type="text/javascript" src="{{ MEDIA_URL }}js/jquery.uploadify.js"></script> <div id="uploadify" class="multi-file-upload"><input id="fileInput" name="fileInput" type="file" /></div> <script type="text/javascript">// <![CDATA[ $(document).ready(function() { $('#fileInput').uploadify({ 'uploader' : '/media/swf/uploadify.swf', 'script' : '{% url uploadify_upload %}', 'cancelImg' : '/media/images/uploadify-remove.png/', 'auto' : true, 'folder' : '/media/images/upload/', 'multi' : true, 'onAllComplete' : allComplete }); }); function allComplete(event, data) { $('#uploadify').load('{{ upload_complete_url }}', { 'filesUploaded' : data.filesUploaded, 'errorCount' : data.errors, 'allBytesLoaded' : data.allBytesLoaded, 'speed' : data.speed }); // raise custom event $('#uploadify') .trigger('allUploadsComplete', data); } // ]]</script>

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  • phonegap.js crashes android app

    - by peirix
    I'm having this weird problem, where including the phonegap.js file in my project causes the app to crash on both the android emulator and my phone. I got the latest file from GitHub, so I can't see why this isn't working. This happens even if I try to build the sample project that's included in the PhoneGap download... Console log: [2010-12-17 11:05:14 - sample] Android Launch! [2010-12-17 11:05:14 - sample] adb is running normally. [2010-12-17 11:05:14 - sample] Performing com.phonegap.sample.sample activity launch [2010-12-17 11:05:14 - sample] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'FirstDevice' [2010-12-17 11:05:16 - sample] Uploading sample.apk onto device 'emulator-5554' [2010-12-17 11:05:16 - sample] Installing sample.apk... [2010-12-17 11:05:21 - sample] Success! [2010-12-17 11:05:22 - sample] Starting activity com.phonegap.sample.sample on device emulator-5554 [2010-12-17 11:05:23 - sample] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.phonegap.sample/.sample } LogCat: 12-17 11:13:12.533: DEBUG/AndroidRuntime(373): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<< 12-17 11:13:12.533: DEBUG/AndroidRuntime(373): CheckJNI is ON 12-17 11:13:13.453: DEBUG/AndroidRuntime(373): Calling main entry com.android.commands.pm.Pm 12-17 11:13:13.503: DEBUG/AndroidRuntime(373): Shutting down VM 12-17 11:13:13.513: DEBUG/dalvikvm(373): GC_CONCURRENT freed 101K, 71% free 297K/1024K, external 0K/0K, paused 2ms+2ms 12-17 11:13:13.523: INFO/AndroidRuntime(373): NOTE: attach of thread 'Binder Thread #3' failed 12-17 11:13:13.523: DEBUG/dalvikvm(373): Debugger has detached; object registry had 1 entries 12-17 11:13:14.113: DEBUG/AndroidRuntime(383): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<< 12-17 11:13:14.113: DEBUG/AndroidRuntime(383): CheckJNI is ON 12-17 11:13:14.853: DEBUG/AndroidRuntime(383): Calling main entry com.android.commands.am.Am 12-17 11:13:14.894: INFO/ActivityManager(62): Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.phonegap.sample/.sample } from pid 383 12-17 11:13:14.973: INFO/ActivityManager(62): Start proc com.phonegap.sample for activity com.phonegap.sample/.sample: pid=391 uid=10031 gids={1006, 3003, 1015} 12-17 11:13:14.983: DEBUG/AndroidRuntime(383): Shutting down VM 12-17 11:13:15.053: DEBUG/dalvikvm(383): GC_CONCURRENT freed 102K, 69% free 319K/1024K, external 0K/0K, paused 2ms+2ms 12-17 11:13:15.093: INFO/AndroidRuntime(383): NOTE: attach of thread 'Binder Thread #3' failed 12-17 11:13:15.143: DEBUG/dalvikvm(383): Debugger has detached; object registry had 1 entries 12-17 11:13:15.523: DEBUG/dalvikvm(33): GC_EXPLICIT freed 11K, 54% free 2520K/5379K, external 716K/1038K, paused 467ms 12-17 11:13:15.663: DEBUG/dalvikvm(33): GC_EXPLICIT freed <1K, 54% free 2520K/5379K, external 716K/1038K, paused 132ms 12-17 11:13:15.772: DEBUG/dalvikvm(33): GC_EXPLICIT freed <1K, 54% free 2520K/5379K, external 716K/1038K, paused 113ms 12-17 11:13:16.333: INFO/ARMAssembler(62): generated scanline__00000177:03515104_00001002_00000000 [ 87 ipp] (110 ins) at [0x43aff6f0:0x43aff8a8] in 686000 ns 12-17 11:13:17.493: INFO/ActivityManager(62): Displayed com.phonegap.sample/.sample: +2s540ms 12-17 11:13:18.163: DEBUG/szipinf(391): Initializing inflate state 12-17 11:13:18.173: DEBUG/szipinf(391): Initializing zlib to inflate 12-17 11:13:18.573: WARN/dalvikvm(391): JNI WARNING: jarray 0x40567330 points to non-array object (Ljava/lang/String;) 12-17 11:13:18.593: INFO/dalvikvm(391): "WebViewCoreThread" prio=5 tid=9 NATIVE 12-17 11:13:18.603: INFO/dalvikvm(391): | group="main" sCount=0 dsCount=0 obj=0x4051b880 self=0x1af760 12-17 11:13:18.603: INFO/dalvikvm(391): | sysTid=400 nice=0 sched=0/0 cgrp=default handle=1778000 12-17 11:13:18.623: INFO/dalvikvm(391): | schedstat=( 851184092 892639082 140 ) 12-17 11:13:18.633: INFO/dalvikvm(391): at android.webkit.LoadListener.nativeFinished(Native Method) 12-17 11:13:18.633: INFO/dalvikvm(391): at android.webkit.LoadListener.nativeFinished(Native Method) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.tearDown(LoadListener.java:1200) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.handleEndData(LoadListener.java:721) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.handleMessage(LoadListener.java:219) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.os.Handler.dispatchMessage(Handler.java:99) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.os.Looper.loop(Looper.java:123) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:629) 12-17 11:13:18.672: INFO/dalvikvm(391): at java.lang.Thread.run(Thread.java:1019) 12-17 11:13:18.672: ERROR/dalvikvm(391): VM aborting 12-17 11:13:18.887: INFO/DEBUG(31): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** 12-17 11:13:18.887: INFO/DEBUG(31): Build fingerprint: 'generic/sdk/generic:2.3/GRH55/79397:eng/test-keys' 12-17 11:13:18.893: INFO/DEBUG(31): pid: 391, tid: 400 >>> com.phonegap.sample <<< 12-17 11:13:18.893: INFO/DEBUG(31): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadd00d 12-17 11:13:18.893: INFO/DEBUG(31): r0 fffffebc r1 deadd00d r2 00000026 r3 00000000 12-17 11:13:18.893: INFO/DEBUG(31): r4 81da45c8 r5 40567330 r6 81d8592c r7 001b2a48 12-17 11:13:18.893: INFO/DEBUG(31): r8 43640b58 r9 42dd1ecc 10 42dd1eb4 fp 4168d82c 12-17 11:13:18.893: INFO/DEBUG(31): ip 81da4728 sp 43640410 lr afd19375 pc 81d45a02 cpsr 20000030 12-17 11:13:19.183: INFO/DEBUG(31): #00 pc 00045a02 /system/lib/libdvm.so 12-17 11:13:19.183: INFO/DEBUG(31): #01 pc 000376fc /system/lib/libdvm.so 12-17 11:13:19.183: INFO/DEBUG(31): #02 pc 000399c4 /system/lib/libdvm.so 12-17 11:13:19.193: INFO/DEBUG(31): #03 pc 0003a4a0 /system/lib/libdvm.so 12-17 11:13:19.203: INFO/DEBUG(31): #04 pc 0032b6d6 /system/lib/libwebcore.so 12-17 11:13:19.203: INFO/DEBUG(31): #05 pc 002a4da4 /system/lib/libwebcore.so 12-17 11:13:19.203: INFO/DEBUG(31): #06 pc 001a6136 /system/lib/libwebcore.so 12-17 11:13:19.213: INFO/DEBUG(31): #07 pc 002a5870 /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #08 pc 00359e36 /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #09 pc 0035d30e /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #10 pc 003638be /system/lib/libwebcore.so 12-17 11:13:19.233: INFO/DEBUG(31): #11 pc 0019f6fa /system/lib/libwebcore.so 12-17 11:13:19.233: INFO/DEBUG(31): #12 pc 0019f780 /system/lib/libwebcore.so 12-17 11:13:19.243: INFO/DEBUG(31): #13 pc 001a3d8a /system/lib/libwebcore.so 12-17 11:13:19.243: INFO/DEBUG(31): #14 pc 000d0dca /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #15 pc 000d0f28 /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #16 pc 000d106e /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #17 pc 000ddef0 /system/lib/libwebcore.so 12-17 11:13:19.263: INFO/DEBUG(31): #18 pc 000ddf62 /system/lib/libwebcore.so 12-17 11:13:19.263: INFO/DEBUG(31): #19 pc 000f3ce2 /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #20 pc 002739ae /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #21 pc 000eac5e /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #22 pc 001b152c /system/lib/libwebcore.so 12-17 11:13:19.283: INFO/DEBUG(31): #23 pc 00017d34 /system/lib/libdvm.so 12-17 11:13:19.283: INFO/DEBUG(31): #24 pc 00048ec0 /system/lib/libdvm.so 12-17 11:13:19.283: INFO/DEBUG(31): #25 pc 00041a6a /system/lib/libdvm.so 12-17 11:13:19.293: INFO/DEBUG(31): #26 pc 0001cf94 /system/lib/libdvm.so 12-17 11:13:19.303: INFO/DEBUG(31): #27 pc 0002209c /system/lib/libdvm.so 12-17 11:13:19.303: INFO/DEBUG(31): #28 pc 00020f90 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #29 pc 0005f328 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #30 pc 0005f54e /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #31 pc 00053b06 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): code around pc: 12-17 11:13:19.313: INFO/DEBUG(31): 81d459e0 447a4479 ed0cf7d1 20004c09 ee34f7d1 12-17 11:13:19.323: INFO/DEBUG(31): 81d459f0 447c4808 6bdb5823 d0002b00 49064798 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a00 700a2226 eea0f7d1 0004355f 0004511d 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a10 0005ebd2 fffffebc deadd00d b510b40e 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a20 4c0a4b09 447bb083 aa05591b 6b5bca02 12-17 11:13:19.323: INFO/DEBUG(31): code around lr: 12-17 11:13:19.333: INFO/DEBUG(31): afd19354 b0834a0d 589c447b 26009001 686768a5 12-17 11:13:19.333: INFO/DEBUG(31): afd19364 220ce008 2b005eab 1c28d003 47889901 12-17 11:13:19.333: INFO/DEBUG(31): afd19374 35544306 d5f43f01 2c006824 b003d1ee 12-17 11:13:19.333: INFO/DEBUG(31): afd19384 bdf01c30 000281a8 ffffff88 1c0fb5f0 12-17 11:13:19.333: INFO/DEBUG(31): afd19394 43551c3d a904b087 1c16ac01 604d9004 12-17 11:13:19.333: INFO/DEBUG(31): stack: 12-17 11:13:19.333: INFO/DEBUG(31): 436403d0 00000015 12-17 11:13:19.333: INFO/DEBUG(31): 436403d4 afd18407 /system/lib/libc.so 12-17 11:13:19.333: INFO/DEBUG(31): 436403d8 afd4270c /system/lib/libc.so 12-17 11:13:19.343: INFO/DEBUG(31): 436403dc afd426b8 /system/lib/libc.so 12-17 11:13:19.343: INFO/DEBUG(31): 436403e0 00000000 12-17 11:13:19.343: INFO/DEBUG(31): 436403e4 afd19375 /system/lib/libc.so 12-17 11:13:19.353: INFO/DEBUG(31): 436403e8 001af760 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403ec afd183d9 /system/lib/libc.so 12-17 11:13:19.353: INFO/DEBUG(31): 436403f0 001b2a48 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403f4 0005ebd2 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403f8 40567330 /dev/ashmem/dalvik-heap (deleted) 12-17 11:13:19.363: INFO/DEBUG(31): 436403fc 81d8592c /system/lib/libdvm.so 12-17 11:13:19.363: INFO/DEBUG(31): 43640400 001b2a48 [heap] 12-17 11:13:19.363: INFO/DEBUG(31): 43640404 afd18437 /system/lib/libc.so 12-17 11:13:19.363: INFO/DEBUG(31): 43640408 df002777 12-17 11:13:19.363: INFO/DEBUG(31): 4364040c e3a070ad 12-17 11:13:19.363: INFO/DEBUG(31): #00 43640410 00000001 12-17 11:13:19.363: INFO/DEBUG(31): 43640414 81d37701 /system/lib/libdvm.so 12-17 11:13:19.363: INFO/DEBUG(31): #01 43640418 00000001 12-17 11:13:19.363: INFO/DEBUG(31): 4364041c 81d399c9 /system/lib/libdvm.so 12-17 11:13:22.753: INFO/BootReceiver(62): Copying /data/tombstones/tombstone_09 to DropBox (SYSTEM_TOMBSTONE) 12-17 11:13:22.943: DEBUG/dalvikvm(62): GC_CONCURRENT freed 876K, 48% free 4240K/8135K, external 2269K/3469K, paused 9ms+10ms 12-17 11:13:23.133: DEBUG/dalvikvm(62): GC_FOR_MALLOC freed 348K, 47% free 4318K/8135K, external 2269K/3469K, paused 147ms 12-17 11:13:23.243: DEBUG/Zygote(33): Process 391 terminated by signal (11) 12-17 11:13:23.253: ERROR/InputDispatcher(62): channel '406defc8 com.phonegap.sample/com.phonegap.sample.sample (server)' ~ Consumer closed input channel or an error occurred. events=0x8 12-17 11:13:23.253: ERROR/InputDispatcher(62): channel '406defc8 com.phonegap.sample/com.phonegap.sample.sample (server)' ~ Channel is unrecoverably broken and will be disposed! 12-17 11:13:23.323: DEBUG/dalvikvm(62): GC_FOR_MALLOC freed 134K, 47% free 4376K/8135K, external 2269K/3469K, paused 174ms 12-17 11:13:23.323: INFO/ActivityManager(62): Process com.phonegap.sample (pid 391) has died. 12-17 11:13:23.333: INFO/WindowManager(62): WIN DEATH: Window{406defc8 com.phonegap.sample/com.phonegap.sample.sample paused=false} 12-17 11:13:23.542: DEBUG/dalvikvm(124): GC_EXPLICIT freed 61K, 51% free 2836K/5767K, external 1973K/2288K, paused 907ms 12-17 11:13:23.693: WARN/InputManagerService(62): Got RemoteException sending setActive(false) notification to pid 391 uid 10031 Sorry about the gigantic log posts, but I don't know what is of importance here...

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  • Sync Vs. Async Sockets Performance in C#

    - by Michael Covelli
    Everything that I read about sockets in .NET says that the asynchronous pattern gives better performance (especially with the new SocketAsyncEventArgs which saves on the allocation). I think this makes sense if we're talking about a server with many client connections where its not possible to allocate one thread per connection. Then I can see the advantage of using the ThreadPool threads and getting async callbacks on them. But in my app, I'm the client and I just need to listen to one server sending market tick data over one tcp connection. Right now, I create a single thread, set the priority to Highest, and call Socket.Receive() with it. My thread blocks on this call and wakes up once new data arrives. If I were to switch this to an async pattern so that I get a callback when there's new data, I see two issues The threadpool threads will have default priority so it seems they will be strictly worse than my own thread which has Highest priority. I'll still have to send everything through a single thread at some point. Say that I get N callbacks at almost the same time on N different threadpool threads notifying me that there's new data. The N byte arrays that they deliver can't be processed on the threadpool threads because there's no guarantee that they represent N unique market data messages because TCP is stream based. I'll have to lock and put the bytes into an array anyway and signal some other thread that can process what's in the array. So I'm not sure what having N threadpool threads is buying me. Am I thinking about this wrong? Is there a reason to use the Async patter in my specific case of one client connected to one server?

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  • C: Running Unix configure file in Windows

    - by Shiftbit
    I would like to port a few applications that I use on Linux to Windows. In particular I have been working on wdiff. A program that compares the differences word by word of two files. Currently I have been able to successfully compile the program on windows through Cygwin. However, I would like to run the program natively on Windows similar to the Project: UnixUtils. How would I go about porting unix utilities on a windows environment? My possible guess it to manually create the ./configure file so that I can create a proper makefile. Am I on the right track? Has anyone had experience porting GNU software to windows? Update: I've compiled it on Code::Blocks and I get two errors: wdiff.c|226|error: `SIGPIPE' undeclared (first use in this function) readpipe.c:71: undefined reference to `_pipe' readpipe.c:74: undefined reference to `_fork This is a linux signal that is not supported by windows... equvilancy? wdiff.c|1198|error: `PRODUCT' undeclared (first use in this function)| this is in the configure.in file... hardcode would probably be the fastest solution... Outcome: MSYS took care of the configure problems, however MinGW couldnt solve the posix issues. I attempt to utilize pthreads as recommended by mrjoltcola. However, after several hours I couldnt get it to compile nor link using the provided libraries. I think if this had worked it would have been the solution I was after. Special mention to Michael Madsen for MSYS.

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  • HttpUtility does not exist in the current context

    - by Shaihi
    I get this error when compiling a C# application. Looks like a trivial error, but I can't get around it. My setup is Windows 7 64 bit. Visual-Studio 2010 C# express B2Rel. I added a reference to System.Web.dll located at C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0, but it has a yellow exclamation symbol and I still get the above error. I also have the using System.Web declaration. What am I doing wrong? Update: After getting the prompt answer pointing me at the root cause, I searched a bit in Google to where it states that System.Web.dll is for the full framework. I did not find such a reference. For newbies like me, this blog summarizes the difference between the frameworks (client and full) nicely. I could not find a spot that says whether a certain Dll is supported in the client framework or not. I guess the exclamation mark in Visual Studio should be the first signal...

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  • Python PyQt Timer Firmata

    - by George Cullins
    Hello. I am pretty new to python and working with firmata I am trying to play around with an arduino . Here is what I want to happen: Set arduino up with an LED as a digital out Set potentiometer to analog 0 Set PyQt timer up to update potentiometer position in application Set a threshold in PyQt to turn LED on (Analog in has 1024bit resolution, so say 800 as the threshold) I am using this firmata library : Link Here is the code that I am having trouble with: import sys from PyQt4 import QtCore, QtGui from firmata import * # Arduino setup self.a = Arduino('COM3') self.a.pin_mode(13, firmata.OUTPUT) # Create timer self.appTimer = QtCore.QTimer(self) self.appTimer.start(100) self.appTimer.event(self.updateAppTimer()) def updateAppTimer(self): self.analogPosition = self.a.analog_read(self, 0) self.ui.lblPositionValue.setNum() I am getting the error message: Traceback (most recent call last): File "D:\Programming\Eclipse\IO Demo\src\control.py", line 138, in myapp = MainWindow() File "D:\Programming\Eclipse\IO Demo\src\control.py", line 56, in init self.appTimer.event(self.updateAppTimer()) File "D:\Programming\Eclipse\IO Demo\src\control.py", line 60, in updateAppTimer self.analogPosition = self.a.analog_read(self, 0) TypeError: analog_read() takes exactly 2 arguments (3 given) If I take 'self' out I get the same error message but that only 1 argument is given What is python doing implicitly that I am not aware of? Blockquote

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  • Open source Java CMS for Google App Engine?

    - by markvgti
    I am looking for an open source Java CMS (Web CMS, actually) to run on Google App Engine. I have looked at related older questions on this topic (What CMS runs on Google AppEngine?, CMS over Google App Engine, with SEO etc.) but the problem is that they all largely list Python-based CMSes. Plus these questions are pretty old, and since GAE is a fast-moving target, I thought it might be worthwhile to ask again. I want a CMS for creating some websites (for myself and for others), but would rather not start writing one from scratch. A "good" (very subjective, I know) open source WCMS allows me to start using a product, while still being able to add to/extend the product/project. On the one hand I am looking for a somewhat mature product/project, on the other hand it's easier to start contributing to the development cycle of a young product/project (conflicting, I know :-). Here are some features that would be preferable: [X]HTML/XML/CSS based templating Ability to create multiple blogs Galleries Ability to create a "Downloads" section (is this pretty much standard?) Separate management for digital assets (images, PDFs, binary files etc.) Roles like "Administrator", "Editor", "Contributor" etc. (or their equivalents) Ability to move/reorganize pages Export to PDF Reformat content for printing Is the CMS you are about to suggest especially well-suited to publishing an online book? My idea is that while the book may be offered as a downloadable eBook, the latest, most current version will be the one available on the website.

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  • WPF Update Binding when Bound directly to DataContext w/ Converter

    - by Adam
    Normally when you want a databound control to 'update,' you use the "PropertyChanged" event to signal to the interface that the data has changed behind the scenes. For instance, you could have a textblock that is bound to the datacontext with a property "DisplayText" <TextBlock Text="{Binding Path=DisplayText}"/> From here, if the DataContext raises the PropertyChanged event with PropertyName "DisplayText," then this textblock's text should update (assuming you didn't change the Mode of the binding). However, I have a more complicated binding that uses many properties off of the datacontext to determine the final look and feel of the control. To accomplish this, I bind directly to the datacontext and use a converter. In this case I am working with an image source. <Image Source="{Binding Converter={StaticResource ImageConverter}}"/> As you can see, I use a {Binding} with no path to bind directly to the datacontext, and I use an ImageConverter to select the image I'm looking for. But now I have no way (that I know of) to tell that binding to update. I tried raising the propertychanged event with "." as the propertyname, which did not work. Is this possible? Do I have to wrap up the converting logic into a property that the binding can attach to, or is there a way to tell the binding to refresh (without explicitly refreshing the binding)? Any help would be greatly appreciated. Thanks! -Adam

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  • Java Swingworker: Not as encapsulated class

    - by Thomas Matthews
    I'm having problems passing information, updating progress and indicating "done" with a SwingWorker class that is not an encapsulated class. I have a simple class that processes files and directories on a hard drive. The user clicks on the Start button and that launches an instance of the SwingWorker. I would like to print the names of the files that are processed on the JTextArea in the Event Driven Thread from the SwingWorker as update a progress bar. All the examples on the web are for an nested class, and the nested class accesses variables in the outer class (such as the done method). I would also like to signal the Event Driven Thread that the SwingWorker is finished so the EDT can perform actions such as enabling the Start button (and clearing fields). Here are my questions: 1. How does the SwingWorker class put text into the JTextArea of the Event Driven Thread and update a progress bar? How does the EDT determine when the {external} SwingWorker thread is finished? {I don't want the SwingWorker as a nested class because there is a lot of code (and processing) done.}

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  • Threading best practice when using SFTP in C#

    - by Christian
    Ok, this is more one of these "conceptual questions", but I hope I got some pointers in the right direction. First the desired scenario: I want to query an SFTP server for directory and file lists I want to upload or download files simulaneously Both things are pretty easy using a SFTP class provided by Tamir.SharpSsh, but if I only use one thread, it is kind of slow. Especially the recursion into subdirs gets very "UI blocking", because we are talking about 10.000 of directories. My basic approach is simple, create some kind of "pool" where I keep 10 open SFTP connections. Then query the first worker for a list of dirs. If this list was obtained, send the next free workers (e.g. 1-10, first one is also free again) to get the subdirectory details. As soon as there is a worker free, send him for the subsubdirs. And so on... I know the ThreadPool, simple Threads and did some Tests. What confuses me a little bit is the following: I basically need... A list of threads I create, say 10 Connect all threads to the server If a connection drops, create a new thread / sftp client If there is work to do, take the first free thread and handle the work I am currently not sure about the implementation details, especially the "work to do" and the "maintain list of threads" parts. Is it a good idea to: Enclose the work in an object, containing a job description (path) and a callback Send the threads into an infinite loop with 100ms wait to wait for work If SFTP is dead, either revive it, or kill the whole thread and create a new one How to encapsulate this, do I write my own "10ThreadsManager" or are there some out Ok, so far... Btw, I could also use PRISM events and commands, but I think the problem is unrelated. Perhaps the EventModel to signal a done processing of a "work package"... Thanks for any ideas, critic.. Chris

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  • Developing a GPS car tracking system in C#

    - by Click Ok
    I'm in the brainstorming phase to develop a GPS car tracking system requested by a customer. I myself know the directions to build some GPS system to mobile phones and etc. But sincerely I don't know how to start in that project. That is the scenario: 1) The cars will get a device with a SIM CARD that will emit GPS signals. 2) My customer will in any place (home, work, etc) with a web connection will see in the map where the car is located. For me, I have not problems at get the GPS data, convert to usable info and show the position in some map system (like Google Maps or MS Bing Maps, by example). My problem is, how I do to retrieve that "GPS Signal" from device in the car? I will need some kind of "Receiver Device" connected to a web server machine in order to my application to consume that data? Or "automagically" my sodtware will receive the info from a third-party web-service? Or what? I thank for any help!

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  • BN_hex2bn magicaly segfaults in openSSL

    - by xunil154
    Greetings, this is my first post on stackoverflow, and i'm sorry if its a bit long. I'm trying to build a handshake protocol for my own project and am having issues with the server converting the clients RSA's public key to a Bignum. It works in my clent code, but the server segfaults when attempting to convert the hex value of the clients public RSA to a bignum. I have already checked that there is no garbidge before or after the RSA data, and have looked online, but i'm stuck. header segment: typedef struct KEYS { RSA *serv; char* serv_pub; int pub_size; RSA *clnt; } KEYS; KEYS keys; Initializing function: // Generates and validates the servers key /* code for generating server RSA left out, it's working */ //Set client exponent keys.clnt = 0; keys.clnt = RSA_new(); BN_dec2bn(&keys.clnt->e, RSA_E_S); // RSA_E_S contains the public exponent Problem code (in Network::server_handshake): // *Recieved an encrypted message from the network and decrypt into 'buffer' (1024 byte long)* cout << "Assigning clients RSA" << endl; // I have verified that 'buffer' contains the proper key if (BN_hex2bn(&keys.clnt->n, buffer) < 0) { Error("ERROR reading server RSA"); } cout << "clients RSA has been assigned" << endl; The program segfaults at BN_hex2bn(&keys.clnt->n, buffer) with the error (valgrind output) Invalid read of size 8 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) by 0x40F23E: Network::server_handshake() (Network.cpp:177) by 0x40EF42: Network::startNet() (Network.cpp:126) by 0x403C38: main (server.cpp:51) Address 0x20 is not stack'd, malloc'd or (recently) free'd Process terminating with default action of signal 11 (SIGSEGV) Access not within mapped region at address 0x20 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) And I don't know why it is, Im using the exact same code in the client program, and it works just fine. Any input is greatly appriciated!

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  • Hidden features of Perl?

    - by Adam Bellaire
    What are some really useful but esoteric language features in Perl that you've actually been able to employ to do useful work? Guidelines: Try to limit answers to the Perl core and not CPAN Please give an example and a short description Hidden Features also found in other languages' Hidden Features: (These are all from Corion's answer) C# Duff's Device Portability and Standardness Quotes for whitespace delimited lists and strings Aliasable namespaces Java Static Initalizers JavaScript Functions are First Class citizens Block scope and closure Calling methods and accessors indirectly through a variable Ruby Defining methods through code PHP Pervasive online documentation Magic methods Symbolic references Python One line value swapping Ability to replace even core functions with your own functionality Other Hidden Features: Operators: The bool quasi-operator The flip-flop operator Also used for list construction The ++ and unary - operators work on strings The repetition operator The spaceship operator The || operator (and // operator) to select from a set of choices The diamond operator Special cases of the m// operator The tilde-tilde "operator" Quoting constructs: The qw operator Letters can be used as quote delimiters in q{}-like constructs Quoting mechanisms Syntax and Names: There can be a space after a sigil You can give subs numeric names with symbolic references Legal trailing commas Grouped Integer Literals hash slices Populating keys of a hash from an array Modules, Pragmas, and command-line options: use strict and use warnings Taint checking Esoteric use of -n and -p CPAN overload::constant IO::Handle module Safe compartments Attributes Variables: Autovivification The $[ variable tie Dynamic Scoping Variable swapping with a single statement Loops and flow control: Magic goto for on a single variable continue clause Desperation mode Regular expressions: The \G anchor (?{}) and '(??{})` in regexes Other features: The debugger Special code blocks such as BEGIN, CHECK, and END The DATA block New Block Operations Source Filters Signal Hooks map (twice) Wrapping built-in functions The eof function The dbmopen function Turning warnings into errors Other tricks, and meta-answers: cat files, decompressing gzips if needed Perl Tips See Also: Hidden features of C Hidden features of C# Hidden features of C++ Hidden features of Java Hidden features of JavaScript Hidden features of Ruby Hidden features of PHP Hidden features of Python

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  • using ghostscript in server mode to convert pdfs to pngs

    - by emh
    while i am able to convert a specific page of a PDF to a PNG like so: gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -dGraphicsAlphaBits=4 -sOutputFile=gymnastics-20.png -dFirstPage=20 -dLastPage=20 gymnastics.pdf i am wondering if i can somehow use ghostscript's JOBSERVER mode to process several conversions without having to incur the cost of starting up ghostscript each time. from: http://pages.cs.wisc.edu/~ghost/doc/svn/Use.htm -dJOBSERVER Define \004 (^D) to start a new encapsulated job used for compatibility with Adobe PS Interpreters that ordinarily run under a job server. The -dNOOUTERSAVE switch is ignored if -dJOBSERVER is specified since job servers always execute the input PostScript under a save level, although the exitserver operator can be used to escape from the encapsulated job and execute as if the -dNOOUTERSAVE was specified. This also requires that the input be from stdin, otherwise an error will result (Error: /invalidrestore in --restore--). Example usage is: gs ... -dJOBSERVER - < inputfile.ps -or- cat inputfile.ps | gs ... -dJOBSERVER - Note: The ^D does not result in an end-of-file action on stdin as it may on some PostScript printers that rely on TBCP (Tagged Binary Communication Protocol) to cause an out-of-band ^D to signal EOF in a stream input data. This means that direct file actions on stdin such as flushfile and closefile will affect processing of data beyond the ^D in the stream. the idea is to run ghostscript in-process. the script would receive a request for a particular page of a pdf and would use ghostscript to generate the specified image. i'd rather not start up a new ghostscript process every time.

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  • POSIX AIO Library and Callback Handlers

    - by Charles Salvia
    According to the documentation on aio_read/write, there are basically 2 ways that the AIO library can inform your application that an async file I/O operation has completed. Either 1) you can use a signal, 2) you can use a callback function I think that callback functions are vastly preferable to signals, and would probably be much easier to integrate into higher-level multi-threaded libraries. Unfortunately, the documentation for this functionality is a mess to say the least. Some sources, such as the man page for the sigevent struct, indicate that you need to set the sigev_notify data member in the sigevent struct to SIGEV_CALLBACK and then provide a function handler. Presumably, the handler is invoked in the same thread. Other documentation indicates you need to set sigev_notify to SIGEV_THREAD, which will invoke the callback handler in a newly created thread. In any case, on my Linux system (Ubuntu with a 2.6.28 kernel) SIGEV_CALLBACK doesn't seem to be defined anywhere, but SIGEV_THREAD works as advertised. Unfortunately, creating a new thread to invoke the callback handler seems really inefficient, especially if you need to invoke many handlers. It would be better to use an existing pool of threads, similar to the way most network I/O event demultiplexers work. Some versions of UNIX, such as QNX, include a SIGEV_SIGNAL_THREAD flag, which allows you to invoke handlers using a specified existing thread, but this doesn't seem to be available on Linux, nor does it seem to even be a part of the POSIX standard. So, is it possible to use the POSIX AIO library in a way that invokes user handlers in a pre-allocated background thread/threadpool, rather than creating/destroying a new thread everytime a handler is invoked?

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