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  • java share data between thread

    - by ayush
    i have a java process that reads data from a socket server. Thus i have a BufferedReader and a PrintWriter object corresponding to that socket. Now in the same java process i have a multithreaded java server that accepts client connections. I want to achieve a functionality where all these clients that i accept can read data from the BufferedReader object that i mentioned above.(so that they can multiplex the data) How do i make these individual client threads read the data from BuffereReader single object? Sorry for the confusion.

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  • Cache consistency & spawning a thread

    - by Dave Keck
    Background I've been reading through various books and articles to learn about processor caches, cache consistency, and memory barriers in the context of concurrent execution. So far though, I have been unable to determine whether a common coding practice of mine is safe in the strictest sense. Assumptions The following pseudo-code is executed on a two-processor machine: int sharedVar = 0; myThread() { print(sharedVar); } main() { sharedVar = 1; spawnThread(myThread); sleep(-1); } main() executes on processor 1 (P1), while myThread() executes on P2. Initially, sharedVar exists in the caches of both P1 and P2 with the initial value of 0 (due to some "warm-up code" that isn't shown above.) Question Strictly speaking – preferably without assuming any particular CPU – is myThread() guaranteed to print 1? With my newfound knowledge of processor caches, it seems entirely possible that at the time of the print() statement, P2 may not have received the invalidation request for sharedVar caused by P1's assignment in main(). Therefore, it seems possible that myThread() could print 0. References These are the related articles and books I've been reading. (It wouldn't allow me to format these as links because I'm a new user - sorry.) Shared Memory Consistency Models: A Tutorial hpl.hp.com/techreports/Compaq-DEC/WRL-95-7.pdf Memory Barriers: a Hardware View for Software Hackers rdrop.com/users/paulmck/scalability/paper/whymb.2009.04.05a.pdf Linux Kernel Memory Barriers kernel.org/doc/Documentation/memory-barriers.txt Computer Architecture: A Quantitative Approach amazon.com/Computer-Architecture-Quantitative-Approach-4th/dp/0123704901/ref=dp_ob_title_bk

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  • Is this ruby code thread safe?

    - by Ben K.
    Is this code threadsafe? It seems like it should be, because @myvar will never be assigned from multiple threads (assuming block completes in < 1s). But do I need to be worried about a situation where the second block is trying to read @myvar as it's being written? require 'rubygems' require 'eventmachine' @myvar = Time.now.to_i EventMachine.run do EventMachine.add_periodic_timer(1) do EventMachine.defer do @myvar = Time.now.to_i # some calculation and reassign end end EventMachine.add_periodic_timer(0.5) do puts @myvar end end

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  • How do I make a background thread in Java that allows the main application to exit completely? This

    - by Bob
    I have a Java application that creates a new thread to do some work. I can launch the new thread with no problems. When the "main" program terminates, I want the thread I created to keep running - which it does... But the problem is, when I run the main application from Eclipse or from Ant under Windows, control doesn't return unless the background process is killed. If I fork the main java process in ant, I want control to return to ant once the main thread is done with its work... But as it is, ant continues to wait until both the main process and the created thread are both terminated. How do I launch the thread in the background such that control will return to ant when the "main" application is finished? (By the way, when I run the same application under Linux, I am able to do this with no problems).

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  • Java Thread - Memory consistency errors

    - by Yatendra Goel
    I was reading a Sun's tutorial on Concurrency. But I couldn't understand exactly what memory consistency errors are? I googled about that but didn't find any helpful tutorial or article about that. I know that this question is a subjective one, so you can provide me links to articles on the above topic. It would be great if you explain it with a simple example.

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  • Why doesn't Perl threading work when I call readdir beforehand?

    - by Kevin
    Whenever I call readdir before I create a thread, I get an error that looks like this: perl(2820,0x7fff70c33ca0) malloc: * error for object 0x10082e600: pointer being freed was not allocated * set a breakpoint in malloc_error_break to debug Abort trap What's strange is that it happens when I call readdir before I create a thread (i.e. readdir is not called in any concurrent code). I don't even use the results from readdir, just making the call to it seems to screw things up. When I get rid of it, things seem to work fine. Some example code is below: opendir(DIR, $someDir); my @allFiles = readdir(DIR); close(DIR); my $thread = threads-create(\&sub1); $thread-join(); sub sub1 { print "in thread\n" }

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  • ID generator with local static variable - thread-safe?

    - by Poseidon
    Will the following piece of code work as expected in a multi-threaded scenario? int getUniqueID() { static int ID=0; return ++ID; } It's not necessary that the IDs to be contiguous - even if it skips a value, it's fine. Can it be said that when this function returns, the value returned will be unique across all threads?

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  • E: Sub-process /usr/bin/dpkg returned an error code (1) seems to be choking on kde-runtime-data version issue

    - by BMT
    12.04 LTS, on a dell mini 10. Install stable until about a week ago. Updated about 1x a week, sometimes more often. Several days ago, I booted up and the system was no longer working correctly. All these symptoms occurred simultaneously: Cannot run (exit on opening, every time): Update manager, software center, ubuntuOne, libreOffice. Vinagre autostarts on boot, no explanation, not set to startup with Ubuntu. Using apt-get to fix install results in the following: maura@pandora:~$ sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following package was automatically installed and is no longer required: libtelepathy-farstream2 Use 'apt-get autoremove' to remove them. The following extra packages will be installed: gwibber gwibber-service kde-runtime-data software-center Suggested packages: gwibber-service-flickr gwibber-service-digg gwibber-service-statusnet gwibber-service-foursquare gwibber-service-friendfeed gwibber-service-pingfm gwibber-service-qaiku unity-lens-gwibber The following packages will be upgraded: gwibber gwibber-service kde-runtime-data software-center 4 upgraded, 0 newly installed, 0 to remove and 39 not upgraded. 20 not fully installed or removed. Need to get 0 B/5,682 kB of archives. After this operation, 177 kB of additional disk space will be used. Do you want to continue [Y/n]? debconf: Perl may be unconfigured (Can't locate Scalar/Util.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/lib/perl/5.14/Hash/Util.pm line 9. BEGIN failed--compilation aborted at /usr/lib/perl/5.14/Hash/Util.pm line 9. Compilation failed in require at /usr/share/perl/5.14/fields.pm line 122. Compilation failed in require at /usr/share/perl5/Debconf/Log.pm line 10. Compilation failed in require at (eval 1) line 4. BEGIN failed--compilation aborted at (eval 1) line 4. ) -- aborting (Reading database ... 242672 files and directories currently installed.) Preparing to replace gwibber 3.4.1-0ubuntu1 (using .../gwibber_3.4.2-0ubuntu1_i386.deb) ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: error processing /var/cache/apt/archives/gwibber_3.4.2-0ubuntu1_i386.deb (--unpack): subprocess new pre-removal script returned error exit status 1 Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace gwibber-service 3.4.1-0ubuntu1 (using .../gwibber-service_3.4.2-0ubuntu1_all.deb) ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: error processing /var/cache/apt/archives/gwibber-service_3.4.2-0ubuntu1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace kde-runtime-data 4:4.8.3-0ubuntu0.1 (using .../kde-runtime-data_4%3a4.8.4-0ubuntu0.1_all.deb) ... Unpacking replacement kde-runtime-data ... dpkg: error processing /var/cache/apt/archives/kde-runtime-data_4%3a4.8.4-0ubuntu0.1_all.deb (--unpack): trying to overwrite '/usr/share/sounds', which is also in package sound-theme-freedesktop 0.7.pristine-2 dpkg-deb (subprocess): subprocess data was killed by signal (Broken pipe) dpkg-deb: error: subprocess <decompress> returned error exit status 2 Preparing to replace python-crypto 2.4.1-1 (using .../python-crypto_2.4.1-1_i386.deb) ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: error processing /var/cache/apt/archives/python-crypto_2.4.1-1_i386.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace software-center 5.2.2.2 (using .../software-center_5.2.4_all.deb) ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: error processing /var/cache/apt/archives/software-center_5.2.4_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace xdiagnose 2.5 (using .../archives/xdiagnose_2.5_all.deb) ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pyclean", line 25, in <module> import logging ImportError: No module named logging dpkg: error processing /var/cache/apt/archives/xdiagnose_2.5_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Could not find platform dependent libraries <exec_prefix> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>] Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook from apport.fileutils import likely_packaged, get_recent_crashes File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module> from apport.report import Report File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module> from xml.parsers.expat import ExpatError File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module> from pyexpat import * ImportError: No module named pyexpat Original exception was: Traceback (most recent call last): File "/usr/bin/pycompile", line 27, in <module> import logging ImportError: No module named logging dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: /var/cache/apt/archives/gwibber_3.4.2-0ubuntu1_i386.deb /var/cache/apt/archives/gwibber-service_3.4.2-0ubuntu1_all.deb /var/cache/apt/archives/kde-runtime-data_4%3a4.8.4-0ubuntu0.1_all.deb /var/cache/apt/archives/python-crypto_2.4.1-1_i386.deb /var/cache/apt/archives/software-center_5.2.4_all.deb /var/cache/apt/archives/xdiagnose_2.5_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1) maura@pandora:~$ ^C maura@pandora:~$

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  • Thread safe GUI programming

    - by James
    I have been programming Java with swing for a couple of years now, and always accepted that GUI interactions had to happen on the Event Dispatch Thread. I recently started to use GTK+ for C applications and was unsurprised to find that GUI interactions had to be called on gtk_main. Similarly, I looked at SWT to see in what ways it was different to Swing and to see if it was worth using, and again found the UI thread idea, and I am sure that these 3 are not the only toolkits to use this model. I was wondering if there is a reason for this design i.e. what is the reason for keeping UI modifications isolated to a single thread. I can see why some modifications may cause issues (like modifying a list while it is being drawn), but I do not see why these concerns pass on to the user of the API. Is there a limit imposed by an operating system? Is there a good reason these concerns are not 'hidden' (i.e. some form of synchronization that is invisible to the user)? Is there any (even purely conceptual) way of creating a thread safe graphics library, or is such a thing actually impossible? I found this http://blogs.operationaldynamics.com/andrew/software/gnome-desktop/gtk-thread-awareness which seems to describe GTK differently to how I understood it (although my understanding was the same as many people's) How does this differ to other toolkits? Is it possible to implement this in Swing (as the EDT model does not actually prevent access from other threads, it just often leads to Exceptions)

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  • What is Perl's relation with hackers?

    - by K.Steff
    I know Perl is a language revered by many hackers (as in hacker vs cracker) and respected by many good programmers for its expressiveness. I also realize it is useful to know and it's very handy at generalizing common Unix tasks (Unix here includes Linux and Cygwin). I also know that being a good hacker probably means you're a good programmer in general (references on this one are sparse around the web, but about everything Paul Graham has ever written seems approving of this statement to me). So my question is whether there is a reason that attracts hackers to Perl in particular? Will learing Perl improve my general programming, problem-solving and hacking skills if done properly? Does it present unique tools that are more useful to a hacker?

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  • Logic / Render phases with a single thread

    - by DevilWithin
    The question I have may generate different opinions from different developers, but I'd still like to have an answer on this. Its all about the updating and rendering steps of the game loop, and their use under multi and single threaded environments. Currently, there is one thread running, which takes care of sequentially executing events , logic and rendering. Sometimes, the logic part may wish to change the game state to something else, and in between do some loading of files. The result is that the game hangs completely while loading, and then proceeds to normal rendering of the new state. To go around this, i could make another thread, do the loading there while the main thread renders a smooth loading animation, and then proceed normally. The real question is about if i don't create another thread. I could refresh the screen from the logic thread, and provide some basic loading screen, which could be not so smoothly updated while the files load. In fact, this approach is not loved by a lot of developers, as it scrambles render code in the logic step, which may cause problems of different sorts.. Hope its clear!

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  • How to do thread management in C++?

    - by Dipan Mehta
    We use pthread for thread management in C based systems. pthread is in general compilable by C++ compiler (like g++). However, what are the better ways of abstractions for threads in C++? Also, for making any system to be working in a multi-threaded system, it is also important to make thread safe. What are the standard libraries that requires alternative (installs) to be thread safe or are they unsafe for multi-threaded environments? Is smart pointers, templates require special measures to make it safe? What are the best practices for the thread managements in C++?

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  • Difference between () and [] in Perl6 [migrated]

    - by Ask and Learn
    Learning Perl 6 and had trouble to understand following Perl 6 one liner. version of Perl 6 - rakudo-star: stable 2014.04 (bottled) This works fine, array/list is sorted [njia@mb-125:~] : perl6 -e 'say [2443,5,33, 90, -9, 2, 764].sort' -9 2 5 33 90 764 2443 But this does not sort the array/list, if [].sort works why @s.sort does not? [njia@mb-125:~] : perl6 -e 'my @s = [2443,5,33, 90, -9, 2, 764]; @s.sort.say' 2443 5 33 90 -9 2 764 Change from [] to () [njia@mb-125:~] : perl6 -e 'my @s = (2443,5,33,90,-9,2,764); @s.sort.say' -9 2 5 33 90 764 2443

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  • What is Perl's relation to hackers? [closed]

    - by K.Steff
    I know Perl is a language revered by many hackers (as in hacker vs cracker) and respected by many good programmers for its expressiveness. I also realize it is useful to know and it's very handy at generalizing common Unix tasks (Unix here includes Linux and Cygwin). I also know that being a good hacker probably means you're a good programmer in general (references on this one are sparse around the web, but about everything Paul Graham has ever written seems approving of this statement to me). So my question is whether there is a reason that attracts hackers to Perl in particular? Will learing Perl improve my general programming, problem-solving and hacking skills if done properly? Does it present unique tools that are more useful to a hacker?

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  • Different behavior when launched from terminal instead of Unity launcher

    - by dgkontopoulos
    I have written two Perl/Gtk programs. When launched from the dash menu, they run just fine. However, if I try to launch them from terminal using the very same command found in their .desktop files, their Unity launcher will be blurry and will remain inactive when clicked, if I keep it in the Unity bar. The problem is solved if the Exec part of the desktop file is replaced with perl path_to_script However, that leads to other problems, including a lintian warning and forcing all Perl GUI applications running from terminal to adopt the same launcher. This issue is quite annoying since one of the programs relies on a different (Python) program in order to be launched and this results in having a blurry and inactive launcher.

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  • Multithreaded game fails on SwapBuffers in render thread at exit

    - by user782220
    The render loop and windows message loop run on separate threads. The way the program exits is that after PostQuitMessage is called in WM_DESTROY the message loop thread signals the render loop thread to exit. As far as I can tell before the render loop thread can even process the signal it tries SwapBuffers and that fails. My question, is there something about how Windows processes WM_DESTROY and WM_QUIT, in maybe DefWindowProc that causes various objects associated with rendering to go away even though I haven't explicitly deleted anything? And that would explain why the rendering thread is making bad calls at exit?

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  • Why can't Perl's DBD::DB2 find dbivport.h during installation?

    - by Liju Mathew
    We are using a Perl utility to dump data from DB2 database. We installed DBI package and it is asking for DBD package also. We dont have root access and when we try to install DBD package we are getting the following error: ERROR BUILDING DB2.pm [lijumathew@intblade03 DBD-DB2-1.78]$ make make[1]: Entering directory '/home/lijumathew/lperl/perlsrc/DBD-DB2-1.78/Constants' gcc -c -I"/db2/db2tf1/sqllib/include" -D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm -O2 -g -pipe -m32 -march=i386 -mtune=pentium4 -DVERSION=\"1.78\" -DXS_VERSION=\"1.78\" -fPIC "-I/usr/lib/perl5/5.8.5/i386-linux-thread-multi/CORE" Constants.c Running Mkbootstrap for DBD::DB2::Constants () chmod 644 Constants.bs rm -f ../blib/arch/auto/DBD/DB2/Constants/Constants.so gcc -shared -L/usr/local/lib Constants.o -o ../blib/arch/auto/DBD/DB2/Constants/Constants.so chmod 755 ../blib/arch/auto/DBD/DB2/Constants/Constants.so cp Constants.bs ../blib/arch/auto/DBD/DB2/Constants/Constants.bs chmod 644 ../blib/arch/auto/DBD/DB2/Constants/Constants.bs make[1]: Leaving directory `/home/lijumathew/lperl/perlsrc/DBD-DB2-1.78/Constants' gcc -c -I"/db2/db2tf1/sqllib/include" -I"/usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/DBI" -I"/usr/lib/perl5/5.8.5/i386-linux-thread-multi/auto/DBI" -I"/usr/lib/perl5/vendor_perl/5.8.5/i386-linux-thread-multi/auto/DBI" -I"/usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi/auto/DBI" -D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm -O2 -g -pipe -m32 -march=i386 -mtune=pentium4 -DVERSION=\"1.78\" -DXS_VERSION=\"1.78\" -fPIC "-I/usr/lib/perl5/5.8.5/i386-linux-thread-multi/CORE" DB2.c In file included from DB2.h:22, from DB2.xs:7: dbdimp.h:10:22: dbivport.h: No such file or directory make: *** [DB2.o] Error 1 How do we fix this? Do we need root access to resolve this?

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  • [C# Thread] I'd like access to a share on the network!

    - by JustLooking
    Some Details I am working with VisualWebGUI, so this app is like ASP.NET, and it is deployed on IIS 7 (for testing) For my 'Web Site', Anonymous Authentication is set to a specific user (DomainName\DomainUser). In my web.config, I have impersonation on. This is how I got my app to access the share in the first place. The Problem There is a point in the the app where we use the Thread class, something similar to: Thread myThread = new Thread(new ThreadStart(objInstance.PublicMethod)); myThread.Start(); What I have noticed is that I can write to my logs (text file on the share), everywhere throughout my code, except in the thread that I kicked off. I added some debugging output and what I see for users is: The thread that's kicked off: NT AUTHORITY\NETWORK SERVICE Everywhere else in my code: DomainName\DomainUser (described in my IIS setup) OK, for some reason the thread gets a different user (NETWORK SERVICE). Fine. But, my share (and the actual log file) was given 'Full Control' to the NETWORK SERVICE user (this share resides on a different server than the one that my app is running). If NETWORK SERVICE has rights to this folder, why do I get access denied? Or is there a way to have the thread I kick off have the same user as the process?

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