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• Wrapping a point-to-point link

  - by user3712955

  I'm using a pair of IP radios (non-WiFi) to bridge my office engineering LAN (172.0.0.0/8) to a lab in another building. The radios work fine, but they expose a web management interface I'd like to hide, and they also generate traffic (ARP, STP, and more) that I need to keep off my (very, very clean) LAN segments. I have some ARM-Linux boards (similar to Beagle/Panda/RasPi) running Ubuntu, and I've put one at each end of the link, between the radio and the LAN. Each of the boards has 2 wired Ethernet interfaces, eth0 and eth1. The LAN segments are connected to eth0, and the radios are connected to eth1. I'd like to accomplish the following: Keep radio-originated traffic off my LAN segments! Hide all services provided by the radio (web, ssh, etc.) Transparently pass all traffic between the LAN segments (including things like ARP). The above also applies to the ARM-Linux boards: No stray traffic my LAN from them either! I'd like the system to look like a switch: LAN packets arriving at one eth0 appear at the other. And neither eth0 should have an IP address: The working system should behave like a CAT6 cable with some latency (instead of ARM boards and radios). Unfortunately, I'm confused about how to properly configure the ARM Ubuntu systems. What I'm guessing I need is a bridge on each board (br0?) and a VLAN (vlan0 or eth0.0?) to isolate the LAN traffic from everything else as it passes through the ARM boards and the radios. Then I need some kind of a firewall to block sending anything out eth0 that isn't from the other eth0 (via the VLAN). I've looked at the ip and ebtables commands (especially -t broute). While the concepts sorta-kinda make sense, I'm completely lost in the details. Edit: In the perverse case that a system on one of my LAN segments has the same IP address as one of the radios, or as eth1 on the ARM-Ubuntu boards, a VLAN won't work. Which I believe means I need to tunnel all traffic between the two eth0 interfaces to get that "like a wire" behavior. Help? Finally, I'd like to have a way to temporarily expose services on the ARM boards (ssh) and the radios (web) for maintenance purposes. Ideally, it would expose an IP address with ssh available on port 22. Once connected, I figure I'd start an X11 session and run a browser on the ARM board to access the radios. Or something. I could login via the console to enable/disable this, or perhaps could use a GPIO to trigger a script. I feel I've identified most of the pieces needed to make all this happen, but I have no idea how to combine them to make a working system. Thanks!

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• Migrating Split Access Database from one domain to another (not working, details in Q)

  - by Expo_Rob

  Some background: I'm a programmer, not a network administrator, who has been asked to migrate some accounting software (Integrated Office Accounting version 3.2) from an existing domain (OLD_NETWORK) to a new domain (NEW_NETWORK). No-body at the office knows how it works under the hood. It is a split Access 2000 database with the back-end shared and on a file server (which is also the DC) using mapped drives. The DC is NT Server 4 SP 6. The new server is server 2003. The two networks are running independently (ie: two computers on each desk). I have been able to get new computers set up on NEW_NETWORK and working with the IOA software just perfectly but for one problem: The company here uses other entirely separate databases which access the tables IOA maintains (specifically the 'customers' table) via links. To switch between these systems, you press F11 then File-Open the appropriate database and away you go (this is necessary to maintain the permissions that the IOA system uses to protect the customers table). The entire database is Access 2000, the links go to other Access databases, SQL-Server is not involved in any way, nor is a migration to SQL server likely. If I can't migrate anything over, everything will stay as it is, and the NEW_NETWORK computers will not be used. The problem: When I try and update these seperate databases (I shall call one "BANK_ACCOUNT", but the name does not matter), it says "this recordset cannot be updated". It also will sometimes not pull information out of the 'customers' table (ie: date_entered) when looking at a report of everyone who opened a bank account on a certain day (ie: today). I have tried: Giving 'everyone' full control via. shared directory permissions Giving 'everyone' full control on a file system level Checking the permissions within Access (everyone has full read/write on all tables) Copying the entire server contents from one file server to another (ie: xcopy everything) Copying the entire local client files from one computer to another, putting them in the exact same position in the file system, with the same permissons (or full control to 'everyone'). Running as an Administrator Taking one of the NEW_NETWORK computers, having it join OLD_NETWORK and run the software (direct copy from a working system with identical drive mappings), this did not work Weeping openly My Question: Is there anything else I can try? (sorry for this being so long)

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• ICalendar not readable by google calendar.

  - by Sagar

  Operating system : WinXP Program and version you use to access Google Calendar (FF3.5): I'm developing a script (based on an existing vCal ASP.NET class I found online) to generate an .ics file. This file works perfectly when importing to Outlook 2003. When I try to import to Google Calendar, I get the following error: Failed to import events: Unable to process your iCal/CSV file.. I don't know too much about the vCal format or syntax, but everything looks fine to me. I'll post the sample test calendar .ics below: BEGIN:VCALENDAR PRODID:-//jpalm.se//iCalendar example with ASP.NET MVC//EN VERSION:2.0 CALSCALE:GREGORIAN METHOD:PUBLISH X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100304T000000Z DTEND:20100304T000000Z TRANSP:OPAQUE SEQUENCE:0 UID:7c9d6dd7-41f2-4171-8ae4-35820974efa4 DESCRIPTION:uba:Project20100321:sagar . SUMMARY:First Milestone END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100330T230000Z DTEND:20100330T230000Z TRANSP:OPAQUE SEQUENCE:0 UID:8a982519-b99b-429a-8dad-c0f95c50d0e6 DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:upcoming milestones END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100329T230000Z DTEND:20100329T230000Z TRANSP:OPAQUE SEQUENCE:0 UID:588750a1-6f10-4b5d-8a51-3f3818024726 DESCRIPTION:uba:Project20100321:sagar . SUMMARY:test END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100407T230000Z DTEND:20100407T230000Z TRANSP:OPAQUE SEQUENCE:0 UID:36eaa726-a0a0-40a1-ba7c-09857f8ed006 DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:Rad apps devs END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100408T125632Z DTEND:20100408T125632Z TRANSP:OPAQUE SEQUENCE:0 UID:8521ad53-916a-43cc-8eeb-42c1b3d670d3 DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:this is a test ms END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100415T125643Z DTEND:20100415T125643Z TRANSP:OPAQUE SEQUENCE:0 UID:e4b295d8-2271-4393-9899-3e9c858f4e8c DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:Test msssss END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100430T055201Z DTEND:20100430T055201Z TRANSP:OPAQUE SEQUENCE:0 UID:1e464698-1064-4cb2-8166-2a843b63ca5a DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:this is a new milestones for testing on 30th april END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100731T093917Z DTEND:20100731T093917Z TRANSP:OPAQUE SEQUENCE:0 UID:5262ef58-73bc-4d66-a207-4e884e249629 DESCRIPTION:uba:Project20100321:imanage2010 pm SUMMARY:555555555555555555 END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100328T230000Z DTEND:20100328T230000Z TRANSP:OPAQUE SEQUENCE:0 UID:f654262d-714e-41d9-9690-005bb467f8aa DESCRIPTION:uba:Untitled project:imanage2010 pm SUMMARY:first milestone END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100401T095537Z DTEND:20100401T095537Z TRANSP:OPAQUE SEQUENCE:0 UID:3f4a6c16-f460-457d-a281-b4c010958796 DESCRIPTION:uba:ProjectIcal:imanage2010 pm SUMMARY:new ms ical END:VEVENT X-MS-OLK-FORCEINSPECTOROPEN:TRUE BEGIN:VEVENT DTSTART:20100331T230000Z DTEND:20100331T230000Z TRANSP:OPAQUE SEQUENCE:0 UID:e5bf28d1-3559-48e9-90f8-2b5233489a13 DESCRIPTION:uba:ProjectIcal:imanage2010 pm SUMMARY:new ms 2 ical END:VEVENT END:VCALENDAR And the source for generating the above code is which is nothing but the mvc view:: <%@ Import Namespace ="iManageProjectPM.Controllers" % <%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage"% BEGIN:VCALENDAR VERSION:2.0<%if (Model.Events.Count 1) {% CALSCALE:GREGORIAN METHOD:PUBLISH<%}% X-MS-OLK-FORCEINSPECTOROPEN:TRUE <%foreach(var evnt in Model.Events){% BEGIN:VEVENT DTSTART<%=Model.GetTimeString(evnt.StartTime)% DTEND<%=Model.GetTimeString(evnt.EndTime)% TRANSP:OPAQUE SEQUENCE:0 UID:<%=evnt.UID% DESCRIPTION:<%=evnt.Desc% SUMMARY:<%=evnt.Title% END:VEVENT<%}% END:VCALENDAR

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• Handwritten linked list is segfaulting and I don't understand why

  - by Born2Smile

  Hi I was working on a bit of fun, making an interface to run gnuplot from within c++, and for some reason the my linked list implementation fails. The code below fails on the line plots-append(&plot). Stepping through the code I discovered that for some reason the destructor ~John() is called immediately after the constructor John(), and I cannot seem to figure out why. The code included below is a stripped down version operating only on Plot*. Originally I made the linked list as a template class. And it worked fine as ll<int and ll<char* but for some reason it fails as ll<Plot*. Could youp please help me figure out why it fails? and perhaps help me understand how to make it work? In advance: Thanks a heap! //B2S #include <string.h class Plot{ char title[80]; public: Plot(){ } }; class Link{ Plot* element; Link* next; Link* prev; friend class ll; }; class ll{ Link* head; Link* tail; public: ll(){ head = tail = new Link(); head-prev = tail-prev = head-next = tail-next = head; } ~ll(){ while (head!=tail){ tail = tail-prev; delete tail-next; } delete head; } void append(Plot* element){ tail-element = element; tail-next = new Link(); tail-next-prev = tail; tail-next = tail; } }; class John{ ll* plots; public: John(){ plots= new ll(); } ~John(){ delete plots; } John(Plot* plot){ John(); plots-append(plot); } }; int main(){ Plot p; John k(&p); }

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• Succinct introduction to C++/CLI for C#/Haskell/F#/JS/C++/... programmer

  - by Henrik

  Hello everybody, I'm trying to write integrations with the operating system and with things like active directory and Ocropus. I know a bunch of programming languages, including those listed in the title. I'm trying to learn exactly how C++/CLI works, but can't find succinct, exact and accurate descriptions online from the searching that I have done. So I ask here. Could you tell me the pitfalls and features of C++/CLI? Assume I know all of C# and start from there. I'm not an expert in C++, so some of my questions' answers might be "just like C++", but could say that I am at C#. I would like to know things like: Converting C++ pointers to CLI pointers, Any differences in passing by value/doubly indirect pointers/CLI pointers from C#/C++ and what is 'recommended'. How do gcnew, __gc, __nogc work with Polymorphism Structs Inner classes Interfaces The "fixed" keyword; does that exist? Compiling DLLs loaded into the kernel with C++/CLI possible? Loaded as device drivers? Invoked by the kernel? What does this mean anyway (i.e. to load something into the kernel exactly; how do I know if it is?)? L"my string" versus "my string"? wchar_t? How many types of chars are there? Are we safe in treating chars as uint32s or what should one treat them as to guarantee language indifference in code? Finalizers (~ClassName() {}) are discouraged in C# because there are no garantuees they will run deterministically, but since in C++ I have to use "delete" or use copy-c'tors as to stack allocate memory, what are the recommendations between C#/C++ interactions? What are the pitfalls when using reflection in C++/CLI? How well does C++/CLI work with the IDisposable pattern and with SafeHandle, SafeHandleZeroOrMinusOneIsInvalid? I've read briefly about asynchronous exceptions when doing DMA-operations, what are these? Are there limitations you impose upon yourself when using C++ with CLI integration rather than just doing plain C++? Attributes in C++ similar to Attributes in C#? Can I use the full meta-programming patterns available in C++ through templates now and still have it compile like ordinary C++? Have you tried writing C++/CLI with boost? What are the optimal ways of interfacing the boost library with C++/CLI; can you give me an example of passing a lambda expression to an iterator/foldr function? What is the preferred way of exception handling? Can C++/CLI catch managed exceptions now? How well does dynamic IL generation work with C++/CLI? Does it run on Mono? Any other things I ought to know about?

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• Succinct introduction to C++/CLI for C#/Haskell/F#/JS/C++/... programmer

  - by Henrik

  Hello everybody, I'm trying to write integrations with the operating system and with things like active directory and Ocropus. I know a bunch of programming languages, including those listed in the title. I'm trying to learn exactly how C++/CLI works, but can't find succinct, exact and accurate descriptions online from the searching that I have done. So I ask here. Could you tell me the pitfalls and features of C++/CLI? Assume I know all of C# and start from there. I'm not an expert in C++, so some of my questions' answers might be "just like C++", but could say that I am at C#. I would like to know things like: Converting C++ pointers to CLI pointers, Any differences in passing by value/doubly indirect pointers/CLI pointers from C#/C++ and what is 'recommended'. How do gcnew, __gc, __nogc work with Polymorphism Structs Inner classes Interfaces The "fixed" keyword; does that exist? Compiling DLLs loaded into the kernel with C++/CLI possible? Loaded as device drivers? Invoked by the kernel? What does this mean anyway (i.e. to load something into the kernel exactly; how do I know if it is?)? L"my string" versus "my string"? wchar_t? How many types of chars are there? Are we safe in treating chars as uint32s or what should one treat them as to guarantee language indifference in code? Finalizers (~ClassName() {}) are discouraged in C# because there are no garantuees they will run deterministically, but since in C++ I have to use "delete" or use copy-c'tors as to stack allocate memory, what are the recommendations between C#/C++ interactions? What are the pitfalls when using reflection in C++/CLI? How well does C++/CLI work with the IDisposable pattern and with SafeHandle, SafeHandleZeroOrMinusOneIsInvalid? I've read briefly about asynchronous exceptions when doing DMA-operations, what are these? Are there limitations you impose upon yourself when using C++ with CLI integration rather than just doing plain C++? Attributes in C++ similar to Attributes in C#? Can I use the full meta-programming patterns available in C++ through templates now and still have it compile like ordinary C++? Have you tried writing C++/CLI with boost? What are the optimal ways of interfacing the boost library with C++/CLI; can you give me an example of passing a lambda expression to an iterator/foldr function? What is the preferred way of exception handling? Can C++/CLI catch managed exceptions now? How well does dynamic IL generation work with C++/CLI? Does it run on Mono? Any other things I ought to know about?

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• Stand-alone Java code formatter/beautifier/pretty printer?

  - by Greg Mattes

  I'm interested in learning about the available choices of high-quality, stand-alone source code formatters for Java. The formatter must be stand-alone, that is, it must support a "batch" mode that is decoupled from any particular development environment. Ideally it should be independent of any particular operating system as well. So, a built-in formatter for the IDE du jour is of little interest here (unless that IDE supports batch mode formatter invocation, perhaps from the command line). A formatter written in closed-source C/C++ that only runs on, say, Windows is not ideal, but is somewhat interesting. To be clear, a "formatter" (or "beautifier") is not the same as a "style checker." A formatter accepts source code as input, applies styling rules, and produces styled source code that is semantically equivalent to the original source code. A style checker also applies styling rules, but it simply reports rule violations without producing modified source code as output. So the picture looks like this: Formatter (produces modified source code that conforms to styling rules) Read Source Code → Apply Styling Rules → Write Styled Source Code Style Checker (does not produce modified source code) Read Source Code → Apply Styling Rules → Write Rule Violations Further Clarifications Solutions must be highly configurable. I want to be able to specify my own style, not simply select from a canned list. Also, I'm not looking for a general purpose pretty-printer written in Java that can pretty-print many things. I want to style Java code. I'm also not necessarily interested in a grand-unified formatter for many languages. I suppose it might be nice for a solution to have support for languages other than Java, but that is not a requirement. Furthermore, tools that only perform code highlighting are right out. I'm also not interested in a web service. I want a tool that I can run locally. Finally, solutions need not be restricted to open source, public domain, shareware, free software, commercial, or anything else. All forms of licensing are acceptable.

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• Installing my sdist from PyPI puts the files in the wrong places

  - by Tartley

  Hey. My problem is that when I upload my Python package to PyPI, and then install it from there using pip, my app breaks because it installs my files into completely different locations than when I simply install the exact same package from a local sdist. Installing from the local sdist puts files on my system like this: /Python27/ Lib/ site-packages/ gloopy-0.1.alpha-py2.7.egg/ (egg and install info files) data/ (images and shader source) doc/ (html) examples/ (.py scripts that use the library) gloopy/ (source) This is much as I'd expect, and works fine (e.g. my source can find my data dir, because they lie next to each other, just like they do in development.) If I upload the same sdist to PyPI and then install it from there, using pip, then things look very different: /Python27/ data/ (images and shader source) doc/ (html) Lib/ site-packages/ gloopy-0.1.alpha-py2.7.egg/ (egg and install info files) gloopy/ (source files) examples/ (.py scripts that use the library) This doesn't work at all - my app can't find its data files, plus obviously it's a mess, polluting the top-level /python27 directory with all my junk. What am I doing wrong? How do I make the pip install behave like the local sdist install? Is that even what I should be trying to achieve? Details I have setuptools installed, and also distribute, and I'm calling distribute_setup.use_setuptools() WindowsXP, Python2.7. My development directory looks like this: /gloopy /data (image files and GLSL shader souce read at runtime) /doc (html files) /examples (some scripts to show off the library) /gloopy (the library itself) My MANIFEST.in mentions all the files I want to be included in the sdist, including everything in the data, examples and doc directories: recursive-include data *.* recursive-include examples *.py recursive-include doc/html *.html *.css *.js *.png include LICENSE.txt include TODO.txt My setup.py is quite verbose, but I guess the best thing is to include it here, right? I also includes duplicate references to the same data / doc / examples directories as are mentioned in the MANIFEST.in, because I understand this is required in order for these files to be copied from the sdist to the system during install. NAME = 'gloopy' VERSION= __import__(NAME).VERSION RELEASE = __import__(NAME).RELEASE SCRIPT = None CONSOLE = False def main(): import sys from pprint import pprint from setup_utils import distribute_setup from setup_utils.sdist_setup import get_sdist_config distribute_setup.use_setuptools() from setuptools import setup description, long_description = read_description() config = dict( name=name, version=version, description=description, long_description=long_description, keywords='', packages=find_packages(), data_files=[ ('examples', glob('examples/*.py')), ('data/shaders', glob('data/shaders/*.*')), ('doc', glob('doc/html/*.*')), ('doc/_images', glob('doc/html/_images/*.*')), ('doc/_modules', glob('doc/html/_modules/*.*')), ('doc/_modules/gloopy', glob('doc/html/_modules/gloopy/*.*')), ('doc/_modules/gloopy/geom', glob('doc/html/_modules/gloopy/geom/*.*')), ('doc/_modules/gloopy/move', glob('doc/html/_modules/gloopy/move/*.*')), ('doc/_modules/gloopy/shapes', glob('doc/html/_modules/gloopy/shapes/*.*')), ('doc/_modules/gloopy/util', glob('doc/html/_modules/gloopy/util/*.*')), ('doc/_modules/gloopy/view', glob('doc/html/_modules/gloopy/view/*.*')), ('doc/_static', glob('doc/html/_static/*.*')), ('doc/_api', glob('doc/html/_api/*.*')), ], classifiers=[ 'Development Status :: 1 - Planning', 'Intended Audience :: Developers', 'License :: OSI Approved :: BSD License', 'Operating System :: Microsoft :: Windows', 'Programming Language :: Python :: 2.7', ], # see classifiers http://pypi.python.org/pypi?:action=list_classifiers ) config.update(dict( author='Jonathan Hartley', author_email='[email protected]', url='http://bitbucket.org/tartley/gloopy', license='New BSD', ) ) if '--verbose' in sys.argv: pprint(config) setup(**config) if __name__ == '__main__': main()

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• How to declare and implement a COM interface on C# that inherits from another COM interface?

  - by Carlos Loth

  I'm trying to understand what is the correct why to implement COM interfaces from C# code. It is straightforward when the interface doesn't inherit from other base interface. Like this one: [ComImport, Guid("2047E320-F2A9-11CE-AE65-08002B2E1262"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IShellFolderViewCB { long MessageSFVCB(uint uMsg, int wParam, int lParam); } However things start to become weired when I need to implement an interface that inherits from other COM interfaces. For example, if I implement the IPersistFolder2 interface which inherits from IPersistFolder which inherits from IPersist as I usually on C# code: [ComImport, Guid("0000010c-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IPersist { void GetClassID([Out] out Guid classID); } [ComImport, Guid("000214EA-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IPersistFolder : IPersist { void Initialize([In] IntPtr pidl); } [ComImport, Guid("1AC3D9F0-175C-11d1-95BE-00609797EA4F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IPersistFolder2 : IPersistFolder { void GetCurFolder([Out] out IntPtr ppidl); } The operating system is not able to call the methods on my object implementation. When I'm debugging I can see the constructor of my IPersistFolder2 implementation is called many times, however the interface methods I've implemented aren't called. I'm implementing the IPersistFolder2 as follows: [Guid("A4603CDB-EC86-4E40-80FE-25D5F5FA467D")] public class PersistFolder: IPersistFolder2 { void IPersistFolder2.GetClassID(ref Guid classID) { ... } void IPersistFolder2.Initialize(IntPtr pidl) { ... } void IPersistFolder2.GetCurFolder(out IntPtr ppidl) { ... } } What seems strange is when I declare the COM interface imports as follow, it works: [ComImport, Guid("0000010c-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] internal interface IPersist { void GetClassID([Out] out Guid classID); } [ComImport, Guid("000214EA-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] internal interface IPersistFolder : IPersist { new void GetClassID([Out] out Guid classID); void Initialize([In] IntPtr pidl); } [ComImport, Guid("1AC3D9F0-175C-11d1-95BE-00609797EA4F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] internal interface IPersistFolder2 : IPersistFolder { new void GetClassID([Out] out Guid classID); new void Initialize([In] IntPtr pidl); void GetCurFolder([Out] out IntPtr ppidl); } I don't know why it works when I declare the COM interfaces that way (hidding the base interface methods using new). Maybe it is related to the way IUnknown works. Does anyone know what is the correct way of implementing COM interfaces in C# that inherits from other COM interfaces and why?

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• file.createNewFile() creates files with last-modified time before actual creation time

  - by Kaleb Pederson

  I'm using JPoller to detect changes to files in a specific directory, but it's missing files because they end up with a timestamp earlier than their actual creation time. Here's how I test: public static void main(String [] files) { for (String file : files) { File f = new File(file); if (f.exists()) { System.err.println(file + " exists"); continue; } try { // find out the current time, I would hope to assume that the last-modified // time on the file will definitely be later than this System.out.println("-----------------------------------------"); long time = System.currentTimeMillis(); // create the file System.out.println("Creating " + file + " at " + time); f.createNewFile(); // let's see what the timestamp actually is (I've only seen it <time) System.out.println(file + " was last modified at: " + f.lastModified()); // well, ok, what if I explicitly set it to time? f.setLastModified(time); System.out.println("Updated modified time on " + file + " to " + time + " with actual " + f.lastModified()); } catch (IOException e) { System.err.println("Unable to create file"); } } } And here's what I get for output: ----------------------------------------- Creating test.7 at 1272324597956 test.7 was last modified at: 1272324597000 Updated modified time on test.7 to 1272324597956 with actual 1272324597000 ----------------------------------------- Creating test.8 at 1272324597957 test.8 was last modified at: 1272324597000 Updated modified time on test.8 to 1272324597957 with actual 1272324597000 ----------------------------------------- Creating test.9 at 1272324597957 test.9 was last modified at: 1272324597000 Updated modified time on test.9 to 1272324597957 with actual 1272324597000 The result is a race condition: JPoller records time of last check as xyz...123 File created at xyz...456 File last-modified timestamp actually reads xyz...000 JPoller looks for new/updated files with timestamp greater than xyz...123 JPoller ignores newly added file because xyz...000 is less than xyz...123 I pull my hair out for a while I tried digging into the code but both lastModified() and createNewFile() eventually resolve to native calls so I'm left with little information. For test.9, I lose 957 milliseconds. What kind of accuracy can I expect? Are my results going to vary by operating system or file system? Suggested workarounds? NOTE: I'm currently running Linux with an XFS filesystem. I wrote a quick program in C and the stat system call shows st_mtime as truncate(xyz...000/1000).

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• get_or_create generic relations in Django & python debugging in general

  - by rabidpebble

  I ran the code to create the generically related objects from this demo: http://www.djangoproject.com/documentation/models/generic_relations/ Everything is good intially: >>> bacon.tags.create(tag="fatty") <TaggedItem: fatty> >>> tag, newtag = bacon.tags.get_or_create(tag="fatty") >>> tag <TaggedItem: fatty> >>> newtag False But then the use case that I'm interested in for my app: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome") Traceback (most recent call last): File "<console>", line 1, in <module> File "/usr/local/lib/python2.6/dist-packages/django/db/models/manager.py", line 123, in get_or_create return self.get_query_set().get_or_create(**kwargs) File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 343, in get_or_create raise e IntegrityError: app_taggeditem.content_type_id may not be NULL I tried a bunch of random things after looking at other code: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem) ValueError: Cannot assign "<class 'generics.app.models.TaggedItem'>": "TaggedItem.content_type" must be a "ContentType" instance. or: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem.content_type) InterfaceError: Error binding parameter 3 - probably unsupported type. etc. I'm sure somebody can give me the correct syntax, but the real problem here is that I have no idea what is going on. I have developed in strongly typed languages for over ten years (x86 assembly, C++ and C#) but am new to Python. I find it really difficult to follow what is going on in Python when things like this break. In the languages I mentioned previously it's fairly straightforward to figure things like this out -- check the method signature and check your parameters. Looking at the Django documentation for half an hour left me just as lost. Looking at the source for get_or_create(self, **kwargs) didn't help either since there is no method signature and the code appears very generic. A next step would be to debug the method and try to figure out what is happening, but this seems a bit extreme... I seem to be missing some fundamental operating principle here... what is it? How do I resolve issues like this on my own in the future?

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• jcuda library usage problem

  - by user513164

  hi m very new to java and Linux i have a code which is taken from examples of jcuda.the code is following import jcuda.CUDA; import jcuda.driver.CUdevprop; import jcuda.driver.types.CUdevice; public class EnumDevices { public static void main(String args[]) { //Init CUDA Driver CUDA cuda = new CUDA(true); int count = cuda.getDeviceCount(); System.out.println("Total number of devices: " + count); for (int i = 0; i < count; i++) { CUdevice dev = cuda.getDevice(i); String name = cuda.getDeviceName(dev); System.out.println("Name: " + name); int version[] = cuda.getDeviceComputeCapability(dev); System.out.println("Version: " + String.format("%d.%d", version[0], version[1])); CUdevprop prop = cuda.getDeviceProperties(dev); System.out.println("Clock rate: " + prop.clockRate + " MHz"); System.out.println("Threads per block: " + prop.maxThreadsPerBlock); } } } I'm using Ubuntu as my operating system i compiled it with following command 1:-javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices i got following error error: Class names, 'EnumDevices', are only accepted if annotation processing is explicitly requested 1 error i don't know what is the meaning of this error.what should i do to compile the program than i changed the compiling option which is javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices.java than i got following error EnumDevices.java:36: clockRate is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Clock rate: " + prop.clockRate + " MHz"); ^ EnumDevices.java:37: maxThreadsPerBlock is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Threads per block: " + prop.maxThreadsPerBlock); ^ 2 errors Now I'm completely confused i don't know what to do? how to compile this program ? how to install the jcuda package or how to use it ? how to use package which have only jar files and .so files and the jar files don't having manifest file ? please help me

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• Favorite Visual Studio keyboard remappings?

  - by hoytster

  Stack Overflow has covered favorite short-cuts and add-ins, optimizations and preferences -- great topics all. If this one has been covered, I can't find it -- so thanks in advance for the link. What are your favorite Visual Studio keyboard remappings? Mine are motivated by the fact that I'm a touch-typist. Mouse, function keys, arrow keys, Home, End -- bleh. These are commands I do all day every day, so I've remapped them to sequences I can execute without moving my hands from the home row. The command that is remapped in Tools = Customize = [Keyboard] is shown in parentheses. I'm 100% positive that there are better remappings than these, so please post yours! Please include the command; oft times, figuring it out is a challenge. -- Hoytster Running the app and operating the debugger Ctrl+Q + Ctrl+R Run the application, in debug mode (Debug.Start) Ctrl+Q + Ctrl+Q Quit (stop) the application (Debug.StopDebugging) Ctrl+T Toggle a breakpoint at the current line (Debug.ToggleBreakpoint) Ctrl+K + Ctrl+I Step Into the method (Debug.StepInto) Ctrl+K + Ctrl+O Step Out of the method (Debug.StepOut) Ctrl+N Step over the method to the Next statement (Debug.StepOver) Ctrl+K + Ctrl+C Run the code, stopping at the Cursor position (Debug.RunToCursor) Ctrl+K + Ctrl+E Set then next statement to Execute (Debug.SetNextStatement) Navigating the code Ctrl+S Move a character LEFT (Edit.CharLeft) Ctrl+D Move a character RIGHT (Edit.CharRight) Ctrl+Q + Ctrl+S Move to the LEFT END of the current line (Edit.LineStart) Ctrl+Q + Ctrl+D Move to the RIGHT END of the current line (Edit.LineEnd) Ctrl+E Move a line UP (Edit.LineUp) Ctrl+X Move a line DOWN (Edit.LineDown) Ctrl+K + Ctrl+K Toggle (add or remove) bookmark (Edit.ToggleBookmark) Ctrl+K + Ctrl+N Move to the NEXT bookmark (Edit.NextBookmark) Ctrl+K + Ctrl+P Move to the PREVIOUS bookmark (Edit.PreviousBookmark) Ctrl+Q + Ctrl+W Save all modified Windows (File.SaveAll) Ctrl+L Find the NEXT instance of the search string (Edit.FindNext) Ctrl+K + Ctrl+L Find the PREVIOUS instance of the search string (Edit.FindPrevious) Ctrl+Q + Ctrl+L Drop down the list of open files (Window.ShowEzMDIFileList) The last sequence is like clicking the downward-facing triangle in the upper-right corner of the code editor window. VS will display a list of all the open windows. You can select from the list by typing the file name; the matching file will be selected as you type. Pause for a second and resume typing, and the matching process starts over, so you can select a different file. Nice, VS Team. The key takes you to the tab for the selected file.

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• What am I not getting about this abstract class implementation?

  - by Schnapple

  PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

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• deleted gen folder, eclipse isn't generating it now :(

  - by LuxuryMode

  I accidentally deleted my gen folder and now, predictably, my resources are all messed up. I just created a gen folder myself and tried to project clean - that didn't work. Tried right-clicking project and going to android tools fix project properties - didn't work. Tried unchecking build automatically...didn't work. cleaned, closed project, closed eclipse, restarted, etc, etc. Nothing is working and I keep seeing this error: gen already exists but is not a source folder. Convert to a source folder or rename it. EDIT - OK was able to generate R.java, but now I'm getting crazy stuff in the console: [2011-06-14 17:06:11 - fastapp] Conversion to Dalvik format failed with error 1 [2011-06-14 17:06:42 - fastapp] Dx trouble processing "java/awt/font/NumericShaper.class": Ill-advised or mistaken usage of a core class (java.* or javax.*) when not building a core library. This is often due to inadvertently including a core library file in your application's project, when using an IDE (such as Eclipse). If you are sure you're not intentionally defining a core class, then this is the most likely explanation of what's going on. However, you might actually be trying to define a class in a core namespace, the source of which you may have taken, for example, from a non-Android virtual machine project. This will most assuredly not work. At a minimum, it jeopardizes the compatibility of your app with future versions of the platform. It is also often of questionable legality. If you really intend to build a core library -- which is only appropriate as part of creating a full virtual machine distribution, as opposed to compiling an application -- then use the "--core-library" option to suppress this error message. If you go ahead and use "--core-library" but are in fact building an application, then be forewarned that your application will still fail to build or run, at some point. Please be prepared for angry customers who find, for example, that your application ceases to function once they upgrade their operating system. You will be to blame for this problem. If you are legitimately using some code that happens to be in a core package, then the easiest safe alternative you have is to repackage that code. That is, move the classes in question into your own package namespace. This means that they will never be in conflict with core system classes. JarJar is a tool that may help you in this endeavor. If you find that you cannot do this, then that is an indication that the path you are on will ultimately lead to pain, suffering, grief, and lamentation. [2011-06-14 17:06:42 - fastapp] Dx 1 error; aborting [2011-06-14 17:06:42 - fastapp] Conversion to Dalvik format failed with error 1 And eclipse can't resolve the import of my resources import com.me.fastapp.R;

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• If Then Statement Condition Being Ignored With Optimisations On

  - by Matma

  I think im going mad but can some show me what im missing, it must be some stupidly simple i just cant see the wood for the trees. BOTH side of this if then else statement are being executed? Ive tried commenting out the true side and moving the condition to a seperate variable with the same result. However if i explicitly set the condition to 1=0 or 1=1 then the if then statement is operating as i would expect. i.e. only executing one side of the equation... The only time ive seen this sort of thing is when the compiler has crashed and is no longer compiling (without visible indication that its not) but ive restarted studio with the same results, ive cleaned the solution, built and rebuilt with no change? please show me the stupid mistake im making using vs2005 if it matters. Dim dset As DataSet = New DataSet If (CboCustomers.SelectedValue IsNot Nothing) AndAlso (CboCustomers.SelectedValue <> "") Then Dim Sql As String = "Select sal.SalesOrderNo As SalesOrder,cus.CustomerName,has.SerialNo, convert(varchar,sal.Dateofpurchase,103) as Date from [dbo].[Customer_Table] as cus " & _ " inner join [dbo].[Hasp_table] as has on has.CustomerID=cus.CustomerTag " & _ " inner join [dbo].[salesorder_table] as sal On sal.Hasp_ID =has.Hasp_ID Where cus.CustomerTag = '" & CboCustomers.SelectedValue.ToString & "'" Dim dap As SqlDataAdapter = New SqlDataAdapter(Sql, FormConnection) dap.Fill(dset, "dbo.Customer_Table") DGCustomer.DataSource = dset.Tables("dbo.Customer_Table") Else Dim erm As String = "wtf" End If EDIT: i have found that this is something to do with the release config settings im using, i guesing its the optimisations bit. does anyone know of any utils/addons for vs that show if a line has been optimised out. delphi, my former language showed blue dots in the left margin to show that it was a compiled line, no dot meaning it wasnt compiled in, is there anything like that for vs? alternatively can someone explain how optimisations would affect this simple if statement causeing it to run both sides? EDIT2: using this thread as possible causes/solutions : http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled. It does the same with release = optimisations on, x86, x64 and AnyCPU Goes away with optimisations off. Im using V2005 on a x64 win7 machine, if that matters. Thanks

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• How to remove music/videos DRM protection and convert to Mobile Devices such as iPod, iPhone, PSP, Z

  - by tonywesley

  The music/video files you purchased from online music stores like iTunes, Yahoo Music or Wal-Mart are under DRM protection. So you can't convert them to the formats supported by your own mobile devices such as Nokia phone, Creative Zen palyer, iPod, PSP, Walkman, Zune… You also can't share your purchased music/videos with your friends. The following step by step tutorial is dedicated to instructing music lovers to how to convert your DRM protected music/videos to mobile devices. Method 1: If you only want to remove DRM protection from your protected music, this method will not spend your money. Step 1: Burn your protected music files to CD-R/RW disc to make an audio CD Step 2: Find a free CD Ripper software to convert the audio CD track back to MP3, WAV, WMA, M4A, AAC, RA… Method 2: This guide will show you how to crack drm from protected wmv, wma, m4p, m4v, m4a, aac files and convert to unprotected WMV, MP4, MP3, WMA or any video and audio formats you like, such as AVI, MP4, Flv, MPEG, MOV, 3GP, m4a, aac, wmv, ogg, wav... I have been using Media Converter software, it is the quickest and easiest solution to remove drm from WMV, M4V, M4P, WMA, M4A, AAC, M4B, AA files by quick recording. It gets audio and video stream at the bottom of operating system, so the output quality is lossless and the conversion speed is fast . The process is as follows. Step 1: Download and install the software Step 2: Run the software and click "Add…" button to load WMA or M4A, M4B, AAC, WMV, M4P, M4V, ASF files Step 3: Choose output formats. If you want to convert protected audio files, please select "Convert audio to" list; If you want to convert protected video files, please select "Convert video to" list. Step 4: You can click "Settings" button to custom preference for output files. Click "Settings" button bellow "Convert audio to" list for protected audio files Click "Settings" button bellow "Convert video to" list for protected video files Step 5: Start remove DRM and convert your DRM protected music and videos by click on "Start" button. What is DRM? DRM, which is most commonly found in movies and music files, doesn't mean just basic copy-protection of video, audio and ebooks, but it basically means full protection for digital content, ranging from delivery to end user's ways to use the content. We can remove the Drm from video and audio files legally by quick recording.

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• How to enable UAC prompt through programming

  - by peter

  I want to implement a UAC prompt for an application in visualc++ the operating system is 32bit x7460(2processor) Windowsserver 2008 the exe is myproject.exe through manifest.. Here for testing i wl build the application in Windows XP OS and copy the exe in to system containg the Windowsserver 2008 machine and replace it So what i did is i added a manifest like this name of that is myproject.exe.manifest My project has 3 folders like Headerfile,Resourcefile and Source file.I added this manifest(myproject.exe.manifest) in the Sourcefile folder containing other cpp and c code <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0"> <assemblyIdentity version="11.1.4.0" processorArchitecture="X7460" name="myproject" type="win32"/> <description>myproject Problem</description> <!-- Identify the application security requirements. --> <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2"> <security> <requestedPrivileges> <requestedExecutionLevel level="requireAdministrator" uiAccess="false"/> </requestedPrivileges> </security> </trustInfo> </assembly> then i added this line of code in Resourcefile(.rc).Means one header file is there(Myproject.h).I added the line of code there #define MANIFEST_RESOURCE_ID 1 MANIFEST_RESOURCE_ID RT_MANIFEST "myproject.exe.manifest" Finally i did the following step 1. Open your project in Microsoft Visual Studio 2005. 2. Under Project, select Properties. 3. In Properties, select Manifest Tool, and then select Input and Output. 4. Add in the name of your application manifest file under Additional manifest files. 5. Rebuild your application. But i am getting lot of Syntax errors Is there any problems in the way which i followed.If i commented the line define MANIFEST_RESOURCE_ID 1 MANIFEST_RESOURCE_ID RT_MANIFEST "myproject.exe.manifest" which added in Myproject.h for adding values in .rc file there willnot any error other than this general error c1010070: Failed to load and parse the manifest. The system cannot find the file specified. .\myproject.exe.manifest How to enable UAC prompt through programming

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• Two seperate tm structs mirroring each other

  - by BSchlinker

  Here is my current situation: I have two tm structs, both set to the current time I make a change to the hour in one of the structs The change is occurring in the other struct magically.... How do I prevent this from occurring? I need to be able to compare and know the number of seconds between two different times -- the current time and a time in the future. I've been using difftime and mktime to determine this. I recognize that I don't technically need two tm structs (the other struct could just be a time_t loaded with raw time) but I'm still interested in understanding why this occurs. void Tracker::monitor(char* buffer){ // time handling time_t systemtime, scheduletime, currenttime; struct tm * dispatchtime; struct tm * uiuctime; double remainingtime; // let's get two structs operating with current time dispatchtime = dispatchtime_tm(); uiuctime = uiuctime_tm(); // set the scheduled parameters dispatchtime->tm_hour = 5; dispatchtime->tm_min = 05; dispatchtime->tm_sec = 14; uiuctime->tm_hour = 0; // both of these will now print the same time! (0:05:14) // what's linking them?? // print the scheduled time printf ("Current Time : %2d:%02d:%02d\n", uiuctime->tm_hour, uiuctime->tm_min, uiuctime->tm_sec); printf ("Scheduled Time : %2d:%02d:%02d\n", dispatchtime->tm_hour, dispatchtime->tm_min, dispatchtime->tm_sec); } struct tm* Tracker::uiuctime_tm(){ time_t uiucTime; struct tm *ts_uiuc; // give currentTime the current time time(&uiucTime); // change the time zone to UIUC putenv("TZ=CST6CDT"); tzset(); // get the localtime for the tz selected ts_uiuc = localtime(&uiucTime); // set back the current timezone unsetenv("TZ"); tzset(); // set back our results return ts_uiuc; } struct tm* Tracker::dispatchtime_tm(){ time_t currentTime; struct tm *ts_dispatch; // give currentTime the current time time(&currentTime); // get the localtime for the tz selected ts_dispatch = localtime(&currentTime); // set back our results return ts_dispatch; }

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• File sizing issue in DOS/FAT

  - by Heather

  I've been tasked with writing a data collection program for a Unitech HT630, which runs a proprietary DOS operating system that can run executables compiled for 16-bit MS DOS with some restrictions. I'm using the Digital Mars C/C++ compiler, which is working well thus far. One of the application requirements is that the data file must be human-readable plain text, meaning the file can be imported into Excel or opened by Notepad. I'm using a variable length record format much like CSV that I've successfully implemented using the C standard library file I/O functions. When saving a record, I have to calculate whether the updated record is larger or smaller than the version of the record currently in the data file. If larger, I first shift all records immediately after the current record forward by the size difference calculated before saving the updated record. EOF is extended automatically by the OS to accommodate the extra data. If smaller, I shift all records backwards by my calculated offset. This is working well, however I have found no way to modify the EOF marker or file size to ignore the data after the end of the last record. Most of the time records will grow in size because the data collection program will be filling some of the empty fields with data when saving a record. Records will only shrink in size when a correction is made on an existing entry, or on a normal record save if the descriptive data in the record is longer than what the program reads in memory. In the situation of a shrinking record, after the last record in the file I'm left with whatever data was sitting there before the shift. I have been writing an EOF delimiter into the file after a "shrinking record save" to signal where the end of my records are and space-filling the remaining data, but then I no longer have a clean file until a "growing record save" extends the size of the file over the space-filled area. The truncate() function in unistd.h does not work (I'm now thinking this is for *nix flavors only?). One proposed solution I've seen involves creating a second file and writing all the data you wish to save into that file, and then deleting the original. Since I only have 4MB worth of disk space to use, this works if the file size is less than 2MB minus the size of my program executable and configuration files, but would fail otherwise. It is very likely that when this goes into production, users would end up with a file exceeding 2MB in size. I've looked at Ralph Brown's Interrupt List and the interrupt reference in IBM PC Assembly Language and Programming and I can't seem to find anything to update the file size or similar. Is reducing a file's size without creating a second file even possible in DOS?

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• C strange array behaviour

  - by LukeN

  After learning that both strncmp is not what it seems to be and strlcpy not being available on my operating system (Linux), I figured I could try and write it myself. I found a quote from Ulrich Drepper, the libc maintainer, who posted an alternative to strlcpy using mempcpy. I don't have mempcpy either, but it's behaviour was easy to replicate. First of, this is the testcase I have #include <stdio.h> #include <string.h> #define BSIZE 10 void insp(const char* s, int n) { int i; for (i = 0; i < n; i++) printf("%c ", s[i]); printf("\n"); for (i = 0; i < n; i++) printf("%02X ", s[i]); printf("\n"); return; } int copy_string(char *dest, const char *src, int n) { int r = strlen(memcpy(dest, src, n-1)); dest[r] = 0; return r; } int main() { char b[BSIZE]; memset(b, 0, BSIZE); printf("Buffer size is %d", BSIZE); insp(b, BSIZE); printf("\nFirst copy:\n"); copy_string(b, "First", BSIZE); insp(b, BSIZE); printf("b = '%s'\n", b); printf("\nSecond copy:\n"); copy_string(b, "Second", BSIZE); insp(b, BSIZE); printf("b = '%s'\n", b); return 0; } And this is its result: Buffer size is 10 00 00 00 00 00 00 00 00 00 00 First copy: F i r s t b = 46 69 72 73 74 00 62 20 3D 00 b = 'First' Second copy: S e c o n d 53 65 63 6F 6E 64 00 00 01 00 b = 'Second' You can see in the internal representation (the lines insp() created) that there's some noise mixed in, like the printf() format string in the inspection after the first copy, and a foreign 0x01 in the second copy. The strings are copied intact and it correctly handles too long source strings (let's ignore the possible issue with passing 0 as length to copy_string for now, I'll fix that later). But why are there foreign array contents (from the format string) inside my destination? It's as if the destination was actually RESIZED to match the new length.

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• Do You Really Know Your Programming Languages?

  - by Kristopher Johnson

  I am often amazed at how little some of my colleagues know or care about their craft. Something that constantly frustrates me is that people don't want to learn any more than they need to about the programming languages they use every day. Many programmers seem content to learn some pidgin sub-dialect, and stick with that. If they see a keyword or construct that they aren't familiar with, they'll complain that the code is "tricky." What would you think of a civil engineer who shied away from calculus because it had "all those tricky math symbols?" I'm not suggesting that we all need to become "language lawyers." But if you make your living as a programmer, and claim to be a competent user of language X, then I think at a minimum you should know the following: Do you know the keywords of the language and what they do? What are the valid syntactic forms? How are memory, files, and other operating system resources managed? Where is the official language specification and library reference for the language? The last one is the one that really gets me. Many programmers seem to have no idea that there is a "specification" or "standard" for any particular language. I still talk to people who think that Microsoft invented C++, and that if a program doesn't compile under VC6, it's not a valid C++ program. Programmers these days have it easy when it comes to obtaining specs. Newer languages like C#, Java, Python, Ruby, etc. all have their documentation available for free from the vendors' web sites. Older languages and platforms often have standards controlled by standards bodies that demand payment for specs, but even that shouldn't be a deterrent: the C++ standard is available from ISO for $30 (and why am I the only person I know who has a copy?). Programming is hard enough even when you do know the language. If you don't, I don't see how you have a chance. What do the rest of you think? Am I right, or should we all be content with the typical level of programming language expertise? Update: Several great comments here. Thanks. A couple of people hit on something that I didn't think about: What really irks me is not the lack of knowledge, but the lack of curiosity and willingness to learn. It seems some people don't have any time to hone their craft, but they have plenty of time to write lots of bad code. And I don't expect people to be able to recite a list of keywords or EBNF expressions, but I do expect that when they see some code, they should have some inkling of what it does. Few people have complete knowledge of every dark corner of their language or platform, but everyone should at least know enough that when they see something unfamiliar, they will know how to get whatever additional information they need to understand it.

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• Implementing coroutines in Java

  - by JUST MY correct OPINION

  This question is related to my question on existing coroutine implementations in Java. If, as I suspect, it turns out that there is no full implementation of coroutines currently available in Java, what would be required to implement them? As I said in that question, I know about the following: You can implement "coroutines" as threads/thread pools behind the scenes. You can do tricksy things with JVM bytecode behind the scenes to make coroutines possible. The so-called "Da Vinci Machine" JVM implementation has primitives that make coroutines doable without bytecode manipulation. There are various JNI-based approaches to coroutines also possible. I'll address each one's deficiencies in turn. Thread-based coroutines This "solution" is pathological. The whole point of coroutines is to avoid the overhead of threading, locking, kernel scheduling, etc. Coroutines are supposed to be light and fast and to execute only in user space. Implementing them in terms of full-tilt threads with tight restrictions gets rid of all the advantages. JVM bytecode manipulation This solution is more practical, albeit a bit difficult to pull off. This is roughly the same as jumping down into assembly language for coroutine libraries in C (which is how many of them work) with the advantage that you have only one architecture to worry about and get right. It also ties you down to only running your code on fully-compliant JVM stacks (which means, for example, no Android) unless you can find a way to do the same thing on the non-compliant stack. If you do find a way to do this, however, you have now doubled your system complexity and testing needs. The Da Vinci Machine The Da Vinci Machine is cool for experimentation, but since it is not a standard JVM its features aren't going to be available everywhere. Indeed I suspect most production environments would specifically forbid the use of the Da Vinci Machine. Thus I could use this to make cool experiments but not for any code I expect to release to the real world. This also has the added problem similar to the JVM bytecode manipulation solution above: won't work on alternative stacks (like Android's). JNI implementation This solution renders the point of doing this in Java at all moot. Each combination of CPU and operating system requires independent testing and each is a point of potentially frustrating subtle failure. Alternatively, of course, I could tie myself down to one platform entirely but this, too, makes the point of doing things in Java entirely moot. So... Is there any way to implement coroutines in Java without using one of these four techniques? Or will I be forced to use the one of those four that smells the least (JVM manipulation) instead?

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• Resize AIR app window while dragging

  - by matt lohkamp

  So I've noticed Windows 7 has a disturbing tendency to prevent you from dragging the title bar of windows off the top of the screen. If you try - in this case, using an air app with a draggable area at the bottom of the window, allowing you to push the top of the window up past the screen - it just kicks the window back down far enough that the title bar is at the top of what it considers the 'visible area.' One solution would be to resize the app window as it moves, so that the title bar is always where windows wants it. How would you resize the window while you're dragging it, though? Would you do it like this? dragHitArea.addEventListener(MouseEvent.MOUSE_DOWN, function(e:MouseEvent):void{ stage.nativeWindow.height += 50; stage.nativeWindow.startMove(); stage.nativeWindow.height -= 50; }); see what's going on there? When I click, I'm doing startMove(), which is hooking into the OS' function for dragging a window around. I'm also increasing and decreasing the height of the window by 50 pixels - which should give me no net increase, right? Wrong - the first '.height +=' gets executed, but the '.height -=' after the .startMove() never runs. Why? update - If you're curious, I'm programming an air widget with fly-out menus which expand rightwards and upwards - and since those element can only be displayed within the boundaries of the application window itself (even though the window is set to be chromeless and transparent) I have to expand the application's borders to include the area that the menu 'pops up' into. In the extreme case, with the widget positioned bottom left, and the menus expanded completely across to the right side and top edge of the screen, the application area could very well cover the entire desktop. The problem is, when it's expanded like this, if the user drags it up and to the right, it causes the 'title bar' area of the application window to move above the top edge of the desktop area, where it would normally be unreachable; and Windows automatically re-positions the window back below that edge once the .startMove() operation is completed. So what I want to do is continually resize the height of the application so that the visual effect will be the same for the user, but for the benefit of the operating system the window's title bar will never be above that top boundary of the desktop area.

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• Newbie - what do I need to do with httpd.conf to make CakePHP work correctly?

  - by EmmyS

  (Not sure if this belongs here or on webmasters; please move if necessary.) I'm a total newbie to Cake and not much better with apache; I've done a lot of PHP but always with a server that's already been set up by someone else. So I'm going through the basic blog tutorial, and it says: A Note On mod_rewrite Occasionally a new user will run in to mod_rewrite issues, so I'll mention them marginally here. If the Cake welcome page looks a little funny (no images or css styles), it probably means mod_rewrite isn't functioning on your system. Here are some tips to help get you up and running: Make sure that an .htaccess override is allowed: in your httpd.conf, you should have a section that defines a section for each Directory on your server. Make sure the AllowOverride is set to All for the correct Directory. Make sure you are editing the system httpd.conf rather than a user- or site-specific httpd.conf. For some reason or another, you might have obtained a copy of CakePHP without the needed .htaccess files. This sometimes happens because some operating systems treat files that start with '.' as hidden, and don't copy them. Make sure your copy of CakePHP is from the downloads section of the site or our SVN repository. Make sure you are loading up mod_rewrite correctly! You should see something like LoadModule rewrite_module libexec/httpd/mod_rewrite.so and AddModule mod_rewrite.c in your httpd.conf." I'm using XAMPP on linux. I've found my httpd.conf file in opt/lampp/ etc, but am not sure what I need to do with it. I've searched for "rewrite", and there's only one line: LoadModule rewrite_module modules/mod_rewrite.so There's nothing about AddModule mod_rewrite.c. Do I just create a Directory section for the directory I've installed Cake in and set AlllowOverride to All? (I created a separate subdirectory of my wwwroot and installed in there, since I also have installs of Joomla and CodeIgniter.) Is there anything else I need to do? My download of Cake did come with two htaccess-type files (._.htaccess and .htaccess) - do I need to do anything with them? Thanks for any help you can provide to this non-server-admin. EDIT TO ADD virtual host sample: <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot /www/docs/dummy-host.example.com ServerName dummy-host.example.com ServerAlias www.dummy-host.example.com ErrorLog logs/dummy-host.example.com-error_log CustomLog logs/dummy-host.example.com-access_log common </VirtualHost>

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