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  • Modeling software for network serialization protocol design

    - by Aurélien Vallée
    Hello, I am currently designing a low level network serialization protocol (in fact, a refinement of an existing protocol). As the work progress, pen and paper documents start to show their limits: i have tons of papers, new and outdated merged together, etc... And i can't show anything to anyone since i describe the protocol using my own notation (a mix of flow chart & C structures). I need a software that would help me to design a network protocol. I should be able to create structures, fields, their sizes, their layout, etc... and the software would generate some nice UMLish diagrams.

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  • How to flush DNS cache in Windows Mobile programmatically?

    - by Bounded
    Hello, My windows mobile application (written in C# with the compact framework) needs to know if a particular machine is active or not. To achieve this goal, I thought to use a ping mechanism. I tried to use the Ping class implemented in the opennetcf framework (the System.Net.NetworkInformation.Ping class for the .NET Framework is not part of the compact framework). Because I give to the Ping.Send function a host name, it first tries to resolve this host name and to retrieve an IP address. But i observe the following problem : If the first dns resolution fails (because the network is down at this moment), and if the application tries immediately again to send the ping, it fails too, even if the network is note down anymore. I check with a famous network protocol analyzer and i saw that only the requests concerning the first dns resolution are sent. The requests concerning the dns resolution of the second ping are not sent. Why is the second dns request not sent ? Is there any dns cache mechanism on such Windows Mobile devices ? If yes, can this mechanism beeing flushed programmatically ? EDIT : I gave up finding a solution to this DNS flush. I chose to ping an IP adress instead of a name machine. The problem of pinging an hard coded adress IP is that we have to be 100% sure that this IP will not change. The gateway IP can be used because it's always reachable (if it does not, it means the network is down).

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  • Why would a variable in Scala code mysteriously become null?

    - by Alex R
    I've isolated the problem down to this: Predef.println("the value of argv1 here is " + argv(1)); var n: $ = undef; n = argv(1); Predef.println("the value of argv1 here is " + argv(1)); Predef.println("the value of n here is " + n); Predef.println("the class of n here is " + n.getClass); Here's the definition of $: class $ { println("constructed a new $ of type: " + this.getClass); def value: $ = this; def toValue: Value = { new ConstStringValue(this.toString()) }; def -(sym: Symbol): $ = { println("looked up: " + sym); this } def -(sym: $): $ = { println("looked up: " + sym); this } def update(sym: Symbol, any: Any) { println("update called: " + sym + "=" + any); } def apply(sym: Symbol) = { this } def apply(obj: $) = { this } def apply() = { this } def +(o:$) = this.toValue.div(o.toValue) def *(o:$) = this.toValue.mul(o.toValue) def >(o:$) = this.toValue.gt(o.toValue) def <(o:$) = this.toValue.lt(o.toValue) def ++() = { this } def -=(o:$) = { this } } When run, the code prints: the value of argv1 here is 10 the value of argv1 here is 10 the value of n here is null java.lang.NullPointerException at test_1_php$.include(_tmp.scala:149) at php.script.main(php.scala:57) at test_1_php.main(_tmp.scala) [...] Why would n mysteriously lose its value (or fail to take one on)?

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  • How to detect internet connectivity using java program

    - by Sunil Kumar Sahoo
    How to write a java program which will tell me whether I have internet access or not. I donot want to ping or create connection with some external url because if that server will be down then my program will not work. I want reliable way to detect which will tell me 100% guarantee that whether I have internet connection or not irrespective of my Operating System. I want the program for the computers who are directly connected to internet. I have tried with the below program URL url = new URL("http://www.xyz.com/"); URLConnection conn = url.openConnection(); conn.connect(); I want something more appropriate than this program Thanks Sunil Kumar Sahoo

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  • Can any genius out there turn this code from generating permutation to generating combination?

    - by mark
    #include <string> int main(int,char**) { std::string default_str = "12345"; int perm=1, digits=default_str.size(); for (int i=1;i<=digits;perm*=i++); for (int a=0;a<perm;a++) { std::string avail=default_str; for (int b=digits,div=perm;b>0; b--) { div/=b; int index = (a/div)%b; printf("%c", avail[index] ); avail.erase(index,1) ; } printf("\n"); } printf("permutations:%d\n",perm); while(1); }

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  • PHP - Best practice to retain form values across postback

    - by Adam
    Hello, Complete PHP novice here, almost all my previous work was in ASP.NET. I am now working on a PHP project, and the first rock I have stumbled upon is retaining values across postback. For the most simple yet still realistic example, i have 10 dropdowns. They are not even databound yet, as that is my next step. They are simple dropdowns. I have my entire page inclosed in a tag. the onclick() event for each dropdown, calls a javascript function that will populate the corrosponding dropdowns hidden element, with the dropdowns selected value. Then, upon page reload, if that hidden value is not empty, i set the selected option = that of my hidden. This works great for a single postback. However, when another dropdown is changed, the original 1'st dropdown loses its value, due to its corrosponding hidden value losing its value as well! This draws me to look into using querystring, or sessions, or... some other idea. Could someone point me in the right direction, as to which option is the best in my situation? I am a PHP novice, however I am being required to do some pretty intense stuff for my skill level, so I need something flexable and preferribly somewhat easy to use. Thanks! -----edit----- A little more clarification on my question :) When i say 'PostBack' I am referring to the page/form being submitted. The control is passed back to the server, and the HTML/PHP code is executed again. As for the dropdowns & hiddens, the reason I used hidden variables to retain the "selected value" or "selected index", is so that when the page is submitted, I am able to redraw the dropdown with the previous selection, instead of defaulting back to the first index. When I use the $_POST[] command, I am unable to retrieve the dropdown by name, but I am able to retrieve the hidden value by name. This is why upon dropdown-changed event, I call javascript which sets the selected value from the dropdown into its corrosponding hidden.

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  • Mathematica equivalent of Ruby's inject

    - by Ben Alpert
    Is there a Mathematica function like inject in Ruby? For example, if I want the product of the elements in a list, in Ruby I can write: list.inject(1) { |prod,el| prod * el } I found I can just use Product in Mathematica: Apply[Product, list] However, this isn't general enough for me (like, if I don't just want the product or sum of the numbers). What's the closest equivalent to inject?

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  • Using static variable in function vs passing variable from caller

    - by Patrick
    I have a function which spawns various types of threads, one of the thread types needs to be spawned every x seconds. I currently have it like this: bool isTime( Time t ) { return t >= now(); } void spawner() { while( 1 ) { Time t = now(); if( isTime( t ) )//is time is called in more than one place in the real function { launchthread() t = now() + offset; } } } but I'm thinking of changing it to: bool isTime() { static Time t = now(); if( t >= now() ) { t = now() + offset; return true; } return false; } void spawner() { if( isTime() ) launchthread(); } I think the second way is neater but I generally avoid statics in much the same way I avoid global data; anyone have any thoughts on the different styles?

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  • Sparse quadratic program solver

    - by Jacob
    This great SO answer points to a good sparse solver, but I've got constraints on x (for Ax = b) such that each element in x is >=0 an <=N. The first thing which comes to mind is an QP solver for large sparse matrices. Also, A is huge (around 2e6x2e6) but very sparse with <=4 elements per row. Any ideas/recommendations?

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  • how to use XML sent by html form?

    - by user32167
    i have html form with textarea in which i paste some XML, for example: <network ip_addr="10.0.0.0/8" save_ip="true"> <subnet interf_used="200" name="lan1" /> <subnet interf_used="254" name="lan2" /> </network> When user submit form, that data is send to Java server, so in headers i get something like that: GET /?we=%3Cnetwork+ip_addr%3D%2210.0.0.0%2F8%22+save_ip%3D%22true%22%3E%0D%0A%3Csubnet+interf_used%3D%22200%22+name%3D%22lan1%22+%2F%3E%0D%0A%3Csubnet+interf_used%3D%22254%22+name%3D%22lan2%22+%2F%3E%0D%0A%3C%2Fnetwork%3E HTTP/1.1 how can i use that in my Java applications? I need to make some calculations on that data and re-send new generated XML.

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  • Aspiring Web Developer

    - by ihaveitnow
    Hi guys, I want to be a web developer and mobile web developer...I know HTML Iv done some research and read that XML and XHTML are necessary. Are there any other languages that I need to know? Would knowledge of Flash help me in my quest? I also want to become an Android App developer :) (go open-source!) But thats for a different post. I hope I can make links within this community, thanks for reading and even more for responses.

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  • 0xDEADBEEF equivalent for 64-bit development?

    - by Peter Mortensen
    For C++ development for 32-bit systems (be it Linux, Mac OS or Windows, PowerPC or x86) I have initialised pointers that would otherwise be undefined (e.g. they can not immediately get a proper value) like so: int *pInt = reinterpret_cast<int *>(0xDEADBEEF); (To save typing and being DRY the right-hand side would normally be in a constant, e.g. BAD_PTR.) If pInt is dereferenced before it gets a proper value then it will crash immediately on most systems (instead of crashing much later when some memory is overwritten or going into a very long loop). Of course the behavior is dependent on the underlying hardware (getting a 4 byte integer from the odd address 0xDEADBEEF from a user process may be perfectly valid), but the crashing has been 100% reliable for all the systems I have developed for so far (Mac OS 68xxx, Mac OS PowerPC, Linux Redhat Pentium, Windows GUI Pentium, Windows console Pentium). For instance on PowerPC it is illegal (bus fault) to fetch a 4 byte integer from an odd address. What is a good value for this on 64-bit systems?

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  • How to iterate over modifed std::map values?

    - by Frank
    I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

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  • How to start the web cam by programmatically?

    - by Nitz
    Hello Guys How to start any web cam through programmatically? my main requirement is it should start webcam? and that should be any application - software not a website. we can use any language. So how can start the web cam using programing language? btw... [I am not talking about the power of the webcam][Any web cam means any companies web cam]

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  • Monitoring outgoing internet traffic

    - by Frane
    Is there a way to monitoring internet traffic programatically? I would like to log the pages users are visiting on the Internet. Can this be achieved with .NET code, is there a 3rd party .NET component that could be used to retrieved data. Information about Internet traffic must be stored to a database so I cannot use a plugin or something for IE. We are also looking to include this code into our existing product so we cannot use a 3rd party product that cannot be redistributed. It would be cool if this thing could monitor traffic for all browsers but monitoring IE traffic might also be sufficient.

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  • Can I make ruby send network traffic over a specific iface?

    - by rjorgenson
    I am writing a script that grabs the external IP address along with some other information about each iface. I can't figure out how to make ruby send traffic over a specific iface(eth0 and wlan0 for example). I am currently using the open-uri library to open http://whatismyip.org and read it into a variable. def get_external_ip begin open("http://whatismyip.org") { |f| return f.read } rescue return "none" end end Is there any way to specify this at runtime of the script or from within the script itself(ideally)?

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  • What is a monad?

    - by kronoz
    Having briefly looked at Haskell recently I wondered whether anybody could give a brief, succinct, practical explanation as to what a monad essentially is? I have found most explanations I've come across to be fairly inaccessible and lacking in practical detail, so could somebody here help me?

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  • Is it possible to change a exe's icon without recompiling it?

    - by Microkernel
    Hi all, I have lot of executable that I have compiled (long time back) for many of which I don't have sourcecode now. But when I compiled them I didn't put any icons for them, so they all look like same dull, bald default icon. So my questions are, (1) is it possible for me to write a software that can change the resources section of the exe and change its looks? If so, can anyone plz point me to the location where its explained? (I am a beginner, I have no idea on the exe format and all) Also its fun to keep changing Icons without having the pain of recompiling everything just for the icon change... (2) This is raises a natural converse question, Is it similarly possible to zap out the icon used by some file and use it for some other file? (If so, plz point me to location where I can get some details. I am a C/C++ developers and I am looking for solution on Windows Platform... Regards, MicroKernel

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  • Coding for fun

    - by Klelky
    I would describe myself as a career coder - i.e. a developer at work but never really coded for fun. Early in my career I've hit the management track though. I really like my current job and can't see me going back to coding anytime soon so: Whats the best way to develop my coding skills and learn new languages in my spare time?

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  • hide cursor on remote terminal

    - by Tyler
    I have an open socket to a remote terminal. Using this SO answer I was able to put that terminal into character mode. My question is, how do I hide the cursor in the remote terminal using this method? Thanks!

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