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  • Socket error 10052 on UDP socket

    - by Jesper
    We have a .NET 2.0 desktop application which sends and receives network packets over UDP. Several users have reported an occasional socket error 10052 which happens when the code calls socket.BeginReceiveFrom on a the UDP socket. What does this mean? The official MS documentation for socket error 10052 says - quote: "WSAENETRESET (10052) Network dropped connection on reset . The connection has been broken due to keep-alive activity detecting a failure while the operation was in progress. It can also be returned by setsockopt if an attempt is made to set SO_KEEPALIVE on a connection that has already failed." This just doesn't make much sense for a UDP socket since UDP is a connectionless protocol. I know that another close error code 10054 in connection with UDP sockets means that an ICMP message "Port Unreachable" was received, and I am wondering if 10052 might map to another ICMP message? I have googled this for months, read network books, etc. but can't find anything. Please help - what does socket error 10052 on a UDP socket mean? Thanks in advance

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  • Please explain some of Paul Graham's points on LISP

    - by kunjaan
    I need some help understanding some of the points from Paul Graham's article http://www.paulgraham.com/diff.html A new concept of variables. In Lisp, all variables are effectively pointers. Values are what have types, not variables, and assigning or binding variables means copying pointers, not what they point to. A symbol type. Symbols differ from strings in that you can test equality by comparing a pointer. A notation for code using trees of symbols. The whole language always available. There is no real distinction between read-time, compile-time, and runtime. You can compile or run code while reading, read or run code while compiling, and read or compile code at runtime. What do these points mean How are they different in languages like C or Java? Do any other languages other than LISP family languages have any of these constructs now?

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  • iPhone - archiving array of custom objects

    - by Dylan
    I've been trying for hours and I cannot solve this problem. I'm making an app that saves unfinished Chess Games, so I'm trying to write an array to a file. This is what the array is, if it makes sense: -NSMutableArray savedGames --GameSave a ---NSMutableArray board; ----Piece a, b, c, etc. -----some ints ---NSString whitePlayer, blackPlayer; ---int playerOnTop, turn; --GameSave b ---NSMutableArray board; ----Piece a, b, c, etc. -----some ints ---NSString whitePlayer, blackPlayer; ---int playerOnTop, turn; etc. And these are my NSCoding methods: GameSave.m - (void)encodeWithCoder:(NSCoder *)coder { [coder encodeObject:whitePlayer forKey:@"whitePlayer"]; [coder encodeObject:blackPlayer forKey:@"blackPlayer"]; [coder encodeInt:playerOnTop forKey:@"playerOnTop"]; [coder encodeInt:turn forKey:@"turn"]; [coder encodeObject:board forKey:@"board"]; } - (id)initWithCoder:(NSCoder *)coder { self = [[GameSave alloc] init]; if (self != nil) { board = [coder decodeObjectForKey:@"board"]; whitePlayer = [coder decodeObjectForKey:@"whitePlayer"]; blackPlayer = [coder decodeObjectForKey:@"blackPlayer"]; playerOnTop = [coder decodeIntForKey:@"playerOnTop"]; turn = [coder decodeIntForKey:@"turn"]; } return self; } Piece.m - (void)encodeWithCoder:(NSCoder *)coder { [coder encodeInt:color forKey:@"color"]; [coder encodeInt:piece forKey:@"piece"]; [coder encodeInt:row forKey:@"row"]; [coder encodeInt:column forKey:@"column"]; } - (id)initWithCoder:(NSCoder *)coder { self = [[Piece alloc] init]; if (self != nil) { color = [coder decodeIntForKey:@"color"]; piece = [coder decodeIntForKey:@"piece"]; row = [coder decodeIntForKey:@"row"]; column = [coder decodeIntForKey:@"column"]; } return self; } And this is the code that tries to archive and save to file: - (void)saveGame { ChessSaverAppDelegate *delegate = (ChessSaverAppDelegate *) [[UIApplication sharedApplication] delegate]; [[delegate gameSave] setBoard:board]; NSMutableArray *savedGames = [NSKeyedUnarchiver unarchiveObjectWithFile:[self dataFilePath]]; if (savedGames == nil) { [NSKeyedArchiver archiveRootObject:[delegate gameSave] toFile:[self dataFilePath]]; } else { [savedGames addObject:[delegate gameSave]]; [NSKeyedArchiver archiveRootObject:savedGames toFile:[self dataFilePath]]; } } - (NSString *)dataFilePath { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; return [documentsDirectory stringByAppendingPathComponent:@"gameSaves.plist"]; } Sorry, here's the problem: After setting some breakpoints, an error is reached after this line from -saveGame: [NSKeyedArchiver archiveRootObject:savedGames toFile:[self dataFilePath]]; And this is what shows up in the console: 2010-05-11 17:04:08.852 ChessSaver[62065:207] *** -[NSCFType encodeWithCoder:]: unrecognized selector sent to instance 0x3d3cd30 2010-05-11 17:04:08.891 ChessSaver[62065:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFType encodeWithCoder:]: unrecognized selector sent to instance 0x3d3cd30' 2010-05-11 17:04:08.908 ChessSaver[62065:207] Stack: ( 32339035, 31077641, 32720955, 32290422, 32143042, 238843, 25827, 238843, 564412, 342037, 238843, 606848, 17686, 2733061, 4646817, 2733061, 3140430, 3149167, 3144379, 2837983, 2746312, 2773089, 41684313, 32123776, 32119880, 41678357, 41678554, 2777007, 9884, 9738 ) If it matters, -saveGame is called from a UIBarButton in a navigation controller. Any help is appreciated, thanks.

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  • Mutation Problem - Clojure

    - by Silanglaya Valerio
    having trouble changing an element of my function represented as a list. code for random function: (defn makerandomtree-10 [pc maxdepth maxwidth fpx ppx] (if-let [output (if (and (< (rand) fpx) (> maxdepth 0)) (let [head (nth operations (rand-int (count operations))) children (doall (loop[function (list) width maxwidth] (if (pos? width) (recur (concat function (list (makerandomtree-10 pc (dec maxdepth) (+ 2 (rand-int (- maxwidth 1))) fpx ppx))) (dec width)) function)))] (concat (list head) children)) (if (and (< (rand) ppx) (>= pc 0)) (nth parameters (rand-int (count parameters))) (rand-int 100)))] output )) I will provide also a mutation function, which is still not good enough. I need to be able to eval my statement, so the following is still insufficient. (defn mutate-5 "chooses a node changes that" [function pc maxwidth pchange] (if (< (rand) pchange) (let [output (makerandomtree-10 pc 3 maxwidth 0.5 0.6)] (if (seq? output) output (list output))) ;mutate the children of root ;declare an empty accumulator list, with root as its head (let [head (list (first function)) children (loop [acc(list) walker (next function)] (println "----------") (println walker) (println "-----ACC-----") (println acc) (if (not walker) acc (if (or (seq? (first function)) (contains? (set operations) (first function))) (recur (concat acc (mutate-5 walker pc maxwidth pchange)) (next walker)) (if (< (rand) pchange) (if (some (set parameters) walker) (recur (concat acc (list (nth parameters (rand-int (count parameters))))) (if (seq? walker) (next walker) nil)) (recur (concat acc (list (rand-int 100))) (if (seq? walker) (next walker) nil))) (recur acc (if (seq? walker) (next walker) nil)))) ))] (concat head (list children))))) (side note: do you have any links/books for learning clojure?)

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  • Just a general THANK YOU to EVERYONE. [closed]

    - by ajax81
    Hi All, I really just wanted to thank everybody that participates in the stackoverflow community. On more than one occasion, your minds have saved me from soul-eating project managers and career-ending deadlines. The commendable awareness exhibited by contributors that their answers are studied/used as learning material by millions of developers all over the world has created a regulated trust that seemingly keeps the nonsense (and egos) at the bottom of the barrel and out of the way. As an up-and-coming developer with so much to learn, I am grateful for each and every one of their patient contributions. I wish I could come up with a catchy/funny sign-off that makes everybody feel good, but I lack the funny bone that so many of the people on this site seem to have been born with. Instead, I can only leave my gratitude and a promise that as long as the community stays this great, I'll stay an avid reader...and one day be experienced enough to carry the torch of contribution. Sincerely, Daniel the Intern

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  • Implicit casting in VB.NET

    - by Shimmy
    The question is intended for lazy VB programmers. Please. In vb I can do and I won't get any errors. Example 1 Dim x As String = 5 Dim y As Integer = "5" Dim b As Boolean = "True" Example 2 Dim a As EnumType = 4 Dim v As Integer = EnumType.EnumValue Example 3 Private Sub ButtonClick(sender As Object, e As EventArgs) Dim btn As Button = sender End Sub Example 4 Private Sub ButtonClick(sender As Button, e As EventArgs) Dim data As Contact = sender.Tag End Sub If I surely know the expected runtime type, is this 'forbidden' to rely on the vb-language built-in casting? When can I rely? Thanks

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  • Relation between [[Prototype]] and prototype in JavaScript

    - by Claudiu
    From http://www.jibbering.com/faq/faq_notes/closures.html : Note: ECMAScript defines an internal [[prototype]] property of the internal Object type. This property is not directly accessible with scripts, but it is the chain of objects referred to with the internal [[prototype]] property that is used in property accessor resolution; the object's prototype chain. A public prototype property exists to allow the assignment, definition and manipulation of prototypes in association with the internal [[prototype]] property. The details of the relationship between to two are described in ECMA 262 (3rd edition) and are beyond the scope of this discussion. What are the details of the relationship between the two? I've browsed through ECMA 262 and all I've read there is stuff like: The constructor’s associated prototype can be referenced by the program expression constructor.prototype, Native ECMAScript objects have an internal property called [[Prototype]]. The value of this property is either null or an object and is used for implementing inheritance. Every built-in function and every built-in constructor has the Function prototype object, which is the initial value of the expression Function.prototype Every built-in prototype object has the Object prototype object, which is the initial value of the expression Object.prototype (15.3.2.1), as the value of its internal [[Prototype]] property, except the Object prototype object itself. From this all I gather is that the [[Prototype]] property is equivalent to the prototype property for pretty much any object. Am I mistaken?

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  • which language to use for building web application?

    - by harshit
    Hi I already have experience in developing websites using java technologies ... Now i have a task to develop another website and i have the liberty to select technology to built. I dont want to built using Java/J2ee standard technology as i want to learn new language. The specification about website i can give is that: 1) its a real estate based site. 2) so it will have a db of real estate data around million records 3) website will have more than 1000 hits /day and will have various functionality like search, add , delete,generate reports etc. So i mean UI should be good and fast. Technologies i have in mind .NEt( i have already worked on it but it licensed so may not go for it) , Groovy, Ruby on rails ,Play, GWT etc ... I am a college student and the website is again of a student(non techie guy) so i have 5-6 mnths to bring the website up I have read about them but all have adv and disadv but would like to hear from people who have used it and can tell me what they felt about the languages and problems while developing it.. Please feel free to drop any opinion you feel . Thanks

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  • Is it possible to connect iPhones through NAT traversal techniques over 3G for peer 2 peer gaming

    - by Dougnukem
    Is it possible to connect an iPhone to another iPhone or any other network client talking that game's protocol. I was thinking that I could use the same NAT Traversal technique used in the XBox 360 to host games on users XBox's through Firewalls. For NAT traversal to work effectively I'd have to have a central server that would allow clients to "broadcast" that they were hosting so that another client could initiate the NAT connection. In the link provided this is called relaying. Is there any inherent limitation of the US AT&T 3G network that will block the NAT traversal techniques (would you be limited to wifi firewall NAT traversal)? NAT Traversal Projects: - PJSIP - providing NAT traversal functionalities by using standard based protocols such as STUN, TURN, and ICE. - Freecast using Apache MINA Java network library for NAT Traversal

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  • C# [Mono]: MPAPI vs MPI.NET vs ?

    - by Olexandr
    Hi. I'm working on college project. I have to develop distributed computing system. And i decided to do some research to make this task fun :) I've found MPAPI and MPI.NET libraries. Yes, they are .NET libraries(Mono, in my case). Why .NET ? I'm choosing between Ada, C++ and C# so to i've choosed C# because of lower development time. I have two goals: Simplicity; Performance; Cluster computing. So, what to choose - MPAPI or MPI.NET or something else ?

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  • which metric(s) show the difference between object-oriented and procedural code

    - by twieger
    Which metric(s) could help to indicate that i have procedural code instead of object-oriented code? I would like to have a set of simple metrics, which indicate with a high probability, that the analyzed code contains procedural transaction scripts and an anemic domain model instead of following sound object-oriented design principles. Would be happy about any set of useful metrics and tools for measuring. Thanks, Thomas!

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  • How to handle corrupt messages arriving on a socket?

    - by Pieter
    I've got a working socket handling mechanism, similar (but a bit more complex) to Qt's Fortune Example http://qt.nokia.com/doc/4.5/network-fortuneclient.html http://qt.nokia.com/doc/4.5/network-fortuneserver.html Now I'm wondering how to handle corrupt messages. Discarding the data is a start, but I need to discard up to a point I can start processing messages again. The corrupt message may be lost, but I need to be able to recover from it. I've got the following idea in mind: Put a fixed header at the start of each message, eg. 0xABCDEF01. When recovering, lookup this header and restart handling incoming messages. = Break off readFortune() on a timeout and recover = When encountering an inconsistent header, recover A huge blocksize is still going to be a problem. To fix that, I should be constantly checking whether or not I'm reading gibberish, but this is not always possible. I can also limit the blocksize on certain message-types. Any ideas on this? Any proposals on what to use as byteword?

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  • Higher-order type constructors and functors in Ocaml

    - by sdcvvc
    Can the following polymorphic functions let id x = x;; let compose f g x = f (g x);; let rec fix f = f (fix f);; (*laziness aside*) be written for types/type constructors or modules/functors? I tried type 'x id = Id of 'x;; type 'f 'g 'x compose = Compose of ('f ('g 'x));; type 'f fix = Fix of ('f (Fix 'f));; for types but it doesn't work. Here's a Haskell version for types: data Id x = Id x data Compose f g x = Compose (f (g x)) data Fix f = Fix (f (Fix f)) -- examples: l = Compose [Just 'a'] :: Compose [] Maybe Char type Natural = Fix Maybe -- natural numbers are fixpoint of Maybe n = Fix (Just (Fix (Just (Fix Nothing)))) :: Natural -- n is 2 -- up to isomorphism composition of identity and f is f: iso :: Compose Id f x -> f x iso (Compose (Id a)) = a

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  • Fair Contract salary compared to permanent salary

    - by Ngu Soon Hui
    Let's say I have a position open, it can either be contract or permanent position. The question is what is the fair amount of money I should pay for the contract position, if I am willing to pay X per month for the permanent role? Contract pays are inevitably higher, because the contractors are not entitled for a lot of benefits, and not guaranteed of a job. I know the exact ratio of contract to permanent varies from person to person, but I need a rule of thumb here.

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  • Personal projects competing with employers projects?

    - by jamesorwood123
    Recently at my place of employment it was discovered that I was developing an outside personal project (personal project being a project I have been working on, in my spare time, for my own purposes, using my personal equipment). My employer has an idea which is very similar to my outside project but has not been started, created, put out to market yet. When I originally started working for the company I signed a non-compete contract. My employer is now saying that because my outside/personal project is similar to theirs that I am now a competitor and breaching my original non-compete agreement. What I would like to know is where do I stand in this situation? Also my personal project has not been fully developed, nor is available to anyone other than myself. So if we both don’t have full/released products (full meaning put out to the public) are we actually competitors? There is going to be a meeting in the coming weeks to discuss this issue and would like to have a proper argument in place. I know some of this conversation is best held with a lawyer but I don’t have the money to do that yet. I’m not looking for full legal advice just anyone who has maybe experienced this or can give any advice. Thanks in advance!

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  • Segmentation fault on MPI, runs properly on OpenMP

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

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  • I dont understand Access modifiers in OOP (JAVA)

    - by Imran
    I know this is a silly question but i don't understand Access Modifiers in OOP. Why do we make for example in JAVA instance variables private and then use public getter and setter methods to access them? I mean whats the reasoning/logic behind this? You still get to the instance variable but why use setter and getter methods when you can just make your variables public? please excuse my ignorance as i'm simply trying to understand why we do this? Thank you in advance;-)

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  • Android ConnectivityManager information

    - by Mike
    I am trying to get a better grip on Android's ConnectivityManager and how it really works under the hood. Using the API is simple enough but I am looking for something lower level such as when it starts and the dirty details of what its doing in the background. I can't seem to find a good resource about it. Everything is just about using the API. Does anyone understand this or have any resources that they could point me to, website, book, white paper, or otherwise? I would really appreciate it. Thanks

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  • Cannot receive email outside domain with Microsoft Exchange

    - by Adi
    This morning we couldn't receive email from outside our company's domain (domain.com.au), but we can send email to outside (e.g hotmail, gmail, yahoo). When I tried to send email to my work email address using my gmail account, I received this message Technical details of permanent failure: Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 Unable to relay for [email protected] (state 14). I tried using telnet to send email, and it works. But still I couldn't figure out why I can't receive email from outside. I'm not sure if I provided enough info. I'll try to provide as much info as needed to help me solve the problem. Thanks

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