Search Results

Search found 7902 results on 317 pages for 'structure'.

Page 264/317 | < Previous Page | 260 261 262 263 264 265 266 267 268 269 270 271  | Next Page >

  • C: socket connection timeout

    - by The.Anti.9
    I have a simple program to check if a port is open, but I want to shorten the timeout length on the socket connection because the default is far too long. I'm not sure how to do this though. Here's the code: #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <arpa/inet.h> #include <netinet/in.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <netdb.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main(int argc, char **argv) { u_short port; /* user specified port number */ char addr[1023]; /* will be a copy of the address entered by u */ struct sockaddr_in address; /* the libc network address data structure */ short int sock = -1; /* file descriptor for the network socket */ if (argc != 3) { fprintf(stderr, "Usage %s <port_num> <address>", argv[0]); return EXIT_FAILURE; } address.sin_addr.s_addr = inet_addr(argv[2]); /* assign the address */ address.sin_port = htons(atoi(argv[2])); /* translate int2port num */ sock = socket(AF_INET, SOCK_STREAM, 0); if (connect(sock,(struct sockaddr *)&address,sizeof(address)) == 0) { printf("%i is open\n", port); } close(sock); return 0; }

    Read the article

  • In SQL can I return a tables with a varying number of columns

    - by Matt
    I have a somewhat more complicated scenario, but I think it should be possible. I have a large SPROC whose result is a set of characteristics for a set of persons. So the Table would look something like this: Property | Client1 Client 2 Client3 ----------------------------------------------------------- Sex | M F M Age | 67 56 67 Income | Low Mid Low It's built using cursors, iterating over different datasets. The problem I am facing is that there is a varying number of Clients and Properties, so an equally valid result over different input sets might be: Property | Client1 Client 2 ------------------------------------------- Sex | M F Age | 67 56 Weight | 122 122 The different number of properties is easy, those are just extra rows. My problem is that I need to declare a temporary table with a varying number of columns. There could be 2 clients or 100. Every client in guaranteed to have every property ultimately listed. What SQL structure would statisfy this and how can I declare it and insert things into it? I can't just flip the columns and rows either because there is a variable number of each.

    Read the article

  • Managing libraries and imports in a programming language

    - by sub
    I've created an interpreter for a stupid programming language in C++ and the whole core structure is finished (Tokenizer, Parser, Interpreter including Symbol tables, core functions, etc.). Now I have a problem with creating and managing the function libraries for this interpreter (I'll explain what I mean with that later) So currently my core function handler is horrible: // Simplified version myLangResult SystemFunction( name, argc, argv ) { if ( name == "print" ) { if( argc < 1 ) { Error('blah'); } cout << argv[ 0 ]; } else if ( name == "input" ) { if( argc < 1 ) { Error('blah'); } string res; getline( cin, res ); SetVariable( argv[ 0 ], res ); } else if ( name == "exit ) { exit( 0 ); } And now think of each else if being 10 times more complicated and there being 25 more system functions. Unmaintainable, feels horrible, is horrible. So I thought: How to create some sort of libraries that contain all the functions and if they are imported initialize themselves and add their functions to the symbol table of the running interpreter. However this is the point where I don't really know how to go on. What I wanted to achieve is that there is e.g.: an (extern?) string library for my language, e.g.: string, and it is imported from within a program in that language, example: import string myString = "abcde" print string.at( myString, 2 ) # output: c My problems: How to separate the function libs from the core interpreter and load them? How to get all their functions into a list and add it to the symbol table when needed? What I was thinking to do: At the start of the interpreter, as all libraries are compiled with it, every single function calls something like RegisterFunction( string namespace, myLangResult (*functionPtr) ); which adds itself to a list. When import X is then called from within the language, the list built with RegisterFunction is then added to the symbol table. Disadvantages that spring to mind: All libraries are directly in the interpreter core, size grows and it will definitely slow it down.

    Read the article

  • Zend Framework - Deny access to folders other than public folder

    - by Vincent
    All, I have the following Zend application structure: helloworld - application - configs - controllers - models - layouts - include - library - public - .htaccess - index.php - design - .htaccess The .htaccess in the root folder has the following contents: ##################################################### # CONFIGURE media caching # Header unset ETag FileETag None Header unset Last-Modified Header set Expires "Fri, 21 Dec 2012 00:00:00 GMT" Header set Cache-Control "max-age=7200, must-revalidate" SetOutputFilter DEFLATE # ##################################################### ErrorDocument 404 /custom404.php RedirectMatch permanent ^/$ /public/ The .htaccess in the public folder has the following: Options -MultiViews ErrorDocument 404 /custom404.php RewriteEngine on # The leading %{DOCUMENT_ROOT} is necessary when used in VirtualHost context RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -s [OR] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -l [OR] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -d RewriteRule ^.*$ - [NC,L] RewriteRule ^.*$ index.php [NC,L] My vhost configuration is as under: <VirtualHost *:80> ServerAdmin [email protected] DocumentRoot "C:\\xampp\\htdocs\\xampp\\helloworld\\" ServerName helloworld ServerAlias helloworld <Directory "C:\\xampp\\htdocs\\xampp\\helloworld\\"> Options Indexes FollowSymLinks AllowOverride all Order Deny,Allow Deny from all Allow from 127.0.0.1 </Directory> </VirtualHost> Currently, if the user visits, http://localhost, my .htaccess files above make sure, the request is routed to http://localhost/public automatically. If the user visits any other folder apart from public folder from the address bar, he gets a directory listing of that folder. How can I make sure to deny the user access to every other folder except the public folder? I want the user to be redirected to the public folder if he visits any other folder. However, if the underlying code requests something from other folders, (ex: ) it should still work.. Thanks

    Read the article

  • axis-java2wsdl task classpath setting problem

    - by qkrsppopcmpt
    Hey Guys, here is my build.xml <?xml version="1.0" standalone="yes"?> <path id='axis2.classpath'> <fileset dir='D:\Tools\axis2-1.5.1-bin\axis2-1.5.1\lib'> <include name='**/*.jar' /> </fileset> </path> <path id='compiled.class.path'> <fileset dir='./bin/pkg'> <include name='*.class' /> </fileset> </path> <taskdef resource="axis-tasks.properties" classpathref="axis2.classpath" /> <target name="run" > <axis-java2wsdl output="out/TestService.wsdl" location="http://localhost:8080/axis2/service/TestService" namespace="service" classname="TestService"> <classpath refid="compiled.class.path"/> <mapping namespace="TestService" package="pkg"/> </axis-java2wsdl> </target> here is my file structure: prj-bin-pkg-TestService.class/////////// prj-src-pkg-TestService.java/////////// prj-build.xml I get java.lang.ClassNotFoundException: TestService. Can anybody tell me how to fix it? Thanks so much. !!!!!!!!!!!!!

    Read the article

  • Trying to write priority queue in Java but getting "Exception in thread "main" java.lang.ClassCastEx

    - by Dan
    For my data structure class, I am trying to write a program that simulates a car wash and I want to give fancy cars a higher priority than regular ones using a priority queue. The problem I am having has something to do with Java not being able to type cast "Object" as an "ArrayQueue" (a simple FIFO implementation). What am I doing wrong and how can I fix it? public class PriorityQueue<E> { private ArrayQueue<E>[] queues; private int highest=0; private int manyItems=0; public PriorityQueue(int h) { highest=h; queues = (ArrayQueue[]) new Object[highest+1]; <----problem is here } public void add(E item, int priority) { queues[priority].add(item); manyItems++; } public boolean isEmpty( ) { return (manyItems == 0); } public E remove() { E answer=null; int counter=0; do { if(!queues[highest-counter].isEmpty()) { answer = queues[highest-counter].remove(); counter=highest+1; } else counter++; }while(highest-counter>=0); return answer; } }

    Read the article

  • Optimize a views drawing code

    - by xon1c
    Hi, in a simple drawing application I have a model which has a NSMutableArray curvedPaths holding all the lines the user has drawn. A line itself is also a NSMutableArray, containing the point objects. As I draw curved NSBezier paths, my point array has the following structure: linePoint, controlPoint, controlPoint, linePoint, controlPoint, controlPoint, etc... I thought having one array holding all the points plus control points would be more efficient than dealing with 2 or 3 different arrays. Obviously my view draws the paths it gets from the model, which leads to the actual question: Is there a way to optimize the following code (inside the view's drawRect method) in terms of speed? int lineCount = [[model curvedPaths] count]; // Go through paths for (int i=0; i < lineCount; i++) { // Get the Color NSColor *theColor = [model getColorOfPath:[[model curvedPaths] objectAtIndex:i]]; // Get the points NSArray *thePoints = [model getPointsOfPath:[[model curvedPaths] objectAtIndex:i]]; // Create a new path for performance reasons NSBezierPath *path = [[NSBezierPath alloc] init]; // Set the color [theColor set]; // Move to first point without drawing [path moveToPoint:[[thePoints objectAtIndex:0] myNSPoint]]; int pointCount = [thePoints count] - 3; // Go through points for (int j=0; j < pointCount; j+=3) { [path curveToPoint:[[thePoints objectAtIndex:j+3] myNSPoint] controlPoint1:[[thePoints objectAtIndex:j+1] myNSPoint] controlPoint2:[[thePoints objectAtIndex:j+2] myNSPoint]]; } // Draw the path [path stroke]; // Bye stuff [path release]; [theColor release]; } Thanks, xonic

    Read the article

  • iPhone development - app design patterns

    - by occulus
    There are tons of resources concerning coding on the iPhone. Most of them concern "how do I do X", e.g. "setup a navigation controller", or "download text from a URL". All good and fine. What I'm more interested in now are the questions that follow the simpler stuff - how to best structure your complex UI, or your app, or the common problems that arise. To illustrate: a book like "Beginning iPhone 3 Development" tells you how to set up a multi viewcontroller app with an top 'switcher' viewcontroller that switches between views owned by other view controllers. Fine, but you're only told how to do that, and nothing about the problems that can follow: for example, if I use their paradigm to switch to a UINavigationViewController, the Navigation bar ends up too low on the screen, because UINavigationViewController expects to be the topmost UIViewController (apparently). Also, delegate methods (e.g. relating to orientation changes) go to the top switcher view controller, not the actual controller responsible for the current view. I have fixes for these things but they feel like hacks which makes me unhappy and makes me feel like I'm missing something. One productive thing might be to look at some open source iPhone projects (see this question). But aside from that?

    Read the article

  • c programming malloc question

    - by user535256
    Hello guys, Just got query regarding c malloc() function. I am read()ing x number of bytes from a file to get lenght of filename, like ' read(file, &namelen, sizeof(unsigned char)); ' . The variable namelen is a type unsigned char and was written into file as that type (1 byte). Now namelen has the lenght of filename ie namelen=8 if file name was 'data.txt', plus extra /0 at end, that working fine. Now I have a structure recording file info, ie filename, filelenght, content size etc. struct fileinfo { char *name; ...... other variable like size etc }; struct fileinfo *files; Question: I want to make that files.name variable the size of namelen ie 8 so I can successfully write the filename into it, like ' files[i].name = malloc(namelen) ' However, I dont want it to be malloc(sizeof(namelen)) as that would make it file.name[1] as the size of its type unsigned char. I want it to be the value thats stored inside variable &namelen ie 8 so file.name[8] so data.txt can be read() from file as 8 bytes and written straight into file.name[8? Is there a way to do this my current code is this and returns 4 not 8 files[i].name = malloc(namelen); //strlen(files[i].name) - returns 4 //perhaps something like malloc(sizeof(&namelen)) but does not work Thanks for any suggestions Have tried suggested suggestions guys, but I now get a segmentation fault error using: printf("\nsizeofnamelen=%x\n",namelen); //gives 8 for data.txt files[i].name = malloc(namelen + 1); read(file, &files[i].name, namelen); int len=strlen(files[i].name); printf("\nnamelen=%d",len); printf("\nname=%s\n",files[i].name); When I try to open() file with that files[i].name variable it wont open so the data does not appear to be getting written inside the read() &files[i].name and strlen() causes segemntation error as well as trying to print the filename

    Read the article

  • How to emulate mod_rewrite in PHP

    - by Tyler Crompton
    I have a few URLs that I want to map to certain files via PHP. Currently, I am just using mod_rewrite in Apache. However, my application is getting too large for the rewriting to be done with regular expressions. So I created a file router.php that does the rewriting. I understand to do a redirect I could just send the Location: header. However, I don't always want to do a redirect. For example, I may want /api/item/ to map to the file /herp/derp.php relative to the document root. I need to preserve the HTTP method as well. "No problem," I thought. I made my .htaccess have the following snippet. RewriteEngine On RewriteRule ^api/item/$ /cgi-bin/router.php [L] And my router.php file looks as follows: <?php $uri = parse_url($_SERVER['REQUEST_URI']); $query = isset($uri['query']) ? $uri['query'] ? array(); // some code that modifies the query require_once "{$_SERVER['DOCUMENT_ROOT']}/herp/derp.php?" . http_build_query($query); ?> However, this doesn't work, because the OS is looking for a file named derp.php?some=query. How can I simulate a rewrite rule such as RewriteRule ^api/item/$ /herp/derp/ [L] in PHP. In other words, how do I tell the server to process a different URL than requested and preserve the query and HTTP method without causing a redirect? Note: Using variables set in router.php is less than desirable and is bad structure since it's only supposed to be responsible for handling URLs. I am open to using a light-weight third party solution.

    Read the article

  • How to make command-line options mandatory with GLib?

    - by ahe
    I use GLib to parse some command-line options. The problem is that I want to make two of those options mandatory so that the program terminates with the help screen if the user omits them. My code looks like this: static gint line = -1; static gint column = -1; static GOptionEntry options[] = { {"line", 'l', 0, G_OPTION_ARG_INT, &line, "The line", "L"}, {"column", 'c', 0, G_OPTION_ARG_INT, &column, "The column", "C"}, {NULL} }; ... int main(int argc, char** argv) { GError *error = NULL; GOptionContext *context; context = g_option_context_new ("- test"); g_option_context_add_main_entries (context, options, NULL); if (!g_option_context_parse(context, &argc, &argv, &error)) { usage(error->message, context); } ... return 0; } If I omit one of those parameters or both on the command-line g_option_context_parse() still succeeds and the values in question (line and or column) are still -1. How can I tell GLib to fail parsing if the user doesn't pass both options on the command-line? Maybe I'm just blind but I couldn't find a flag I can put into my GOptionEntry data structure to tell it to make those fields mandatory. Of course I could check if one of those variables is still -1 but then the user could just have passed this value on the command-line and I want to print a separate error message if the values are out of range.

    Read the article

  • PHP - Parse XML subitems using foreach()

    - by Nate Shoffner
    I have an XML file that needs parsing in PHP. I am currenlty using simplexml_load_file to load the file like so: $xml = simplexml_load_file('Project.xml'); Inside that XML file lies a structure like this: <?xml version="1.0" encoding="ISO-8859-1"?> <project> <name>Project 1</name> <features> <feature>Feature 1</feature> <feature>Feature 2</feature> <feature>Feature 3</feature> <feature>Feature 4</feature> </features> </project> What I am trying to do is print the <name> contents along with EACH <feature> element within <features>. I'm not sure how to do this because there is more than 1 element called <feature>. Any help is greatly appreciated.

    Read the article

  • How do you perform arithmetic calculations on symbols in Scheme/Lisp?

    - by kunjaan
    I need to perform calculations with a symbol. I need to convert the time which is of hh:mm form to the minutes passed. ;; (get-minutes symbol)->number ;; convert the time in hh:mm to minutes ;; (get-minutes 6:19)-> 6* 60 + 19 (define (get-minutes time) (let* ((a-time (string->list (symbol->string time))) (hour (first a-time)) (minutes (third a-time))) (+ (* hour 60) minutes))) This is an incorrect code, I get a character after all that conversion and cannot perform a correct calculation. Do you guys have any suggestions? I cant change the input type. Context: The input is a flight schedule so I cannot alter the data structure. ;; ---------------------------------------------------------------------- Edit: Figured out an ugly solution. Please suggest something better. (define (get-minutes time) (let* ((a-time (symbol->string time)) (hour (string->number (substring a-time 0 1))) (minutes (string->number (substring a-time 2 4)))) (+ (* hour 60) minutes)))

    Read the article

  • Database for managing large volumes of (system) metrics

    - by symcbean
    Hi, I'm looking at building a system for managing and reporting stats on web page performance. I'll be collecting a lot more stats than are available in the standard log formats (approx 20 metrics) but compared to most types of database applications, the base data structure will be very simple. My problem is that I'll be accumulating a lot of data - in the region of 100,000 records (i.e. sets of metrics) per hour. Of course, resources are very limited! So that its possible to sensibly interact with the data, I'd need to consolidate each metric into one minute bins, broken down by URL, then for anything more than 1 day old, consolidated into 10 minute bins, then at 1 week, hourly bins. At the front end, I want to provide a view (prefereably as plots) of the last hour of data, with the facility for users to drill up/down through defined hierarchies of URLs (which do not always map directly to the hierarchy expressed in the path of the URL) and to view different time frames. Rather than coding all this myself and using a relational database, I was wondering if there were tools available which would facilitate both the management of the data and the reporting. I had a look at Mondrian however I can't see from the documentation I've looked at whether it's possible to drop the more granular information while maintaining the consolidated views of the data. RRDTool looks promising in terms of managing the data consolidation, but seems to be rather limited in terms of querying the dataset as a multi-dimensional/relational database. What else whould I be looking at?

    Read the article

  • How to invoke make install for one subdirectory of Qt project

    - by chalup
    I'm working on custom library and I wish users could just use it by adding: CONFIG += mylib to their pro files. This can be done by installing mylib.prf file to %QTDIR%/mkspec/features. I've checked out in Qt Mobility project how to create and install such file, but there is one thing I'd like to do differently. If I correctly understood the pro/pri files of Qt Mobility, inside the example projects they don't really use CONFIG += mobility, instead they add QtMobility sources to include path and share the *.obj directory with main library project. For my library I'd like to have examples that are as independent projects as possible, i.e. projects that can be compiled from anywhere once MyLib is compiled and installed. I have following directory structure: mylib | |- examples |- src |- tests \- mylib.pro It seems that the easiest way to achieve what I described above is creating mylib.pro like this: TEMPLATE = subdirs SUBDIRS += src SUBDIRS += examples tests:SUBDIRS += tests And somehow enforce invoking "cd src && make install" after building src. What is the best way to do this? Of course any other suggestions for automatic library deployment before examples compilation are welcome.

    Read the article

  • Windows Forms application C# | Sending Tweet

    - by Andrew Craswell
    I've been able to get my Twitter web app working just fine, but I've recently decided to add Tweeting functionality from a Windows Form, but I'm having no luck sending tweets. No errors are thrown or anything. Mind looking over my code? using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using TweetSharp; namespace TwitterAdvirtiser { public partial class Form1 : Form { private string cKey = "xxx"; private string cSecret = "xxx"; private string oToken = "xxx"; private string aToken = "xxx"; public Form1() { InitializeComponent(); OnStart(); } private void OnStart() { //Authenticate with Twitter TwitterService service = new TwitterService(cKey, cSecret); service.AuthenticateWith(oToken, aToken); service.SendTweet("testing"); } } } It seems like I'm authenticating just fine, I can walk through debug mode and see all my details in the TwitterUser structure, and yet my tweets never show up on my feed. Whats up? By the way, I'm using Visual Studios 2010, and .NET 4.0. I have verified that the oToken and aToken strings have my developer tokens.

    Read the article

  • Void* array casting to float, int32, int16, etc.

    - by Griffin
    Hey guys, I've got an array of PCM data, it could be 16 bit, 24 bit packed, 32 bit, etc.. It could be signed, or unsigned, and it could be 32 or 64 bit floating point. It is currently stored as a "void**" matrix, indexed by channel, then by frame. The goal is to allow my library to take in any PCM format and buffer it, without requiring manipulation of the data to fit a designated structure. If the A/D converter spits out 24 bit packed arrays of interleaved PCM, I need to accept it gracefully. I also need to support 16 bit non interleaved, as well as any permutation of the above formats. I know the bit depth and other information at runtime, and I'm trying to code efficiently while not duplicating code. What I need is an effective way to cast the matrix, put PCM data into the matrix, and then pull it out later. I can cast the matrix to int32_t, or int16_t for the 32 and 16 bit signed PCM respectively, I'll probably have to store the 24 bit PCM in an int32_t for 32 bit, 8 bit byte systems as well. Can anyone recommend a good way to put data into this array, and pull it out later? I'd like to avoid large sections of code which look like: switch( mFormat ) { case 1: // unsigned 8 bit for( int i = 0; i < mChannels; i++ ) framesArray = (uint8_t*)pcm[i]; break; case 2: // signed 8 bit for( int i = 0; i < mChannels; i++ ) framesArray = (int8_t*)pcm[i]; break; case 3: // unsigned 16 bit ... Limitations: I'm working in C/C++, no templates, no RTTI, no STL. Think embedded. Things get trickier when I have to port this to a DSP with 16 bit bytes. Does anybody have any useful macros they might be willing to share? Thanks, -Griff

    Read the article

  • Tomcat does not pick up the class file - the JSP file is not displayed

    - by blueSky
    I have a Java code which is a controller for a jsp page, called: HomeController.java. Code is as follows: @Controller public class HomeController { protected final transient Log log = LogFactory.getLog(getClass()); @RequestMapping(value = "/mypage") public String home() { System.out.println("HomeController: Passing through..."); return "home"; } } There is nothing especial in the jsp page: home.jsp. If I go to this url: http://localhost:8080/adcopyqueue/mypage I can view mypage and everything works fine. Also in the tomcat Dos page I can see the comment: HomeController: Passing through... As expected. Now under the same directory that I have HomeController.java, I've created another file called: LoginController.java. Following is the code: @Controller public class LoginController { protected final transient Log log = LogFactory.getLog(getClass()); @RequestMapping(value = "/loginpage") public String login() { System.out.println("LoginController: Passing through..."); return "login"; } } And under the same place which I have home.jsp, I've created login.jsp. Also under tomcat folders, LoginController.class exists under the same folder that HomeController.class exists and login.jsp exists under the same folder which home.jsp exists. But when I go to this url: http://localhost:8080/adcopyqueue/loginpage Nothing is displayed! I think tomcat does not pick up LoginController.class b/c on the tomcat Dos window, I do NOT see this comment: LoginController: Passing through... Instead I see following which I do not know what do they mean? [ INFO] [http-8080-1 01:43:45] (AppInfo.java:populateAppInfo:34) got manifest [ INFO] [http-8080-1 01:43:45] (AppInfo.java:populateAppInfo:36) manifest entrie s 8 The structure and the code for HomeController.java and LoginController.java plus the jsp files match. I have no idea why tomcat sees one of the files and not the other? Clean build did not help. Does anybody have any idea? Any help is greatly appraciated.

    Read the article

  • Organising UI code in .NET forms

    - by sb3700
    Hi I'm someone who has taught myself programming, and haven't had any formal training in .NET programming. A while back, I started C# in order to develop a GUI program to control sensors, and the project has blossomed. I was just wondering how best to organise the code, particularly UI code, in my forms. My forms currently are a mess, or at least seem a mess to me. I have a constructor which initialises all the parameters and creates events. I have a giant State property, which updates the Enabled state of all my form control as users progress through the application (ie: disconnected, connected, setup, scanning) controlled by a States enum. I have 3-10 private variables accessed through properties, some of which have side-effects in changing the values of form elements. I have a lot of "UpdateXXX" functions to handle UI elements that depend on other UI elements - ie: if a sensor is changed, then change the baud rate drop down list. They are separated into regions I have a lot of events calling these Update functions I have a background worker which does all the scanning and analysis. My problem is this seems like a mess, particularly the State property, and is getting unmaintainable. Also, my application logic code and UI code are in the same file and to some degree, intermingled which seems wrong and means I need to do a lot of scrolling to find what I need. How do you structure your .net forms? Thanks

    Read the article

  • Debugging instance of another thread altering my data

    - by Mick
    I have a huge global array of structures. Some regions of the array are tied to individual threads and those threads can modify their regions of the array without having to use critical sections. But there is one special region of the array which all threads may have access to. The code that accesses these parts of the array needs to carefully use critical sections (each array element has its own critical section) to prevent any possibility of two threads writing to the structure simultaneously. Now I have a mysterious bug I am trying to chase, it is occurring unpredictably and very infrequently. It seems that one of the structures is being filled with some incorrect number. One obvious explanation is that another thread has accidentally been allowed to set this number when it should be excluded from doing so. Unfortunately it seems close to impossible to track this bug. The array element in which the bad data appears is different each time. What I would love to be able to do is set some kind of trap for the bug as follows: I would enter a critical section for array element N, then I know that no other thread should be able to touch the data, then (until I exit the critical section) set some kind of flag to a debugging tool saying "if any other thread attempts to change the data here please break and show me the offending patch of source code"... but I suspect no such tool exists... or does it? Or is there some completely different debugging methodology that I should be employing.

    Read the article

  • Use JQuery to check a checkbox in a parent list-item?

    - by Daniel O'Connor
    Hey Everyone, I'm brand new to Javascript and JQuery, so I've been reading up on it and am trying to check (and set inactive) a checkbox in a parent list-item when one of the children are checked. If this doesn't make any sense, take a look at the list structure. <ul> <li><input type="checkbox" name="items[]" value="88712003" id="88712003" /> Parent 1</li> <li><input type="checkbox" name="items[]" value="88712003" id="88712003" /> Parent 2 <ul> <li><input type="checkbox" name="items[]" value="21312341" id="21312341" /> Child 1</li> <li><input type="checkbox" name="items[]" value="21312341" id="21312341" /> Child 2</li> </ul> </li> <li><input type="checkbox" name="items[]" value="88712003" id="88712003" /> Parent 3</li> <li><input type="checkbox" name="items[]" value="88712003" id="88712003" /> Parent 4</li> </ul> If Child 1 or Child 2 is checked, I want the input in Parent 2 to be checked and set inactive. I've started working on it, but got stuck here: $(function(){ $('.child').click(function() { $(this).parent().parent().parent().toggle(); }); }); As you can see, I didn't make it far. Any help would be appreciated. Thanks!

    Read the article

  • Starting a code library.

    - by Rob Stevenson-Leggett
    Hi, I've been meaning to start a library of reusable code snippets for a while and never seem to get round to it. I think my main problems are: Where to start. What structure should my library take? Should it be a compiled library (where appropriate or just classes I can drop into any project? Or a library project that can be included? In my experience, a built library will quickly become out of date and the source will get lost. So I'm leaning towards source libraries that I can export from SVN and include in any project. Intellectual property. I am employeed, so a lot of the code I write is not my IP. How can I ensure that I don't give my own IP away using it on projects in work and at home? I'm thinking the best way would be to licence my library with an open source licence and make sure I only add to it in my own time using my own equipment and therefore making sure that if I use it in a work project the same rules apply as if I was using a third party library. I write in many different languages and often would require two or more parts of this library. Should I look at implementing a few template projects and a core project for each of my chosen reusable components and languages? Has anyone else got this sort of library and how do you organise and update it?

    Read the article

  • Designing a chain of states

    - by devoured elysium
    I want to model a kind of FSM(Finite State Machine). I have a sequence of states (let's say, from StateA to StateZ). This sequence is called a Chain and is implemented internally as a List. I will add states by the order I want them to run. My purpose is to be able to make a sequence of actions in my computer (for example, mouse clicks). (I know this has been done a zillion times). So a state is defined as a: boolean Precondition() <- Checks to see if for this state, some condition is true. For example, if I want to click in the Record button of a program, in this method I would check if the program's process is running or not. If it is, go to the next state in the chain list, otherwise, go to what was defined as the fail state (generally is the first state of them all). IState GetNextState() <- Returns the next state to evaluate. If Precondition() was sucessful, it should yield the next state in the chain otherwise it should yield the fail state. Run() Simply checks the Precondition() and sets the internal data so GetNextState() works as expected. So, a naive approach to this would be something like this: Chain chain = new Chain(); //chain.AddState(new State(Precondition, FailState, NextState) <- Method structure chain.AddState(new State(new WinampIsOpenCondition(), null, new <problem here, I want to referr to a state that still wasn't defined!>); The big problem is that I want to make a reference to a State that at this point still wasn't defined. I could circumvent the problem by using strings when refrering to states and using an internal hashtable, but isn't there a clearer alternative? I could just pass only the pre-condition and failure states in the constructor, having the chain just before execution put in each state the correct next state in a public property but that seems kind of awkward.

    Read the article

  • How to write a "thread safe" function in C ?

    - by Andrei Ciobanu
    Hello I am writing some data structures in C, and I've realized that their associated functions aren't thread safe. The i am writing code uses only standard C, and I want to achieve some sort of 'synchronization'. I was thinking to do something like this: enum sync_e { TRUE, FALSE }; typedef enum sync_e sync; struct list_s { //Other stuff struct list_node_s *head; struct list_node_s *tail; enum sync_e locked; }; typedef struct list_s list; , to include a "boolean" field in the list structure that indicates the structures state: locked, unlocked. For example an insertion function will be rewritten this way: int list_insert_next(list* l, list_node *e, int x){ while(l->locked == TRUE){ /* Wait */ } l->locked = TRUE; /* Insert element */ /* -------------- */ l->locked = FALSE; return (0); } While operating on the list the 'locked' field will be set to TRUE, not allowing any other alterations. After operation completes the 'locked' field will be again set to 'TRUE'. Is this approach good ? Do you know other approaches (using only standard C).

    Read the article

  • How to achieve interaction between GUI class with logic class

    - by volting
    Im new to GUI programming, and haven't done much OOP. Im working on a basic calculator app to help me learn GUI design and to brush up on OOP. I understand that anything GUI related should be kept seperate from the logic, but Im unsure how to implement interaction between logic an GUI classes when needed i.e. basically passing variables back and forth... Im using TKinter and when I pass a tkinter variable to my logic it only seems to hold the string PY_VAR0. def on_equal_btn_click(self): self.entryVariable.set(self.entryVariable.get() + "=") calculator = Calc(self.entryVariable) self.entryVariable.set(calculator.calculate()) Im sure that im probably doing something fundamentally wrong and probabaly really stupid, I spent a considerable amount of time experimenting (and searching for answers online) but Im getting no where. Any help would be appreciated. Thanks, V The Full Program (well just enough to show the structure..) import Tkinter class Gui(Tkinter.Tk): def __init__(self,parent): Tkinter.Tk.__init__(self,parent) self.parent = parent self.initialize() def initialize(self): self.grid() self.create_widgets() """ grid config """ #self.grid_columnconfigure(0,weight=1,pad=0) self.resizable(False, False) def create_widgets(self): """row 0 of grid""" """Create Text Entry Box""" self.entryVariable = Tkinter.StringVar() self.entry = Tkinter.Entry(self,width=30,textvariable=self.entryVariable) self.entry.grid(column=0,row=0, columnspan = 3 ) self.entry.bind("<Return>", self.on_press_enter) """create equal button""" equal_btn = Tkinter.Button(self,text="=",width=4,command=self.on_equal_btn_click) equal_btn.grid(column=3, row=0) """row 1 of grid""" """create number 1 button""" number1_btn = Tkinter.Button(self,text="1",width=8,command=self.on_number1_btn_click) number1_btn.grid(column=0, row=1) . . . def on_equal_btn_click(self): self.entryVariable.set(self.entryVariable.get() + "=") calculator = Calc(self.entryVariable) self.entryVariable.set(calculator.calculate()) class Calc(): def __init__(self, equation): self.equation = equation def calculate(self): #TODO: parse string and calculate... return self.equation if __name__ == "__main__": app = Gui(None) app.title('Calculator') app.mainloop()

    Read the article

< Previous Page | 260 261 262 263 264 265 266 267 268 269 270 271  | Next Page >