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  • How to return a record from function, executed by INSERT/UPDATE rule (trigger)?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • Convert C function to Objective C or alternative way to include C library?

    - by Moshe
    Background: I'm new to Objective-C and I've never touched C before. I'm trying to include a C library in my iPhone/iPod Touch project and I could not successfully compile the library's source code using the included instructions, so I've resorted to including the .h and .c files in Xcode. The library is for Hebrew Dates and corresponding Jewish Holidays. It can be found here: http://sourceforge.net/projects/libhdate/ I cannot seem to import the .c files into my implementation files. I can import the .h files though. When I try to use #import "file.c", where file.c is a file that is in XCode, it doesn't work. Why not? I've considered just writing the functions over in Objective-C, albeit only my needed functions and not the whole library. How can I make the following C function work in Objective-C? Are there other things that need to be included/re-coded/compiled? How so? I am almost certain something is missing, but I'm not sure what. Code: int hdate_get_omer_day(hdate_struct const * h) { int omer_day; hdate_struct sixteen_nissan; hdate_set_hdate(&sixteen_nissan, 16, 7, h->hd_year); omer_day = h->hd_jd - sixteen_nissan.hd_jd + 1; if ((omer_day > 49) || (omer_day < 0)) omer_day = 0; return omer_day; } So... should I be converting it, or trying somehow to compile to an appropriate format and how so? (I don't know what format a static library should be in, by the way, or if it should be static... - I'm so lost here....) I appreciate the help!

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  • Is it possible, in a django template, to check if an object is contained in a list

    - by AlexH
    I'm very new to django, about a week into it. I'm making a site where users enter stuff, then other users can vote on whether they like the stuff or not. I know it's not so novel, but it's a good project to learn a bunch of tools. I have a many-to-many table for storing who likes or dislikes what. Before I render the page, I pull out all the likes and dislikes for the current user, along with the stuff I'm going to show on the page. When I render the page, I go through the list of stuff I'm going to show and print them out one at a time. I want to show the user which stuff they liked, and which they didn't. So in my django template, I have an object called entry. I also have two lists of objects called likes and dislikes. Is there any way to determine if entry is a member of either list, inside my django template. I think what I'm looking for is a filter where I can say something like {% if entry|in:likes %} or {% if likes|contains:entry %} I know I could add a method to my model and check for each entry individually, but that seems like it would be database intensive. Is there a better way to think about this problem?

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  • How to get address the object of an related entity with CoreData ?

    - by eemceebee
    Hi Ok, after I ran into a dead end modifieing an existing Apple example for CoreData, I started completely new creating my own project and that worked fine,..... until I tried to access a related entity. So here is what I did. I created 2 entities, where one is just the detail information of the other one, so there is a one-2-one relationship. Entity #1, Stocks: name value details -- relationship to Entity #2 Entity #2, StockDetails: bank published stock -- relationship to Entity #1 Now, I created the "Managed Object Class" for both of the Entities. Then I created a few lines to put some data into it NSManagedObjectContext *context = [self managedObjectContext]; Stocks *stockinfo= [NSEntityDescription insertNewObjectForEntityForName:@"Stocks" inManagedObjectContext:context]; stockinfo.name = @"Apple"; stockinfo.value = [NSNumber numberWithInt:200]; StockDetails *thestockdetails = [NSEntityDescription insertNewObjectForEntityForName:@"StockDetails" inManagedObjectContext:context]; thestockdetails.bank = @"Bank of America"; thestockdetails.published = [NSDate date]; thestockdetails.stock = stocks_; stockinfo.details = thestockdetails ; NSError *error; if (![context save:&error]) { NSLog(@"A Problem occured, couldn't save: %@", [error localizedDescription]); } Just want to mention here, that I do not get an error with this. Next I put everything into a UITableViewController for a preview and another for a detail view. The preview just shows infos form Entity #1 (Stocks) and when selected it shows the detail view. Now here I also display the infos form Entity #1 (Stocks) but I want to show the Entity #2 (StockDetails) aswell. This is how I try to access the data : StockDetails *details_ = [stockinfo details]; And this gives me a EXC_BAD_ACCESS. So any idea what I am doing wrong here ? Thanks

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  • Catchable fatal error: Object of class view_user could not be converted to string in C:\xampp\xampp\htdocs\textile\admin\view_class.php on line 9 [closed]

    - by user1282142
    <?php include('config.inc'); class view_user { function view($user) { $temp = mysql_query("SELECT * from register_user where user_name = '$user'"); $value = mysql_fetch_array($temp); $query = mysql_query("SELECT order_user.design_name, order_user.reaad, order_user.pick, order_user.yarn_detail FROM register_user INNER JOIN order_user ON register_user.register_id = '$value[register_id]' and order_user.register_id = $value[register_id]"); if($query) { echo "<center><table border = 1> <tr> <th>Design Name</th> <th>Read</th> <th>Pick</th> <th>Design Detail</th> </tr>"; while($row = mysql_fetch_array($query)) { echo "<tr>"; echo "<td>$row[design_name]</td>"; echo "<td>$row[reaad]</td>"; echo "<td>$row[pick]</td>"; echo "<td>$row[yarn_detail]</td>"; echo"</tr></center>"; } } else { echo"User doesn't Exist"; include('footer1.php'); } } } ?>

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  • how to run href="#var=something" before onclick function fires in javascript?

    - by korben
    i'm using the below javascript to change an image on an aspx in asp.net c# <script language="JavaScript" type="text/javascript"> var updateImageWhenHashChanges = function() { theImage = document.getElementById("ctl00_ContentPlaceHolder1_Image1a"); if(window.location.hash == "#size=2") { theImage.src = "<%# Eval("realfilename", "/files/l{0}") %>"; } else if(window.location.hash == "#size=3") { theImage.src = "<%# Eval("realfilename", "/files/{0}") %>"; } else if(window.location.hash == "#size=1") { theImage.src = "<%# Eval("fullthumbname", "/thumbnails/{0}") %>"; } else { } } </script> here's how i call it with a link <a href="#size=3" onclick="updateImageWhenHashChanges();">test</a> the problem is that it only does what i'm expecting on the SECOND click of the link, because it seems onclick fires before the href, so the first time i'm just placing the var and the 2nd time i'm actually getting what i want. does anyone know how i can fix this? i'm trying to get the image to change on each click

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  • LINQ .Cast() extension method fails but (type)object works.

    - by Ben Robinson
    To convert between some LINQ to SQL objects and DTOs we have created explicit cast operators on the DTOs. That way we can do the following: DTOType MyDTO = (LinqToSQLType)MyLinq2SQLObj; This works well. However when you try to cast using the LINQ .Cast() extension method it trows an invalid cast exception saying cannot cast type Linq2SQLType to type DTOType. i.e. the below does not work List<DTO.Name> Names = dbContact.tNames.Cast<DTO.Name>() .ToList(); But the below works fine: DAL.tName MyDalName = new DAL.tName(); DTO.Name MyDTOName = (DTO.Name)MyDalName; and the below also works fine List<DTO.Name> Names = dbContact.tNames.Select(name => (DTO.Name)name) .ToList(); Why does the .Cast() extension method throw an invalid cast exception? I have used the .Cast() extension method in this way many times in the past and when you are casting something like a base type to a derived type it works fine, but falls over when the object has an explicit cast operator.

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  • How does one force construction of a global object in a statically linked library? [MSVC9]

    - by Peter C O Johansson
    I have a global list of function pointers. This list should be populated at startup. Order is not important and there are no dependencies that would complicate static initialization. To facilitate this, I've written a class that adds a single entry to this list in its constructor, and scatter global instances of this class via a macro where necessary. One of the primary goals of this approach is to remove the need for explicitly referencing every instance of this class externally, instead allowing each file that needs to register something in the list to do it independently. Nice and clean. However, when placing these objects in a static library, the linker discards (or rather never links in) these units because no code in them is explicitly referenced. Explicitly referencing symbols in the compilation units would be counterproductive, directly contradicting one of the main goals of the approach. For the same reason, /INCLUDE is not an acceptable option, and /OPT:NOREF is not actually related to this problem. Metrowerks has a __declspec directive for it, GCC has -force_load, but I cannot find any equivalent for MSVC.

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  • How to customize Bootstrap typeahead layout/function for more than just text?

    - by Loolooii
    I'm working on a search functionality for my website and I'm using Bootstrap's typeahead to show the results. So far so good. But what I want is to extend the function so that I could add an image and some other item, say description, etc. According to this post, that is possible: custom typeahead. Basically I need something like this as each result item: <div class="resultContainer"> <div class="resultImage"><img /></div> <div class="resultDesc"></div> <div class="resultLabel"></div> </div> Now it's: <li><a href="#"></a></li> And this doesn't even work with a longer text than the width of the typeahead. So the text doesn't go to the next line and hence doesn't fit the <li>. How can I use the the custom layout I want? (btw I have an array of arrays of results. Each sub-array contains img, desc, etc.). This is what I have right now: Thanks in advance.

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  • Is there any function in Matlab for changing the form of matrix?

    - by niko
    Hi, I have to get the unknown matrix by changing the form of known matrix considering the following rules: H = [-P'|I] G = [I|P] where H is known matrix G is unknown matrix which has to be calculated I is identity matrix So for example if we had a matrix H = [1 1 1 1 0 0; 0 0 1 1 0 1; 1 0 0 1 1 0] its form has to be changed to H = [1 1 1 1 0 0; 0 1 1 0 1 0; 1 1 0 0 0 1] so -P' = [1 1 1; 0 1 0; 1 1 0] and in case of binary matrices -P = P therefore G = [1 0 0 1 1 1; 0 1 0 0 1 0; 0 0 1 1 1 0] I know how to solve it on the paper by performing basic row operations but don't know how if there is any function already written in Matlab to calculate G from H or H from G by considering the above rules. I would be very thankful if anyone of you could suggest any method for solving the given problem. Thank you.

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  • Am I using the getch() function from the ncurses library incorrectly?

    - by user1692446
    I am writing a Pacman game in c++ using the ncurses library, but I am not able to move the Pacman properly. I have used getch() to move it it up, down, left and right, but it only moves right and does not move anywhere else when I press any other key. This is a code snippet for moving up. I have written similar code with some conditions altered accordingly for moving left, right and down. int ch = getch(); if (ch == KEY_RIGHT) { int i,row,column; //getting position of cursor by getyx function for (i=column; i<=last_column; i+=2) { //time interval of 1 sec mvprintw(row,b,"<"); //print < in given (b,row) coordinates //time interval of 1 sec mvprintw(row,(b+1),"O"); //print "O" next to "<" int h = getch(); //to give the option for pressing another key if (h != KEY_RIGHT) //break current loop if another key is pressed { break; } } } if (condition) { //code to move left } Am I using getch() wrong, or is there something else I have to do?

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  • 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).

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  • Is it okay for multiple objects to retain the same object in Objective-C/Cocoa?

    - by Andrew Arrow
    Say I have a tableview class that lists 100 Foo objects. It has: @property (nonatomic, retain) NSMutableArray* fooList; and I fill it up with Foos like: self.fooList = [NSMutableArray array]; while (something) { Foo* foo = [[Foo alloc] init]; [fooList addObject:foo]; [foo release]; } First question: because the NSMutableArray is marked as retain, that means all the objects inside it are retained too? Am I correctly adding the foo and releasing the local copy after it's been added to the array? Or am I missing a retain call? Then if the user selects one specific row in the table and I want to display a detail Foo view I call: FooView* localView = [[FooView alloc] initWithFoo:[self.fooList objectAtIndex:indexPath.row]]; [self.navigationController pushViewController:localView animated:YES]; [localView release]; Now the FooView class has: @property (nonatomic, retain) Foo* theFoo; so now BOTH the array is holding on to that Foo as well as the FooView. But that seems okay right? When the user hits the back button dealloc will be called on FooView and [theFoo release] will be called. Then another back button is hit and dealloc is called on the tableview class and [fooList release] is called. You might argue that the FooView class should have: @property (nonatomic, assign) Foo* theFoo; vs. retain. But sometimes the FooView class is called with a Foo that's not also in an array. So I wanted to make sure it was okay to have two objects holding on to the same other object.

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  • Why don't I need to bind my vertex buffer object before calling glDrawArrays?

    - by valmo
    I'm a bit confused why this still renders. I thought you need to bind a vertex buffer object so that glDrawArrays knows which vertex buffer to use. Here is my initialisation code.. // Create and bind vertex array to store vertex attribute states. glGenVertexArraysOES(NUM_VERTEX_ARRAYS, &m_vertexArray); glBindVertexArrayOES(m_vertexArray); // Create and bind vertex buffer to store vertex data. glGenBuffers(NUM_VERTEX_BUFFERS, &m_vertexBuffer); glBindBuffer(GL_ARRAY_BUFFER, m_vertexBuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * 36, &m_vertices[0], GL_STATIC_DRAW); glEnableVertexAttribArray(VertexAttribPosition); glVertexAttribPointer(VertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(0)); glEnableVertexAttribArray(VertexAttribNormal); glVertexAttribPointer(VertexAttribNormal, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(12)); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArrayOES(0); Here is my render code. I'm confused why glDrawArrays still works when I bind 0 to GL_ARRAY_BUFFER. glBindVertexArrayOES(m_vertexArray); glBindBuffer(GL_ARRAY_BUFFER, 0); glDrawArrays(GL_TRIANGLES, 0, 36); glBindVertexArrayOES(0);

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  • Is there a way for -webkit-animtion-timing-function to apply to the entire animation instead of each keyframe?

    - by Ken Sykora
    I'm a bit new to animation, so forgive me if I'm missing a huge concept here. I need to animate an arrow that is pointing to a point on a curve, let's just say it's a cubic curve for the sake of this post. The arrow moves along the curve's line, always pointing a few pixels below it. So what I did, is I setup keyframes along the curve's line using CSS3: @-webkit-keyframes ftch { 0% { opacity: 0; left: -10px; bottom: 12px; } 25% { opacity: 0.25; left: 56.5px; bottom: -7px; } 50% { opacity: 0.5; left: 143px; bottom: -20px; } 75% { opacity: 0.75; left: 209.5px; bottom: -24.5px; } 100% { opacity: 1; left: 266px; bottom: -26px; } } However, when I run this animation using -webkit-animation-timing-function: ease-in, it applies that easing to each individual keyframe, which is definitely not what I want. I want the easing to apply to the entire animation. Is there a different way that I should be doing this? Is there some property to apply the easing to the entire sequence rather than each keyframe?

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  • Terminate function on System.in .. possible?

    - by Ronald
    I am currently working on a project where I have to make an agent to interact with a server. Each 50ms, the server will receive the last thing I outputted to System.out and send me a new set of lines as a 'state' through the System.in printstream to analyze and send my next message to System.out. Also, if the server receives multiple outputs from me, it only regards the most recent one. .. As for my question: My program originally constructed a tree and then analyzed each leaf node to see which would be optimal, and then waited around for the next input, but I can recursively do a deeper tree search that would make my output 'better' (and again and again to keep returning a better result). Using this and the fact that if the server receives multiple outputs, it only takes the most recent one, I could do each level, print my result and start the next level. But here comes my problem... I can't be stuck in some complex algorithm while I am supposed to receiving the next input as I will then miss it. So I was wondering if there is a way to cancel anything else I am doing when I receive something via System.in and then go back to the beginning of the function and start the search again with the new set of input (and rinse and repeat..) I hope this all makes sense, Thank ye all

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  • PHP mail function, some clients aren't showing my mails as html?

    - by Don
    I'm trying to send emails to my website members using the mail() function with PHP, The mails are in hebrew, and I want to send an html email, That's pretty much how I send it $mail_to = "[email protected]"; $message = " <html> some content here </html> "; $headers = "MIME-Version: 1.0" . "\r\n"; $headers .= "Content-type:text/html;charset=windows-1255" . "\r\n"; $headers .= 'From: "MyWebsiteName" <[email protected]>' . "\r\n"; $mail = mail($mail_to, $subject, $message, $headers ); It works completely fine with clients such as Gmail, or thunderbird users, but I viewed it in a few other clients, that aren't so famous, but still widely used in my country, and it just shows me the html source.. I'll also add that I've seen other mails in those clients that are working fine, so they are supporting html mails. What am I doing wrong?

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  • How am i overriding this C++ inherited member function without the virtual keyword being used?

    - by Gary Willoughby
    I have a small program to demonstrate simple inheritance. I am defining a Dog class which is derived from Mammal. Both classes share a simple member function called ToString(). How is Dog overriding the implementation in the Mammal class, when i'm not using the virtual keyword? (Do i even need to use the virtual keyword to override member functions?) mammal.h #ifndef MAMMAL_H_INCLUDED #define MAMMAL_H_INCLUDED #include <string> class Mammal { public: std::string ToString(); }; #endif // MAMMAL_H_INCLUDED mammal.cpp #include <string> #include "mammal.h" std::string Mammal::ToString() { return "I am a Mammal!"; } dog.h #ifndef DOG_H_INCLUDED #define DOG_H_INCLUDED #include <string> #include "mammal.h" class Dog : public Mammal { public: std::string ToString(); }; #endif // DOG_H_INCLUDED dog.cpp #include <string> #include "dog.h" std::string Dog::ToString() { return "I am a Dog!"; } main.cpp #include <iostream> #include "dog.h" using namespace std; int main() { Dog d; std::cout << d.ToString() << std::endl; return 0; } output I am a Dog! I'm using MingW on Windows via Code::Blocks.

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  • Why does JavaScript's getElementsByClassName provide an object that is NOT an array?

    - by Paragon
    I'm trying to get a list in JavaScript (not using jQuery) of all the elements on the page with a specific class name. I therefore employ the getElementsByClassName() function as follows: var expand_buttons = document.getElementsByClassName('expand'); console.log(expand_buttons, expand_buttons.length, expand_buttons[0]); Note that I have three anchor elements on my page with the class 'expand'. This console.log() outputs [] 0 undefined Next, for kicks, I threw expand_buttons into its own array as follows: var newArray = new Array(expand_buttons); console.log(newArray, newArray.length); This suddenly outputs [NodeList[3]] 1 and I can click through the nodelist and see the attributes of the three 'expand' anchor elements on the page. It's also worth noting that I was able to get my code working in a w3schools test page. It may also be of note that my use of document.getElementsByName actually does output (to the console) an array of elements, but when I ask for its length, it tells me 0. Similarly, if I try to access an array element using array_name[0] as normal, it outputs 'undefined', despite there clearly being an element inside of an array when I print the object to the console. Does anybody have any idea why this might be? I just want to loop through DOM elements, and I'm avoiding jQuery at the moment because I'm trying to practice coding with vanilla JavaScript. Thanks, ParagonRG

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  • Recursive breadth-first travel function in Java or C++?

    - by joejax
    Here is a java code for breadth-first travel: void breadthFirstNonRecursive(){ Queue<Node> queue = new java.util.LinkedList<Node>(); queue.offer(root); while(!queue.isEmpty()){ Node node = queue.poll(); visit(node); if (node.left != null) queue.offer(node.left); if (node.right != null) queue.offer(node.right); } } Is it possible to write a recursive function to do the same? At first, I thought this would be easy, so I came out with this: void breadthFirstRecursive(){ Queue<Node> q = new LinkedList<Node>(); breadthFirst(root, q); } void breadthFirst(Node node, Queue<Node> q){ if (node == null) return; q.offer(node); Node n = q.poll(); visit(n); if (n.left != null) breadthFirst(n.left, q); if (n.right != null) breadthFirst(n.right, q); } Then I found it doesn't work. It is actually does the same thing as this: void preOrder(Node node) { if (node == null) return; visit(node); preOrder(node.left); preOrder(node.right); } Has any one thought about this before?

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  • How can one enforce calling a base class function after derived class constructor?

    - by Mike Elkins
    I'm looking for a clean C++ idiom for the following situation: class SomeLibraryClass { public: SomeLibraryClass() { /* start initialization */ } void addFoo() { /* we are a collection of foos */ } void funcToCallAfterAllAddFoos() { /* Making sure this is called is the issue */ } }; class SomeUserClass : public SomeLibraryClass { public: SomeUserClass() { addFoo(); addFoo(); addFoo(); // SomeUserClass has three foos. } }; class SomeUserDerrivedClass : public SomeUserClass { public: SomeUserDerrivedClass() { addFoo(); // This one has four foos. } }; So, what I really want is for SomeLibraryClass to enforce the calling of funcToCallAfterAllAddFoos at the end of the construction process. The user can't put it at the end of SomeUserClass::SomeUserClass(), that would mess up SomeUserDerrivedClass. If he puts it at the end of SomeUserDerrivedClass, then it never gets called for SomeUserClass. To further clarify what I need, imagine that /* start initialization */ acquires a lock, and funcToCallAfterAllAddFoos() releases a lock. The compiler knows when all the initializations for an object are done, but can I get at that information by some nice trick?

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  • How do i find if an object is before or after a waypoint?

    - by BoMann Andersen
    Im working on a racing game for a school project. Using Visual studio 10 pro, and Irrlicht. Sorry for bad grammar ., and its my first question so not sure if its done right. How i want it to work is that i make waypoints at different points on the track, and then i run my waypoint check to see if a car is past its next waypoint (the next it "needs" to go past), if yes then it updates the next waypoint, else nothing. The way i hope this will work is, i make a vector from n to n+1, then find the vector that is perpendicular to the first vector at n. Then i see if the object is in front or behind that vector. I found a Gamedev.net forumpost that helped me make this function: void Engine::checkWaypoint(Vehicle* vehicle) { btVector3 vector = waypoints[vehicle->nextWaypoint]; // n btVector3 nextVector = waypoints[vehicle->nextWaypoint + 1]; // n+1 vector = nextVector - vector; // First vector btVector3 pos = btVector3(vehicle->position.X,vehicle->position.Y,vehicle->position.Z); float product = vector.dot(pos - waypoints[vehicle->nextWaypoint]); // positiv = before, negative = behind if(product < 0) vehicle->nextWaypoint += 1; } Current bugs with this is: Updates the nextwaypoint more then ones without going past a new point. When it gets to the end and resets, it stops triggering on the first waypoints. So my questions: Is this an good way to do this? Did i do it right?

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  • What is the fastest (to access) struct-like object in Python?

    - by DNS
    I'm optimizing some code whose main bottleneck is running through and accessing a very large list of struct-like objects. Currently I'm using namedtuples, for readability. But some quick benchmarking using 'timeit' shows that this is really the wrong way to go where performance is a factor: Named tuple with a, b, c: >>> timeit("z = a.c", "from __main__ import a") 0.38655471766332994 Class using __slots__, with a, b, c: >>> timeit("z = b.c", "from __main__ import b") 0.14527461047146062 Dictionary with keys a, b, c: >>> timeit("z = c['c']", "from __main__ import c") 0.11588272541098377 Tuple with three values, using a constant key: >>> timeit("z = d[2]", "from __main__ import d") 0.11106188992948773 List with three values, using a constant key: >>> timeit("z = e[2]", "from __main__ import e") 0.086038238242508669 Tuple with three values, using a local key: >>> timeit("z = d[key]", "from __main__ import d, key") 0.11187358437882722 List with three values, using a local key: >>> timeit("z = e[key]", "from __main__ import e, key") 0.088604143037173344 First of all, is there anything about these little timeit tests that would render them invalid? I ran each several times, to make sure no random system event had thrown them off, and the results were almost identical. It would appear that dictionaries offer the best balance between performance and readability, with classes coming in second. This is unfortunate, since, for my purposes, I also need the object to be sequence-like; hence my choice of namedtuple. Lists are substantially faster, but constant keys are unmaintainable; I'd have to create a bunch of index-constants, i.e. KEY_1 = 1, KEY_2 = 2, etc. which is also not ideal. Am I stuck with these choices, or is there an alternative that I've missed?

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  • What collection object is appropriate for fixed ordering of values?

    - by makerofthings7
    Scenario: I am tracking several performance counters and have a CounterDescription[] correlate to DataSnapshot[]... where CounterDescription[n] describes the data loaded within DataSnapshot[n]. I want to expose an easy to use API within C# that will allow for the easy and efficient expansion of the arrays. For example CounterDescription[0] = Humidity; DataSnapshot[0] = .9; CounterDescription[1] = Temp; DataSnapshot[1] = 63; My upload object is defined like this: Note how my intent is to correlate many Datasnapshots with a dattime reference, and using the offset of the data to refer to its meaning. This was determined to be the most efficient way to store the data on the back-end, and has now reflected itself into the following structure: public class myDataObject { [DataMember] public SortedDictionary<DateTime, float[]> Pages { get; set; } /// <summary> /// An array that identifies what each position in the array is supposed to be /// </summary> [DataMember] public CounterDescription[] Counters { get; set; } } I will need to expand each of these arrays (float[] and CounterDescription[] ), but whatever data already exists must stay in that relative offset. Which .NET objects support this? I think Array[] , LinkedList<t>, and List<t> Are able to keep the data fixed in the right locations. What do you think?

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  • How to run a javascript function before postback of asp.net button?

    - by Curtis White
    I'm using Javascript to create a DIV element and open up a new page by using onclientclick. This works great. Now, I need to write to it from the server side and this element must be created before it is posted back. How do I get the javascript to execute before the postback? Currently, I have to press the button twice because the element doesn't exist to write too on the first click. To be clear, I need this to execute before the "OnClick" of the button. Update: It looks like the Javascript function is called before the postback but the element is not updated until I run the second postback. Hmm Update: Unfortunately it is a bit more complicated then this. I'm creating a div tag in javascript to open a new window. Inside the div tag, I'm using a databinding syntax <%=Preview% so that I can get access to this element on the server side. From the server side, I'm injecting the code. I'm thinking this may be a chicken-egg problem but not sure. UPDATE! It is not the Javascript not running first. It is the databinding mechanism which is reading the blank variable before I'm able to set it. Hmm

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