Search Results

Search found 12194 results on 488 pages for 'reference counting'.

Page 40/488 | < Previous Page | 36 37 38 39 40 41 42 43 44 45 46 47  | Next Page >

• ORACLE: Parameter reference in WHERE doesn't work

  - by Gainder

  Hello, I have created a simple static function in oracle 10g to get the reference of an object based on his pk. STATIC FUNCTION getRef(nome IN VARCHAR2) RETURN REF folder_typ IS fl_r REF folder_typ := null; BEGIN SELECT REF(fl) INTO fl_r FROM folder_tab fl WHERE fl.nome = nome; RETURN fl_r; END getRef; This gives me an error because it could't fetch a row. If insted of WHERE fl.nome = nome; I write WHERE fl.nome = 'folder1'; -- it works. I think im not using the parameter in the right way. How can I use it?

  Read the article

• How to I reference a pointer from a different class

  - by Justagruvn

  Hey team of awesomeness!, (Iphone Objective-C question) First off, I despise singletons with a passion. Though I should probably be trying to use one, I just dont want to. I want to create a data class (that is instantiated only once by a view controller on loading), and then using a different class, message the crap out of that data instance until it is brimming with so much data, it smiles. So, how do i do that? I made a pointer to the instance of the data class when I instantiated it. I'm now over in a separate view controller, action occurs, and I want to update the initial data object. I think I need to reference that object by way of pointer, but I have no idea how to do that. yes I've set properties and getters and setters, which seem to work, but only in the initial view controller class. Peace Love applesauce.

  Read the article

• passing Perl method results as a reference

  - by arareko

  Some XML::LibXML methods return arrays instead of references to arrays. Instead of doing this: $self->process_items($xml->findnodes('items/item')); I want to do something like: $self->process_items(\$xml->findnodes('items/item')); So that in process_items() I can dereference the original array instead of creating a copy: sub process_items { my ($self, $items) = @_; foreach my $item (@$items) { # do something... } } I can always store the results of findnodes() into an array and then pass the array reference to my own method, but let's say I want to try a reduced version of my code. Is that the correct syntax for passing the method results or should I use something different? Thanks!

  Read the article

• Count the number of ways in which a number 'A' can be broken into a sum of 'B' numbers such that all numbers are co-prime to 'C'

  - by rajneesh2k10

  I came across the solution of a problem which involve dynamic-programming approach, solved using a three dimensional matrix. Link to actual problem is: http://community.topcoder.com/stat?c=problem_statement&pm=12189&rd=15177 Solution to this problem is here under MuddyRoad2: http://apps.topcoder.com/wiki/display/tc/SRM+555 In the last paragraph of explanation, author describes a dynamic programming approach to count the number of ways in which a number 'A' can be broken into a sum of 'B' numbers (not necessarily different), such that every number is co-prime to 3 and the order in which these numbers appear does matter. I am not able to grasp that approach. Can anyone help me understand how DP is acting here. I can't understand what is a state here and how it is derived from the previous state.

  Read the article

• How to copy an object by value, not by reference

  - by Blankman

  I want to make a copy of an object, then after some logic, re-assign the original object the value of the copy. example: User userCopy = //make a copy foreach(...) { user.Age = 1; user.ID = -1; UserDao.Update(user) user = userCopy; } I don't want a copy by reference, it has to be a copy by value. The above is just a sample, not how I really want to use it but I need to learn how to copy by value.

  Read the article

• Reference table values in a war against magic numbers

  - by Alex N.

  This question bugged me for years now and can't seem to find good solution still. I working in PHP and Java but it sounds like this maybe language-agnostic :) Say we have a standard status reference table that holds status ids for some kind of entity. Further let's assume the table will have just 5 values, and will remain like this for a long time, maybe edited occasionally with addition of a new status. When you fetch a row and need to see what status it is you have 2 options(as I see it at least) - put it straight ID values(magic numbers that is) or use a named constant. Latter seem much cleaner, the question though is where those named constants should leave? In a model class? In a class that uses this particular constant? Somewhere else?

  Read the article

• ASP.NET null reference exception

  - by nanek

  Please help me to figure out what is wrong with this code: I have ASP.NET page with one button visible. When user clicks it - it instances MyClass (its implementation is in AppCode directory) and turns invisible (button2 becomes visible). When I click button2 it raises "Object reference not set to an instance of an object" Exception. What seems to be the problem? { public MyClass noviTest; protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { noviTest = new MyClass(TextBox1.Text); Button1.Visible = false; Button2.Visible = true; } protected void Button2_Click(object sender, EventArgs e) { Label1.Text=noviTest.getID; //this is the critical line } } Thank You in advance, Regards

  Read the article

• Count in base 2, 3, 4 etc in Java and output all permutations

  - by tree-hacker

  I want to write a function in Java that takes as input an integer and outputs every possible permutation of numbers up to that integer. For example: f(1) 0 f(2) should output: 00 01 10 11 f(3) should output: 000 001 002 010 011 012 020 021 022 100 .... 220 221 222 That is it should output all 27 permutations of the digits of the numbers 0, 1, 2. f(4) should output 0000 0001 0002 0003 0010 ... 3330 3331 3332 3333 f(4) should output 00000 00001 ... 44443 44444 I have been trying to solve this problem but cannot seem to work out how to do it and keep getting confused by how many loops I need. Does anyone know how to solve this problem? Thanks in advance.

  Read the article

• How do you reference another element in a xaml list

  - by Ball

  I'm using xaml as a datastore because It's quick and we haven't yet defined a file format. But I can only seem to create xaml that is a pure tree, even if it is acyclic. I know how to create a list of items in xaml, but How do I share objects in two lists? Below is an example of what I'm trying to say. <CreaturFile> <CreatureFile.Monsters> <Monster Name="Kobold" x:Name="Mepo"/> <Monster Name="Goblin"/> </CreatureFile.Monsters> <CreatureFile.Encounters> <Encounter> <Reference ElementName="Mepo"/> </Encounter> </CreatureFile.Encounters> </CreatureFile>

  Read the article

• Is it guaranteed that new Integer(i) == i in Java?

  - by polygenelubricants

  Consider the following snippet: int i = 99999999; byte b = 99; short s = 9999; Integer ii = Integer.valueOf(9); // should be within cache System.out.println(new Integer(i) == i); // "true" System.out.println(new Integer(b) == b); // "true" System.out.println(new Integer(s) == s); // "true" System.out.println(new Integer(ii) == ii); // "false" It's obvious why the last line will ALWAYS prints "false": we're using == reference identity comparison, and a new object will NEVER be == to an already existing object. The question is about the first 3 lines: are those comparisons guaranteed to be on the primitive int, with the Integer auto-unboxed? Are there cases where the primitive would be auto-boxed instead, and reference identity comparisons are performed? (which would all then be false!)

  Read the article

• Proper usage of Java Weak Reference in case of nested collections

  - by Tong Wang

  I need to define a weak reference Map, whose value is a Set. I use Google collections' MapMaker, like this: Map<Class<? extends Object>, Set<Foo>> map = new MapMaker().weakKeys().weakValues().makeMap(); So, for Set<Foo>, can I use a normal HashSet? Or, do I have to create a weak HashSet, like this: Collections.newSetFromMap(new WeakHashMap<Foo, Boolean>()); And why? Another question, the key of my map is Class objects, when will a Class object become weakly reachable? In other words, what is the lifetime of a Class object? Thanks.

  Read the article

• Linking Error: undefined reference to `MPI_Init' on Windows 7

  - by fatpipp

  I am using OpenMPI library to write a program to run on Windows 7. I compile and build with C Free 4.0, Mingw. Compiling is Ok but when the compiler links object, errors "undefined reference to ..." occurs. I have set the environment already: I added OpenMPI lib, include and bin folder into C Free Build Directories. I added them into Windows environment variables too. But the error still occurs. Can anyone tell me how to fix it? Thanks a lot.

  Read the article

• how to avoid temporaries when copying weakly typed object

  - by Truncheon

  Hi. I'm writing a series classes that inherit from a base class using virtual. They are INT, FLOAT and STRING objects that I want to use in a scripting language. I'm trying to implement weak typing, but I don't want STRING objects to return copies of themselves when used in the following way (instead I would prefer to have a reference returned which can be used in copying): a = "hello "; b = "world"; c = a + b; I have written the following code as a mock example: #include <iostream> #include <string> #include <cstdio> #include <cstdlib> std::string dummy("<int object cannot return string reference>"); struct BaseImpl { virtual bool is_string() = 0; virtual int get_int() = 0; virtual std::string get_string_copy() = 0; virtual std::string const& get_string_ref() = 0; }; struct INT : BaseImpl { int value; INT(int i = 0) : value(i) { std::cout << "constructor called\n"; } INT(BaseImpl& that) : value(that.get_int()) { std::cout << "copy constructor called\n"; } bool is_string() { return false; } int get_int() { return value; } std::string get_string_copy() { char buf[33]; sprintf(buf, "%i", value); return buf; } std::string const& get_string_ref() { return dummy; } }; struct STRING : BaseImpl { std::string value; STRING(std::string s = "") : value(s) { std::cout << "constructor called\n"; } STRING(BaseImpl& that) { if (that.is_string()) value = that.get_string_ref(); else value = that.get_string_copy(); std::cout << "copy constructor called\n"; } bool is_string() { return true; } int get_int() { return atoi(value.c_str()); } std::string get_string_copy() { return value; } std::string const& get_string_ref() { return value; } }; struct Base { BaseImpl* impl; Base(BaseImpl* p = 0) : impl(p) {} ~Base() { delete impl; } }; int main() { Base b1(new INT(1)); Base b2(new STRING("Hello world")); Base b3(new INT(*b1.impl)); Base b4(new STRING(*b2.impl)); std::cout << "\n"; std::cout << b1.impl->get_int() << "\n"; std::cout << b2.impl->get_int() << "\n"; std::cout << b3.impl->get_int() << "\n"; std::cout << b4.impl->get_int() << "\n"; std::cout << "\n"; std::cout << b1.impl->get_string_ref() << "\n"; std::cout << b2.impl->get_string_ref() << "\n"; std::cout << b3.impl->get_string_ref() << "\n"; std::cout << b4.impl->get_string_ref() << "\n"; std::cout << "\n"; std::cout << b1.impl->get_string_copy() << "\n"; std::cout << b2.impl->get_string_copy() << "\n"; std::cout << b3.impl->get_string_copy() << "\n"; std::cout << b4.impl->get_string_copy() << "\n"; return 0; } It was necessary to add an if check in the STRING class to determine whether its safe to request a reference instead of a copy: Script code: a = "test"; b = a; c = 1; d = "" + c; /* not safe to request reference by standard */ C++ code: STRING(BaseImpl& that) { if (that.is_string()) value = that.get_string_ref(); else value = that.get_string_copy(); std::cout << "copy constructor called\n"; } If was hoping there's a way of moving that if check into compile time, rather than run time.

  Read the article

• How to extract object reference from property access lamda

  - by Jim C

  Here's a follow-up question to http://stackoverflow.com/questions/2820660/get-name-of-property-as-a-string. Given a method Foo (error checking omitted for brevity): // Example usage: Foo(() => SomeClass.SomeProperty) // Example usage: Foo(() => someObject.SomeProperty) void Foo(Expression<Func<T>> propertyLambda) { var me = propertyLambda.Body as MemberExpression; var pi = me.Member as PropertyInfo; bool propertyIsStatic = pi.GetGetMethod().IsStatic; object owner = propertyIsStatic ? me.Member.DeclaringType : ???; ... // Execute property access object value = pi.GetValue(owner, null); } I've got the static property case working but don't know how to get a reference to someObject in the instance property case. Thanks in advance.

  Read the article

• Basic class returns object reference instead of Array

  - by php-b-grader

  I have very basic class: class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; return $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); $this->customer = mysql_fetch_row($query); return $this->customer; } } $customer = new Customer($order->customer->id); print_r($customer); This is not doing what I want it to but I understand why... $customer returns a reference to the Customer Object... What I want is the MySQL row array from the mysql_fetch_row() - How do I return the array? What am I missing?

  Read the article

• Scala : reference is ambiguous (imported twice)

  - by tk

  I want to use a method as a parameter of another method of the same class. I have a class and objects which are companions: class mM(var elem:Matrix){ //apply a function on a dimension rows (1) or cols (2) def app(func:Iterable[Double]=>Double)(dim : Int) : Matrix = { ... } //utility function def logsumexp(): Double = {...} } object mM{ def apply(elem:Matrix):mM={new mM(elem)} def logsumexp(elem:Iterable[Double]): Double ={ this.apply(elem.asInstanceOf[Matrix]).logsumexp() } } Normally I use logsumexp like this mM(matrix).logsumexp but if want to apply it to the rows I can't use mM(matrix).app(mM.logsumexp)(1), I get the error: error: reference to mM is ambiguous; it is imported twice in the same scope by import mM and import mM What is the most elegant solution ? Should I change logsumexp() to another class ? Thanks,=)

  Read the article

• ARC and __unsafe_unretained

  - by J Shapiro

  I think I have a pretty good understanding of ARC and the proper use cases for selecting an appropriate lifetime qualifiers (__strong, __weak, __unsafe_unretained, and __autoreleasing). However, in my testing, I've found one example that doesn't make sense to me. As I understand it, both __weak and __unsafe_unretained do not add a retain count. Therefore, if there are no other __strong pointers to the object, it is instantly deallocated. The only difference in this process is that __weak pointers are set to nil, and __unsafe_unretained pointers are left alone. If I create a __weak pointer to a simple, custom object (composed of one NSString property), I see the expected (null) value when trying to access a property: Test * __weak myTest = [[Test alloc] init]; myTest.myVal = @"Hi!"; NSLog(@"Value: %@", myTest.myVal); // Prints Value: (null) Similarly, I would expect the __unsafe_unretained lifetime qualifier to cause a crash, due to the resulting dangling pointer. However, it doesn't. In this next test, I see the actual value: Test * __unsafe_unretained myTest = [[Test alloc] init]; myTest.myVal = @"Hi!"; NSLog(@"Value: %@", myTest.myVal); // Prints Value: Hi! Why doesn't the __unsafe_unretained object become deallocated?

  Read the article

• UIViewController maintains state after being nilled

  - by Eric

  In my app, I made a BookViewController class that displays and animates the pages of a book and a MainMenuViewController class that displays a set of books the user can read. In the latter class, when the user taps on one of the books, a function is called that should create a completely new instance of BookViewController, but for some reason the instance maintains its state (i.e. it resumes from the page the user left off). How can this be if I set it to nil? What am I missing here? (Note that I'm using ARC). MainMenuViewController.m @interface MainMenuViewController () @property (strong) BookViewController *bookViewController; @end @implementation MainMenuViewController @synthesize bookViewController; -(void)bookTapped:(UIButton *)sender{ NSString *bookTitle; if(sender == book1button) bookTitle = @"book1"; else if(sender == book2button) bookTitle = @"book2"; bookViewController = nil; bookViewController = [[BookViewController alloc] initWithBookTitle:bookTitle]; [self presentViewController:bookViewController animated:YES completion:nil]; } BookViewController.h @interface BookViewController : UIViewController -(id)initWithBookTitle:(NSString *)bookTitle; @end BookViewController.m @implementation BookViewController -(id)initWithBookTitle:(NSString *)theBookTitle{ self = [super init]; if(self){ bookTitle = [NSString stringWithFormat:@"%@", theBookTitle]; [self setModalTransitionStyle:UIModalTransitionStyleCrossDissolve]; NSLog(@"init a BookViewController with bookTitle: %@", bookTitle); } return self; } Every time a book is tapped, bookTapped: is called, and thee console always prints: 2012-08-31 16:29:51.750 AppName[25713:c07] init a BookViewController with bookTitle: book1 So if a new instance of BookViewController is being created, how come it seems to be returning the old one?

  Read the article

• update value of a variable outside a class in VB.NET

  - by dpp

  I have a class derived from a Form, it has textbox for username and password and an OK button. I want it to behave like an InputBox so I can use it like this: Dim Username As String = "" Dim Password As String = "" Dim authorization As New Authorization(Username, Password) authorization.ShowDialog() 'The user will click OK and I will expect the Username and Password to change based on the user input MsgBox(Username & " " & Password) The Authorization class: Public Class Authorization Dim RefUsername As String Dim RefPassword As String Public Sub New(ByRef Username As String, ByRef Password As String) InitializeComponent() RefUsername = Username 'I'm trying to pass reference instead of value RefPassword = Password 'I'm trying to pass reference instead of value End Sub Private Sub OKButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles AuthorizeButton.Click RefUsername = Username.Text 'I'm trying to change value of variable outside the class RefPassword = Password.Text 'I'm trying to change value of variable outside the class Me.Close() End Sub End Class In short, I want to change the value of variables outside the class when the user clicks the OK, how am I going to accomplish that?

  Read the article

• C undefined reference to `some_foo'

  - by sterh

  Hello, I have 3 files in my gtk+ app: main.c: #include <gtk/gtk.h> #include <glib/gi18n.h> #include "mainwindow.h" int main(int argc, char** argv) { MainWin* win; GError* err = NULL; int a = 0; a = some_foo(); gtk_main(); return 0; } mainwindo.h #include <gtk/gtk.h> typedef struct _MainWin { GtkWindow parent; } MainWin; GtkWidget* main_win_new(); int some_foo(); MainWindow.c #include "mainwindow.h" int some_foo() { return 1; } When i try to call some_foo in main function, and try to compile i see error: undefined reference to `some_foo'. What's wrong? Thank you.

  Read the article

• undefined reference to "func" when complied with GCC

  - by hotlemontea

  I implement a link list in two files in linklist.h and linklist.c, and I call some functions defined in linklist.h in main function of main.c. linklist.h is included in both linklist.c and main.c. When I compile this program by GCC with Makefile, the error named "undefined reference to xxx" occurs. I think my Makefile is written correctly as below. So what is the possible reason for this linking error CC=gcc CFLAGS= -g -O2 TARGET=target OBJECTS=main.o linklist.o TARGET: $(OBJECTS) $(CC) $(CFLAGS) $(OBJECTS) -o $(TARGET) clean: rm target $(OBJECTS) main.o:linklist.h linklist.o:linklist.h

  Read the article

• SQL - sub count

  - by Andy Clarke

  Hi I've got some SQL ... SELECT AdviceNo, Registration FROM tblSalesDetail that produces something like ... ADV00001, ABC123 ADV00001, CDE564 ADV00002, FGE432 ADV00003, HUY789 ADV00003, MJS532 ADV00003, JFY428 Can anyone tell me how I'd adjust it to see the following please? ADV00001, ABC123, 1 ADV00001, CDE564, 2 ADV00002, FGE432, 1 ADV00003, HUY789, 1 ADV00003, MJS532, 2 ADV00003, JFY428, 3

  Read the article

• Circular reference while setting up bidirectional communication line between two remote objects

  - by mphair

  I'm using .Net remoting to set up a bidirectional communication line between two objects. The basic structure is as follows: Instances of RemoteObjectA call methods on StaticObjectA. Instances of RemoteObjectB call methods on StaticObjectB. StaticObjectA needs to be able to call methods provided by RemoteObjectB. StaticObjectB needs to be able to call methods provided by RemoteObjectA. The problem with this setup is the circular reference in RemoteObjectA gets StaticObjectA gets RemoteObjectB gets StaticObjectB gets RemoteObjectA... I implemented an interface IRemoteObjectA and IRemoteObjectB and had the remote objects inheret from their respective interfaces, but then setting up the remoting fails. If the solution to this problem is: "don't use remoting", I can deal with that. Just wanted to make sure I wasn't missing a simple solution.

  Read the article

• Objective C @autoreleasepool directive

  - by Cemre

  I am reading a book which says (if I am not getting it wrong) wrapping some code with @autoreleasepool statement enables the ARC. First of all is this the case ? My second concern is when I am doing some iOS example programs, although I enable ARC when creating a new project, I never see this directive being used anywhere (in the automatically generated code). Does this mean that ARC is not being used ? Any ideas/pointers is appreciated.

  Read the article

• c# - best way to initialize an array of reference type object

  - by lidong

  I wonder if there is better way to initialize an array of reference type object, like this. Queue<int>[] queues = new Queue<int>[10]; for (int i = 0; i < queues.Length; i++) { queues[i] = new Queue<int>(); } I tried Enumerable.Repeat, but all elements in the array refer to same instance, Queue<int>[] queues = Enumerable.Repeat(new Queue<int>(), 10).ToArray(); I also tried Array.ForEach, but it doesn't work without ref keyword: Queue<int>[] queues = Array.ForEach(queues, queue => queue = new Queue<int>()); any other idea?

  Read the article

< Previous Page | 36 37 38 39 40 41 42 43 44 45 46 47  | Next Page >