pass-by-reference

Origin of term "reference" as in "pass-by-reference"

Java/C# language lawyers like to say that their language passes references by value. This would mean that a "reference" is an object-pointer which is copied when calling a function. Meanwhile, in C++ (and also in a more dynamic form in Perl and PHP) a reference is an alias to some other name (or run-time value in the dynamic case). I'm...

pass strings by reference in C

I'm having trouble figuring out how to pass strings back through the parameters of a function. I'm new to programming, so I imagine this this probably a beginner question. Any help you could give would be most appreciated. This code seg faults, and I'm not sure why, but I'm providing my code to show what I have so far. I have made this ...

How to pass properties by reference in c#?

I am not sure if I have asked the question correctly. Please correct me if I am wrong. Anyways, we would like to use a variable's value on a different phases of the page's life cycle. So for example, public partial class TestUserControl: UserControl{ public TestUserControl(){ Objects = new List<object>(){ Prope...

Porting C# to javascript is causing scoping issues

Hi, I am trying to implement an algorithm I found in C# in javaScript and am facing some issues. Basically I am finding it difficult to pass by reference in JS. I have broken down the problem I have to the following example code, let say you have the following C#: using System; using System.Collections.Generic; using System.Linq; usin...

Is Ruby pass by reference or by value?

I am having this problem which I can't seem to get my head around. I would like some help on this. @user.update_languages(params[:language][:language1], params[:language][:language2], params[:language][:language3]) lang_errors = @user.errors logger.debug "--------------------LANG_ERRORS----------101-------------" + lang_erro...

Javascript function parameter names at time of call?

I know this is a really long shot, but I figure I'd ask: Is there a way to to find the names of the variables passed as parameters in a function call? Assuming I have: function test(tmp1, tmp2) { // ... } var a; var b; test(a, b); I'd like to get an array like so: [a, b]. Strings would also be acceptable: ["a", "b"]. I do not w...

Portably passing arguments to PHP's ReflectionMethod::invokeArgs by reference

Seemingly something of a misnomer, as pass by reference is deprecated in PHP 5.3... anyway, what I'm trying to do is write a unit test framework using reflection, that allows you to pass arguments to a method which requires a reference. e.g. class Bar { function TestMethod($arg1, &$result) { $result = 'hello'; return...

Modify smarty object by reference

Hey Guys, I am having an issue modifying a smarty variable by reference. Here is what I am trying to do: class foo { $property; public function getProperty(){ return $this->$property; } public function index(&$smarty){ $smarty->assign('test',$this->getProperty()); } } $smarty = new Smarty(); $foo ...

PHP: variable-length argument list by reference?

Is it possible to create a PHP function that takes a variable number of parameters all of them by reference? It doesn't help me a function that receives by reference an array of values nor a function that takes its arguments wrapped in an object because I'm working on function composition and argument binding. Don't think about call-tim...

Why do C++ allow constant to be transformed to reference argument in another method?

void outputString(const string &ss) { cout << "outputString(const string& ) " + ss << endl; } int main(void) { outputString("constant tranformed to reference argument"); //! outputString(new string("abc")); new only return pointer to object return 0; } Since its prohibited to create temporary object reference transform...

Any differences between f(const string &) and f(const string )?

class mystring { friend ostream& operator<<(ostream &out, const mystring ss) { out << ss.s; return out; } private: string s; public: mystring(const char ss[]) { cout << "constructing mystring : " << ss << endl; s = ss; } }; void outputStringByRef(const mystring &ss) { cout << "outputStri...

When to modify and when duplicate arguments?

Consider the functions sort and array_reverse. Why does one modify the variable passed, whereas the other return a new version? $a = array(3, 1, 2); sort($a); // $a === array(1, 2, 3) array_reverse($a); // $a === array(1, 2, 3) sort could just as easily been written to return a modified copy of the argument, and vice-versa for arra...

Adding .net COM wrapper to cache by value instead of by ref

In my code I'm instantiating a legacy Delphi object through a COM interface. This class needs to be instantiated many times, so in order to lower the overhead of instantiating it I cache it at a point where 70% of all the calls have the common resulting object. However, when I alter the object after it is cached, the changes are persi...

Java object references with cache layer

We've created a caching layer to our J2EE-application. In this instance we use Ehcache. This has created a few challenges. Let's take this example. OrderItem orderitem = cache.getOrderItemByID("id"); OrderItem old_orderitem = cache.getOrderItemID("id"); orderitem.setStatus(1); old_orderitem.setStatus(2); If we're not carefull, any ...

Cache integrity problem

I have an application that uses ehcache for cache (but I think this problem is framework-agnostic), with a method interceptor so basically if I mark my method for caching something like this happnes: public Object invoke(MethodInvocation mi) throws Throwable { Object result = cache.get(key); //key comes from MethodInvoc...

shouldn't PHP array recursion throw an error?

This is the test and the response I get. I think this could be problematic and should throw an error or a notice but I cannot understand why is tolerated. <?php $test = array( 0 => 'test', 1=> &$test ); var_dump( $test ); // array(2) { [0]=> string(4) "test" [1]=> &array(2) { [0]=> string(4) "test" [1]=> &array(2) { [0]=> s...

C++: how to prevent destructing of objects constructed in argument?

I have a questing around such staff. There is a class A which has a object of type class B as it's member. Since I'd like B to be a base class of group of other classes I need to use pointer or reference to the object, not it's copy, to use virtual methods of B inside A properly. But when I write such code class B {public: B(in...

How c# handles memory.

I have a class "skImage". This class has a private variable (with a public property that exposes it) private Image _capturedImage; the constructor of this class looks like: public skImage(Image captured) { _capturedImage = captured; } It also has the following method: public bool Invert() { Bitm...

How do I create a CLI value class containing a List (or similar) which is passed by value?

We have a C++ library which uses a struct containing an STL vector of structs, like so: struct Params { // values... } struct Settings { std::vector<Params> m_params; // values... } I'm writing a CLI wrapper for the library, and I want equivalents for the above struct types. I had been thinking about using a List as the...

Singleton Referencing

Okay...I have a situation where a C# .dll is a singleton. Now, what I want to be able to do is when the singletonInstance is instantiated be able to provide a reference to any other applications that may start. So, I looked up NamedPipes and that would work - except for one thing, this must be cross-platform, or platform independent. I h...