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  • Python ctypes argument errors

    - by Patrick Moriarty
    Hello. I wrote a test dll in C++ to make sure things work before I start using a more important dll that I need. Basically it takes two doubles and adds them, then returns the result. I've been playing around and with other test functions I've gotten returns to work, I just can't pass an argument due to errors. My code is: import ctypes import string nDLL = ctypes.WinDLL('test.dll') func = nDLL['haloshg_add'] func.restype = ctypes.c_double func.argtypes = (ctypes.c_double,ctypes.c_double) print(func(5.0,5.0)) It returns the error for the line that called "func": ValueError: Procedure probably called with too many arguments (8 bytes in excess) What am I doing wrong? Thanks.

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  • C#: why Base class is allowed to implement an interface contract without inheriting from it?

    - by etarassov
    I've stumbled upon this "feature" of C# - the base class that implements interface methods does not have to derive from it. Example: public interface IContract { void Func(); } // Note that Base does **not** derive from IContract public abstract class Base { public void Func() { Console.WriteLine("Base.Func"); } } // Note that Derived does *not* provide implementation for IContract public class Derived : Base, IContract { } What happens is that Derived magically picks-up a public method Base.Func and decides that it will implement IContract.Func. What is the reason behind this magic? IMHO: this "quasi-implementation" feature is very-unintuitive and make code-inspection much harder. What do you think?

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  • Passing a pointer to a function that doesn't match the requirements of the formal parameter

    - by Andreas Grech
    int valid (int x, int y) { return x + y; } int invalid (int x) { return x; } int func (int *f (int, int), int x, int y) { //f is a pointer to a function taking 2 ints and returning an int return f(x, y); } int main () { int val = func(valid, 1, 2), inval = func(invalid, 1, 2); // <- 'invalid' does not match the contract printf("Valid: %d\n", val); printf("Invalid: %d\n", inval); /* Output: * Valid: 3 * Invalid: 1 */ } At the line inval = func(invalid, 1, 2);, why am I not getting a compiler error? If func expects a pointer to a function taking 2 ints and I pass a pointer to a function that takes a single int, why isn't the compiler complaining? Also, since this is happening, what happens to the second parameter y in the invalid function?

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  • Mootools periodical funcion and time rewind

    - by hsz
    Hello ! I have some function taht is caller periodically: var func = function() { alert('Hello world!'); }; func.periodical(5000); This function is also called with click event: $('element').addEvent('click', function(){ func(); }); The timer starts and counts 2500msec, then I click $('element'), func() is executed and I want right now to reset the timer that func() will not be called in next 2500msec but in following 5000msec. How to do that ?

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  • Problems with variadic macros in C

    - by imikedaman
    Hi, I'm having a problem with optional arguments in #define statements in C, or more specifically with gcc 4.2: bool func1(bool tmp) { return false; } void func2(bool tmp, bool tmp2) {} #define CALL(func, tmp, ...) func(tmp, ##__VA_ARGS__) int main() { // this compiles CALL(func2, CALL(func1, false), false); // this fails with: Implicit declaration of function 'CALL' CALL(func2, false, CALL(func1, false)); } That's obviously a contrived example, but does show the problem. Does anyone know how I can get the optional arguments to "resolve" correctly? Additional information: If I remove the ## before _VA_ARGS_, and do something like this: bool func2(bool tmp, bool tmp2) { return false; } #define CALL(func, tmp, ...) func(tmp, __VA_ARGS__) int main() { CALL(func2, false, CALL(func2, false, false)); } That compiles, but it no longer works with zero arguments since it would resolve to func(tmp, )

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  • How to implement a private virtual function within derived classes?

    - by Dane
    Hi, I know why I want to use private virtual functions, but how exactly can I implement them? For example: class Base{ [...] private: virtual void func() = 0; [...] } class Derived1: puplic Base{ void func() { //short implementation is ok here } } class Derived2: puplic Base{ void func(); //long implementation elsewhere (in cpp file) } [...] void Derived2::func() { //long implementation } The first version is ok but not always possible. Isn't the second version simply name hiding? How do you define the Base::func() of Derived2, if you cannot do it within the class declaration of Dereived2? Thanks

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  • Problem with optional arguments in C #defines

    - by imikedaman
    Hi, I'm having a problem with optional arguments in #define statements in C, or more specifically with gcc 4.2: bool func1(bool tmp) { return false; } void func2(bool tmp, bool tmp2) {} #define CALL(func, tmp, ...) func(tmp, ##__VA_ARGS__) int main() { // this compiles CALL(func2, CALL(func1, false), false); // this fails with: Implicit declaration of function 'CALL' CALL(func2, false, CALL(func1, false)); } That's obviously a contrived example, but does show the problem. Does anyone know how I can get the optional arguments to "resolve" correctly? Additional information: If I remove the ## before _VA_ARGS_, and do something like this: bool func2(bool tmp, bool tmp2) { return false; } #define CALL(func, tmp, ...) func(tmp, __VA_ARGS__) int main() { CALL(func2, false, CALL(func2, false, false)); } That compiles, but it no longer works with zero arguments since it would resolve to func(tmp, )

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  • doubt in - Function Objects - c++

    - by Eternal Learner
    I have a class class fobj{ public: fobj(int i):id(i) {} void operator()() { std::cout<<"Prints"<<std::endl; } private: int id; }; template<typename T> void func(T type) { type(); } My Doubt is if I invoke func like Method 1: func(fobj(1); the message I wanted to print is printed. I was always thinking I needed to do something like Method 2: fobj Iobj(1); // create an instance of the fobj class func(Iobj); //call func by passing Iobj(which is a function object) How does Method 1 work? I mean what exactly happens? and how is a call made to the operator() in class fobj ?

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  • Why can't c# use inline anonymous lambdas or delegates?

    - by Samuel Meacham
    I hope I worded the title of my question appropriately. In c# I can use lambdas (as delegates), or the older delegate syntax to do this: Func<string> fnHello = () => "hello"; Console.WriteLine(fnHello()); Func<string> fnHello2 = delegate() { return "hello 2"; }; Console.WriteLine(fnHello2()); So why can't I "inline" the lambda or the delegate body, and avoid capturing it in a named variable (making it anonymous)? // Inline anonymous lambda not allowed Console.WriteLine( (() => "hello inline lambda")() ); // Inline anonymous delegate not allowed Console.WriteLine( (delegate() { return "hello inline delegate"; })() ); An example that works in javascript (just for comparison) is: alert( (function(){ return "hello inline anonymous function from javascript"; })() ); Which produces the expected alert box. UPDATE: It seems you can have an inline anonymous lambda in C#, if you cast appropriately, but the amount of ()'s starts to make it unruly. // Inline anonymous lambda with appropriate cast IS allowed Console.WriteLine( ((Func<string>)(() => "hello inline anonymous lambda"))() ); Perhaps the compiler can't infer the sig of the anonymous delegate to know which Console.WriteLine() you're trying to call? Does anyone know why this specific cast is required?

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  • Properly declare delegation in Objective C (iPhone)

    - by Gordon Fontenot
    Ok, This has been explained a few times (I got most of the way there using this post on SO), but I am missing something. I am able to compile cleanly, and able to set the delegate as well as call methods from the delegate, but I'm getting a warning on build: No definition of protocol 'DetailViewControllerDelegate' is found I have a DetailViewController and a RootViewController only. I am calling a method in RootViewController from DetailViewController. I have the delegate set up as so: In RootViewController.h: #import "DetailViewController.h" @interface RootViewController : UITableViewController <NSFetchedResultsControllerDelegate, DetailViewControllerDelegate> //Error shows up here { //Some Stuff Here } //Some other stuff here @end In RootViewController.m I define the delegate when I create the view using detailViewController.delegate = self In DetailViewController.h: @protocol DetailViewControllerDelegate; #import "RootViewController.h" @interface DetailViewController : UITableViewController <UITextFieldDelegate> { id <DetailViewControllerDelegate> delegate; } @property (nonatomic, assign) id <DetailViewControllerDelegate> delegate; @end @protocol DetailViewControllerDelegate //some methods that reside in RootViewController.m @end I feel weird about declaring the protocol above the import in DetailViewController.h, but if I don't it doesn't build. Like I said, the methods are called fine, and there are no other errors going on. What am I missing here?

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  • Getting around IBActions limited scope

    - by Septih
    Hello, I have an NSCollectionView and the view is an NSBox with a label and an NSButton. I want a double click or a click of the NSButton to tell the controller to perform an action with the represented object of the NSCollectionViewItem. The Item View is has been subclassed, the code is as follows: #import <Cocoa/Cocoa.h> #import "WizardItem.h" @interface WizardItemView : NSBox { id delegate; IBOutlet NSCollectionViewItem * viewItem; WizardItem * wizardItem; } @property(readwrite,retain) WizardItem * wizardItem; @property(readwrite,retain) id delegate; -(IBAction)start:(id)sender; @end #import "WizardItemView.h" @implementation WizardItemView @synthesize wizardItem, delegate; -(void)awakeFromNib { [self bind:@"wizardItem" toObject:viewItem withKeyPath:@"representedObject" options:nil]; } -(void)mouseDown:(NSEvent *)event { [super mouseDown:event]; if([event clickCount] > 1) { [delegate performAction:[wizardItem action]]; } } -(IBAction)start:(id)sender { [delegate performAction:[wizardItem action]]; } @end The problem I've run into is that as an IBAction, the only things in the scope of -start are the things that have been bound in IB, so delegate and viewItem. This means that I cannot get at the represented object to send it to the delegate. Is there a way around this limited scope or a better way or getting hold of the represented object? Thanks.

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  • What is the delegate method that is called when an MKPinAnnotationView is touched?

    - by Jake Schwartz
    I have been searching for this all night and I have just so frustrated. When a MKPinAnnotationView is clicked, the name and the subtitle comes up. I also want to center that point on the view. I figured there was some method I had to override because the information that pops up happened without me having to code it. Hopefully this was clear enough for you all. And in the mean time, I feel like there is some hidden guide on this use of MKMaps and other classes. Either that or it is terribly documented because I am having a lot of trouble finding information. Thanks.

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  • pushing view controller inside a tab bar from app delegate, after a notification.

    - by shani
    hi i have an app with tab bar and a navigation controller inside every tab. i have set a notification that when it lunches the user can get lunch the app by pressing the action on the alert. i want to redirect the user to one of the views inside one of the controllers. i have tried this: (void)application:(UIApplication *)app didReceiveLocalNotification:(UILocalNotification *)notif { NSArray *data = [notif.userInfo objectForKey:@"todoDate"]; NSInteger ind = [[data objectAtIndex:2] integerValue]; QuickViewController *detailViewController ; detailViewController = [[QuickViewController alloc] initWithNibName:@"QuickViewController" bundle:nil]; detailViewController.title = @"Edit"; detailViewController.personName = [data objectAtIndex:0]; detailViewController.DelitionDate=[data objectAtIndex:1]; detailViewController.personCategory=@"NO Category"; detailViewController.personID = ind r ; rootControler.selectedIndex = 1; [rootControler.tabBarController.selectedViewController.navigationController pushViewController:detailViewController animated:YES]; } but nothing is happening (no crashing) except of the :rootControler.selectedIndex = 1; when i tried : presentModalViewController i got the view perfectly but without the navigation controller. thanks shani

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  • Can you have too many Delegate.BeginInvoke calls at once?

    - by stewsha
    I am cleaning up some old code converting it to work asynchronously. psDelegate.GetStops decStops = psLoadRetrieve.GetLoadStopsByLoadID; var arStops = decStops.BeginInvoke(loadID, null, null); WaitHandle.WaitAll(new WaitHandle[] { arStops.AsyncWaitHandle }); var stops = decStops.EndInvoke(arStops); Above is a single example of what I am doing for asynchronous work. My plan is to have close to 20 different delegates running. All will call BeginInvoke and wait until they are all complete before calling EndInvoke. My question is will having so many delegates running cause problems? I understand that BeginInvoke uses the ThreadPool to do work and that has a limit of 25 threads. 20 is under that limit but it is very likely that other parts of the system could be using any number of threads from the ThreadPool as well. Thanks!

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  • Is there a way to determine the Variance of an Interface / Delegate in C# 4.0?

    - by BFree
    So now that we have generic Covariance and Contravariance on interfaces and delegates in C#, I was just curious if given a Type, you can figure out the covariance/contravariance of its generic arguments. I started trying to write my own implementation, which would look through all of the methods on a given type and see if the return types and or arguments match the types in the generic arguments. The problem is that even if I have this: public interface IFoo<T> { void DoSomething(T item); } using my logic, it LOOKS like it should be contravariant, but since we didn't actually specify: public interface IFoo<in T> { void DoSomething(T item); } (the in parameter) it isn't actually contravariant. Which leads to my question: Is there a way to determine the variance of generic parameters?

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  • Reason for getting error in Reverse Geocoder Delegate method in the morning times.

    - by Srilakshmi
    - (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error { NSLog(@"reverseGeocoder:%@ didFailWithError:%@", geocoder, error); } This method is getting called in morning times and it is not showing the placemark while running the application in simulator. From Afternoon it is showing the placemark as "Cupertino". Will you give me the reason for not getting the placeMark at morning times?

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  • How do I combine similar method calls into a delegate pattern?

    - by Daniel T.
    I have three methods: public void Save<T>(T entity) { using (new Transaction()) { Session.Save(entity); } } public void Create<T>(T entity) { using (new Transaction()) { Session.Create(entity); } } public void Delete<T>(T entity) { using (new Transaction()) { Session.Delete(entity); } } As you can see, the only thing that differs is the method call inside the using block. How can I rewrite this so it's something like this instead: public void Save<T>(T entity) { TransactionWrapper(Session.Save(entity)); } public void Create<T>(T entity) { TransactionWrapper(Session.Create(entity)); } public void Save<T>(T entity) { TransactionWrapper(Session.Save(entity)); } So in other words, I pass a method call as a parameter, and the TransactionWrapper method wraps a transaction around the method call.

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  • iOS6: do we have to set rootViewController in App delegate in order to support different orientations?

    - by Centurion
    The app was perfectly fine working in iOS5 in landscape orientation. However in iOS6, it started to use portrait orientation in all view controllers. The methods shouldAutorotateToInterfaceOrientation are not called anymore. I read the new stuff about changed rotation mechanism in iOS6 and I was able to fix that by adding a line in my AppDelegate: self.window.rootViewController = _viewController _viewControler is the starting screen (Home-menu). All other view controllers implement shouldAutorotateToInterfaceOrientation method and returns YES for landscape orientations only. So, it's perfectly working solution for the app that needs to support only one orientation. However, the problem is I need one view controller (lets call it phone-VC) to be presented in portrait orientation. Now, if I want this view controller would be rotated then I need to return YES in Home-menu controller that is assigned to rootViewControler in appDelegate. However, I can't do that because this rootViewController is starting window that need to presented in landscape only, otherwise the layout with graphics in this window will break. But if I don't return YES from its shouldAutorotateToInterfaceOrientation (Home-menu) then the same method is not called in my view phone-VC that needs to be presented in portrait. Any ideas? Does the assignation of rootViewController is mandatory in AppDelegate? UPDATE: the problem exists on device (at least on iPhone4).

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  • iPhone Simulator:Just show Default img and finish the delegate method appDidFinishLaunching after quit iPhone Simulator and rebuild...

    - by David_iDev
    Hi all, After I quit simulator and click build the app from XCode, the iPhone Simulator loading and my app will be install and run. But the app just show only Default image (finish the applicationDidFinishLaunching method - I logs it) and do nothing. I can't do anything in Simulator, event click the "Home" button of Simulator. But the other time, when Simulator already running, I select the "Build" button in XCode and everything is fine. Can you tell me why and how does this issue effect my app when I build it with real device? Thanks a lot!

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  • Vector of pointers to base class, odd behaviour calling virtual functions

    - by Ink-Jet
    I have the following code #include <iostream> #include <vector> class Entity { public: virtual void func() = 0; }; class Monster : public Entity { public: void func(); }; void Monster::func() { std::cout << "I AM A MONSTER" << std::endl; } class Buddha : public Entity { public: void func(); }; void Buddha::func() { std::cout << "OHMM" << std::endl; } int main() { const int num = 5; // How many of each to make std::vector<Entity*> t; for(int i = 0; i < num; i++) { Monster m; Entity * e; e = &m; t.push_back(e); } for(int i = 0; i < num; i++) { Buddha b; Entity * e; e = &b; t.push_back(e); } for(int i = 0; i < t.size(); i++) { t[i]->func(); } return 0; } However, when I run it, instead of each class printing out its own message, they all print the "Buddha" message. I want each object to print its own message: Monsters print the monster message, Buddhas print the Buddha message. What have I done wrong?

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  • Wrapping FUSE from Go

    - by Matt Joiner
    I'm playing around with wrapping FUSE with Go. However I've come stuck with how to deal with struct fuse_operations. I can't seem to expose the operations struct by declaring type Operations C.struct_fuse_operations as the members are lower case, and my pure-Go sources would have to use C-hackery to set the members anyway. My first error in this case is "can't set getattr" in what looks to be the Go equivalent of a default copy constructor. My next attempt is to expose an interface that expects GetAttr, ReadLink etc, and then generate C.struct_fuse_operations and bind the function pointers to closures that call the given interface. This is what I've got (explanation continues after code): package fuse // #include <fuse.h> // #include <stdlib.h> import "C" import ( //"fmt" "os" "unsafe" ) type Operations interface { GetAttr(string, *os.FileInfo) int } func Main(args []string, ops Operations) int { argv := make([]*C.char, len(args) + 1) for i, s := range args { p := C.CString(s) defer C.free(unsafe.Pointer(p)) argv[i] = p } cop := new(C.struct_fuse_operations) cop.getattr = func(*C.char, *C.struct_stat) int {} argc := C.int(len(args)) return int(C.fuse_main_real(argc, &argv[0], cop, C.size_t(unsafe.Sizeof(cop)), nil)) } package main import ( "fmt" "fuse" "os" ) type CpfsOps struct { a int } func (me *CpfsOps) GetAttr(string, *os.FileInfo) int { return -1; } func main() { fmt.Println(os.Args) ops := &CpfsOps{} fmt.Println("fuse main returned", fuse.Main(os.Args, ops)) } This gives the following error: fuse.go:21[fuse.cgo1.go:23]: cannot use func literal (type func(*_Ctype_char, *_Ctype_struct_stat) int) as type *[0]uint8 in assignment I'm not sure what to pass to these members of C.struct_fuse_operations, and I've seen mention in a few places it's not possible to call from C back into Go code. If it is possible, what should I do? How can I provide the "default" values for interface functions that acts as though the corresponding C.struct_fuse_operations member is set to NULL?

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  • Moq, a translator and an expression

    - by jeriley
    I'm working with an expression within a moq-ed "Get Service" and ran into a rather annoying issue. In order to get this test to run correctly and the get service to return what it should, there's a translator in between that takes what you've asked for, sends it off and gets what you -really- want. So, thinking this was easy I attempt this ... the fakelist is the TEntity objects (translated, used by the UI) and TEnterpriseObject is the actual persistance. mockGet.Setup(mock => mock.Get(It.IsAny<Expression<Func<TEnterpriseObject, bool>>>())).Returns( (Expression<Func<TEnterpriseObject, bool>> expression) => { var items = new List<TEnterpriseObject>(); var translator = (IEntityTranslator<TEntity, TEnterpriseObject>) ObjectFactory.GetInstance(typeof (IEntityTranslator<TEntity, TEnterpriseObject>)); fakeList.ForEach(fake => items.Add(translator.ToEnterpriseObject(fake))); items = items.Where(expression); var result = new List<TEnterpriseObject>(items); fakeList.Clear(); result.ForEach(item => translator.ToEntity(item)); return items; }); I'm getting the red squigglie under there items.where(expression) -- says it can't be infered from usage (confused between <Func<TEnterpriseObject,bool>> and <Func<TEnterpriseObject,int,bool>>) A far simpler version works great ... mockGet.Setup(mock => mock.Get(It.IsAny<Expression<Func<TEntity, bool>>>())).Returns( (Expression<Func<TEntity, bool>> expression) => fakeList.AsQueryable().Where(expression)); so I'm not sure what I'm missing... ideas?

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  • C#: Is it possible to use expressions or functions as keys in a dictionary?

    - by Svish
    Would it work to use Expression<Func<T>> or Func<T> as keys in a dictionary? For example to cache the result of heavy calculations. For example, changing my very basic cache from a different question of mine a bit: public static class Cache<T> { // Alternatively using Expression<Func<T>> instead private static Dictionary<Func<T>, T> cache; static Cache() { cache = new Dictionary<Func<T>, T>(); } public static T GetResult(Func<T> f) { if (cache.ContainsKey(f)) return cache[f]; return cache[f] = f(); } } Would this even work? Edit: After a quick test, it seems like it actually works. But I discovered that it could probably be more generic, since it would now be one cache per return type... not sure how to change it so that wouldn't happen though... hmm Edit 2: Noo, wait... it actually doesn't. Well, for regular methods it does. But not for lambdas. They get various random method names even if they look the same. Oh well c",)

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  • Generic callbacks

    - by bobobobo
    Extends So, I'm trying to learn template metaprogramming better and I figure this is a good exercise for it. I'm trying to write code that can callback a function with any number of arguments I like passed to it. // First function to call int add( int x, int y ) ; // Second function to call double square( double x ) ; // Third func to call void go() ; The callback creation code should look like: // Write a callback object that // will be executed after 42ms for "add" Callback<int, int, int> c1 ; c1.func = add ; c1.args.push_back( 2 ); // these are the 2 args c1.args.push_back( 5 ); // to pass to the "add" function // when it is called Callback<double, double> c2 ; c2.func = square ; c2.args.push_back( 52.2 ) ; What I'm thinking is, using template metaprogramming I want to be able to declare callbacks like, write a struct like this (please keep in mind this is VERY PSEUDOcode) <TEMPLATING ACTION <<ANY NUMBER OF TYPES GO HERE>> > struct Callback { double execTime ; // when to execute TYPE1 (*func)( TYPE2 a, TYPE3 b ) ; void* argList ; // a stored list of arguments // to plug in when it is time to call __func__ } ; So for when called with Callback<int, int, int> c1 ; You would automatically get constructed for you by < HARDCORE TEMPLATING ACTION > a struct like struct Callback { double execTime ; // when to execute int (*func)( int a, int b ) ; void* argList ; // this would still be void*, // but I somehow need to remember // the types of the args.. } ; Any pointers in the right direction to get started on writing this?

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  • Adding functions to Java class libraries

    - by Eric
    I'm using a Java class library that is in many ways incomplete: there are many classes that I feel ought to have additional member functions built in. However, I am unsure of the best practice of adding these member functions. Lets call the insufficient base class A. class A { public A(/*long arbitrary arguments*/) { //... } public A(/*long even more arbitrary arguments*/) { //... } public int func() { return 1; } } Ideally, I would like to add a function to A. However, I can't do that. My choice is between: class B extends A { //Implement ALL of A's constructors here public int reallyUsefulFunction() { return func()+1; } } and class AddedFuncs { public int reallyUsefulFunction(A a) { return a.func()+1; } } The way I see it, they both have advantages and disadvantages. The first choice gives a cleaner syntax than the second, and is more logical, but has problems: Let's say I have a third class, C, within the class library. class C { public A func() { return new A(/*...*/); } } As I see it, there is no easy way of doing this: C c; int useful = c.func().reallyUsefulFunction(); as the type returned by C.func() is an A, not a B, and you can't down-cast. So what is the best way of adding a member function to a read-only library class?

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