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"Does not name a type" error, but class pointer already has forward declaration?
The #ifndef header guard doesn't prevent circular dependencies. It just prevents multiple inclusions of the same header in a single file. Looks like a circular dependency to me. This means you #include a header in DataAudit.h that #includes DataAudit.h either directly or indirectly.

Categories : C++

Incomplete type: class usage before definition vs. forward declaration
The logic is not the same. The difference is that in your second example function Base::test() uses objects of its own class Base (as opposed to a completely foreign class Derived). The language gives a special treatment to this situation in 8.3.5/6 (C++03) The type of a parameter or the return type for a function definition shall not be an incomplete class type (possibly cv-qualified) unless the function definition is nested within the member-specification for that class (including definitions in nested classes defined within the class). This rule can be seen as a "satellite" for another similar rule - the one that says that the class type is always seen in its entirety (and as complete type) from bodies of class member functions, default arguments and constructor initializ

Categories : C++

C forward declaration of struct in header
I think you just have to name your structure, and do a forward declaration of it and after re typedef it. First file: typedef struct structName {} t_structName; Second file: struct stuctName; typedef struct structName t_structName

Categories : C

forward declaration not working , does not have a type error
You declare a type called struct link, it's not just link, so write: struct node { struct link *head_link; struct node *next_node; }; Alternatively, declare a type called link with a typedef.

Categories : Misc

Why would I need forward class declaration in qt?
You're using a pointer to a QPushButton in the declaration of the class Window. That's why you have to #include <QPushButton> before using it, or at least to tell the compiler that it exists and it's declared further in your code with a forward declaration. If nothing happens when you remove the forward declaration from your header file is because somewhere before it is included or declared. May be qwidget.h ore one of its included headers is doing that for you... or a .h file generated by the "Qt User Interface Compiler" in the case you were using Qt designer forms. But as @chris said: "Don't count on headers to include other headers for you." There's no extra job in doing it explicitly.

Categories : C++

Any way to resolve forward declaration in a template class?
I don't think the code you've shown us exhibits the problem you're asking about. I made minimal changes to get past the earlier compiler errors, so I could get to the point where I could reproduce your problem. But, having done so, your problem does not exist. Here are my changes: Add #include <list>. Replace each instance of iterator with typename Container::iterator Make Container inherit from list publicly instead of privately, so I get access to its iterator type. You can try adding them one by one to see what errors each one solves—none of them have anything to do with your problem. Or you can download the code and compile it yourself. I compiled this with a three different compilers, clang-4.2, g++-4.6, and g++-4.2-apple; in both C++11 and C++98 modes where appropriate

Categories : C++

A missing or empty content type header was found when trying to read a message. The content type header is required
Thanks Vitek Karas MSFT for your suggestion. The issue is sovled by installing the latest version of WCF Data Services 5.6.0. and thanks to Maikel who tried in on our dev and was able to solve the issue.

Categories : Web Services

Forward declaration of template class in nested namespace: where should default template arguments go?
template<class T> using myname = some::templatething<T>; Then you can use myname In your case stick a template<class T,class S=X> using A = n2::A<T,S>; in your n1 Just wrote a gem of an answer related to this Symbol not found when using template defined in a library there btw, have a read. Okay it's not been ticked, so I'm gonna help some more! will not compile #include <iostream> namespace n1 { namespace n2 { template<class U,class V> struct A; } template<class U,class V> using A = n2::A<U,V>; } static n1::A<int,int>* test; struct X {}; namespace n1 { namespace n2 { template<class U,class V> struct A {}; } template<class U,class V=X> using A = n2::A<U,V>; } static n1::A<int> test2; int main(int,char*

Categories : C++

Class instance declaration syntax error in Python
Python likes to make syntax very clear - the ()s after a function are not optional when calling a function without parameters like in some other languages. You're not calling the functions just 'stating' them. Try class Abc: def a(self): print ("not to be seen") def b(self): print("inaccessible is") self.a() say = Abc() say.b() Here is the code working. Syntactically, the code is valid.

Categories : Python

-[Not A Type _cfTypeID]: message sent to deallocated instance
Look like what you release app.image or somewhere. May be you have extra CGImageRelease(app.image.CGImage); or [app.image release] Note, what you don't need release image after ALAsset.fullResolutionImage and fullScreenImage method

Categories : IOS

type mismatch in class template declaration
You're referencing a template as the parameter to ITipos, not a class. Change it to: template<typename Tipoentrada,typename TipoSalida > class TipoString : public ITipos<TipoString<Tipoentrada, TipoSalida>,TipoSalida> { using ITipos<TipoString<Tipoentrada, TipoSalida>,TipoSalida>::mconversionOk; /*...*/ };

Categories : C++

C++ - invalid use of undefined type ... - declaration of `class
By specializing the way you are, you are not actually instantiating NULLPOSITION (or POSIZIONENULLA, check your code) 14.7.1.2 in particular, the initialization (and any associated side-effects) of a static data member does not occur unless the static data member is itself used in a way that requires the definition of the static data member to exist You might want to explicitely define the data member with another class, as in template<typename P> class PositionClass { public: typedef P position; static const position NULLPOSITION; }; template <typename T, class P> class SuperClass : public PositionClass<P> { public: typedef T type; }; const PositionClass<int>::position PositionClass<int>::NULLPOSITION = 0;

Categories : C++

Java Pass instance type of Object to generic class type parameter
No.. generic type should be known at compile time. Generics are there to catch possible runtime exceptions at compile time itself. List<Integer> list = new ArrayList<Integer>(); //..some code String s = list.get(0); // this generates compilation error because compiler knows that list is meant to store only Integer objects and assigning the value got from list to String is definitely an error. If the generic type was determined at run-time this would have been difficult.

Categories : Java

Forward declaration C
Actually, your dummy is not a structure, but a typedef to an unnamed structure. Try naming the structure, you can then forward-declare it: typedef struct sdummy dummy; // forward declaration void foo(dummy *); struct sdummy { ... }; // definition

Categories : C

Forward declaration cv::Mat
You cannot use a forward declaration here. The compiler needs to have the definition of cv::Mat in order for it to be a data member of OpenGLImpl. If you want to avoid this constraint, you could have OpneGLImpl hold a (smart) pointer to cv::Mat: #include <memory> namespace cv { class Mat; } class OpenGLImpl { private: std::unique_ptr<cv::Mat> frame; }; You can then instantiate the cv::Mat owned by the unique_ptr in an implementation file. Note that a reference would also work with a forward declaration, but it is unlikely you need refernce semantics here.

Categories : C++

Broadcast Receiver declaration in manifest error on intellij
You also have to define the intent-filter with the receiver <receiver android:name="Your receiver Name"> <intent-filter> <action android:name="android.intent.action.BOOT_COMPLETED" /> //your action to perform on broadcast receiver </intent-filter> after this in your receiver class you have to check if(intent(object of intent in onreceive method).equals("android.intent.action.BOOT_COMPLETED")) { // action to perform }

Categories : Java

C++ Forward declaration and destructor
Yep, that's what the (draft) standard says (§5.3.5.5); If the object being deleted has incomplete class type at the point of deletion and the complete class has a non-trivial destructor or a deallocation function, the behavior is undefined. (a non trivial destructor being one you defined yourself) To fix it, just #include "Character.h" in header.cpp before invoking delete to allow the type to be completely declared.

Categories : C++

C/C++ forward declaration in typedef
In C, when you declare a struct like: struct foo { }; To declare an instance of this struct, you would say: struct foo f; Therefore C programmers tend to declare structs like: typedef struct foo { } foo; As in, foo is a typedef for struct foo This requirement is gone for C++. I don't think that typedef struct cl_context; compiles. Maybe you meant typedef struct _cl_context cl_context;? Is it just so the API calls can take cl_context instead of cl_context*? That typedef takes care of both that and eliminating the need to prepend your type declarations with struct. You would certainly not want to use typedef void *cl_context; because then you lose type safety.

Categories : C++

Possible forward declaration error
Without seeing your code, it is a shot in the dark, but it sounds like you are getting a linker error. // main.cpp #include "MouseController.h" int main() { // do stuff return 0; } // MouseController.cpp #include "MouseController.h" // implement MouseController here // MouseController.h // define MouseController here If MouseController.cpp does not exist, is not being compiled (i.e. is not part of your project or Makefile), or MouseController.h does not implement the class inline, the compiler knows what MouseController should look like, but the linker can't find it.

Categories : C++

What is a parameter forward declaration?
This form of function definition: void fun(int i; int i) { } uses a GNU C extension called the parameter forward declaration feature. http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html This feature allows you to have parameter forward declarations before the actual list of parameters. This can be used for example for functions with variable length array parameters to declare a size parameter after the variable length array parameter. For example: // valid, len parameter is used after its declaration void foo(int len, char data[len][len]) {} // not valid, len parameter is used before its declaration void foo(char data[len][len], int len) {} // valid in GNU C, there is a forward declaration of len parameter // Note: foo is also function with two parameters void foo(int len; c

Categories : C

class declaration error: insufficient contextual information to determine type
Yes, the error is here: CBall ball(const CBox&, ALLEGRO_COLOR); CPlayer player1(const CBox&, ALLEGRO_COLOR); CPlayer player2(const CBox&, ALLEGRO_COLOR); This doesn't declare members called ball, player1 and player2, as you think it does (according to code like: player1.draw();). Instead, what you've written is a declaration of methods with these names, taking in argument the parameters you've specified. Instead, you should do: CBall ball; CPlayer player1; CPlayer player2; Then in the constructor of GameLoop, initialize them with whatever value you want, using initialization lists: GameLoop::GameLoop(Allegro& alObject) : ball(/* ... */), player1(/* ... */), player2(/* ... */) { // .... }

Categories : C++

The relation between Forward declaration and destructors
Indeed, your forward declaration introduces an incomplete type that is later defined with a non-trivial destructor, and that can't be used in a delete expression: From n3337, paragraph 5.3.5/5: 5 If the object being deleted has incomplete class type at the point of deletion and the complete class has a non-trivial destructor or a deallocation function, the behavior is undefined.

Categories : C++

Why does empty variable declaration of type show compile error but not for null declaration?
Because s2 is not initialized and s1 is initialized with null For Que 1: You are performing trim() Operation on null actually, so it will throw NPE (NullPointerException) as it should be. For Que 2: See §4.12.5 of the JLS for a very detailed explanation: A local variable must be explicitly given a value before it is used, by either initialization or assignment, in a way that can be verified by the compiler using the rules for definite assignment.

Categories : Java

c++ Polymorphism: Forward Declaration?, Include guard?, or something else?
Well, use forward declarations. As you said, there are millions of explanations out there, and now there are millions and one: ErrorToken.h: #ifndef H_ERROR_TOKEN #define H_ERROR_TOKEN #include "Token.h" class EndToken; class ErrorToken : public Token { public: EndToken makeEndToken(); }; #endif EndToken.h: #ifndef H_END_TOKEN #define H_END_TOKEN #include "Token.h" class ErrorToken; class EndToken : public Token { public: ErrorToken makeErrorToken(); }; #endif In each implementation file, you can now happily include both headers: #include "ErrorToken.h" #include "EndToken.h" ErrorToken EndToken::makeErrorToken() { return ErrorToken(); // example } EndToken ErrorToken::makeEndToken() { return EndToken(); } As @James Kanze pointed out, you might be con

Categories : C++

C++, forward declaration and recursive data types
So, I'm not sure why anyone would do this, but the same maps value type pointer in this case would be the KeyType, i.e. you could define it as std::map<KeyType,KeyType> , but that makes no sense, so what I really think you are looking for is a std::map inside another std::map, I use those all the time, example: typedef std::map<int,const void*> map1; std::map<int,const map1*> map2;

Categories : C++

Unsatisfied forward or external declaration, with new C++ obj-files
The Pascal files are designed to be used with .obj files that are compiled in a very specific way. You cannot compile using the bzip2 makefile. You need to compile the files in the specific way that is compatible with the Delphi library. Take a look at Abbrevia. In the sourceforge repo we have this: bzip2 SDK v1.0.6 Original download available from http://bzip.org/1.0.6/bzip2-1.0.6.tar.gz Compile 32-bit with bcc32 -q -c -u- -w-8004 -w-8008 -w-8057 -w-8066 -w-8068 -DBZ_NO_STDIO *.c Compile 64-bit with cl -c -nologo -GS- -Z7 -wd4068 -Gs32768 -DBZ_NO_STDIO *.c So this tells you that 32 bit Abbrevia is designed to be used with bcc32 compiled object files (using that specific command line). Perhaps you can get it to work with cl also. And certainly Craig has managed to do so for his

Categories : Visual Studio

template class instance receiving another instance of the same template class of different type
You need a template member operator+. Also, it should return a value, not a reference: template<class T> class MyClass { public: template <typename T2> MyClass operator+ (const MyClass<T2>& r) const { return _val + r.retval(); } T retval() const {return _val;} // as before }; Note that this will return a value of the same type as the LHS in an expression involving operator+. Note that it would be a better idea to implement operator+ as a non-member binary operator. But you have to implement some compile-time logic to determine the return type: template <typename T1, typename T2> MyClass< ?? > operator+(const MyClass<T1>& lhs, const MyClass<T1>& rhs) { return lhs.retval() + rhs.retval(); } where ?? should be replaced

Categories : C++

The best way to know an instance type from a class method of the same class?
existingObjectWithID:error: is explicitly typecast to return NSManagedObject*. That, frankly, is a bug in the API and you should file it. Because of that, you'll need the cast.

Categories : Objective C

Member with same type as class instance
One solution that should work is to use "Recursive generics" (See this post). We change the definition of Node<T> to Node<N, T> where N has to implement Node<N, T>... abstract class Node<N, T> where N : Node<N, T> // Here is the recursive definition where T : IComparable<T> { T value; public N NextNode; public N GetLastNode() { N current = (N)this; while (this.NextNode != null) { current = current.NextNode; } return current; } // etc. } Then, you just have to change the base class of AdvancedNode<T> to Node<AdvancedNode<T>, T>. class AdvancedNode<T> : Node<AdvancedNode<T>, T> where T : IComparable<T> { int Height;

Categories : C#

Getting a Class instance corresponding to a generic type instantiation
Here's an easier solution.. which totally hides the ugliness. The approach here, is to implicitly bind the result-type -- and separate that from the passed-in raw Class. public class GenericClass<T> { public GenericClass(Class<T> cls) {} // static constructor; // - hides unchecked ugliness, & implicitly binds 'nicely typed' to result. // public static <T> GenericClass<T> create (Class<? super T> clazz) { // ugly cast is hidden in here; no type checking. Class<T> clazz_ = (Class<T>)(Class) clazz; return new GenericClass( clazz_); } } Usage: GenericClass<List<String>> g = GenericClass.create( List.class); I've bounded the 'passed-in Class' clazz as ? super T for now, but -- i

Categories : Java

1 broadcast receiver instance at any given time
You could just a static boolean field in your ConnectivityChangeBroadcastReceiver to keep track of whether the method is currently executing. public class ConnectivityChangeBroadcastReceiver extends BroadcastReceiver { private static boolean currentlyReceiving = false; @Override public void onReceive(Context context, Intent intent) { if(!currentlyReceiving) { currentlyReceiving = true; doYourLongTaskHere(); currentlyReceiving = false; } } } I'm not sure if every broadcast will be run in a different thread or not, so you may want to throw the block within the if statement into a synchronized block.

Categories : Android

Resolving ambiguous instance for multiparam type class
You can use functional dependencies to specify that "ret is uniquely determined by a and b". ... {-# LANGUAGE FunctionalDependencies #-} ... class MyNum a b ret | a b -> ret where ... This lets the typechecker know that it can pick the correct instance definition, knowing only the a and b from the arguments in your: myLessThan (NamedList n l) x = myLessThan l x The compiler will now complain if you define an additional instance with the same a and b but a different ret, such as instance MyNum MyList Double SomeOtherType where

Categories : Haskell

Can we Use Idempotent Receiver against Jms message with ActiveMq
I don't think this would suit your requirement. What the resequencing processor does is, order the messages according to the number in seqNumXpath property. So the messages should include a number and you should obtain this number using a xpath expression. When deleteDuplicateMessages parameter is set to true, it will delete duplicate messages that have the same sequence number as obtained from seqNumXpath parameter. In your case you can use a store and forward scenario to prevent client having to send multiple requests. Set FORCE_SC_ACCEPTED property to true in your proxy service to always return 202 response to client. Then message will be stored in msg store and will be forwarded using message processor. http://docs.wso2.org/wiki/display/ESB470/Store+and+Forward+Using+JMS+Message+Stor

Categories : Wso2

XMPP double message receiver Ios
You can login simultaneously in two different devices provided you are using different resource names when logging in. You can check sessions and resources the user has used to sign in on the server

Categories : Iphone

OOP design reaching the type outside the class or create instance inside it
I believe your question is more related to good programming practice and there could be multiple solution or design technique for this question. I would create classes like this - // create interface for providing {x} features public interface IBObj_Sf { ... ... } // create class which provides {x} features of IBObj_Sf interface public class BObj_Sf : IBObj_Sf { ... ... } // now implement BObj_Sub class like - public class BObj_Sub { // mark as readonly depending it is modifiable or // not withing BObj_Sub's lifecycle private readonly IBObj_Sf _Sn; public BObj_Sub(IBObj_Sf sn) { _Sn = sn; } public BObj_Sf Sn { get { return _Sn; } private set { _Sn = value; } } }

Categories : C#

change property of C# class type instance (e.g. dictionary) after it's defined
By recreating it... SomeDict = new Dictionary<string, long>(SomeDict, StringComparer.InvariantCultureIgnoreCase); In the end the change you want is too much radical (all the hashes of the items would probably change. Only "probably" because if the keys are all in the form "123", "456" the hashes would remain the same, but here we are speaking of the general case). The dictionary would have to be cleaned and refilled, so recreated nearly from scratch.

Categories : C#

Message not picked up by component from receiver (threading issue?)
Mule has a limit to max thread default to 16, so you can go ahead and change: First thing you can Set the numberOfConsumers attribute on the JMS connector Set the maxThreadsActive attribute on the JMS connector’s receiver-threading-profile element <jms:activemq-connector name="jmsConnector" numberOfConsumers="15" brokerURL="vm://localhost"> <receiver-threading-profile maxThreadsActive="15"/> </jms:activemq-connector> Another solution is you can set flow processing strategy, please refer to the below link: https://docs.mulesoft.com/mule-user-guide/v/3.5/flow-processing-strategies

Categories : Multithreading

Sending forward windows message
You should not pass pointer from process A to process B, in process B such pointer (address) might point to freed memory or memory used by some other structures. WM_COPYDATA is one way to pass data between processes, you can actually pack each of you message into binary array, send it to other process using WM_COPYDATA, and in this second process unpack it and then send to itself unpacked message. The only safe way to pass lParam and wPAram between processes is when they contain only DWORD data.

Categories : C++

Can one call an instance's method inside a class without recreating the instance within class' scope?
You have to import the global $errorhandler variable into your local scope: class AnotherClass { function __construct() { global $errorhandler; try { $not_possible = 1/0; } catch (Exception $e) { $errorhandler->log($e); # Doesn't work } } } P.S. 1/0 is not an exception, it's a runtime error. You can't catch those with a try/catch block.

Categories : PHP

Spring Framework: The document type declaration for root element type "beans" must end with '>'
Try this... <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd" > <bean id="data" class="com.blah.tests.DataProviderClass" /> <bean id="wdcm" class="com.blah.tests.WebDriverCustomMethods"/> </beans>

Categories : Java



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