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  • Dynamic allocated array is not freed

    - by Stefano
    I'm using the code above to dynamically allocate an array, do some work inside the function, return an element of the array and free the memory outside of the function. But when I try to deallocate the array it doesn't free the memory and I have a memory leak. The debugger pointed to the myArray variable shows me the error CXX0030. Why? struct MYSTRUCT { char *myvariable1; int myvariable2; char *myvariable2; .... }; void MyClass::MyFunction1() { MYSTRUCT *myArray= NULL; MYSTRUCT *myElement = this->MyFunction2(myArray); ... delete [] myArray; } MYSTRUCT* MyClass::MyFunction2(MYSTRUCT *array) { array = (MYSTRUCT*)operator new(bytesLength); ... return array[X]; }

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  • What is Ruby's double-colon (::) all about?

    - by Meltemi
    I'd probably be able to answer this for myself if "::" wasn't so hard to Google. Didn't see anything on SO so thought I'd try my luck. What is this double-colon :: all about? I see it everywhere in Rails: class User < ActiveRecord::Base or… ActionController::Routing::Routes.draw do |map| I found a definition from this guy: The :: is a unary operator that allows: constants, instance methods and class methods defined within a class or module, to be accessed from anywhere outside the class or module. but that just leads to more questions. What good is scope (private, protected) if you can just use :: to expose anything?

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  • Is this a correct implementation of singleton C++?

    - by Kamal
    class A{ static boost::shared_ptr<A> getInstance(){ if(pA==NULL){ pA = new A(); } return boost::shared_ptr(pA); } //destructor ~A(){ delete pA; pA=NULL; } private: A(){ //some initialization code } //private assigment and copy constructors A(A const& copy); // Not Implemented A& operator=(A const& copy); // Not Implemented static A* pA; }; A* A::pA = NULL;

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  • Forcing a templated object to construct from a pointer

    - by SalamiArmi
    I have a fictional class: template<typename T> class demonstration { public: demonstration(){} ... T *m_data; } At some point in the program's execution, I want to set m_data to a big block of allocated memory and construct an object T there. At the moment, I've been using this code: void construct() { *m_data = T(); } Which I've now realised is probably not the best idea... wont work under certain cirumstances, if T has a private assignment operator for example. Is there a normal/better way to do what I'm attempting here?

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  • How to display Preferences in a View

    - by Sybiam
    I'm building some sort of wizard to create user accounts in Sync and Manage account. I use a ViewFlipper my activity has to be an AccountAuthenticatorActivity. That said it also means I can't inherit PreferenceActivity. So I looked up in the code of PreferenceActivity and I believe it should be possible to have a PreferenceView that inherit from ListView. The Activity part of PreferenceActivity isn't really needed as far as I know. Though the PreferenceManager is what really blocks me. private PreferenceManager onCreatePreferenceManager() { PreferenceManager preferenceManager = new PreferenceManager(this, FIRST_REQUEST_CODE); preferenceManager.setOnPreferenceTreeClickListener(this); return preferenceManager; } This function imply that we can instatiate PreferenceManager using the operator new. Apparently, the sdk hide the constructor of the PreferenceManager. I'm kind of confused. Is there a way to inflate my preferences and display them without PreferenceActivity?

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  • On Memory Allocation and C++

    - by Arpan
    And I quote from MSDN http://msdn.microsoft.com/en-us/library/aa366533(VS.85).aspx: The malloc function has the disadvantage of being run-time dependent. The new operator has the disadvantage of being compiler dependent and language dependent. Now the questions folks: a) What do we mean that malloc is run-time dependent? What kind of dynamic memory allocation functions can be independent of run-time? This statement sounds real strange. b) new is language dependent? Of course it should be right? Are HeapAlloc, LocalAlloc etc language independent? c) From a pure performance perspective are the MSVC provided routines preferable? Arpan

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  • What happens when a computer program runs?

    - by gaijinco
    I know the general theory but I can't fit in the details. I know that a program resides in the secondary memory of a computer. Once the program begins execution it is entirely copied to the RAM. Then the processor retrive a few instructions (it depends on the size of the bus) at a time, puts them in registers and executes them. I also know that a computer program uses two kinds of memory: stack and heap, which are also part of the primary memory of the computer. The stack is used for non-dynamic memory, and the heap for dynamic memory (for example, everything related to the new operator in C++) What I can't understand is how those two things connect. At what point is the stack used for the execution of the instructions? Instructions go from the RAM, to the stack, to the registers?

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  • C++ refactor common code with one different statement

    - by user231536
    I have two methods f(vector<int>& x, ....) and g(DBConn& x, ....) where the (....) parameters are all identical. The code inside the two methods are completely identical except for one statement where we do different actions based on the type of x: in f(): we do x.push_back(i) in g(): we do x.DeleteRow(i) What is the simplest way to extract the common code into one method and yet have the two different statements? I am thinking of having a templated functor that overloads operator () (int a) but that seems overkill.

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  • Unreachable code detected in case statement

    - by alex
    I have a code: protected override bool ProcessCmdKey(ref Message msg, Keys keyData) { switch (keyData) { case Keys.Alt|Keys.D1: if (this._condition1) { return true; } else { return base.ProcessCmdKey(ref msg, keyData); } break; case Keys.Control |Keys.U: if (this._condition2) { return true; } else { return base.ProcessCmdKey(ref msg, keyData); } break; default: return base.ProcessCmdKey(ref msg, keyData); } return true; It gives me "unreachable code detected" warning on breaks. Is it good practice not to use break operator here ? I don't want to turn off "unreachable code detected" warning. PS: There are many case in my ProcessCmdKey method.

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  • How to call a bool function...

    - by Gerri
    Hello, I did not see anything that address my particular code problem. I have a bool function in a class; the bool function is named: bool Triplet::operator ==(const Triplet& operand)const And I am trying to call it in Main but having problems just getting the call right. Apparently if I leave out any thing in the wording it gives an error that I have too few aruguments and if I try to use the entire wording of the function, I get the error that I need a semi-colon, but I already have a semi-colon at the end of the call, so I know that something else is wrong and I simply cannot figure out what is wrong! Any help would be appreciated! Thanks in advance.

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  • Purpose of boost::checked_delete

    - by Channel72
    I don't understand the purpose of boost::checked_delete. The documentation says: The C++ Standard allows, in 5.3.5/5, pointers to incomplete class types to be deleted with a delete-expression. When the class has a non-trivial destructor, or a class-specific operator delete, the behavior is undefined. Some compilers issue a warning when an incomplete type is deleted, but unfortunately, not all do, and programmers sometimes ignore or disable warnings. The supplied function and class templates can be used to prevent these problems, as they require a complete type, and cause a compilation error otherwise. So the C++ standard allows you to delete incomplete types, which causes undefined behavior if the type has a non-trivial destructor. What? How can an incomplete type have any destructor at all? Isn't an incomplete type just a prototype?

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  • C++ Segementation fault in binary_function

    - by noryb009
    I'm using Visual Studio 2010 Beta 2 (also tried with NetBeans), and I'm having a segmentation fault in the following code: // One of the @link s20_3_3_comparisons comparison functors@endlink. template <class _Tp> struct less : public binary_function<_Tp, _Tp, bool> { bool operator()(const _Tp& __x, const _Tp& __y) const { return __x < __y; } //this is the problem line }; I don't know what in my program calls it, but I am trying to find out. (I think it's a map) Does anyone know what to do, or has encountered this before?

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  • Calling this[int index] via reflection

    - by tkutter
    I try to implement a reflection-based late-bound library to Microsoft Office. The properties and methods of the Offce COM objects are called the following way: Type type = Type.GetTypeFromProgID("Word.Application"); object comObject = Activator.CreateInstance(type); type.InvokeMember(<METHOD NAME>, <BINDING FLAGS>, null, comObject, new object[] { <PARAMS>}); InvokeMember is the only possible way because Type.GetMethod / GetProperty works improperly with the COM objects. Methods and properties can be called using InvokeMember but now I have to solve the following problem: Method in the office-interop wrapper: Excel.Workbooks wb = excel.Workbooks; Excel.Workbook firstWb = wb[0]; respectively foreach(Excel.Workbook w in excel.Workbooks) // doSmth. How can I call the this[int index] operator of Excel.Workbooks via reflection?

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  • Filter objects within two seconds of one another using SQLAlchemy

    - by Arrieta
    Hello: I have two tables with a column 'date'. One holds (name, date) and the other holds (date, p1, p2). Given a name, I want to use the date in table 1 to query p1 and p2 from table two; the match should happen if date in table one is within two seconds of date in table two. How can you accomplish this using SQLAlchemy? I've tried (unsuccessfully) to use the between operator and with a clause like: td = datetime.timedelta(seconds=2) q = session.query(table1, table2).filter(table1.name=='my_name').\ filter(between(table1.date, table2.date - td, table2.date + td)) Any thoughts?

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  • bitfield mask calculation macro

    - by Aidan Cully
    We have a set of C macros, here, for using the preprocessor to do bitfield operations, and we run into warnings when attempting to use these macros in visual studio. The problem can be demonstrated very easily: #define BITFIELD_WIDTHMASK(Width) \ ((Width) >= 32 ? ~0x0ul : (1ul << (Width)) - 1) unsigned long foo(void) { return BITFIELD_WIDTHMASK(32); } Compiling this with MSVC yields the warning: test.c(12) : warning C4293: '<<' : shift count negative or too big, undefined behavior This isn't a behavior problem - the << operator won't be used in this case, and that should be detected at compile time. But does anyone have any suggestions about how to rewrite the macro to avoid the warning? Or, failing that, how to redesign the macro interface for this? Thanks in advance

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  • jQuery basics - selector

    - by rkrauter
    I feel dumb.. Why is my "header" div not being selected? It's background color is not being changed. I am learning about the + operator so I am not looking for a different selector. E + F an F element immediately preceded by an E element $("#divA + div").css("background-color", "red"); Html <div id="divA"> <div> Header</div> Lorem Ipsum is simply dummy text of the printing and typesetting industry. </div> Thanks!

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  • How to Detect Trusted Connection in Crystal Reports using VB.NET?

    - by Michael
    I have some Crystal Reports connecting to a Sql Server db that I would like to detect whether the connection is trusted or whether I need to supply the log on info (reports are not supplied by me so I can't control the connect method). If I just blindly supply login credentials, it won't connect if it is a trusted connection. The following does not work: oRpt = oCR.OpenReport("C:\MyReport.rpt") if oRpt.Database.Tables(1).ConnectionProperties.Item("Integrated Security") = True then 'trusted connection else 'supply login credentials end if It gives the following error: Operator '=' is not defined for type 'IConnectionProperty' and type 'Boolean'. I cannot find how create a construct in vb.net for IConnectionProperty. I can't find any documents from Crystal that explain it. I am using Crystal Reports XI - Developer

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  • Possible to fire asp.net validation from jQuery?

    - by Abe Miessler
    I have a form with several text boxes on it. I only want to accept floats, but it is likely that users will enter a dollar sign. I'm using the following code to remove dollar signs and validate the content: jQuery: $("#<%= tb.ClientID %>").change(function() { var ctrl = $("#<%= tb.ClientID %>"); ctrl.val(ctrl.val().replace('$','')) }); asp.net validation: <asp:CompareValidator ID="CompareValidator4" runat="server" Type="Double" ControlToValidate="tb" Operator="DataTypeCheck" ValidationGroup="vld_Page" ErrorMessage="Some error" /> My problem is that when someone enters a dollar sign in the TextBox "tb" and changes focus the validation happens first and THEN the jQuery removes the dollar sign. Is it possible to have the jQuery run first or to force the validation to run again after the jQuery executes?

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  • How do I do proximity search in Oracle right?

    - by hko19
    Oracle's NEAR operator for full text search returns a score based on the proximity of two or more query terms. For example: near((dog, bite), 6) matches if 'dog' and 'bite' occurs within 6 words. What if I'd like it to match if either 'dog' or 'cat' or any other type of animal occurs within 6 words of the word 'bite'? I tried: near(((dog OR cat OR animal), bite), 6) but I got: NEAR operand not a phrase, equivalence or another NEAR expression Rather than expanding all possible combination into multiple NEAR and 'or' them together, what is the proper way to write such query?

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  • Double Inner Join generates unexpected error

    - by Itamar Marom
    In my database I have three tables: Users: UserID (Auto Numbering), UserName, UserPassword and a few other unimportant fields. PrivateMessages: MessageID (Auto Numbering), SenderID and a few other fields defining the message content. MessageStatus: MessageID, ReceiverID, MessageWasRead (Boolean) What I need is a query to which I input a user's id and I get all the private messages he has received. In addition, I also need to receive each message's sender UserName. For this I wrote the following query: SELECT Users.*, PrivateMessages.*, MessageStatus.* FROM PrivateMessages INNER JOIN Users ON PrivateMessages.SenderID = Users.UserID INNER JOIN MessageStatus ON PrivateMessages.MessageID = MessageStatus.MessageID WHERE MessageStatus.ReceiverID=[@userid]; But for some reason when I try saving it in my Access database, I get the following error (translated to English by me, since my office is in a different language): Syntax error (missing operator) at expression: "PrivateMessages.SenderID = Users.UserID INNER JOIN MessageStatus ON PrivateMessages.MessageID = MessageStatus.MessageI". Any ideas what could cause this? Thanks.

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  • How often do you implement the big three?

    - by Neil Butterworth
    I was just musing about the number of questions here that either are about the "big three" (copy constructor, assignment operator and destructor) or about problems caused by them not being implemented correctly, when it occurred to me that I could not remember the last time I had implemented them myself. A swift grep on my two most active projects indicate that I implement all three in only one class out of about 150. That's not to say I don't implement/declare one or more of them - obviously base classes need a virtual destructor, and a large number of my classes forbid copying using the private copy ctor & assignment op idiom. But fully implemented, there is this single lonely class, which does some reference counting. So I was wondering am I unusual in this? How often do you implement all three of these functions? Is there any pattern to the classes where you do implement them?

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  • C++ Segmentation fault in binary_function

    - by noryb009
    I'm using Visual Studio 2010 Beta 2 (also tried with NetBeans), and I'm having a segmentation fault in the following code: // One of the @link s20_3_3_comparisons comparison functors@endlink. template <class _Tp> struct less : public binary_function<_Tp, _Tp, bool> { bool operator()(const _Tp& __x, const _Tp& __y) const { return __x < __y; } //this is the problem line }; I don't know what in my program calls it, but I am trying to find out. (I think it's a map) Does anyone know what to do, or has encountered this before?

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  • Boost::asio bug in MSVC10 - Failing BOOST_WORKAROUND in ~buffer_debug_check() in buffer.hpp

    - by shaz
    A straight compilation of example http://www.boost.org/doc/libs/1_43_0/doc/html/boost_asio/tutorial/tutdaytime3/src.html results in a runtime null pointer exception. Stack trace points to the buffer_debug_check destructor which contains this comment: // MSVC's string iterator checking may crash in a std::string::iterator // object's destructor when the iterator points to an already-destroyed // std::string object, unless the iterator is cleared first. The test #if BOOST_WORKAROUND(BOOST_MSVC, = 1400) succeeds in MSVC10 and (but) results in a null pointer exception in c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility line 123 _Iterator_base12& operator=(const _Iterator_base12& _Right) { // assign an iterator if (_Myproxy != _Right._Myproxy) _Adopt(_Right._Myproxy->_Mycont); return (*this); } _Right._Myproxy is NULL

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  • How to test Text Search accuracy and efficiency?

    - by DEN
    I have created a web application. One of the feature is text search which perform the boolean operator ( NOT, AND, OR) as well. However, I have no idea on calculating the search's accuracy and efficiency. For example: 1 . Probe identification system for a measurement instrument 2 . Pulse-based impedance measurement instrument 3 . Millimeter with filtered measurement mode when the user key in will return the result as below input :measurement instrument Result: 1,2 input : measurement OR instrument NOT milimeter Result: 1,2,3 so, i have no idea on what issue and what algorithm to calculate on the accuracy and efficiency of the text search.. anyone have any idea on that?

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  • sql boolean truth test: zero OR null

    - by AK
    Is there way to test for both 0 and NULL with one equality operator? I realize I could do this: WHERE field = 0 OR field IS NULL But my life would be a hundred times easier if this would work: WHERE field IN (0, NULL) (btw, why doesn't that work?) I've also read about converting NULL to 0 in the SELECT statement (with COALESCE). The framework I'm using would also make this unpleasant. Realize this is oddly specific, but is there any way to test for 0 and NULL with one WHERE predicate?

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