Search Results

Search found 13476 results on 540 pages for 'non lazy ptr'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 48/540 | < Previous Page | 44 45 46 47 48 49 50 51 52 53 54 55  | Next Page >

  • What's the performance penalty of weak_ptr?

    - by Kornel Kisielewicz
    I'm currently designing a object structure for a game, and the most natural organization in my case became a tree. Being a great fan of smart pointers I use shared_ptr's exclusively. However, in this case, the children in the tree will need access to it's parent (example -- beings on map need to be able to access map data -- ergo the data of their parents. The direction of owning is of course that a map owns it's beings, so holds shared pointers to them. To access the map data from within a being we however need a pointer to the parent -- the smart pointer way is to use a reference, ergo a weak_ptr. However, I once read that locking a weak_ptr is a expensive operation -- maybe that's not true anymore -- but considering that the weak_ptr will be locked very often, I'm concerned that this design is doomed with poor performance. Hence the question: What is the performance penalty of locking a weak_ptr? How significant is it?

    Read the article

  • jQuery Stop non-css animation

    - by Mark
    I'm trying to stop a non-css animation: http://jsbin.com/aqute4/4/edit Button 1 starts the animation nicely, totally lost on how to stop it though, since .stop() seems to need a DOM element... rather than a random object. Thanks in advance. PS: Original code comes from: http://james.padolsey.com/javascript/fun-with-jquerys-animate/

    Read the article

  • How to declare a 2D array of 2D array pointers and access them?

    - by vikramtheone
    Hi Guys, How can I declare an 2D array of 2D Pointers? And later access the individual array elements of the 2D arrays. Is my approach correct? void alloc_2D(int ***memory, unsigned int rows, unsigned int cols); int main() { int i, j; int **ptr; int **array[10][10]; for(i=0;i<10;i++) { for(j=0;j<10;j++) { alloc_2D(&ptr, 10, 10); array[i][j] = ptr; } } //After I do this, how can I access the 10 individual 2D arrays? return 0; } void alloc_2D(int ***memory, unsigned int rows, unsigned int cols) { int **ptr; *memory = NULL; ptr = malloc(rows * sizeof(int*)); if(ptr == NULL) { printf("\nERROR: Memory allocation failed!"); } else { int i; for(i = 0; i< rows; i++) { ptr[i] = malloc(cols * sizeof(float)); if(ptr[i]==NULL) { printf("\nERROR: Memory allocation failed!"); } } } *memory = ptr; }

    Read the article

  • Is there a way to increase the efficiency of shared_ptr by storing the reference count inside the co

    - by BillyONeal
    Hello everyone :) This is becoming a common pattern in my code, for when I need to manage an object that needs to be noncopyable because either A. it is "heavy" or B. it is an operating system resource, such as a critical section: class Resource; class Implementation : public boost::noncopyable { friend class Resource; HANDLE someData; Implementation(HANDLE input) : someData(input) {}; void SomeMethodThatActsOnHandle() { //Do stuff }; public: ~Implementation() { FreeHandle(someData) }; }; class Resource { boost::shared_ptr<Implementation> impl; public: Resource(int argA) explicit { HANDLE handle = SomeLegacyCApiThatMakesSomething(argA); if (handle == INVALID_HANDLE_VALUE) throw SomeTypeOfException(); impl.reset(new Implementation(handle)); }; void SomeMethodThatActsOnTheResource() { impl->SomeMethodThatActsOnTheHandle(); }; }; This way, shared_ptr takes care of the reference counting headaches, allowing Resource to be copyable, even though the underlying handle should only be closed once all references to it are destroyed. However, it seems like we could save the overhead of allocating shared_ptr's reference counts and such separately if we could move that data inside Implementation somehow, like boost's intrusive containers do. If this is making the premature optimization hackles nag some people, I actually agree that I don't need this for my current project. But I'm curious if it is possible.

    Read the article

  • How to accomplish covariant return types when returning a shared_ptr?

    - by Kyle
    using namespace boost; class A {}; class B : public A {}; class X { virtual shared_ptr<A> foo(); }; class Y : public X { virtual shared_ptr<B> foo(); }; The return types aren't covariant (nor are they, therefore, legal), but they would be if I was using raw pointers instead. What's the commonly accepted idiom to work around this, if there is one?

    Read the article

  • boost::shared_ptr<const T> to boost::shared_ptr<T>

    - by Flevine
    I want to cast the const-ness out of a boost::shared_ptr, but I boost::const_pointer_cast is not the answer. boost::const_pointer_cast wants a const boost::shared_ptr, not a boost::shared_ptr. Let's forego the obligitory 'you shouldn't be doing that'. I know... but I need to do it... so what's the best/easiest way to do it? For clarity sake: boost::shared_ptr<const T> orig_ptr( new T() ); boost::shared_ptr<T> new_ptr = magic_incantation(orig_ptr); I need to know the magic_incantation() Thanks!

    Read the article

  • Fastest and stable non-sql database?

    - by Pavel
    What is the fastest and most stable non-sql database to store big data and process thousands requests during the day (it's for traffic exchange service)? I've found Kdb+ and Berkeley DB. Are they good? Are there other options?

    Read the article

  • Can't inherit from auto_str without problems

    - by fret
    What I want to do is this: #include <memory> class autostr : public std::auto_ptr<char> { public: autostr(char *a) : std::auto_ptr<char>(a) {} autostr(autostr &a) : std::auto_ptr<char>(a) {} // define a bunch of string utils here... }; autostr test(char a) { return autostr(new char(a)); } void main(int args, char **arg) { autostr asd = test('b'); return 0; } (I actually have a copy of the auto_ptr class that handles arrays as well, but the same error applies to the stl one) The compile error using GCC 4.3.0 is: main.cpp:152: error: no matching function for call to `autostr::autostr(autostr)' main.cpp:147: note: candidates are: autostr::autostr(autostr&) main.cpp:146: note: autostr::autostr(char*) I don't understand why it's not matching the autostr argument as a valid parameter to autostr(autostr&).

    Read the article

  • How to handle 'this' pointer in constructor?

    - by Kyle
    I have objects which create other child objects within their constructors, passing 'this' so the child can save a pointer back to its parent. I use boost::shared_ptr extensively in my programming as a safer alternative to std::auto_ptr or raw pointers. So the child would have code such as shared_ptr<Parent>, and boost provides the shared_from_this() method which the parent can give to the child. My problem is that shared_from_this() cannot be used in a constructor, which isn't really a crime because 'this' should not be used in a constructor anyways unless you know what you're doing and don't mind the limitations. Google's C++ Style Guide states that constructors should merely set member variables to their initial values. Any complex initialization should go in an explicit Init() method. This solves the 'this-in-constructor' problem as well as a few others as well. What bothers me is that people using your code now must remember to call Init() every time they construct one of your objects. The only way I can think of to enforce this is by having an assertion that Init() has already been called at the top of every member function, but this is tedious to write and cumbersome to execute. Are there any idioms out there that solve this problem at any step along the way?

    Read the article

  • 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;

    Read the article

  • How to attach boost::shared_ptr (or another smart pointer) to reference counter of object's parent?

    - by Checkers
    I remember encountering this concept before, but can't find it in Google now. If I have an object of type A, which directly embeds an object of type B: class A { B b; }; How can I have a smart pointer to B, e. g. boost::shared_ptr<B>, but use reference count of A? Assume an instance of A itself is heap-allocated I can safely get its shared count using, say, enable_shared_from_this.

    Read the article

  • Can't inherit from auto_ptr without problems

    - by fret
    What I want to do is this: #include <memory> class autostr : public std::auto_ptr<char> { public: autostr(char *a) : std::auto_ptr<char>(a) {} autostr(autostr &a) : std::auto_ptr<char>(a) {} // define a bunch of string utils here... }; autostr test(char a) { return autostr(new char(a)); } void main(int args, char **arg) { autostr asd = test('b'); return 0; } (I actually have a copy of the auto_ptr class that handles arrays as well, but the same error applies to the stl one) The compile error using GCC 4.3.0 is: main.cpp:152: error: no matching function for call to `autostr::autostr(autostr)' main.cpp:147: note: candidates are: autostr::autostr(autostr&) main.cpp:146: note: autostr::autostr(char*) I don't understand why it's not matching the autostr argument as a valid parameter to autostr(autostr&).

    Read the article

  • Warning: control reaches end of non-valid function - iPhone

    - by Dave
    I keep getting 'warning: control reaches end of non-void function' with this code: - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { if (section ==0) { return [comparativeList count]; } if (section==1) { return [generalList count]; } if (section==2) { return [contactList count]; How can I get rid of this warning? Thanks.

    Read the article

  • Is boost shared_ptr <XXX> thread safe?

    - by sxingfeng
    I have a question about boost :: shared_ptr. There are lots of thread. class CResource { xxxxxx } class CResourceBase { public: void SetResource(shared_ptr<CResource> res) { m_Res = res; } shared_ptr<CResource> GetResource() { return m_Res; } private: shared_ptr<CResource> m_Res; } CResourceBase base; //---------------------------------------------- Thread A: while (true) { ...... shared_ptr<CResource> nowResource = base.GetResource(); nowResource.doSomeThing(); ... } Thread B: shared_ptr<CResource> nowResource; base.SetResource(nowResource); ... //----------------------------------------------------------- If thread A do not care the nowResource is the newest . Will this part of code have problem? I mean when ThreadB do not SetResource completely, Thread A get a wrong smart point by GetResource? Another question : what does thread-safe mean? If I do not care about whether the resource is newest, will the shared_ptr nowResource crash the program when the nowResource is released or will the problem destroy the shared_point?

    Read the article

  • How to declare array of 2D array pointers and access them?

    - by vikramtheone
    Hi Guys, How can I declare an 2D array of 2D Pointers? And later access the individual array elements of the 2D arrays. Is my approach correct? main() { int i, j; int **array[10][10]; int **ptr = NULL; for(i=0;i<10;i++) { for(j=0j<10;j++) { alloc_2D(&ptr, 10, 10); array[i][j] = ptr; } } //After I do this, how can I access the individual 2D array //and then the individual elements of the 2D arrays? } void alloc_2D(float ***memory, unsigned int rows, unsigned int cols) { float **ptr; *memory = NULL; ptr = malloc(rows * sizeof(float*)); if(ptr == NULL) { status = ERROR; printf("\nERROR: Memory allocation failed!"); } else { int i; for(i = 0; i< rows; i++) { ptr[i] = malloc(cols * sizeof(float)); if(ptr[i]==NULL) { status = ERROR; printf("\nERROR: Memory allocation failed!"); } } } *memory = ptr; }

    Read the article

  • Trouble assigning a tr1::shared_ptr

    - by Max
    I've got a class that has a tr1::shared_ptr as a member, like so: class Foo { std::tr1::shared_ptr<TCODBsp> bsp; void Bar(); } In member function Bar, I try to assign it like this: bsp = newTCODBsp(x,y,w,h); g++ then gives me this error no match for ‘operator=’ in ‘((yarl::mapGen::MapGenerator*)this)->yarl::mapGen::MapGenerator::bsp = (operator new(40u), (<statement>, ((TCODBsp*)<anonymous>)))’ /usr/include/c++/4.4/tr1/shared_ptr.h:834: note: candidates are: std::tr1::shared_ptr<TCODBsp>& std::tr1::shared_ptr<TCODBsp>::operator=(const std::tr1::shared_ptr<TCODBsp>&) in my code, Foo is actually yarl::mapGen::MapGenerator. What am I doing wrong?

    Read the article

  • Casting a container of shared_ptr

    - by Jamie Cook
    Hi all, I have a method void foo(list<shared_ptr<Base>>& myList); Which I'm trying to call with a two different types of lists, one of DerivedClass1 and one of DerivedClass2 list<shared_ptr<DerivedClass1>> myList1; foo(myList1); list<shared_ptr<DerivedClass2>> myList2; foo(myList2); However this obviously generates a compiler error error: a reference of type "std::list<boost::shared_ptr<Base>, std::allocator<boost::shared_ptr<Base>>> &" (not const-qualified) cannot be initialized with a value of type "std::list<boost::shared_ptr<DerivedClass1>, std::allocator<boost::shared_ptr<DerivedClass1>>>" Is there any easy way to cast a container of shared_ptr? Of alternate containers that can accomplish this?

    Read the article

  • vba Loop over a non-contiguous range

    - by Jeffrey
    I have a non-contiguous range on rows (example address of myRange: $2:$2,$4:$205,$214:$214) and I would like to access a specific row and column within the range. I have tried the following: 'Get the value of the 2nd row, 1st column within the range myRange.rows(2).Cells(, 1).Value However, this is giving me the value of the 2nd row in the WorkSheet, and NOT in the range - meaning it is giving me address $3$1 - and not $4$1 Can someone please explain how I can access the values within in my range? (It may have to do with different areas) Thank You

    Read the article

  • How Do I grep For non-ASCII Characters in UNIX

    - by Peter Conrey
    I have several very large XML files and I'm trying to find the lines that contain non-ASCII characters. I've tried the following: grep -e "[\x{00FF}-\x{FFFF}]" file.xml But this returns every line in the file, regardless of whether the line contains a character in the range specified. Do I have the syntax wrong or am I doing something else wrong? I've also tried: egrep "[\x{00FF}-\x{FFFF}]" file.xml (with both single and double quotes surrounding the pattern).

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 44 45 46 47 48 49 50 51 52 53 54 55  | Next Page >