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Questions tagged [const-cast]

Anything related to the `const_cast` operation in C++, i.e. a form of compile-time conversion where the `const` or `volatile` qualifiers are cast away (removed) from a variable.

Anything related to the const_cast operation in C++, i.e. a form of compile-time conversion where the const or volatile qualifiers are cast away (removed) from a variable.

See CPPreference page on const_cast.

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interprocess object passing

I need to have a class with one activity that is performed once per 5 seconds in its own thread. It is a web service one, so it needs an endpoint to be specified. During the object runtime the main thread can change the endpoint. This is my…
Adam Trhon
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implicit const cast in templates

i ran across something similar to the below code snippet, which throws a compiler error because its using a const_iterator. is there a reason why vec.end() in std::copy does not implicitly get a const cast ? int main(int argc, char* argv[]) { …
keety
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Advice about const (member and function)

I am studying tree exploration, I implemented a class "CNode" for the nodes where each node has a pointer member to point to his parent, my question is about a const function and a const member, see below in my code. So below is a simplified version…
Calivernon
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How to use the non-const getter if there's a const one too?

If I have a class with getters of return type both const and non-const, how can I use the non-const one? The class (MeshManipulator.h): namespace vortex::meshSculptEngine { class MeshManipulator { public: ... …
Zoltán Orosz
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casting iterator returned by thrust::find_if to a struct pointer

I am using c++ for my project and facing this error in one of my functions. "a const_cast can only adjust type qualifiers; it cannot change the underlying type" I am working with thrust library and all my vectors are device type. The problem is that…
Lida
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Modifying const members of non-const object in C++20

Is it possible to modify a const field of a non-const object (using const_cast) in C++20? Yes, I know it probably shouldn't be allowed, and that there are very similar questions (Move construction and assignment of class with constant member,…
Joel Niemelä
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How can cpp show 2 different values at the same memory location after using const_cast on a const int variable

I am trying to change the value of a const int variable (should not be done ideally). This is how I did it. const int x{5}; //line 1 int* y{const_cast(&x)}; //line 2 std::cout<
Raj Kumar Singh
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Removing Const: Casting from std::shared_ptr to T

Is there a way to cast from T = std::shared_ptr to TCV = A please? I used this: template struct is_shared_ptr : std::false_type {}; template struct is_shared_ptr> : std::true_type…
Vero
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How do I assign to a const variable using an out parameter in C++?

In a class header file Texture.h I declare a static const int. static const int MAX_TEXTURE_SLOTS; In Texture.cpp I define the variable as 0. const int Texture::MAX_TEXTURE_SLOTS = 0; Now in Window.cpp class's constructor I attempt to assign to…
Freddy Cansick
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can C++20 concepts be used to avoid const/not const duplication?

Can C++20 concepts be used instead of templates to avoid (const/not const) code duplication ? For example (Range has nothing to do with C++20 ranges in this example), twice the same code, one const, the other not: I know there is the possibility to…
Ludovic Aubert
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Eigen::Ref and const_cast

In C++ I can use const_cast to convert a const Eigen::VectorXd& object to an Eigen::VectorXd& one. I wonder if it's possible to do the same with Eigen::Ref objects, i.e., is there a way to convert a const Eigen::Ref& object to…
fdev
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Removing const qualifier from type-inference return type

Quick question for the folks out there. I have the function signature below that under some but not all circumstances returns a const type qualifier on the return type. template
hdamlaj
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strange output after const_cast

here is my code: #include using namespace std; int main() { const int a = 10; cout << a << endl; int *b = const_cast(&a); cout << *b << endl; (*b)++; cout << *b << endl; cout << a << endl; return…
Melvin Levett
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Could const_cast ever return a null pointer for inputs other than null pointer?

cppreference explains that one possible const_cast conversion is a "null pointer value may be converted to the null pointer value of new_type". Is there any other way const_cast can return a null pointer?
jesses
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change the value of const_cast ptr/ref doesn't change the original object value?

I found a weird problem of same address with different values after change const_cast ptr/ref object value. #include using namespace std; int main(void){ const auto i=123; auto &ref2i=i; auto ptr2i=&i; auto…
Larry
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