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Questions tagged [noncopyable]

The boost::noncopyable class is used as a base class to make a C++ type unable to be copied or assigned. This tag is for the boost library utility noncopyable.

The boost::noncopyable class is used as a base class (usually private) to make a C++ type unable to be copied or assigned.

It is intended to be used as a private base. boost::noncopyable has private (under C++03) or deleted (under C++11) copy constructor and a copy assignment operator and can't be copied or assigned; a class that derives from it inherits these properties.

Use this tag is for the boost library utility noncopyable.

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Prevent assignment of a type in C

Given a C function: void f(T x, T y) { x = y; } I want to make sure that all instances of T assignments will fail. So far, the best solution I have is something like: #define T const void * is there a better solution? (Ideally I would like T…
tohava
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noncopyable static const member class in template class

I have a non-copyable (inherited from boost::noncopyable) class that I use as a custom namespace. Also, I have another class, that uses previous one, as shown here: #include #include template< typename F > struct…
Tomilov Anatoliy
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make_pair like trick for noncopyable classes

make_pair can create pairs without mentioning the types. I want to use the same trick for my class, but it inherits from boost::noncopyable, so this does not compile: template struct bit_writer : boost:noncopyable { Iter iter; …
Bruno Martinez
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How to stop users from copying or printing text from my web page?

I have a web page (on .Net platform, with C#) with text content and I would like to block users from copying the text or printing the document. If the user is hard out on attaining a copy of the page, I know he can. But I would like to make it as…
Null Head
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Customized error message for deleted function use

Let's say I have a noncopyable class and I want to provide a customized error message when users try to copy. struct A { A() = default; private: [[deprecated("customized message")]] A(const A&); [[deprecated("customized…
Home of the Brave
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Replace const std::string passed by reference, with std::string_view

I've got the following method which gets std::string as input argument. int func(const std::string &filename); From it's signature, the input type refers passed by reference (no copy is made) and shouldn't be changed (by the const prefix). Would it…
Zohar81
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Error setting up unordered_map with non copying-able type with gcc 8.4

See here: https://godbolt.org/z/MW3jW6 Using gcc 8.4 (8.3 in godbolt) my code is failing to compile. With gcc 10.x it seems to compile ok. But I can't figure out what the error is telling me exactly... Here is the code for reference: #include…
code_fodder
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std::optional taking non-copyable?

Suppose i have something akin to this pseudocode: std::optional > > getDataTogetherWithLock() { if (!some_ptr) { return std::nullopt; } return some_ptr->getDataTogetherWithLock();//just…
darune
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What are the limitations of using boost mapped_matrix with std::unique_ptr?

Are there any limitations using boost's mapped_matrix with non-copyable objects like std::unique_ptr? I'm on VS2017 in C++14 mode. #include #include "boost/numeric/ublas/matrix_sparse.hpp" class myClass { public: myClass() {} …
Don Pedro
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Difference between std::unordered_map < K, boost::ptr_deque < T > >'s operator[] (K const &) and emplace

#include #include #include #include #include struct T { T() = default; T(T const &) = delete; T & operator = (T const &) = delete; T(T &&) = default; …
zrb
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SFML Input system problem

So I was porting my game engine from SDL to SFML, and now I have a problem with my input system. Input.h #ifndef BULLWHIP_INPUT_H #define BULLWHIP_INPUT_H #include class bc_Input { public: bool bm_KeyHit(sf::Key::Code key); …
Chris
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`noncopyable` with custom destructor

I need a noncopyable class which has a declared destructor, and naive approach doesn't work: see https://ideone.com/mU8aoc. What's the problem with the destructor, why moving doesn't work the same way as without it? And of course, how to fix it? For…
aplavin
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Macro to make class noncopyable

Is there any problem with following macro that makes a class non-copyable? #define PREVENT_COPY(class_name) \ class_name(const class_name&) = delete;\ class_name& operator=(const class_name&) = delete; class Foo { public: PREVENT_COPY(Foo) …
quantum_well
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C++ how noncopyable works?

How inheriting a noncopyable class with a private copy constructor and an assignment operator is going to prohibit the use of copy constructor and assignment operator on the derived class? Please consider the following scenario while replying,…
user3157434
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What is the best syntax to declare a class as noncopyable?

(assuming I cannot use boost::noncopyable, which was explicitly designed for that purpose) (assuming I cannot use C++11) When making a class noncopyable, I usually see the following syntax: class MyClass { public: ... stuff …
anatolyg
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