logo
Tags down

shadow

c++ function overload resolution regarding templated type and class hierarchy


By : Kunal Khairnar
Date : October 15 2020, 01:18 AM
hop of those help? All things being equal, overload resolution prefers nontemplate functions to function templates. However, in this case, all things are not equal. To match your overload for Base*, a derived-to-base pointer conversion is necessary; no conversion is necessary to match the function template. Thus, the function template is selected for Derived*.
The "simple," albeit probably error-prone, solution would be to cast your Derived* to a Base* before you call the function.
code :


Share : facebook icon twitter icon

Templated operator overload resolution, member vs non-member function


By : Red Knight
Date : March 29 2020, 07:55 AM
Any of those help Overload resolution adds an additional parameter to a member function just for the purpose of overload resolution:
[over.match.funcs]/2
code :
template<class T>
ostr& ostr::operator<<(ostr&, const T&);    // F1

template<class Stream>
Stream& ::operator<<(Stream&, const xy&);    // F2
ostr& ostr::operator<<(ostr&, const xy&);
ostr& ::    operator<<(ostr&, const xy&);
struct unique_T {};
struct unique_Stream {};
ostr& ostr::operator<<(ostr&, const unique_T&);
ostr& ::    operator<<(unique_Stream&, const xy&);
ostr a0;
unique_T a1; // no reference, no cv-qualifier
::operator<<(a0, a1) // does template argument deduction succeed?

// reminder: signature of ::operator<<
template<class Stream>
Stream& ::operator<<(Stream&, const xy&);
unique_Stream a0;
xy a1;
ostr::operator<<(a0, a1);

// reminder: signature of ostr::operator<<
template<class T>
ostr& ostr::operator<<(ostr&, const T&);

How can I specialize/overload a template function for a templated type


By : TruckIn
Date : March 29 2020, 07:55 AM
This might help you You can't partial specialize the constructor but you don't have necessarily to partial specialize the full class.
code :
#include<iostream>

template <class... T>
class thing {};

template <class T>
class container {
    template<typename>
    struct tag {};

    template<typename U>
    container(int, tag<thing<U>>) {
        std::cout << "thing<U>" << std::endl;
    }

    container(char, tag<T>) {
        std::cout << "normal constructor" << std::endl;
    }

public:
    container(): container(0, tag<T>{}) {}
};

int main() {
    container<int> c1;
    container<thing<int>> c2{};
}
#include<iostream>

template <class... T>
class thing {};

template<typename> struct tag {};
template<int N> struct prio: prio<N-1> {};
template<> struct prio<0> {};

template <class T>
class container {    
    template<typename U>
    container(prio<2>, tag<thing<U>>) {
        std::cout << "thing<U>" << std::endl;
    }

    container(prio<1>, tag<double>) {
        std::cout << "double" << std::endl;
    }

    container(prio<0>, tag<T>) {
        std::cout << "normal constructor" << std::endl;
    }

public:
    container(): container(prio<2>{}, tag<T>{}) {}
};

int main() {
    container<int> c1;
    container<double> c2;
    container<thing<int>> c3{};
}

Specialized inheritance of a templated class causes member function to return templated class type rather than inherited


By : pbenavent
Date : March 29 2020, 07:55 AM
With these it helps You can utilize CRTP here. By supplying extra template parameter you can make base class function return a reference to a derived class:
code :
#include <iostream>

template<typename Derived, typename T>
class Base {
public:
    Derived & operator()(const T& value) {
        this->value = value;
        return *static_cast<Derived *>(this);
    }
    T value;
};

class InheritedFloat : public Base<InheritedFloat, float> {} inheritedFloat;


void function(const InheritedFloat& inherited) {
    std::cout << inherited.value << '\n';
}

int main() {
    function(inheritedFloat(10.f));

    return 0;
}

A type trait identifying which class provides the function selected by overload resolution


By : Jin Cai
Date : March 29 2020, 07:55 AM
should help you out You can derive a class from derived and base1. This way all calls to operator() coming from base1 will be ambiguous:
code :
struct derived_check: base1, derived {
    using base1::operator();
    using base2::operator();
};
// Main
int main(int argc, char* argv[]) {
    const derived_check d1;
    derived_check d2;
    derived_check d3;
    call(d1, 1);    // error:ambiguous
    call(d2, 1);    // OK
    call(d1, 1, 2); // error:ambiguous
    call(d2, 1, 2); // error:ambiguous

    return 0;
}

Overload resolution for templated conversion operators


By : user2923882
Date : March 29 2020, 07:55 AM
To fix this issue This is a real tour-de-force of the standard.
When foo is instantiated, the specialization looks like this:
code :
struct foo<uint8_t> {
    operator uint8_t(){
        std::cout << "T conversion ";         
        print_type<uint8_t>();
        return {};
    }
    template <typename S>
    operator S(){
        std::cout << "ANY conversion ";
        print_type<S>();
        return {};
    }
};
LR operator*(L, R);
// ...
Related Posts Related Posts :
  • intellisense for empty Win32 projects
  • Parsing mathematical functions of custom types
  • Android play raw Audio from C++ side
  • How to access Active Directory using C++Builder?
  • String statements
  • Instruction-Level-Parallelism Exploration
  • Select from SQLite with Qt
  • Dynamic Memory Allocation
  • Maximum number of characters in a string
  • Float Values as an index in an Array in C++
  • Is 'using namespace std;' a standard C++ function?
  • Building a suffix tree in C++
  • Passing ifstream to a function in C++
  • Where would you use a friend function vs. a static member function?
  • Invalid free while performing a std::string assign with -O2 set in g++
  • Shutting down multithreaded NSDocument
  • C(++) malloc confusion
  • Portable c++ atomic swap (Windows - GNU/Linux - MacOSX)
  • C++ array initialization
  • How (i.e. what tool to use) to monitior headers sent by Curl (Cookie problem)
  • Understanding the library functions in c++
  • C++, read and write to a binary file at the same time
  • strange result when calling SHFileOperation to delete file after install MS office2003
  • C++ multiple inheritance preventing diamond
  • How do you create a simple comment header template for all new classes in Visual C++ 2010?
  • Is it possible to use cin with Qt?
  • How to debug a strange memory leak (C++)
  • What is meant by Resource Acquisition is Initialization (RAII)?
  • How should I go about building a simple LR parser?
  • Is there any non-GPL-opensource C\C++ H264 encoding library?
  • return pointer to data declared in function
  • How can I determine the current exception in a catch (...) block?
  • Dependency difference between Release & Debug
  • Help with memory allocation for multiplayer game server
  • C++ malloc - dynamic array
  • c++ InterlockedExchangePointer and pointer alignment
  • Using SQLite with Qt
  • How to select against which version of the Visual C++ libraries the application is compiled?
  • How to access image Data from a RGB image (3channel image) in opencv
  • Adding default arguments to variadic macro
  • Any exit status without explicitly using return /exit
  • Using C++ types in an ANTLR-generated C parser
  • How to ignore false positive memory leaks from _CrtDumpMemoryLeaks?
  • how to use dll?
  • C++ string literal data type storage
  • How to get qmake to generate "project dependencies" in a Visual Studio .sln project
  • Why would someone use C instead of C++?
  • C ReadProcessMemory - how to examine the memory area associated with a process
  • how can I force C++ macro substitution at the time I choose in this case?
  • C++: What is the appropriate use for the std::logic_error exception?
  • Is there a working C++ grammar file for ANTLR?
  • Copy Constructor?
  • How to start a voice quality PESQ test?
  • I'm trying to change my Maze traversal recursive coding part into a while loop
  • Providing less than operator for one element of a pair
  • Question about exact time of destruction of temporaries in C++
  • Please suggest some algorithm to find the node in a tree whose distance to its farthest node is minimum among all the no
  • Best practices with object manager
  • Using input to call a member function
  • How to find out if a character in a string is an integer
  • shadow
    Privacy Policy - Terms - Contact Us © bighow.org