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Passing a function identifier as an rvalue reference and applying std::move() to it


Passing a function identifier as an rvalue reference and applying std::move() to it

By : Irvinc
Date : January 12 2021, 01:40 AM
Does that help Consider the following snippet , You move a pointer to function, not function:
code :
callback c = std::move(sum);


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binding of lvalue into rvalue reference move ctor and return of function

binding of lvalue into rvalue reference move ctor and return of function


By : user3354399
Date : March 29 2020, 07:55 AM
it fixes the issue return_foo() returns a prvalue (because it returns unnamed temporary object). Quote from §3.10/1, emphasis mine:
Passing std::forward_as_tuple() result to multiple functions that may move from that object's rvalue-reference members?

Passing std::forward_as_tuple() result to multiple functions that may move from that object's rvalue-reference members?


By : Vinoth
Date : March 29 2020, 07:55 AM
will be helpful for those in need In this code func_i_dont_control cannot silently steal the parameter. Only rvalues bind to rvalue references and a named variable is not a rvalue. Your code either fails to compile, or func_i_dont_control (has an overload that) doesn't use move semantics.
To give func_i_dont_control the chance to steal the tuple (to bind the tuple to a rvalue reference), it would have to be explicitly cast to rvalue with std::move(tup).
disallow passing of rvalue reference to a function

disallow passing of rvalue reference to a function


By : alanxyz
Date : March 29 2020, 07:55 AM
it should still fix some issue We have the following convenience function that fetches a value from a map or returns a fallback default value if key not found. , Adding this additional overload should work (untested):
code :
template <class Collection>
const typename Collection::value_type::second_type&
FindWithDefault(const Collection& collection,
                const typename Collection::value_type::first_type& key,
                const typename Collection::value_type::second_type&& value) = delete;
template <class Collection>
const typename Collection::value_type::second_type&
FindWithDefault(const Collection& collection,
                const typename Collection::value_type::first_type& key,
                const typename Collection::value_type::second_type&& value) {
    static_assert(
        !std::is_same<Collection, Collection>::value, // always false
        "No rvalue references allowed!");
}
void foo(char const&) { };
void foo(char const&&) = delete;

int main()
{
    char c = 'c';
    foo(c);   // OK
    foo('x'); // Compiler error
}
rval.cpp(8) : error C2280: 'void foo(const char &&)' : attempting to reference a deleted function
        rval.cpp(2): See declaration of 'foo'
Move reference (rvalue) to function

Move reference (rvalue) to function


By : Moisesello
Date : March 29 2020, 07:55 AM
this one helps. I was reading some documentation and saw this: ,
How can you have a rvalue reference to a function?
std::move Not Working on RValue Reference Function

std::move Not Working on RValue Reference Function


By : user3197580
Date : March 29 2020, 07:55 AM
I wish this help you std::move only casts to Rvalue reference.
foo takes Rvalue ref to vector. By move(vecNumbers) you get vector&&. Inside foo you just access vecNumbers which is defined in main. You didn't do any action which changed the content of this vector.
code :
void foo(  std::vector<int>&& value)
{
    std::vector<int> v1{std::move(value)}; // invoke move ctor which steals content of value
    std::cout<<"size in Function:"<<value.size()<<"\n";
}
void foo(std::vector<int> value) {

}
foo(std::move(vecNumbers))
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