From cppreference.com
constevalboolreference_converts_from_temporary(std::meta::infodst,std::meta::infosrc);(since C++26)Checks if a reference is bound to a temporary in
Let T and U be types represented by dst and src, respectively.
Equivalent to returnstd::reference_converts_from_temporary_v<T,U>;.
If T is an lvalue reference type to a const- but not volatile-qualified object type or an rvalue reference type, both std::remove_reference_t<T> and std::remove_reference_t<U> must be
,
void, or an
; otherwise the program is ill-formed.
If an instantiation of a template above depends, directly or indirectly, on an incomplete type, and that instantiation could yield a different result if that type were hypothetically completed, the program is ill-formed.
Parameters
dst, src - reflection values to check Return value
true if the reference type T is bound to a temporary of the type U as described above; otherwise false.
Exceptions
Throws
if either dst or src does not represent a type or type alias.
Notes
reference_converts_from_temporary can be used for rejecting some cases that always produce dangling references.
It is also possible to use member initializer list to reject binding a temporary object to a reference if the compiler has implemented
.
Example
Run this code
#include<meta>static_assert(""andreference_converts_from_temporary(^^int&&,^^int)andreference_converts_from_temporary(^^constint&,^^int)andnotreference_converts_from_temporary(^^int&&,^^int&&)andnotreference_converts_from_temporary(^^constint&,^^int&&)andreference_converts_from_temporary(^^int&&,^^long&&)andreference_converts_from_temporary(^^int&&,^^long));intmain(){}See also
is_convertible_typeis_nothrow_convertible_type
(C++26)(C++26)
checks if reflected type can be converted to the other type
(function)
(C++17)(C++23)
invokes any
object with given arguments and possibility to specify return type(since C++23)
(function template)
(C++11)
binds one or more arguments to a function object
(function template)
(C++17)
calls the provided functor with the arguments held by one or more variants
(function template)
constructs a new std::function instance
(public member function of std::function<R(Args...)>)
constructs a new std::move_only_function object
(public member function of std::move_only_function)
constructs the task object
(public member function of std::packaged_task<R(Args...)>)
reference_constructs_from_temporary
(C++26)
checks if a reference is bound to a temporary in
(function)
reference_converts_from_temporary
(C++23)
checks if a reference is bound to a temporary in
(class template)