|
R operator(
)
( Args... args
)
/*cv*/
/*ref*/
noexcept
(
/*noex*/
)
;
|
|
(since C++23) |
| | |
Invokes the stored callable target with the parameters args. The /*cv*/, /*ref*/, and /*noex*/ parts of operator() are identical to those of the template parameter of std::move_only_function
Equivalent to
return
std::invoke_r
<R>
(
/*cv-ref-cast*/
(f), std::forward
<Args>
(args)...)
;
, where f is a cv-unqualified lvalue that denotes the target object of *this, and /*cv-ref-cast*/(f)
-
f if cv
ref is either empty or &
-
std::as_const(f) if cv
ref is either const or const &
-
std::move(f) if cv
ref is &&
-
std::
move
(
std::as_const
(f)
)
if cv
ref is const &&
The behavior is undefined if *this is empty.
Parameters
| args
|
-
|
parameters to pass to the stored callable target
|
Return value
std::invoke_r
<R>
(
/*cv-ref-cast*/
(f), std::forward
<Args>
(args)...)
Exceptions
Propagates the exception thrown by the underlying function call.
Example
The following example shows how std::move_only_function can passed to other functions by value. Also, it shows how std::move_only_function can store lambdas.
#include <iostream>
#include <functional>
void call(std::move_only_function<int() const> f) // can be passed by value
{
std::cout << f() << '\n';
}
int normal_function()
{
return 42;
}
int main()
{
int n = 1;
auto lambda = [&n](){ return n; };
std::move_only_function<int() const> f = lambda;
call(std::move(f));
n = 2;
call(lambda);
f = normal_function;
call(std::move(f));
}
Output:
See also
|
|
invokes the target
(public member function of std::function<R(Args...)>) |
|
|
calls the stored function
(public member function of std::reference_wrapper<T>) |
|
|
invokes any Callable object with given arguments and possibility to specify return type(since C++23)
(function template)
|