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# std::function::operator=

From cppreference.com
< cpp‎ | utility‎ | functional‎ | function

function& operator=( const function& other ); | (1) | (since C++11)
function& operator=( function&& other ); | (2) | (since C++11)
function& operator=( std::nullptr_t ); | (3) | (since C++11)
template< class F > function& operator=( F&& f ); | (4) | (since C++11)
template< class F > function& operator=( std::reference_wrapper<F> f ); | (5) | (since C++11)

Assigns a new target to `std::function`.

1) Assigns a copy of target of `other`, as if by executing function(other).swap(*this);
2) Moves the target of `other` to *this. `other` is in a valid state with an unspecified value.
3) Drops the current target. *this is empty after the call.
4) Moves the callable `f` to the target of *this, as if by executing function(std::forward<F>(f)).swap(*this);. This operator does not participate in overload resolution unless `f` is `Callable` for argument types `Args...` and return type `R`. (since C++14)
5) Assigns a copy of `f`, as if by executing function(f).swap(*this);

### [edit] Parameters

other | - | another `std::function` object to copy the target of
f | - | a callable to initialize the target with
Type requirements
- `F` must meet the requirements of `Callable`.

### [edit] Return value

*this

### [edit] Exceptions

1-2) (none)
3)

(none) | (until C++17)
`noexcept` specification: noexcept | (since C++17)

4) (none)
5)
`noexcept` specification:
noexcept

### [edit] Notes

The move assignment operator uses the default allocator rather than the allocator of `*this` or the allocator of `other` (LWG #2386)

### [edit] See also

assign (until C++17) | assigns a new target (public member function) [edit]

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Category:

- unconditionally noexcept