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## Constructors

### promise()

Creates a promise with an unsatisfied shared state.

### promise(std::function\< void()\>)

Creates a promise with an unsatisfied shared state.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
| `cancellation_callback` | `std::function< void()>` |

### promise(null_promise_t)

Creates a promise *without* a shared state.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
| `x` | `null_promise_t` |

### promise(promise \&\&)

Constructs a new promise and transfer any shared state from `rhs`.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `promise &&` |

### promise(promise const \&)

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `promise const &` |

## Operators

### operator=(promise \&\&)

Abandons the shared state in `*this`, if any, and transfers the shared state from `rhs`.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
| `rhs` | `promise &&` |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `promise &` |   |

### operator=(promise const \&)

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `promise const &` |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `promise &` |   |

## Functions

### swap(promise \&)

Swaps the shared state in `*this` with `rhs`.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
| `other` | `promise &` |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `void` |   |

### get_future()

Creates the `future<T>` using the same shared state as `*this`.

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `future< T >` |   |

### set_value(T)

Satisfies the shared state.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
| `value` | `T` |

| **Exceptions** ||
|---|---|
| **Type** | **Description** |
| `std::future_error` | with std::future_errc::promise_already_satisfied if the shared state is already satisfied. |
| `std::future_error` | with std::no_state if the promise does not have a shared state. |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `void` |   |