# Struct ocl::async::FutureGuard [−] [src]

    #[must_use = "futures do nothing unless polled"]
    pub struct FutureGuard<V, G> where
        G: OrderGuard<V>,  { /* fields omitted */ }

A future that resolves to a read or write guard after ensuring that the data being guarded is appropriately locked during the execution of an OpenCL command.

1. Waits until both an exclusive data lock can be obtained and all prerequisite OpenCL commands have completed.
2. Triggers an OpenCL command, remaining locked while the command executes.
3. Returns a guard which provides exclusive (write) or shared (read) access to the locked data.

## Methods

### `impl<V, G> FutureGuard<V, G> where
G: OrderGuard<V>,`
[src]

#### `pub fn set_lock_wait_events<L: Into<EventList>>(&mut self, wait_events: L)`
[src]

Sets an event wait list.

Setting a wait list will cause this `FutureGuard` to wait until contained events have their status set to complete before obtaining a lock on the guarded internal value.

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn ewait_lock<L: Into<EventList>>(self, wait_events: L) -> FutureGuard<V, G>`
[src]

Sets an event wait list.

See `::set_lock_wait_events`.

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn create_lock_event<C: ClContextPtr>(
&mut self,
context: C
) -> OclResult<&Event>`
[src]

Creates an event which will be triggered when a lock is obtained on the guarded internal value.

The returned event can be added to the wait list of subsequent OpenCL commands with the expectation that when all preceding futures are complete, the event will automatically be 'triggered' by having its status set to complete, causing those commands to execute. This can be used to inject host side code in amongst OpenCL commands without thread blocking or extra delays of any kind.

#### `pub fn enew_lock<C, En>(self, context: C, enew: En) -> FutureGuard<V, G> where
C: ClContextPtr,
En: ClNullEventPtr,`
[src]

Creates an event which will be triggered when a lock is obtained on the guarded internal value.

`enew` must be an empty (null) event or event list.

See `::create_lock_event`

## Panics

Panics if there is an error creating the lock event.

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn set_command_wait_event(&mut self, command_event: Event)`
[src]

Sets a command completion wait event.

`command_event` must be an event created by enqueuing an OpenCL command which interacts (reads/writes) with the data associated with this `FutureGuard`.

If the command completion event is specified, this `FutureGuard` will "suffix" itself with an additional future that will wait until the command completes before resolving.

Not specifying a command completion event will cause this `FutureGuard` to resolve into an `OrderGuard` immediately after the lock is obtained (indicated by the optionally created lock event).

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn ewait_command(self, command_event: Event) -> FutureGuard<V, G>`
[src]

Sets a command completion wait event.

See `::set_command_wait_event`.

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn create_release_event<C: ClContextPtr>(
&mut self,
context: C
) -> OclResult<&Event>`
[src]

Creates an event which will be triggered after this future resolves and the ensuing `OrderGuard` is dropped or manually released.

The returned event can be added to the wait list of subsequent OpenCL commands with the expectation that when all preceding futures are complete, the event will automatically be 'triggered' by having its status set to complete, causing those commands to execute. This can be used to inject host side code in amongst OpenCL commands without thread blocking or extra delays of any kind.

#### `pub fn enew_release<C, En>(self, context: C, enew: En) -> FutureGuard<V, G> where
C: ClContextPtr,
En: ClNullEventPtr,`
[src]

Creates an event which will be triggered after this future resolves and the ensuing `OrderGuard` is dropped or manually released.

`enew` must be an empty (null) event or event list.

See `::create_release_event`.

## Panics

Panics if there is an error creating the release event.

[UNSTABLE]: This method may be renamed or otherwise changed at any time.

#### `pub fn lock_event(&self) -> Option<&Event>`
[src]

Returns a reference to the event previously created with `::create_lock_event` or `::enew_lock` which will trigger (be completed) when the wait events are complete and the lock is locked.

#### `pub fn release_event(&self) -> Option<&Event>`
[src]

Returns a reference to the event previously created with `::create_release_event` or `::enew_release` which will trigger (be completed) when a lock is obtained on the guarded internal value.

#### `pub fn wait(self) -> OclResult<G>`
[src]

Blocks the current thread until the OpenCL command is complete and an appropriate lock can be obtained on the underlying data.

#### `pub fn as_ptr(&self) -> *const V`
[src]

Returns a mutable pointer to the data contained within the internal value, bypassing all locks and protections.

## Panics

This future must not have already resolved into a guard.

#### `pub fn as_mut_ptr(&self) -> *mut V`
[src]

Returns a mutable pointer to the data contained within the internal value, bypassing all locks and protections.

## Panics

This future must not have already resolved into a guard.

#### `pub fn order_lock(&self) -> &OrderLock<V>`
[src]

Returns a reference to the `OrderLock` used to create this future.

### `impl<V> FutureGuard<V, ReadGuard<V>>`
[src]

#### `pub fn upgrade_after_command(self) -> FutureGuard<V, WriteGuard<V>>`
[src]

## Trait Implementations

### `impl<V: Debug, G: Debug> Debug for FutureGuard<V, G> where
G: OrderGuard<V>,`
[src]

#### `fn fmt(&self, __arg_0: &mut Formatter) -> Result`
[src]

Formats the value using the given formatter. Read more

### `impl<V, G> Future for FutureGuard<V, G> where
G: OrderGuard<V>,`
[src]

#### `type Item = G`

The type of value that this future will resolved with if it is successful. Read more

#### `type Error = OclError`

The type of error that this future will resolve with if it fails in a normal fashion. Read more

#### `fn poll(&mut self) -> Poll<Self::Item, Self::Error>`
[src]

Query this future to see if its value has become available, registering interest if it is not. Read more

#### `fn wait(self) -> Result<Self::Item, Self::Error>`
[src]

Block the current thread until this future is resolved. Read more

#### `fn map<F, U>(self, f: F) -> Map<Self, F> where
F: FnOnce(Self::Item) -> U,`
[src]

Map this future's result to a different type, returning a new future of the resulting type. Read more

#### `fn map_err<F, E>(self, f: F) -> MapErr<Self, F> where
F: FnOnce(Self::Error) -> E,`
[src]

Map this future's error to a different error, returning a new future. Read more

#### `fn from_err<E>(self) -> FromErr<Self, E> where
E: From<Self::Error>,`
[src]

Map this future's error to any error implementing `From` for this future's `Error`, returning a new future. Read more

#### `fn then<F, B>(self, f: F) -> Then<Self, B, F> where
B: IntoFuture,
F: FnOnce(Result<Self::Item, Self::Error>) -> B,`
[src]

Chain on a computation for when a future finished, passing the result of the future to the provided closure `f`. Read more

#### `fn and_then<F, B>(self, f: F) -> AndThen<Self, B, F> where
B: IntoFuture<Error = Self::Error>,
F: FnOnce(Self::Item) -> B,`
[src]

Execute another future after this one has resolved successfully. Read more

#### `fn or_else<F, B>(self, f: F) -> OrElse<Self, B, F> where
B: IntoFuture<Item = Self::Item>,
F: FnOnce(Self::Error) -> B,`
[src]

Execute another future if this one resolves with an error. Read more

#### `fn select<B>(self, other: B) -> Select<Self, <B as IntoFuture>::Future> where
B: IntoFuture<Item = Self::Item, Error = Self::Error>,`
[src]

Waits for either one of two futures to complete. Read more

#### `fn select2<B>(self, other: B) -> Select2<Self, <B as IntoFuture>::Future> where
B: IntoFuture,`
[src]

Waits for either one of two differently-typed futures to complete. Read more

#### `fn join<B>(self, other: B) -> Join<Self, <B as IntoFuture>::Future> where
B: IntoFuture<Error = Self::Error>,`
[src]

Joins the result of two futures, waiting for them both to complete. Read more

#### `fn join3<B, C>(
self,
b: B,
c: C
) -> Join3<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future> where
B: IntoFuture<Error = Self::Error>,
C: IntoFuture<Error = Self::Error>,`
[src]

Same as `join`, but with more futures.

#### `fn join4<B, C, D>(
self,
b: B,
c: C,
d: D
) -> Join4<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future> where
B: IntoFuture<Error = Self::Error>,
C: IntoFuture<Error = Self::Error>,
D: IntoFuture<Error = Self::Error>,`
[src]

Same as `join`, but with more futures.

#### `fn join5<B, C, D, E>(
self,
b: B,
c: C,
d: D,
e: E
) -> Join5<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future, <E as IntoFuture>::Future> where
B: IntoFuture<Error = Self::Error>,
C: IntoFuture<Error = Self::Error>,
D: IntoFuture<Error = Self::Error>,
E: IntoFuture<Error = Self::Error>,`
[src]

Same as `join`, but with more futures.

#### `fn into_stream(self) -> IntoStream<Self>`
[src]

Convert this future into a single element stream. Read more

#### `fn flatten(self) -> Flatten<Self> where
Self::Item: IntoFuture,
<Self::Item as IntoFuture>::Error: From<Self::Error>,`
[src]

Flatten the execution of this future when the successful result of this future is itself another future. Read more

#### `fn flatten_stream(self) -> FlattenStream<Self> where
Self::Item: Stream,
<Self::Item as Stream>::Error == Self::Error,`
[src]

Flatten the execution of this future when the successful result of this future is a stream. Read more

#### `fn fuse(self) -> Fuse<Self>`
[src]

Fuse a future such that `poll` will never again be called once it has completed. Read more

#### `fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnOnce(&Self::Item),`
[src]

Do something with the item of a future, passing it on. Read more

#### `fn catch_unwind(self) -> CatchUnwind<Self> where
Self: UnwindSafe,`
[src]

Catches unwinding panics while polling the future. Read more

#### `fn shared(self) -> Shared<Self>`
[src]

Create a cloneable handle to this future where all handles will resolve to the same result. Read more

### `impl<V, G> Drop for FutureGuard<V, G> where
G: OrderGuard<V>,`
[src]

#### `fn drop(&mut self)`
[src]

Drops this FutureGuard.

Blocks the current thread until the command associated with this `FutureGuard` (represented by the command completion event) completes. This ensures that the underlying value is not dropped before the command completes (which would cause obvious problems).

## `future_guard_drop_panic` Feature

If the `future_guard_drop_panic` feature is enabled, dropping a `FutureGuard` before it is polled will cause a panic.

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