[−][src]Struct lv2_sys::LV2UI_Request_Value
A feature to request a new parameter value from the host.
Fields
handle: LV2UI_Feature_Handle
Pointer to opaque data which must be passed to request().
request: Option<unsafe extern "C" fn(handle: LV2UI_Feature_Handle, key: LV2_URID, type_: LV2_URID, features: *const *const LV2_Feature) -> LV2UI_Request_Value_Status>
Request a value for a parameter from the host.
This is mainly used by UIs to request values for complex parameters that don't change often, such as file paths, but it may be used to request any parameter value.
This function returns immediately, and the return value indicates whether the host can fulfill the request. The host may notify the plugin about the new parameter value, for example when a file is selected by the user, via the usual mechanism. Typically, the host will send a message to the plugin that sets the new parameter value, and the plugin will notify the UI via a message as usual for any other parameter change.
To provide an appropriate UI, the host can determine details about the parameter from the plugin data as usual. The additional parameters of this function provide support for more advanced use cases, but in the simple common case, the plugin will simply pass the key of the desired parameter and zero for everything else.
@param handle The handle field of this struct.
@param key The URID of the parameter.
@param type The optional type of the value to request. This can be used to request a specific value type for parameters that support several. If non-zero, it must be the URID of an instance of rdfs:Class or rdfs:Datatype.
@param features Additional features for this request, or NULL.
@return A status code which is 0 on success.
Trait Implementations
impl Clone for LV2UI_Request_Value
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fn clone(&self) -> LV2UI_Request_Value
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fn clone_from(&mut self, source: &Self)
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impl Copy for LV2UI_Request_Value
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impl Debug for LV2UI_Request_Value
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Auto Trait Implementations
impl RefUnwindSafe for LV2UI_Request_Value
impl !Send for LV2UI_Request_Value
impl !Sync for LV2UI_Request_Value
impl Unpin for LV2UI_Request_Value
impl UnwindSafe for LV2UI_Request_Value
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,