Struct Pv 

pub struct Pv(/* private fields */);

A handle to a live PV. Cheap to clone.

Implementations

impl Pv

pub fn name(&self) -> &PvName

pub fn dropped(&self) -> bool

Whether the PV connected once and has since lost its connection. A write to it is refused at once; one to a PV that has yet to connect is queued.

pub fn state(&self) -> PvState

The latest value, alarm and metadata.

pub fn connected(&self) -> bool

Whether it is connected, without copying its state.

pub fn version(&self) -> u64

A number that changes whenever its state does (bar read-only mode), so a caller can skip work on a PV that has not changed.

pub fn listen(&self, listener: &Listener)

Call listener with the current state now and with each change after, until the caller drops it: unlike Pv::state read once a frame, this sees every monitor update.

pub fn write(&self, value: impl Into<String>)

Write a value given as text; the backend converts it to the PV’s type.

pub fn write_long_string(&self, value: impl Into<String>)

Write text as Phoebus does for a widget whose format is string: into a char array as a long string (see long_string_bytes). Any other PV is written as by Pv::write.

Over CA, as in Phoebus, a char array is a DBF_CHAR channel of more than one element, and the text is cut to that element count with its NUL kept. Over PVA and loc:// it is any array of numbers. A PVA array has no fixed element count to cut to, so an IOC that stores only its first NELM elements may lose the NUL (and part of a multi-byte character), as it does with Phoebus.

Trait Implementations

impl Clone for Pv

fn clone(&self) -> Pv

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.