Struct WallTime 

pub struct WallTime { /* private fields */ }

Wall-clock instant carrying the full EPICS nsec (1 ns precision) on every platform.

Stored as a Duration since the Unix epoch (integer seconds + nanos), so a wire-sourced epicsTimeStamp.nsec survives a store→serve round-trip exactly. std::time::SystemTime is backed by FILETIME on Windows and only resolves to 100 ns, which truncated the low nanosecond digits of an externally supplied timestamp (a PVA PUT, a gateway pass-through, a Q:time:tag nsec split); WallTime keeps integers end-to-end and never truncates. On Linux/macOS SystemTime already holds 1 ns, so this only changes behaviour on Windows.

Implementations

impl WallTime

pub const UNIX_EPOCH: Self

The Unix epoch (1970-01-01T00:00:00Z) — the zero instant.

pub fn now() -> Self

Current wall-clock time from the OS clock.

On Windows the OS clock itself is 100 ns-granular (the same limit C EPICS hits), so “now” loses no precision relative to C; only an externally supplied sub-100 ns nsec would, and that arrives through WallTime::from_unix.

pub fn from_unix(secs: u64, nanos: u32) -> Self

Build from an integer (unix_seconds, nanoseconds) pair. nanos at or above 1e9 carries into seconds, matching Duration::new.

pub fn since_unix_epoch(self) -> Duration

Time elapsed since the Unix epoch as a Duration (1 ns precision).

pub fn unix_secs(self) -> u64

Whole seconds since the Unix epoch.

pub fn subsec_nanos(self) -> u32

Sub-second nanoseconds in 0..1_000_000_000.

pub fn saturating_sub(self, d: Duration) -> Self

This instant minus d, saturating at WallTime::UNIX_EPOCH rather than panicking on underflow.

Trait Implementations

impl Clone for WallTime

fn clone(&self) -> WallTime

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for WallTime

impl Debug for WallTime

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for WallTime

impl From<SystemTime> for WallTime

fn from(t: SystemTime) -> Self

Times before the Unix epoch clamp to WallTime::UNIX_EPOCH (unwrap_or_default), matching the previous duration_since(UNIX_EPOCH).unwrap_or(ZERO) behaviour at the snapshot/codec boundaries.

impl From<WallTime> for SystemTime

fn from(t: WallTime) -> Self

For display/formatting interop (e.g. chrono). On Windows this re-introduces the platform’s 100 ns SystemTime granularity, so use the integer accessors (WallTime::unix_secs / WallTime::subsec_nanos) when the full nsec must be preserved.

impl Hash for WallTime

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for WallTime

fn cmp(&self, other: &WallTime) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for WallTime

fn eq(&self, other: &WallTime) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for WallTime

fn partial_cmp(&self, other: &WallTime) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for WallTime