Struct AnErr 

pub struct AnErr<K, const REASON_LEN: usize = 31>
where
    K: Copy + Clone + Debug + PartialEq + Eq,
{
    pub kind: K,
    pub reason: LiteStr<REASON_LEN>,
}

A compact, Copy, zero-allocation error type consisting of a single error kind and a human-readable reason string.

When context is added via context, context_fmt, or the => form of an_err!, the new reason text is appended to the existing reason.

The total is silently truncated to REASON_LEN bytes if necessary.

Fields

kind: K

The error kind.

reason: LiteStr<REASON_LEN>

Accumulated reason string (controlled by REASON_LEN). Can be empty.

Implementations

impl<K, const REASON_LEN: usize> AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

pub fn new(kind: K) -> Self

Creates a new error with the given kind and empty reason.

pub fn with_reason(kind: K, reason: LiteStr<REASON_LEN>) -> Self

Creates a new error with the given kind and reason.

pub fn with_fmt(kind: K, args: Arguments<'_>) -> Self

Creates a new error with the given kind and a formatted reason.

The formatted text is truncated if it exceeds REASON_LEN bytes.

pub fn context(&mut self, new_reason: LiteStr<REASON_LEN>)

Appends context by appending the given reason text to the accumulated reason. Truncates if the total would exceed REASON_LEN bytes.

pub fn context_fmt(&mut self, args: Arguments<'_>)

Appends context using a formatted reason string.

pub fn kind(&self) -> K

Returns the current error kind.

pub fn reason(&self) -> &LiteStr<REASON_LEN>

Returns the accumulated reason.

impl<K, const REASON_LEN: usize> AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

pub fn to_wire_bytes( &self, kind_to_u16: impl Fn(K) -> u16, buf: &mut [u8], ) -> Result<usize, ()>

Serialize this error to a fixed-size byte buffer for transmission.

The provided buffer must be at least Self::wire_size() bytes long. Returns the number of bytes written.

pub const fn wire_size() -> usize

Returns the exact size (in bytes) of the wire representation.

pub fn from_wire_bytes( bytes: &[u8], u16_to_kind: impl Fn(u16) -> Option<K>, ) -> Option<Self>

Deserialize from a wire buffer directly into an AnErr.

Requires a closure that maps the stored u16 back to your concrete K. Returns None on corruption, wrong size, unknown version, or mapping failure.

Trait Implementations

impl<K, const REASON_LEN: usize> Clone for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq + Clone,

fn clone(&self) -> AnErr<K, REASON_LEN>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<K, const REASON_LEN: usize> Copy for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq + Copy,

impl<K, const REASON_LEN: usize> Debug for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

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

Formats the value using the given formatter.

impl<K, const REASON_LEN: usize> Display for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

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

Formats the value using the given formatter.

impl<K, const REASON_LEN: usize> Eq for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq + Eq,

impl<K, const REASON_LEN: usize> Error for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl<K, const REASON_LEN: usize> From<K> for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq,

fn from(kind: K) -> Self

Converts to this type from the input type.

impl<K, const REASON_LEN: usize> PartialEq for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq + PartialEq,

fn eq(&self, other: &AnErr<K, REASON_LEN>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<K, const REASON_LEN: usize> StructuralPartialEq for AnErr<K, REASON_LEN>

where K: Copy + Clone + Debug + PartialEq + Eq + PartialEq,