Enum Error 

#[non_exhaustive]
pub enum Error {
    NoLicense,
    UnknownLicenseType {
        bits: i32,
    },
    RecursionLimit {
        path: String,
        limit: usize,
    },
    Engine {
        code: i32,
        dispid: i32,
    },
    Com {
        hresult: i32,
        dispid: i32,
    },
    UnexpectedType {
        expected: &'static str,
        actual: &'static str,
    },
}

An error from a TestStand™ COM operation.

Every fallible member of the public API returns Result<_, Error> (i.e. rs_teststand::Error). Library code never panics; failures always arrive here.

Engine failures are reported by name where the engine defines one, so a caller is not left decoding a bare number:

use rs_teststand::Error;

// `dispid` names the member that failed; 0 means the failure came from
// outside a member call.
let out_of_memory = Error::Engine { code: -17000, dispid: 0 };
assert_eq!(out_of_memory.code_name(), Some("TS_Err_OutOfMemory"));
assert!(out_of_memory.to_string().contains("TS_Err_OutOfMemory"));

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

NoLicense

The station holds no license.

Raised by Engine::require_license, not by the engine, so that “unlicensed” is reported once and up front rather than as whatever operation later happened to need a license.

UnknownLicenseType

The engine named a license value this build does not know.

A newer engine may define one this crate predates. The number is carried through rather than mapped onto a near neighbour.

Fields

bits: i32

The value the engine reported.

RecursionLimit

A property tree was walked deeper than the caller allowed.

Usually a cycle rather than genuine depth. A live SequenceContext lists ThisContext among its own sub-properties, so it contains itself, and a walk with no limit recurses until the stack is gone. path is where the limit was reached, which is normally enough to see the loop.

Fields

path: String

The lookup path at which the limit was hit.

limit: usize

The limit that was exceeded.

Engine

The engine raised a failure it has a name for.

code is the engine’s own error code, taken from the raised exception rather than the generic COM DISP_E_EXCEPTION wrapper.

Fields

code: i32

The engine error code.

dispid: i32

The dispatch id of the member that failed, or 0 when the failure did not come from a member call.

A bare engine code does not say which call refused, which is the first thing worth knowing; this narrows it to one member.

Com

A COM call failed with a code the engine does not name, a standard Windows HRESULT, or a code newer than the generated table.

Fields

hresult: i32

The 32-bit HRESULT.

dispid: i32

The dispatch id of the member that failed, or 0.

UnexpectedType

A returned value was not the type the wrapper expected, an internal mismatch between the wrapper and the live object model.

Fields

expected: &'static str

The type the wrapper asked for.

actual: &'static str

The type actually returned.

Implementations

impl Error

pub const fn code_name(&self) -> Option<&'static str>

The engine’s name for this error, when it has one.

Returns None for plain Windows HRESULTs and for type mismatches.

pub const fn code(&self) -> Option<i32>

The underlying numeric code, when the failure came from COM.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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 From<ComError> for Error

fn from(error: ComError) -> Self

Converts to this type from the input type.