Struct rand::Error

pub struct Error { /* fields omitted */ }

Error type of random number generators

In order to be compatible with std and no_std, this type has two possible implementations: with std a boxed Error trait object is stored, while with no_std we merely store an error code.

Implementations

impl Error

pub const CUSTOM_START: u32

Codes at or above this point can be used by users to define their own custom errors.

This has a fixed value of (1 << 31) + (1 << 30) = 0xC000_0000, therefore the number of values available for custom codes is 1 << 30.

This is identical to getrandom::Error::CUSTOM_START.

pub const INTERNAL_START: u32

Codes below this point represent OS Errors (i.e. positive i32 values). Codes at or above this point, but below Error::CUSTOM_START are reserved for use by the rand and getrandom crates.

This is identical to getrandom::Error::INTERNAL_START.

pub fn new<E>(err: E) -> Error where
    E: Into<Box<dyn Error + 'static + Sync + Send, Global>>, 

Construct from any type supporting std::error::Error

Available only when configured with std.

See also From<NonZeroU32>, which is available with and without std.

pub fn inner(&self) -> &(dyn Error + 'static + Sync + Send)

Reference the inner error (std only)

When configured with std, this is a trivial operation and never panics. Without std, this method is simply unavailable.

pub fn take_inner(self) -> Box<dyn Error + 'static + Sync + Send, Global>

Unwrap the inner error (std only)

When configured with std, this is a trivial operation and never panics. Without std, this method is simply unavailable.

pub fn raw_os_error(&self) -> Option<i32>

Extract the raw OS error code (if this error came from the OS)

This method is identical to std::io::Error::raw_os_error(), except that it works in no_std contexts. If this method returns None, the error value can still be formatted via the Diplay implementation.

pub fn code(&self) -> Option<NonZeroU32>

Retrieve the error code, if any.

If this Error was constructed via From<NonZeroU32>, then this method will return this NonZeroU32 code (for no_std this is always the case). Otherwise, this method will return None.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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

The lower-level source of this error, if any.

pub fn backtrace(&self) -> Option<&Backtrace>

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

Returns a stack backtrace, if available, of where this error occurred.

pub fn description(&self) -> &str

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

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

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

impl From<Error> for Error

pub fn from(error: Error) -> Error

Performs the conversion.

impl From<NonZeroU32> for Error

pub fn from(code: NonZeroU32) -> Error

Performs the conversion.