impl<F: ErrorFormatter> Error<F>

fn raw<impl Display: Display>(kind: ErrorKind, message: impl Display) -> Self

Create an unformatted error

This is for you need to pass the error up to a place that has access to the Command at which point you can call Error::format.

Prefer Command::error for generating errors.

fn format(self: Self, cmd: &mut Command) -> Self

Format the existing message with the Command's context

fn new(kind: ErrorKind) -> Self

Create an error with a pre-defined message

See also

• Error::insert
• Error::with_cmd

Example

# #[cfg(feature = "error-context")] {
# use clap_builder as clap;
# use clap::error::ErrorKind;
# use clap::error::ContextKind;
# use clap::error::ContextValue;

let cmd = clap::Command::new("prog");

let mut err = clap::Error::new(ErrorKind::ValueValidation)
    .with_cmd(&cmd);
err.insert(ContextKind::InvalidArg, ContextValue::String("--foo".to_owned()));
err.insert(ContextKind::InvalidValue, ContextValue::String("bar".to_owned()));

err.print();
# }

fn with_cmd(self: Self, cmd: &Command) -> Self

Apply Command's formatting to the error

Generally, this is used with Error::new

fn apply<EF: ErrorFormatter>(self: Self) -> Error<EF>

Apply an alternative formatter to the error

Example

# use clap_builder as clap;
# use clap::Command;
# use clap::Arg;
# use clap::error::KindFormatter;
let cmd = Command::new("foo")
    .arg(Arg::new("input").required(true));
let matches = cmd
    .try_get_matches_from(["foo", "input.txt"])
    .map_err(|e| e.apply::<KindFormatter>())
    .unwrap_or_else(|e| e.exit());

fn kind(self: &Self) -> ErrorKind

Type of error for programmatic processing

fn context(self: &Self) -> impl Iterator<Item = (ContextKind, &ContextValue)>

Additional information to further qualify the error

fn get(self: &Self, kind: ContextKind) -> Option<&ContextValue>

Lookup a piece of context

fn insert(self: &mut Self, kind: ContextKind, value: ContextValue) -> Option<ContextValue>

Insert a piece of context

fn use_stderr(self: &Self) -> bool

Should the message be written to stdout or not?

fn exit_code(self: &Self) -> i32

Returns the exit code that .exit will exit the process with.

When the error's kind would print to stderr this returns 2, else it returns 0.

fn exit(self: &Self) -> never

Prints the error and exits.

Depending on the error kind, this either prints to stderr and exits with a status of 2 or prints to stdout and exits with a status of 0.

fn print(self: &Self) -> io::Result<()>

Prints formatted and colored error to stdout or stderr according to its error kind

Example

# use clap_builder as clap;
use clap::Command;

match Command::new("Command").try_get_matches() {
    Ok(matches) => {
        // do_something
    },
    Err(err) => {
        err.print().expect("Error writing Error");
        // do_something
    },
};

fn render(self: &Self) -> StyledStr

Render the error message to a StyledStr.

Example

# use clap_builder as clap;
use clap::Command;

match Command::new("Command").try_get_matches() {
    Ok(matches) => {
        // do_something
    },
    Err(err) => {
        let err = err.render();
        println!("{err}");
        // do_something
    },
};

impl<F = RichFormatter> RefUnwindSafe for Error<F>

impl<F = RichFormatter> UnwindSafe for Error<F>

impl<F> Freeze for Error<F>

impl<F> Send for Error<F>

impl<F> Sync for Error<F>

impl<F> Unpin for Error<F>

impl<F: ErrorFormatter> Debug for Error<F>

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

impl<F: ErrorFormatter> Display for Error<F>

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

impl<F: ErrorFormatter> Error for Error<F>

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

impl<F: ErrorFormatter> From for Error<F>

fn from(e: io::Error) -> Self

impl<F: ErrorFormatter> From for Error<F>

fn from(e: fmt::Error) -> Self

impl<T> Any for Error<F>

fn type_id(self: &Self) -> TypeId

impl<T> Borrow for Error<F>

fn borrow(self: &Self) -> &T

impl<T> BorrowMut for Error<F>

fn borrow_mut(self: &mut Self) -> &mut T

impl<T> From for Error<F>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> ToString for Error<F>

fn to_string(self: &Self) -> String

impl<T, U> Into for Error<F>

fn into(self: Self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom for Error<F>

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto for Error<F>

fn try_into(self: Self) -> Result<U, <U as TryFrom<T>>::Error>