Struct std::fmt::Arguments

pub struct Arguments<'a> { /* fields omitted */ }

This structure represents a safely precompiled version of a format string and its arguments. This cannot be generated at runtime because it cannot safely be done, so no constructors are given and the fields are private to prevent modification.

The format_args! macro will safely create an instance of this structure and pass it to a function or closure, passed as the first argument. The macro validates the format string at compile-time so usage of the write and format functions can be safely performed.

You can use the Arguments<'a> that format_args! returns in Debug and Display contexts as seen below. The example also shows that Debug and Display format to the same thing: the interpolated format string in format_args!.

let display = format!("{:?}", format_args!("{} foo {:?}", 1, 2));
let debug = format!("{}", format_args!("{} foo {:?}", 1, 2));
assert_eq!("1 foo 2", display);
assert_eq!(display, debug);

Trait Implementations

impl<'a> Copy for Arguments<'a>

impl<'a> Debug for Arguments<'a>

fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> Display for Arguments<'a>

fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> Clone for Arguments<'a>

fn clone(&self) -> Arguments<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.