Trait std::fmt::Write
pub trait Write {
// Required method
fn write_str(&mut self, s: &str) -> Result<(), Error>;
// Provided methods
fn write_char(&mut self, c: char) -> Result<(), Error> { ... }
fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error> { ... }
}A trait for writing or formatting into Unicode-accepting buffers or streams.
This trait only accepts UTF-8–encoded data and is not flushable. If you only want to accept Unicode and you don’t need flushing, you should implement this trait; otherwise you should implement std::io::Write.
Required Methods
fn write_str(&mut self, s: &str) -> Result<(), Error>Writes a string slice into this writer, returning whether the write succeeded.
This method can only succeed if the entire string slice was successfully written, and this method will not return until all data has been written or an error occurs.
Errors
This function will return an instance of std::fmt::Error on error.
The purpose of that error is to abort the formatting operation when the underlying destination encounters some error preventing it from accepting more text; it should generally be propagated rather than handled, at least when implementing formatting traits.
Examples
use std::fmt::{Error, Write};
fn writer<W: Write>(f: &mut W, s: &str) -> Result<(), Error> {
f.write_str(s)
}
let mut buf = String::new();
writer(&mut buf, "hola").unwrap();
assert_eq!(&buf, "hola");Provided Methods
fn write_char(&mut self, c: char) -> Result<(), Error>Writes a char into this writer, returning whether the write succeeded.
A single char may be encoded as more than one byte. This method can only succeed if the entire byte sequence was successfully written, and this method will not return until all data has been written or an error occurs.
Errors
This function will return an instance of Error on error.
Examples
use std::fmt::{Error, Write};
fn writer<W: Write>(f: &mut W, c: char) -> Result<(), Error> {
f.write_char(c)
}
let mut buf = String::new();
writer(&mut buf, 'a').unwrap();
writer(&mut buf, 'b').unwrap();
assert_eq!(&buf, "ab");fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>Glue for usage of the write! macro with implementors of this trait.
This method should generally not be invoked manually, but rather through the write! macro itself.
Errors
This function will return an instance of Error on error. Please see write_str for details.
Examples
use std::fmt::{Error, Write};
fn writer<W: Write>(f: &mut W, s: &str) -> Result<(), Error> {
f.write_fmt(format_args!("{s}"))
}
let mut buf = String::new();
writer(&mut buf, "world").unwrap();
assert_eq!(&buf, "world");Implementors
impl Write for OsStringimpl Write for Stringimpl Write for Formatter<'_>impl<W> Write for &mut W
where
W: Write + ?Sized,© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/fmt/trait.Write.html