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> { ... }
}Expand description
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§
1.0.0 · sourcefn write_str(&mut self, s: &str) -> Result<(), Error>
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; in particular, it does not communicate any information about what error occurred. 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§
1.1.0 · sourcefn write_char(&mut self, c: char) -> Result<(), Error>
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");1.0.0 · sourcefn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>
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");