std::try!
[−]
[src]
macro_rules! try { ($expr:expr) => { ... }; }
Helper macro for unwrapping Result
values while returning early with an
error if the value of the expression is Err
. Can only be used in
functions that return Result
because of the early return of Err
that
it provides.
Examples
use std::io; use std::fs::File; use std::io::prelude::*; fn write_to_file_using_try() -> Result<(), io::Error> { let mut file = try!(File::create("my_best_friends.txt")); try!(file.write_all(b"This is a list of my best friends.")); println!("I wrote to the file"); Ok(()) } // This is equivalent to: fn write_to_file_using_match() -> Result<(), io::Error> { let mut file = try!(File::create("my_best_friends.txt")); match file.write_all(b"This is a list of my best friends.") { Ok(_) => (), Err(e) => return Err(e), } println!("I wrote to the file"); Ok(()) }