Stdio in std::process - Rust (original) (raw)
Struct Stdio
1.0.0 · Source
pub struct Stdio(/* private fields */);Expand description
Describes what to do with a standard I/O stream for a child process when passed to the stdin, stdout, and stderr methods of Command.
1.0.0 · Source
A new pipe should be arranged to connect the parent and child processes.
§Examples
With stdout:
use std::process::{Command, Stdio};
let output = Command::new("echo")
.arg("Hello, world!")
.stdout(Stdio::piped())
.output()
.expect("Failed to execute command");
assert_eq!(String::from_utf8_lossy(&output.stdout), "Hello, world!\n");
// Nothing echoed to consoleWith stdin:
use std::io::Write;
use std::process::{Command, Stdio};
let mut child = Command::new("rev")
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.spawn()
.expect("Failed to spawn child process");
let mut stdin = child.stdin.take().expect("Failed to open stdin");
std::thread::spawn(move || {
stdin.write_all("Hello, world!".as_bytes()).expect("Failed to write to stdin");
});
let output = child.wait_with_output().expect("Failed to read stdout");
assert_eq!(String::from_utf8_lossy(&output.stdout), "!dlrow ,olleH");Writing more than a pipe buffer’s worth of input to stdin without also reading stdout and stderr at the same time may cause a deadlock. This is an issue when running any program that doesn’t guarantee that it reads its entire stdin before writing more than a pipe buffer’s worth of output. The size of a pipe buffer varies on different targets.
1.0.0 · Source
The child inherits from the corresponding parent descriptor.
§Examples
With stdout:
use std::process::{Command, Stdio};
let output = Command::new("echo")
.arg("Hello, world!")
.stdout(Stdio::inherit())
.output()
.expect("Failed to execute command");
assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// "Hello, world!" echoed to consoleWith stdin:
use std::process::{Command, Stdio};
use std::io::{self, Write};
let output = Command::new("rev")
.stdin(Stdio::inherit())
.stdout(Stdio::piped())
.output()?;
print!("You piped in the reverse of: ");
io::stdout().write_all(&output.stdout)?;1.0.0 · Source
This stream will be ignored. This is the equivalent of attaching the stream to /dev/null.
§Examples
With stdout:
use std::process::{Command, Stdio};
let output = Command::new("echo")
.arg("Hello, world!")
.stdout(Stdio::null())
.output()
.expect("Failed to execute command");
assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Nothing echoed to consoleWith stdin:
use std::process::{Command, Stdio};
let output = Command::new("rev")
.stdin(Stdio::null())
.stdout(Stdio::piped())
.output()
.expect("Failed to execute command");
assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Ignores any piped-in input🔬This is a nightly-only experimental API. (stdio_makes_pipe #98288)
Returns true if this requires Command to create a new pipe.
§Example
#![feature(stdio_makes_pipe)]
use std::process::Stdio;
let io = Stdio::piped();
assert_eq!(io.makes_pipe(), true);Converts a ChildStderr into a Stdio.
§Examples
use std::process::{Command, Stdio};
let reverse = Command::new("rev")
.arg("non_existing_file.txt")
.stderr(Stdio::piped())
.spawn()
.expect("failed reverse command");
let cat = Command::new("cat")
.arg("-")
.stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
.output()
.expect("failed echo command");
assert_eq!(
String::from_utf8_lossy(&cat.stdout),
"rev: cannot open non_existing_file.txt: No such file or directory\n"
);Converts a ChildStdin into a Stdio.
§Examples
ChildStdin will be converted to Stdio using Stdio::from under the hood.
use std::process::{Command, Stdio};
let reverse = Command::new("rev")
.stdin(Stdio::piped())
.spawn()
.expect("failed reverse command");
let _echo = Command::new("echo")
.arg("Hello, world!")
.stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
.output()
.expect("failed echo command");
// "!dlrow ,olleH" echoed to consoleConverts a ChildStdout into a Stdio.
§Examples
ChildStdout will be converted to Stdio using Stdio::from under the hood.
use std::process::{Command, Stdio};
let hello = Command::new("echo")
.arg("Hello, world!")
.stdout(Stdio::piped())
.spawn()
.expect("failed echo command");
let reverse = Command::new("rev")
.stdin(hello.stdout.unwrap()) // Converted into a Stdio here
.output()
.expect("failed reverse command");
assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");§Examples
File will be converted to Stdio using Stdio::from under the hood.
use std::fs::File;
use std::process::Command;
// With the `foo.txt` file containing "Hello, world!"
let file = File::open("foo.txt")?;
let reverse = Command::new("rev")
.stdin(file) // Implicit File conversion into a Stdio
.output()?;
assert_eq!(reverse.stdout, b"!dlrow ,olleH");Available on Unix only.
Takes ownership of a file descriptor and returns a Stdiothat can attach a stream to it.
Available on Windows only.
Takes ownership of a handle and returns a Stdiothat can attach a stream to it.
Converts to this type from the input type.
Converts to this type from the input type.
Redirect command stdout/stderr to our stderr
§Examples
#![feature(exit_status_error)]
use std::io;
use std::process::Command;
let output = Command::new("whoami")
.stdout(io::stderr())
.output()?;
output.status.exit_ok()?;
assert!(output.stdout.is_empty());Redirect command stdout/stderr to our stdout
§Examples
#![feature(exit_status_error)]
use std::io;
use std::process::Command;
let output = Command::new("whoami")
.stdout(io::stdout())
.output()?;
output.status.exit_ok()?;
assert!(output.stdout.is_empty());Available on Unix only.
Constructs a new instance of Self from the given raw file descriptor. Read more
Available on Windows only.