devela::_dep::_std::io

Struct Stdout

1.0.0 · Source
pub struct Stdout { /* private fields */ }
Available on crate feature std only.
Expand description

A handle to the global standard output stream of the current process.

Each handle shares a global buffer of data to be written to the standard output stream. Access is also synchronized via a lock and explicit control over locking is available via the lock method.

Created by the io::stdout method.

§Note: Windows Portability Considerations

When operating in a console, the Windows implementation of this stream does not support non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return an error.

In a process with a detached console, such as one using #![windows_subsystem = "windows"], or in a child process spawned from such a process, the contained handle will be null. In such cases, the standard library’s Read and Write will do nothing and silently succeed. All other I/O operations, via the standard library or via raw Windows API calls, will fail.

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impl Stdout

1.0.0 · Source

pub fn lock(&self) -> StdoutLock<'static>

Locks this handle to the standard output stream, returning a writable guard.

The lock is released when the returned lock goes out of scope. The returned guard also implements the Write trait for writing data.

§Examples
use std::io::{self, Write};

fn main() -> io::Result<()> {
    let mut stdout = io::stdout().lock();

    stdout.write_all(b"hello world")?;

    Ok(())
}

Trait Implementations§

1.63.0 · Source§

impl AsFd for Stdout

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fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor. Read more
1.21.0 · Source§

impl AsRawFd for Stdout

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fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor. Read more
1.16.0 · Source§

impl Debug for Stdout

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

Formats the value using the given formatter. Read more
1.74.0 · Source§

impl From<Stdout> for Stdio

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fn from(inherit: Stdout) -> Stdio

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());
1.70.0 · Source§

impl IsTerminal for Stdout

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fn is_terminal(&self) -> bool

Returns true if the descriptor/handle refers to a terminal/tty. Read more
1.48.0 · Source§

impl Write for &Stdout

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fn write(&mut self, buf: &[u8]) -> Result<usize, Error>

Writes a buffer into this writer, returning how many bytes were written. Read more
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fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
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fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
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fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
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fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered. Read more
1.0.0 · Source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more
1.0.0 · Source§

impl Write for Stdout

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fn write(&mut self, buf: &[u8]) -> Result<usize, Error>

Writes a buffer into this writer, returning how many bytes were written. Read more
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fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Writer has an efficient write_vectored implementation. Read more
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fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
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fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)
Attempts to write multiple buffers into this writer. Read more
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fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered. Read more
1.0.0 · Source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more
1.9.0 · Source§

impl RefUnwindSafe for Stdout

1.9.0 · Source§

impl UnwindSafe for Stdout

Auto Trait Implementations§

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impl Freeze for Stdout

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impl Send for Stdout

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impl Sync for Stdout

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impl Unpin for Stdout

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> ArchivePointee for T

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type ArchivedMetadata = ()

The archived version of the pointer metadata for this type.
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fn pointer_metadata( _: &<T as ArchivePointee>::ArchivedMetadata, ) -> <T as Pointee>::Metadata

Converts some archived metadata to the pointer metadata for itself.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> ByteSized for T

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const BYTE_ALIGN: usize = _

The alignment of this type in bytes.
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const BYTE_SIZE: usize = _

The size of this type in bytes.
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fn byte_align(&self) -> usize

Returns the alignment of this type in bytes.
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fn byte_size(&self) -> usize

Returns the size of this type in bytes. Read more
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fn ptr_size_ratio(&self) -> [usize; 2]

Returns the size ratio between Ptr::BYTES and BYTE_SIZE. Read more
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impl<T, R> Chain<R> for T
where T: ?Sized,

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fn chain<F>(self, f: F) -> R
where F: FnOnce(Self) -> R, Self: Sized,

Chain a function which takes the parameter by value.
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fn chain_ref<F>(&self, f: F) -> R
where F: FnOnce(&Self) -> R,

Chain a function which takes the parameter by shared reference.
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fn chain_mut<F>(&mut self, f: F) -> R
where F: FnOnce(&mut Self) -> R,

Chain a function which takes the parameter by exclusive reference.
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impl<T> ExecutableCommand for T
where T: Write + ?Sized,

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fn execute(&mut self, command: impl Command) -> Result<&mut T, Error>

Executes the given command directly.

The given command its ANSI escape code will be written and flushed onto Self.

§Arguments
  • Command

    The command that you want to execute directly.

§Example
use std::io;
use crossterm::{ExecutableCommand, style::Print};

fn main() -> io::Result<()> {
     // will be executed directly
      io::stdout()
        .execute(Print("sum:\n".to_string()))?
        .execute(Print(format!("1 + 1= {} ", 1 + 1)))?;

      Ok(())

     // ==== Output ====
     // sum:
     // 1 + 1 = 2
}

Have a look over at the Command API for more details.

§Notes
  • In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
  • In case of Windows versions lower than 10, a direct WinAPI call will be made. The reason for this is that Windows versions lower than 10 do not support ANSI codes, and can therefore not be written to the given writer. Therefore, there is no difference between execute and queue for those old Windows versions.
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impl<T> ExtAny for T
where T: Any + ?Sized,

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fn type_id() -> TypeId

Returns the TypeId of Self. Read more
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fn type_of(&self) -> TypeId

Returns the TypeId of self. Read more
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fn type_name(&self) -> &'static str

Returns the type name of self. Read more
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fn type_is<T: 'static>(&self) -> bool

Returns true if Self is of type T. Read more
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fn as_any_ref(&self) -> &dyn Any
where Self: Sized,

Upcasts &self as &dyn Any. Read more
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fn as_any_mut(&mut self) -> &mut dyn Any
where Self: Sized,

Upcasts &mut self as &mut dyn Any. Read more
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fn as_any_box(self: Box<Self>) -> Box<dyn Any>
where Self: Sized,

Upcasts Box<self> as Box<dyn Any>. Read more
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fn downcast_ref<T: 'static>(&self) -> Option<&T>

Available on crate feature unsafe_layout only.
Returns some shared reference to the inner value if it is of type T. Read more
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fn downcast_mut<T: 'static>(&mut self) -> Option<&mut T>

Available on crate feature unsafe_layout only.
Returns some exclusive reference to the inner value if it is of type T. Read more
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impl<T> ExtMem for T
where T: ?Sized,

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const NEEDS_DROP: bool = _

Know whether dropping values of this type matters, in compile-time.
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fn mem_align_of<T>() -> usize

Returns the minimum alignment of the type in bytes. Read more
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fn mem_align_of_val(&self) -> usize

Returns the alignment of the pointed-to value in bytes. Read more
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fn mem_size_of<T>() -> usize

Returns the size of a type in bytes. Read more
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fn mem_size_of_val(&self) -> usize

Returns the size of the pointed-to value in bytes. Read more
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fn mem_copy(&self) -> Self
where Self: Copy,

Bitwise-copies a value. Read more
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fn mem_needs_drop(&self) -> bool

Returns true if dropping values of this type matters. Read more
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fn mem_drop(self)
where Self: Sized,

Drops self by running its destructor. Read more
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fn mem_forget(self)
where Self: Sized,

Forgets about self without running its destructor. Read more
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fn mem_replace(&mut self, other: Self) -> Self
where Self: Sized,

Replaces self with other, returning the previous value of self. Read more
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fn mem_take(&mut self) -> Self
where Self: Default,

Replaces self with its default value, returning the previous value of self. Read more
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fn mem_swap(&mut self, other: &mut Self)
where Self: Sized,

Swaps the value of self and other without deinitializing either one. Read more
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unsafe fn mem_zeroed<T>() -> T

Available on crate feature unsafe_layout only.
Returns the value of type T represented by the all-zero byte-pattern. Read more
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unsafe fn mem_transmute_copy<Src, Dst>(src: &Src) -> Dst

Available on crate feature unsafe_layout only.
Returns the value of type T represented by the all-zero byte-pattern. Read more
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fn mem_as_bytes(&self) -> &[u8]
where Self: Sync + Unpin,

Available on crate feature unsafe_slice only.
View a Sync + Unpin self as &[u8]. Read more
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fn mem_as_bytes_mut(&mut self) -> &mut [u8]
where Self: Sync + Unpin,

Available on crate feature unsafe_slice only.
View a Sync + Unpin self as &mut [u8]. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<S> FromSample<S> for S

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fn from_sample_(s: S) -> S

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impl<T> Hook for T

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fn hook_ref<F>(self, f: F) -> Self
where F: FnOnce(&Self),

Applies a function which takes the parameter by shared reference, and then returns the (possibly) modified owned value. Read more
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fn hook_mut<F>(self, f: F) -> Self
where F: FnOnce(&mut Self),

Applies a function which takes the parameter by exclusive reference, and then returns the (possibly) modified owned value. Read more
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<F, T> IntoSample<T> for F
where T: FromSample<F>,

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fn into_sample(self) -> T

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impl<S> IsTty for S
where S: AsRawFd,

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fn is_tty(&self) -> bool

Returns true when an instance is a terminal teletype, otherwise false.
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impl<T> LayoutRaw for T

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fn layout_raw(_: <T as Pointee>::Metadata) -> Result<Layout, LayoutError>

Returns the layout of the type.
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impl<T, N1, N2> Niching<NichedOption<T, N1>> for N2
where T: SharedNiching<N1, N2>, N1: Niching<T>, N2: Niching<T>,

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unsafe fn is_niched(niched: *const NichedOption<T, N1>) -> bool

Returns whether the given value has been niched. Read more
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fn resolve_niched(out: Place<NichedOption<T, N1>>)

Writes data to out indicating that a T is niched.
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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Pointee for T

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type Metadata = ()

The metadata type for pointers and references to this type.
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impl<T> QueueableCommand for T
where T: Write + ?Sized,

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fn queue(&mut self, command: impl Command) -> Result<&mut T, Error>

Queues the given command for further execution.

Queued commands will be executed in the following cases:

  • When flush is called manually on the given type implementing io::Write.
  • The terminal will flush automatically if the buffer is full.
  • Each line is flushed in case of stdout, because it is line buffered.
§Arguments
  • Command

    The command that you want to queue for later execution.

§Examples
use std::io::{self, Write};
use crossterm::{QueueableCommand, style::Print};

 fn main() -> io::Result<()> {
    let mut stdout = io::stdout();

    // `Print` will executed executed when `flush` is called.
    stdout
        .queue(Print("foo 1\n".to_string()))?
        .queue(Print("foo 2".to_string()))?;

    // some other code (no execution happening here) ...

    // when calling `flush` on `stdout`, all commands will be written to the stdout and therefore executed.
    stdout.flush()?;

    Ok(())

    // ==== Output ====
    // foo 1
    // foo 2
}

Have a look over at the Command API for more details.

§Notes
  • In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
  • In case of Windows versions lower than 10, a direct WinAPI call will be made. The reason for this is that Windows versions lower than 10 do not support ANSI codes, and can therefore not be written to the given writer. Therefore, there is no difference between execute and queue for those old Windows versions.
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impl<W> SynchronizedUpdate for W
where W: Write + ?Sized,

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fn sync_update<T>( &mut self, operations: impl FnOnce(&mut W) -> T, ) -> Result<T, Error>

Performs a set of actions within a synchronous update.

Updates will be suspended in the terminal, the function will be executed against self, updates will be resumed, and a flush will be performed.

§Arguments
  • Function

    A function that performs the operations that must execute in a synchronized update.

§Examples
use std::io;
use crossterm::{ExecutableCommand, SynchronizedUpdate, style::Print};

fn main() -> io::Result<()> {
    let mut stdout = io::stdout();

    stdout.sync_update(|stdout| {
        stdout.execute(Print("foo 1\n".to_string()))?;
        stdout.execute(Print("foo 2".to_string()))?;
        // The effects of the print command will not be present in the terminal
        // buffer, but not visible in the terminal.
        std::io::Result::Ok(())
    })?;

    // The effects of the commands will be visible.

    Ok(())

    // ==== Output ====
    // foo 1
    // foo 2
}
§Notes

This command is performed only using ANSI codes, and will do nothing on terminals that do not support ANSI codes, or this specific extension.

When rendering the screen of the terminal, the Emulator usually iterates through each visible grid cell and renders its current state. With applications updating the screen a at higher frequency this can cause tearing.

This mode attempts to mitigate that.

When the synchronization mode is enabled following render calls will keep rendering the last rendered state. The terminal Emulator keeps processing incoming text and sequences. When the synchronized update mode is disabled again the renderer may fetch the latest screen buffer state again, effectively avoiding the tearing effect by unintentionally rendering in the middle a of an application screen update.

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impl<T, U> ToSample<U> for T
where U: FromSample<T>,

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fn to_sample_(self) -> U

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<S, T> Duplex<S> for T
where T: FromSample<S> + ToSample<S>,

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impl<T> Ungil for T
where T: Send,