1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
/// Prints to the standard output.
///
/// Equivalent to the [`println!`] macro except that a newline is not printed at
/// the end of the message.
///
/// Note that stdout is frequently line-buffered by default so it may be
/// necessary to use [`io::stdout().flush()`][flush] to ensure the output is emitted
/// immediately.
///
/// Use `print!` only for the primary output of your program. Use
/// [`eprint!`] instead to print error and progress messages.
///
/// [`println!`]: macro.println.html
/// [flush]: io/trait.Write.html#tymethod.flush
/// [`eprint!`]: macro.eprint.html
///
/// # Panics
///
/// Panics if writing to `io::stdout()` fails.
///
/// # Examples
///
/// ```
/// # async_std::task::block_on(async {
/// #
/// use async_std::io;
/// use async_std::prelude::*;
/// use async_std::print;
///
/// print!("this ").await;
/// print!("will ").await;
/// print!("be ").await;
/// print!("on ").await;
/// print!("the ").await;
/// print!("same ").await;
/// print!("line ").await;
///
/// io::stdout().flush().await.unwrap();
///
/// print!("this string has a newline, why not choose println! instead?\n").await;
///
/// io::stdout().flush().await.unwrap();
/// #
/// # })
/// ```
#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
#[macro_export]
macro_rules! print {
($($arg:tt)*) => ($crate::io::_print(format_args!($($arg)*)))
}
/// Prints to the standard output, with a newline.
///
/// On all platforms, the newline is the LINE FEED character (`\n`/`U+000A`) alone
/// (no additional CARRIAGE RETURN (`\r`/`U+000D`)).
///
/// Use the [`format!`] syntax to write data to the standard output.
/// See [`std::fmt`] for more information.
///
/// Use `println!` only for the primary output of your program. Use
/// [`eprintln!`] instead to print error and progress messages.
///
/// [`format!`]: macro.format.html
/// [`std::fmt`]: https://doc.rust-lang.org/std/fmt/index.html
/// [`eprintln!`]: macro.eprintln.html
/// # Panics
///
/// Panics if writing to `io::stdout` fails.
///
/// # Examples
///
/// ```
/// # async_std::task::block_on(async {
/// #
/// use async_std::println;
///
/// println!().await; // prints just a newline
/// println!("hello there!").await;
/// println!("format {} arguments", "some").await;
/// #
/// # })
/// ```
#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
#[macro_export]
macro_rules! println {
() => ($crate::print!("\n"));
($($arg:tt)*) => (async {
$crate::io::_print(format_args!($($arg)*)).await;
$crate::io::_print(format_args!("\n")).await;
})
}
/// Prints to the standard error.
///
/// Equivalent to the [`print!`] macro, except that output goes to
/// [`io::stderr`] instead of `io::stdout`. See [`print!`] for
/// example usage.
///
/// Use `eprint!` only for error and progress messages. Use `print!`
/// instead for the primary output of your program.
///
/// [`io::stderr`]: io/struct.Stderr.html
/// [`print!`]: macro.print.html
///
/// # Panics
///
/// Panics if writing to `io::stderr` fails.
///
/// # Examples
///
/// ```
/// # async_std::task::block_on(async {
/// #
/// use async_std::eprint;
///
/// eprint!("Error: Could not complete task").await;
/// #
/// # })
/// ```
#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
#[macro_export]
macro_rules! eprint {
($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)))
}
/// Prints to the standard error, with a newline.
///
/// Equivalent to the [`println!`] macro, except that output goes to
/// [`io::stderr`] instead of `io::stdout`. See [`println!`] for
/// example usage.
///
/// Use `eprintln!` only for error and progress messages. Use `println!`
/// instead for the primary output of your program.
///
/// [`io::stderr`]: io/struct.Stderr.html
/// [`println!`]: macro.println.html
///
/// # Panics
///
/// Panics if writing to `io::stderr` fails.
///
/// # Examples
///
/// ```
/// # async_std::task::block_on(async {
/// #
/// use async_std::eprintln;
///
/// eprintln!("Error: Could not complete task").await;
/// #
/// # })
/// ```
#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
#[macro_export]
macro_rules! eprintln {
() => (async { $crate::eprint!("\n").await; });
($($arg:tt)*) => (
async {
$crate::io::_eprint(format_args!($($arg)*)).await;
$crate::io::_eprint(format_args!("\n")).await;
}
);
}
/// Declares task-local values.
///
/// The macro wraps any number of static declarations and makes them task-local. Attributes and
/// visibility modifiers are allowed.
///
/// Each declared value is of the accessor type [`LocalKey`].
///
/// [`LocalKey`]: task/struct.LocalKey.html
///
/// # Examples
///
/// ```
/// #
/// use std::cell::Cell;
///
/// use async_std::prelude::*;
/// use async_std::task;
///
/// task_local! {
/// static VAL: Cell<u32> = Cell::new(5);
/// }
///
/// task::block_on(async {
/// let v = VAL.with(|c| c.get());
/// assert_eq!(v, 5);
/// });
/// ```
#[cfg(feature = "default")]
#[macro_export]
macro_rules! task_local {
() => ();
($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = $init:expr) => (
$(#[$attr])* $vis static $name: $crate::task::LocalKey<$t> = {
#[inline]
fn __init() -> $t {
$init
}
$crate::task::LocalKey {
__init,
__key: ::std::sync::atomic::AtomicU32::new(0),
}
};
);
($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
$crate::task_local!($(#[$attr])* $vis static $name: $t = $init);
$crate::task_local!($($rest)*);
);
}