🛈 Note: This is pre-release documentation for the upcoming tracing 0.2.0 ecosystem.

For the release documentation, please see docs.rs, instead.

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macro_rules! warn {
    (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => { ... };
    (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => { ... };
    (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => { ... };
    (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => { ... };
    (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => { ... };
    (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => { ... };
    (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => { ... };
    (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => { ... };
    (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => { ... };
    (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => { ... };
    (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => { ... };
    (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => { ... };
    (parent: $parent:expr, $($arg:tt)+) => { ... };
    (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => { ... };
    (target: $target:expr, $($k:ident).+ $($field:tt)* ) => { ... };
    (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => { ... };
    (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => { ... };
    (target: $target:expr, $($arg:tt)+ ) => { ... };
    ({ $($field:tt)+ }, $($arg:tt)+ ) => { ... };
    ($($k:ident).+ = $($field:tt)*) => { ... };
    (?$($k:ident).+ = $($field:tt)*) => { ... };
    (%$($k:ident).+ = $($field:tt)*) => { ... };
    ($($k:ident).+, $($field:tt)*) => { ... };
    (?$($k:ident).+, $($field:tt)*) => { ... };
    (%$($k:ident).+, $($field:tt)*) => { ... };
    (?$($k:ident).+) => { ... };
    (%$($k:ident).+) => { ... };
    ($($k:ident).+) => { ... };
    ($($arg:tt)+) => { ... };
}
Expand description

Constructs an event at the warn level.

This functions similarly to the event! macro. See the top-level documentation for details on the syntax accepted by this macro.

Examples

use tracing::warn;

let warn_description = "Invalid Input";
let input = &[0x27, 0x45];

warn!(?input, warning = warn_description);
warn!(
    target: "input_events",
    warning = warn_description,
    "Received warning for input: {:?}", input,
);