# [−] [src] Struct log::Metadata

    pub struct Metadata<'a> { /* fields omitted */ }

Metadata about a log message.

# Use

`Metadata` structs are created when users of the library use logging macros.

They are consumed by implementations of the `Log` trait in the `enabled` method.

`Record`s use `Metadata` to determine the log message's severity and target.

Users should use the `log_enabled!` macro in their code to avoid constructing expensive log messages.

# Examples

ⓘThis code runs with edition 2018

    use log::{Record, Level, Metadata};

    struct MyLogger;

    impl log::Log for MyLogger {
        fn enabled(&self, metadata: &Metadata) -> bool {
            metadata.level() <= Level::Info
        }

        fn log(&self, record: &Record) {
            if self.enabled(record.metadata()) {
                println!("{} - {}", record.level(), record.args());
            }
        }
        fn flush(&self) {}
    }

## Implementations

### `impl<'a> Metadata<'a>` [src]

#### `pub fn builder() -> MetadataBuilder<'a>` [src]

Returns a new builder.

#### `pub fn level(&self) -> Level` [src]

The verbosity level of the message.

#### `pub fn target(&self) -> &'a str` [src]

The name of the target of the directive.

## Trait Implementations

### `impl<'a> Clone for Metadata<'a>` [src]

#### `fn clone(&self) -> Metadata<'a>` [src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0 [src]

Performs copy-assignment from `source`. Read more

### `impl<'a> Debug for Metadata<'a>` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl<'a> Eq for Metadata<'a>` [src]

### `impl<'a> Hash for Metadata<'a>` [src]

#### `fn hash<__H: Hasher>(&self, state: &mut __H)` [src]

Feeds this value into the given `Hasher`. Read more

#### `fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,` 1.3.0 [src]

Feeds a slice of this type into the given `Hasher`. Read more

### `impl<'a> Ord for Metadata<'a>` [src]

#### `fn cmp(&self, other: &Metadata<'a>) -> Ordering` [src]

This method returns an `Ordering` between `self` and `other`. Read more

#### `#[must_use]fn max(self, other: Self) -> Self` 1.21.0 [src]

Compares and returns the maximum of two values. Read more

#### `#[must_use]fn min(self, other: Self) -> Self` 1.21.0 [src]

Compares and returns the minimum of two values. Read more

#### `#[must_use]fn clamp(self, min: Self, max: Self) -> Self` [src]

🔬 This is a nightly-only experimental API. (`clamp`)

Restrict a value to a certain interval. Read more

### `impl<'a> PartialEq<Metadata<'a>> for Metadata<'a>` [src]

#### `fn eq(&self, other: &Metadata<'a>) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &Metadata<'a>) -> bool` [src]

This method tests for `!=`.

### `impl<'a> PartialOrd<Metadata<'a>> for Metadata<'a>` [src]

#### `fn partial_cmp(&self, other: &Metadata<'a>) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `fn lt(&self, other: &Metadata<'a>) -> bool` [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `fn le(&self, other: &Metadata<'a>) -> bool` [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `fn gt(&self, other: &Metadata<'a>) -> bool` [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `fn ge(&self, other: &Metadata<'a>) -> bool` [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl<'a> StructuralEq for Metadata<'a>` [src]

### `impl<'a> StructuralPartialEq for Metadata<'a>` [src]

## Auto Trait Implementations

### `impl<'a> Send for Metadata<'a>`

### `impl<'a> Sync for Metadata<'a>`

### `impl<'a> Unpin for Metadata<'a>`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

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

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.