Struct fern::FormatCallback
source · [−]pub struct FormatCallback<'a>(_);
Expand description
Callback struct for use within a formatter closure
Callbacks are used for formatting in order to allow usage of
std::fmt
-based formatting without the allocation of the formatted
result which would be required to return it.
Example usage:
fern::Dispatch::new().format(|callback: fern::FormatCallback, message, record| {
callback.finish(format_args!("[{}] {}", record.level(), message))
})
Implementations
sourceimpl<'a> FormatCallback<'a>
impl<'a> FormatCallback<'a>
sourcepub fn finish(self, formatted_message: Arguments<'_>)
pub fn finish(self, formatted_message: Arguments<'_>)
Complete the formatting call that this FormatCallback was created for.
This will call the rest of the logging chain using the given formatted message as the new payload message.
Example usage:
callback.finish(format_args!("[{}] {}", record.level(), message))
See format_args!
.
Auto Trait Implementations
impl<'a> !RefUnwindSafe for FormatCallback<'a>
impl<'a> !Send for FormatCallback<'a>
impl<'a> !Sync for FormatCallback<'a>
impl<'a> Unpin for FormatCallback<'a>
impl<'a> !UnwindSafe for FormatCallback<'a>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more