Primitive Type unit
Expand description
The ()
type, also called “unit”.
The ()
type has exactly one value ()
, and is used when there
is no other meaningful value that could be returned. ()
is most
commonly seen implicitly: functions without a -> ...
implicitly
have return type ()
, that is, these are equivalent:
The semicolon ;
can be used to discard the result of an
expression at the end of a block, making the expression (and thus
the block) evaluate to ()
. For example,
Trait Implementations§
1.28.0 · source§impl Extend<()> for ()
impl Extend<()> for ()
1.23.0 · source§impl FromIterator<()> for ()
impl FromIterator<()> for ()
Collapses all unit items from an iterator into one.
This is more useful when combined with higher-level abstractions, like
collecting to a Result<(), E>
where you only care about errors:
1.6.0 · source§impl Ord for ()
impl Ord for ()
1.6.0 · source§impl PartialOrd for ()
impl PartialOrd for ()
impl ConstParamTy_ for ()
impl Eq for ()
impl StructuralPartialEq for ()
impl UnsizedConstParamTy for ()
Auto Trait Implementations§
impl Freeze for ()
impl RefUnwindSafe for ()
impl Send for ()
impl Sync for ()
impl Unpin for ()
impl UnwindSafe for ()
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more