Trait std::fmt::Debug
[−]
[src]
pub trait Debug {
fn fmt(&self, &mut Formatter) -> Result<(), Error>;
}Format trait for the ? character.
Debug should format the output in a programmer-facing, debugging context.
Generally speaking, you should just derive a Debug implementation.
When used with the alternate format specifier #?, the output is pretty-printed.
For more information on formatters, see the module-level documentation.
This trait can be used with #[derive].
Examples
Deriving an implementation:
fn main() { #[derive(Debug)] struct Point { x: i32, y: i32, } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin); }#[derive(Debug)] struct Point { x: i32, y: i32, } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin);
Manually implementing:
fn main() { use std::fmt; struct Point { x: i32, y: i32, } impl fmt::Debug for Point { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y) } } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin); }use std::fmt; struct Point { x: i32, y: i32, } impl fmt::Debug for Point { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y) } } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:?}", origin);
This outputs:
The origin is: Point { x: 0, y: 0 }
There are a number of debug_* methods on Formatter to help you with manual
implementations, such as debug_struct.
Debug implementations using either derive or the debug builder API
on Formatter support pretty printing using the alternate flag: {:#?}.
Pretty printing with #?:
#[derive(Debug)] struct Point { x: i32, y: i32, } let origin = Point { x: 0, y: 0 }; println!("The origin is: {:#?}", origin);
This outputs:
The origin is: Point {
x: 0,
y: 0
}
Required Methods
Implementors
impl<T> Debug for Wrapping<T> where T: Debugimpl Debug for Decodedimpl Debug for FullDecodedimpl<'a> Debug for Part<'a>impl Debug for Signimpl Debug for Unpackedimpl Debug for Signimpl<'a> Debug for Decimal<'a>impl<'a> Debug for ParseResult<'a>impl Debug for ParseFloatErrorimpl Debug for FloatErrorKindimpl Debug for Big32x40impl Debug for Big8x3impl Debug for Fpimpl Debug for FpCategoryimpl Debug for ParseIntErrorimpl Debug for IntErrorKindimpl<T> Debug for NonZero<T> where T: Zeroable + Debugimpl<Ret> Debug for fn() -> Retimpl<Ret> Debug for extern "C" fn() -> Retimpl<Ret> Debug for unsafe fn() -> Retimpl<Ret> Debug for unsafe extern "C" fn() -> Retimpl<Ret, A> Debug for fn(A) -> Retimpl<Ret, A> Debug for extern "C" fn(A) -> Retimpl<Ret, A> Debug for unsafe fn(A) -> Retimpl<Ret, A> Debug for unsafe extern "C" fn(A) -> Retimpl<Ret, A, B> Debug for fn(A, B) -> Retimpl<Ret, A, B> Debug for extern "C" fn(A, B) -> Retimpl<Ret, A, B> Debug for unsafe fn(A, B) -> Retimpl<Ret, A, B> Debug for unsafe extern "C" fn(A, B) -> Retimpl<Ret, A, B, C> Debug for fn(A, B, C) -> Retimpl<Ret, A, B, C> Debug for extern "C" fn(A, B, C) -> Retimpl<Ret, A, B, C> Debug for unsafe fn(A, B, C) -> Retimpl<Ret, A, B, C> Debug for unsafe extern "C" fn(A, B, C) -> Retimpl<Ret, A, B, C, D> Debug for fn(A, B, C, D) -> Retimpl<Ret, A, B, C, D> Debug for extern "C" fn(A, B, C, D) -> Retimpl<Ret, A, B, C, D> Debug for unsafe fn(A, B, C, D) -> Retimpl<Ret, A, B, C, D> Debug for unsafe extern "C" fn(A, B, C, D) -> Retimpl<Ret, A, B, C, D, E> Debug for fn(A, B, C, D, E) -> Retimpl<Ret, A, B, C, D, E> Debug for extern "C" fn(A, B, C, D, E) -> Retimpl<Ret, A, B, C, D, E> Debug for unsafe fn(A, B, C, D, E) -> Retimpl<Ret, A, B, C, D, E> Debug for unsafe extern "C" fn(A, B, C, D, E) -> Retimpl<Ret, A, B, C, D, E, F> Debug for fn(A, B, C, D, E, F) -> Retimpl<Ret, A, B, C, D, E, F> Debug for extern "C" fn(A, B, C, D, E, F) -> Retimpl<Ret, A, B, C, D, E, F> Debug for unsafe fn(A, B, C, D, E, F) -> Retimpl<Ret, A, B, C, D, E, F> Debug for unsafe extern "C" fn(A, B, C, D, E, F) -> Retimpl<Ret, A, B, C, D, E, F, G> Debug for fn(A, B, C, D, E, F, G) -> Retimpl<Ret, A, B, C, D, E, F, G> Debug for extern "C" fn(A, B, C, D, E, F, G) -> Retimpl<Ret, A, B, C, D, E, F, G> Debug for unsafe fn(A, B, C, D, E, F, G) -> Retimpl<Ret, A, B, C, D, E, F, G> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G) -> Retimpl<Ret, A, B, C, D, E, F, G, H> Debug for fn(A, B, C, D, E, F, G, H) -> Retimpl<Ret, A, B, C, D, E, F, G, H> Debug for extern "C" fn(A, B, C, D, E, F, G, H) -> Retimpl<Ret, A, B, C, D, E, F, G, H> Debug for unsafe fn(A, B, C, D, E, F, G, H) -> Retimpl<Ret, A, B, C, D, E, F, G, H> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G, H) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I> Debug for fn(A, B, C, D, E, F, G, H, I) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I> Debug for extern "C" fn(A, B, C, D, E, F, G, H, I) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I> Debug for unsafe fn(A, B, C, D, E, F, G, H, I) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J> Debug for fn(A, B, C, D, E, F, G, H, I, J) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J> Debug for extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J> Debug for unsafe fn(A, B, C, D, E, F, G, H, I, J) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K> Debug for fn(A, B, C, D, E, F, G, H, I, J, K) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K> Debug for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K> Debug for unsafe fn(A, B, C, D, E, F, G, H, I, J, K) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Debug for fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Debug for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Debug for unsafe fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Retimpl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Debug for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Retimpl Debug for RangeFullimpl<Idx> Debug for Range<Idx> where Idx: Debugimpl<Idx> Debug for RangeFrom<Idx> where Idx: Debugimpl<Idx> Debug for RangeTo<Idx> where Idx: Debugimpl Debug for Orderingimpl Debug for Any + 'staticimpl Debug for Any + 'static + Sendimpl Debug for TypeIdimpl<T> Debug for [T; 0] where T: Debugimpl<T> Debug for [T; 1] where T: Debugimpl<T> Debug for [T; 2] where T: Debugimpl<T> Debug for [T; 3] where T: Debugimpl<T> Debug for [T; 4] where T: Debugimpl<T> Debug for [T; 5] where T: Debugimpl<T> Debug for [T; 6] where T: Debugimpl<T> Debug for [T; 7] where T: Debugimpl<T> Debug for [T; 8] where T: Debugimpl<T> Debug for [T; 9] where T: Debugimpl<T> Debug for [T; 10] where T: Debugimpl<T> Debug for [T; 11] where T: Debugimpl<T> Debug for [T; 12] where T: Debugimpl<T> Debug for [T; 13] where T: Debugimpl<T> Debug for [T; 14] where T: Debugimpl<T> Debug for [T; 15] where T: Debugimpl<T> Debug for [T; 16] where T: Debugimpl<T> Debug for [T; 17] where T: Debugimpl<T> Debug for [T; 18] where T: Debugimpl<T> Debug for [T; 19] where T: Debugimpl<T> Debug for [T; 20] where T: Debugimpl<T> Debug for [T; 21] where T: Debugimpl<T> Debug for [T; 22] where T: Debugimpl<T> Debug for [T; 23] where T: Debugimpl<T> Debug for [T; 24] where T: Debugimpl<T> Debug for [T; 25] where T: Debugimpl<T> Debug for [T; 26] where T: Debugimpl<T> Debug for [T; 27] where T: Debugimpl<T> Debug for [T; 28] where T: Debugimpl<T> Debug for [T; 29] where T: Debugimpl<T> Debug for [T; 30] where T: Debugimpl<T> Debug for [T; 31] where T: Debugimpl<T> Debug for [T; 32] where T: Debugimpl Debug for AtomicUsizeimpl Debug for AtomicIsizeimpl Debug for AtomicBoolimpl<T> Debug for AtomicPtr<T>impl Debug for BorrowStateimpl<T> Debug for Option<T> where T: Debugimpl<T, E> Debug for Result<T, E> where E: Debug, T: Debugimpl Debug for i8x16impl Debug for i16x8impl Debug for i32x4impl Debug for i64x2impl Debug for u8x16impl Debug for u16x8impl Debug for u32x4impl Debug for u64x2impl Debug for f32x4impl Debug for f64x2impl Debug for SearchStepimpl<'a, 'b> Debug for StrSearcher<'a, 'b>impl Debug for StrSearcherImplimpl Debug for EmptyNeedleimpl Debug for TwoWaySearcherimpl Debug for ParseBoolErrorimpl Debug for Utf8Errorimpl Debug for RadixFmt<isize, Radix>impl Debug for isizeimpl Debug for RadixFmt<usize, Radix>impl Debug for usizeimpl Debug for RadixFmt<i8, Radix>impl Debug for i8impl Debug for RadixFmt<u8, Radix>impl Debug for u8impl Debug for RadixFmt<i16, Radix>impl Debug for i16impl Debug for RadixFmt<u16, Radix>impl Debug for u16impl Debug for RadixFmt<i32, Radix>impl Debug for i32impl Debug for RadixFmt<u32, Radix>impl Debug for u32impl Debug for RadixFmt<i64, Radix>impl Debug for i64impl Debug for RadixFmt<u64, Radix>impl Debug for u64impl Debug for Errorimpl<'a> Debug for Arguments<'a>impl<'a, T> Debug for &'a T where T: Debug + ?Sizedimpl<'a, T> Debug for &'a mut T where T: Debug + ?Sizedimpl Debug for boolimpl Debug for strimpl Debug for charimpl Debug for f32impl Debug for f64impl<T> Debug for *const Timpl<T> Debug for *mut Timpl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T8: Debug, T2: Debug, T5: Debug, T11: Debug, T6: Debug, T9: Debug, T4: Debug, T1: Debug, T10: Debug, T0: Debug, T3: Debug, T7: Debugimpl<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T1: Debug, T5: Debug, T9: Debug, T3: Debug, T8: Debug, T11: Debug, T10: Debug, T4: Debug, T7: Debug, T6: Debug, T2: Debugimpl<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T2, T3, T4, T5, T6, T7, T8, T9, T10, T11) where T7: Debug, T8: Debug, T6: Debug, T9: Debug, T5: Debug, T10: Debug, T11: Debug, T2: Debug, T3: Debug, T4: Debugimpl<T3, T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T3, T4, T5, T6, T7, T8, T9, T10, T11) where T7: Debug, T8: Debug, T5: Debug, T11: Debug, T9: Debug, T3: Debug, T6: Debug, T4: Debug, T10: Debugimpl<T4, T5, T6, T7, T8, T9, T10, T11> Debug for (T4, T5, T6, T7, T8, T9, T10, T11) where T10: Debug, T9: Debug, T11: Debug, T6: Debug, T4: Debug, T5: Debug, T7: Debug, T8: Debugimpl<T5, T6, T7, T8, T9, T10, T11> Debug for (T5, T6, T7, T8, T9, T10, T11) where T5: Debug, T8: Debug, T10: Debug, T11: Debug, T6: Debug, T9: Debug, T7: Debugimpl<T6, T7, T8, T9, T10, T11> Debug for (T6, T7, T8, T9, T10, T11) where T7: Debug, T8: Debug, T6: Debug, T9: Debug, T11: Debug, T10: Debugimpl<T7, T8, T9, T10, T11> Debug for (T7, T8, T9, T10, T11) where T9: Debug, T11: Debug, T10: Debug, T7: Debug, T8: Debugimpl<T8, T9, T10, T11> Debug for (T8, T9, T10, T11) where T11: Debug, T9: Debug, T10: Debug, T8: Debugimpl<T9, T10, T11> Debug for (T9, T10, T11) where T11: Debug, T10: Debug, T9: Debugimpl<T10, T11> Debug for (T10, T11) where T11: Debug, T10: Debugimpl<T11> Debug for (T11,) where T11: Debugimpl<T> Debug for [T] where T: Debugimpl Debug for ()impl<T> Debug for PhantomData<T>impl<T> Debug for Cell<T> where T: Copy + Debugimpl<T> Debug for RefCell<T> where T: Debug + ?Sizedimpl<'b, T> Debug for Ref<'b, T> where T: Debug + ?Sizedimpl<'b, T> Debug for RefMut<'b, T> where T: Debug + ?Sizedimpl<T> Debug for Box<T> where T: Debug + ?Sizedimpl<T> Debug for Weak<T> where T: Debug + ?Sizedimpl<T> Debug for Arc<T> where T: Debug + ?Sizedimpl<T> Debug for Rc<T> where T: Debug + ?Sizedimpl<T> Debug for Weak<T> where T: Debug + ?Sizedimpl<T> Debug for BinaryHeap<T> where T: Ord + Debugimpl<K, V> Debug for BTreeMap<K, V> where V: Debug, K: Debugimpl<T> Debug for BTreeSet<T> where T: Debugimpl<'a, B> Debug for Cow<'a, B> where B: Debug + ToOwned + ?Sized, B::Owned: Debugimpl<E> Debug for EnumSet<E> where E: CLike + Debugimpl<A> Debug for LinkedList<A> where A: Debugimpl Debug for FromUtf8Errorimpl Debug for FromUtf16Errorimpl Debug for Stringimpl Debug for ParseErrorimpl<T> Debug for Vec<T> where T: Debugimpl<T> Debug for VecDeque<T> where T: Debugimpl<T> Debug for Bound<T> where T: Debugimpl Debug for Utf16Itemimpl Debug for Threadimpl<K, V, S> Debug for HashMap<K, V, S> where K: Eq + Hash + Debug, V: Debug, S: HashStateimpl<T, S> Debug for HashSet<T, S> where T: Eq + Hash + Debug, S: HashStateimpl Debug for VarErrorimpl Debug for JoinPathsErrorimpl Debug for NulErrorimpl Debug for IntoStringErrorimpl Debug for CStringimpl Debug for CStrimpl Debug for OsStringimpl Debug for OsStrimpl Debug for Permissionsimpl Debug for Fileimpl<R> Debug for BufReader<R> where R: Debugimpl<W: Debug> Debug for IntoInnerError<W>impl<W: Write> Debug for BufWriter<W> where W: Debugimpl<W: Write> Debug for LineWriter<W> where W: Debugimpl<T: Debug> Debug for Cursor<T>impl Debug for Errorimpl Debug for ErrorKindimpl Debug for SeekFromimpl Debug for CharsErrorimpl Debug for IpAddrimpl Debug for Ipv6MulticastScopeimpl Debug for Ipv4Addrimpl Debug for Ipv6Addrimpl Debug for SocketAddrimpl Debug for SocketAddrV4impl Debug for SocketAddrV6impl Debug for TcpStreamimpl Debug for TcpListenerimpl Debug for UdpSocketimpl Debug for AddrParseErrorimpl Debug for Shutdownimpl<'a> Debug for Prefix<'a>impl<'a> Debug for PrefixComponent<'a>impl<'a> Debug for Component<'a>impl Debug for PathBufimpl Debug for Pathimpl<'a> Debug for Display<'a>impl Debug for Commandimpl Debug for ExitStatusimpl Debug for RecvErrorimpl Debug for TryRecvErrorimpl<T> Debug for SendError<T>impl<T> Debug for TrySendError<T>impl Debug for WaitTimeoutResultimpl<T: ?Sized + Debug + 'static> Debug for Mutex<T>impl<T: ?Sized + Debug> Debug for RwLock<T>impl Debug for Durationimpl Debug for SystemTimeErrorimpl Debug for Instantimpl Debug for SystemTimeimpl<T> Debug for PoisonError<T>impl<T> Debug for TryLockError<T>