Trait alloc::fmt::Pointer

1.0.0 · source ·
pub trait Pointer {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
Expand description

p formatting.

The Pointer trait should format its output as a memory location. This is commonly presented as hexadecimal.

For more information on formatters, see the module-level documentation.

Examples

Basic usage with &i32:

let x = &42;

let address = format!("{x:p}"); // this produces something like '0x7f06092ac6d0'
Run

Implementing Pointer on a type:

use std::fmt;

struct Length(i32);

impl fmt::Pointer for Length {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // use `as` to convert to a `*const T`, which implements Pointer, which we can use

        let ptr = self as *const Self;
        fmt::Pointer::fmt(&ptr, f)
    }
}

let l = Length(42);

println!("l is in memory here: {l:p}");

let l_ptr = format!("{l:018p}");
assert_eq!(l_ptr.len(), 18);
assert_eq!(&l_ptr[..2], "0x");
Run

Required Methods§

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

Implementors§

1.33.0 · source§

impl<P> Pointer for Pin<P>where
    P: Pointer,

1.4.0 · source§

impl<Ret, T> Pointer for fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

1.4.0 · source§

impl<Ret, T> Pointer for extern "C" fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

1.4.0 · source§

impl<Ret, T> Pointer for extern "C" fn (T₁, T₂, …, Tₙ, ...) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

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impl<Ret, T> Pointer for extern "C-unwind" fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

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impl<Ret, T> Pointer for extern "C-unwind" fn (T₁, T₂, …, Tₙ, ...) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

1.4.0 · source§

impl<Ret, T> Pointer for unsafe fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

1.4.0 · source§

impl<Ret, T> Pointer for unsafe extern "C" fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

1.4.0 · source§

impl<Ret, T> Pointer for unsafe extern "C" fn (T₁, T₂, …, Tₙ, ...) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

source§

impl<Ret, T> Pointer for unsafe extern "C-unwind" fn (T₁, T₂, …, Tₙ) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

source§

impl<Ret, T> Pointer for unsafe extern "C-unwind" fn (T₁, T₂, …, Tₙ, ...) -> Ret

This trait is implemented for function pointers with up to twelve arguments.

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impl<T> Pointer for *const Twhere
    T: ?Sized,

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impl<T> Pointer for *mut Twhere
    T: ?Sized,

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impl<T> Pointer for &Twhere
    T: ?Sized,

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impl<T> Pointer for &mut Twhere
    T: ?Sized,

1.25.0 · source§

impl<T> Pointer for NonNull<T>where
    T: ?Sized,

1.24.0 · source§

impl<T> Pointer for AtomicPtr<T>

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impl<T: ?Sized> Pointer for Rc<T>

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impl<T: ?Sized> Pointer for Arc<T>

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impl<T: ?Sized, A: Allocator> Pointer for Box<T, A>