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

Formats the value using the given formatter.

Implementors

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

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

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

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

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

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