Struct std::net::Ipv4Addr

pub struct Ipv4Addr { /* private fields */ }

An IPv4 address.

IPv4 addresses are defined as 32-bit integers in IETF RFC 791. They are usually represented as four octets.

See IpAddr for a type encompassing both IPv4 and IPv6 addresses.

Textual representation

Ipv4Addr provides a FromStr implementation. The four octets are in decimal notation, divided by . (this is called “dot-decimal notation”). Notably, octal numbers (which are indicated with a leading 0) and hexadecimal numbers (which are indicated with a leading 0x) are not allowed per IETF RFC 6943.

Examples

use std::net::Ipv4Addr;

let localhost = Ipv4Addr::new(127, 0, 0, 1);
assert_eq!("127.0.0.1".parse(), Ok(localhost));
assert_eq!(localhost.is_loopback(), true);
assert!("012.004.002.000".parse::<Ipv4Addr>().is_err()); // all octets are in octal
assert!("0000000.0.0.0".parse::<Ipv4Addr>().is_err()); // first octet is a zero in octal
assert!("0xcb.0x0.0x71.0x00".parse::<Ipv4Addr>().is_err()); // all octets are in hex

Implementations

impl Ipv4Addr

pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr

Creates a new IPv4 address from four eight-bit octets.

The result will represent the IP address a.b.c.d.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(127, 0, 0, 1);

pub const BITS: u32 = 32u32

🔬This is a nightly-only experimental API. (ip_bits #113744)

The size of an IPv4 address in bits.

Examples

#![feature(ip_bits)]
use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::BITS, 32);

pub fn to_bits(self) -> u32

🔬This is a nightly-only experimental API. (ip_bits #113744)

Converts an IPv4 address into a u32 representation using native byte order.

Although IPv4 addresses are big-endian, the u32 value will use the target platform’s native byte order. That is, the u32 value is an integer representation of the IPv4 address and not an integer interpretation of the IPv4 address’s big-endian bitstring. This means that the u32 value masked with 0xffffff00 will set the last octet in the address to 0, regardless of the target platform’s endianness.

Examples

#![feature(ip_bits)]
use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(0x12, 0x34, 0x56, 0x78);
assert_eq!(0x12345678, addr.to_bits());

#![feature(ip_bits)]
use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(0x12, 0x34, 0x56, 0x78);
let addr_bits = addr.to_bits() & 0xffffff00;
assert_eq!(Ipv4Addr::new(0x12, 0x34, 0x56, 0x00), Ipv4Addr::from_bits(addr_bits));

pub fn from_bits(bits: u32) -> Ipv4Addr

🔬This is a nightly-only experimental API. (ip_bits #113744)

Converts a native byte order u32 into an IPv4 address.

See Ipv4Addr::to_bits for an explanation on endianness.

Examples

#![feature(ip_bits)]
use std::net::Ipv4Addr;

let addr = Ipv4Addr::from(0x12345678);
assert_eq!(Ipv4Addr::new(0x12, 0x34, 0x56, 0x78), addr);

pub const LOCALHOST: Ipv4Addr = _

An IPv4 address with the address pointing to localhost: 127.0.0.1

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::LOCALHOST;
assert_eq!(addr, Ipv4Addr::new(127, 0, 0, 1));

pub const UNSPECIFIED: Ipv4Addr = _

An IPv4 address representing an unspecified address: 0.0.0.0

This corresponds to the constant INADDR_ANY in other languages.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::UNSPECIFIED;
assert_eq!(addr, Ipv4Addr::new(0, 0, 0, 0));

pub const BROADCAST: Ipv4Addr = _

An IPv4 address representing the broadcast address: 255.255.255.255

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::BROADCAST;
assert_eq!(addr, Ipv4Addr::new(255, 255, 255, 255));

pub const fn octets(&self) -> [u8; 4]

Returns the four eight-bit integers that make up this address.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(127, 0, 0, 1);
assert_eq!(addr.octets(), [127, 0, 0, 1]);

pub const fn is_unspecified(&self) -> bool

Returns true for the special ‘unspecified’ address (0.0.0.0).

This property is defined in UNIX Network Programming, Second Edition, W. Richard Stevens, p. 891; see also ip7.

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(0, 0, 0, 0).is_unspecified(), true);
assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_unspecified(), false);

pub const fn is_loopback(&self) -> bool

Returns true if this is a loopback address (127.0.0.0/8).

This property is defined by IETF RFC 1122.

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(127, 0, 0, 1).is_loopback(), true);
assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_loopback(), false);

pub const fn is_private(&self) -> bool

Returns true if this is a private address.

The private address ranges are defined in IETF RFC 1918 and include:

• 10.0.0.0/8
• 172.16.0.0/12
• 192.168.0.0/16

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(10, 0, 0, 1).is_private(), true);
assert_eq!(Ipv4Addr::new(10, 10, 10, 10).is_private(), true);
assert_eq!(Ipv4Addr::new(172, 16, 10, 10).is_private(), true);
assert_eq!(Ipv4Addr::new(172, 29, 45, 14).is_private(), true);
assert_eq!(Ipv4Addr::new(172, 32, 0, 2).is_private(), false);
assert_eq!(Ipv4Addr::new(192, 168, 0, 2).is_private(), true);
assert_eq!(Ipv4Addr::new(192, 169, 0, 2).is_private(), false);

pub const fn is_link_local(&self) -> bool

Returns true if the address is link-local (169.254.0.0/16).

This property is defined by IETF RFC 3927.

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(169, 254, 0, 0).is_link_local(), true);
assert_eq!(Ipv4Addr::new(169, 254, 10, 65).is_link_local(), true);
assert_eq!(Ipv4Addr::new(16, 89, 10, 65).is_link_local(), false);

pub fn is_global(&self) -> bool

🔬This is a nightly-only experimental API. (ip #27709)

Returns true if the address appears to be globally reachable as specified by the IANA IPv4 Special-Purpose Address Registry. Whether or not an address is practically reachable will depend on your network configuration.

Most IPv4 addresses are globally reachable; unless they are specifically defined as not globally reachable.

Non-exhaustive list of notable addresses that are not globally reachable:

• The unspecified address (is_unspecified)
• Addresses reserved for private use (is_private)
• Addresses in the shared address space (is_shared)
• Loopback addresses (is_loopback)
• Link-local addresses (is_link_local)
• Addresses reserved for documentation (is_documentation)
• Addresses reserved for benchmarking (is_benchmarking)
• Reserved addresses (is_reserved)
• The broadcast address (is_broadcast)

For the complete overview of which addresses are globally reachable, see the table at the IANA IPv4 Special-Purpose Address Registry.

Examples

#![feature(ip)]

use std::net::Ipv4Addr;

// Most IPv4 addresses are globally reachable:
assert_eq!(Ipv4Addr::new(80, 9, 12, 3).is_global(), true);

// However some addresses have been assigned a special meaning
// that makes them not globally reachable. Some examples are:

// The unspecified address (`0.0.0.0`)
assert_eq!(Ipv4Addr::UNSPECIFIED.is_global(), false);

// Addresses reserved for private use (`10.0.0.0/8`, `172.16.0.0/12`, 192.168.0.0/16)
assert_eq!(Ipv4Addr::new(10, 254, 0, 0).is_global(), false);
assert_eq!(Ipv4Addr::new(192, 168, 10, 65).is_global(), false);
assert_eq!(Ipv4Addr::new(172, 16, 10, 65).is_global(), false);

// Addresses in the shared address space (`100.64.0.0/10`)
assert_eq!(Ipv4Addr::new(100, 100, 0, 0).is_global(), false);

// The loopback addresses (`127.0.0.0/8`)
assert_eq!(Ipv4Addr::LOCALHOST.is_global(), false);

// Link-local addresses (`169.254.0.0/16`)
assert_eq!(Ipv4Addr::new(169, 254, 45, 1).is_global(), false);

// Addresses reserved for documentation (`192.0.2.0/24`, `198.51.100.0/24`, `203.0.113.0/24`)
assert_eq!(Ipv4Addr::new(192, 0, 2, 255).is_global(), false);
assert_eq!(Ipv4Addr::new(198, 51, 100, 65).is_global(), false);
assert_eq!(Ipv4Addr::new(203, 0, 113, 6).is_global(), false);

// Addresses reserved for benchmarking (`198.18.0.0/15`)
assert_eq!(Ipv4Addr::new(198, 18, 0, 0).is_global(), false);

// Reserved addresses (`240.0.0.0/4`)
assert_eq!(Ipv4Addr::new(250, 10, 20, 30).is_global(), false);

// The broadcast address (`255.255.255.255`)
assert_eq!(Ipv4Addr::BROADCAST.is_global(), false);

// For a complete overview see the IANA IPv4 Special-Purpose Address Registry.

pub fn is_shared(&self) -> bool

🔬This is a nightly-only experimental API. (ip #27709)

Returns true if this address is part of the Shared Address Space defined in IETF RFC 6598 (100.64.0.0/10).

Examples

#![feature(ip)]
use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(100, 64, 0, 0).is_shared(), true);
assert_eq!(Ipv4Addr::new(100, 127, 255, 255).is_shared(), true);
assert_eq!(Ipv4Addr::new(100, 128, 0, 0).is_shared(), false);

pub fn is_benchmarking(&self) -> bool

🔬This is a nightly-only experimental API. (ip #27709)

Returns true if this address part of the 198.18.0.0/15 range, which is reserved for network devices benchmarking. This range is defined in IETF RFC 2544 as 192.18.0.0 through 198.19.255.255 but errata 423 corrects it to 198.18.0.0/15.

Examples

#![feature(ip)]
use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(198, 17, 255, 255).is_benchmarking(), false);
assert_eq!(Ipv4Addr::new(198, 18, 0, 0).is_benchmarking(), true);
assert_eq!(Ipv4Addr::new(198, 19, 255, 255).is_benchmarking(), true);
assert_eq!(Ipv4Addr::new(198, 20, 0, 0).is_benchmarking(), false);

pub fn is_reserved(&self) -> bool

🔬This is a nightly-only experimental API. (ip #27709)

Returns true if this address is reserved by IANA for future use. IETF RFC 1112 defines the block of reserved addresses as 240.0.0.0/4. This range normally includes the broadcast address 255.255.255.255, but this implementation explicitly excludes it, since it is obviously not reserved for future use.

Warning

As IANA assigns new addresses, this method will be updated. This may result in non-reserved addresses being treated as reserved in code that relies on an outdated version of this method.

Examples

#![feature(ip)]
use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(240, 0, 0, 0).is_reserved(), true);
assert_eq!(Ipv4Addr::new(255, 255, 255, 254).is_reserved(), true);

assert_eq!(Ipv4Addr::new(239, 255, 255, 255).is_reserved(), false);
// The broadcast address is not considered as reserved for future use by this implementation
assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_reserved(), false);

pub const fn is_multicast(&self) -> bool

Returns true if this is a multicast address (224.0.0.0/4).

Multicast addresses have a most significant octet between 224 and 239, and is defined by IETF RFC 5771.

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(224, 254, 0, 0).is_multicast(), true);
assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_multicast(), true);
assert_eq!(Ipv4Addr::new(172, 16, 10, 65).is_multicast(), false);

pub const fn is_broadcast(&self) -> bool

Returns true if this is a broadcast address (255.255.255.255).

A broadcast address has all octets set to 255 as defined in IETF RFC 919.

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(255, 255, 255, 255).is_broadcast(), true);
assert_eq!(Ipv4Addr::new(236, 168, 10, 65).is_broadcast(), false);

pub const fn is_documentation(&self) -> bool

Returns true if this address is in a range designated for documentation.

This is defined in IETF RFC 5737:

• 192.0.2.0/24 (TEST-NET-1)
• 198.51.100.0/24 (TEST-NET-2)
• 203.0.113.0/24 (TEST-NET-3)

Examples

use std::net::Ipv4Addr;

assert_eq!(Ipv4Addr::new(192, 0, 2, 255).is_documentation(), true);
assert_eq!(Ipv4Addr::new(198, 51, 100, 65).is_documentation(), true);
assert_eq!(Ipv4Addr::new(203, 0, 113, 6).is_documentation(), true);
assert_eq!(Ipv4Addr::new(193, 34, 17, 19).is_documentation(), false);

pub const fn to_ipv6_compatible(&self) -> Ipv6Addr

Converts this address to an IPv4-compatible IPv6 address.

a.b.c.d becomes ::a.b.c.d

Note that IPv4-compatible addresses have been officially deprecated. If you don’t explicitly need an IPv4-compatible address for legacy reasons, consider using to_ipv6_mapped instead.

Examples

use std::net::{Ipv4Addr, Ipv6Addr};

assert_eq!(
    Ipv4Addr::new(192, 0, 2, 255).to_ipv6_compatible(),
    Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0xc000, 0x2ff)
);

pub const fn to_ipv6_mapped(&self) -> Ipv6Addr

Converts this address to an IPv4-mapped IPv6 address.

a.b.c.d becomes ::ffff:a.b.c.d

Examples

use std::net::{Ipv4Addr, Ipv6Addr};

assert_eq!(Ipv4Addr::new(192, 0, 2, 255).to_ipv6_mapped(),
           Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x2ff));

impl Ipv4Addr

pub fn parse_ascii(b: &[u8]) -> Result<Ipv4Addr, AddrParseError>

🔬This is a nightly-only experimental API. (addr_parse_ascii #101035)

Parse an IPv4 address from a slice of bytes.

#![feature(addr_parse_ascii)]

use std::net::Ipv4Addr;

let localhost = Ipv4Addr::new(127, 0, 0, 1);

assert_eq!(Ipv4Addr::parse_ascii(b"127.0.0.1"), Ok(localhost));

Trait Implementations

impl BitAnd<&Ipv4Addr> for &Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the & operator.

fn bitand(self, rhs: &Ipv4Addr) -> Ipv4Addr

Performs the & operation.

impl BitAnd<&Ipv4Addr> for Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the & operator.

fn bitand(self, rhs: &Ipv4Addr) -> Ipv4Addr

Performs the & operation.

impl BitAnd<Ipv4Addr> for &Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the & operator.

fn bitand(self, rhs: Ipv4Addr) -> Ipv4Addr

Performs the & operation.

impl BitAnd for Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the & operator.

fn bitand(self, rhs: Ipv4Addr) -> Ipv4Addr

Performs the & operation.

impl BitAndAssign<&Ipv4Addr> for Ipv4Addr

fn bitand_assign(&mut self, rhs: &Ipv4Addr)

Performs the &= operation.

impl BitAndAssign for Ipv4Addr

fn bitand_assign(&mut self, rhs: Ipv4Addr)

Performs the &= operation.

impl BitOr<&Ipv4Addr> for &Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the | operator.

fn bitor(self, rhs: &Ipv4Addr) -> Ipv4Addr

Performs the | operation.

impl BitOr<&Ipv4Addr> for Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the | operator.

fn bitor(self, rhs: &Ipv4Addr) -> Ipv4Addr

Performs the | operation.

impl BitOr<Ipv4Addr> for &Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the | operator.

fn bitor(self, rhs: Ipv4Addr) -> Ipv4Addr

Performs the | operation.

impl BitOr for Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the | operator.

fn bitor(self, rhs: Ipv4Addr) -> Ipv4Addr

Performs the | operation.

impl BitOrAssign<&Ipv4Addr> for Ipv4Addr

fn bitor_assign(&mut self, rhs: &Ipv4Addr)

Performs the |= operation.

impl BitOrAssign for Ipv4Addr

fn bitor_assign(&mut self, rhs: Ipv4Addr)

Performs the |= operation.

impl Clone for Ipv4Addr

fn clone(&self) -> Ipv4Addr

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Ipv4Addr

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

Formats the value using the given formatter.

impl Display for Ipv4Addr

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

Formats the value using the given formatter.

impl From<[u8; 4]> for Ipv4Addr

fn from(octets: [u8; 4]) -> Ipv4Addr

Creates an Ipv4Addr from a four element byte array.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);

impl From<Ipv4Addr> for IpAddr

fn from(ipv4: Ipv4Addr) -> IpAddr

Copies this address to a new IpAddr::V4.

Examples

use std::net::{IpAddr, Ipv4Addr};

let addr = Ipv4Addr::new(127, 0, 0, 1);

assert_eq!(
    IpAddr::V4(addr),
    IpAddr::from(addr)
)

impl From<Ipv4Addr> for u32

fn from(ip: Ipv4Addr) -> u32

Uses Ipv4Addr::to_bits to convert an IPv4 address to a host byte order u32.

impl From<u32> for Ipv4Addr

fn from(ip: u32) -> Ipv4Addr

Uses Ipv4Addr::from_bits to convert a host byte order u32 into an IPv4 address.

impl FromStr for Ipv4Addr

type Err = AddrParseError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Ipv4Addr, AddrParseError>

Parses a string s to return a value of this type.

impl Hash for Ipv4Addr

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Not for &Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the ! operator.

fn not(self) -> Ipv4Addr

Performs the unary ! operation.

impl Not for Ipv4Addr

type Output = Ipv4Addr

The resulting type after applying the ! operator.

fn not(self) -> Ipv4Addr

Performs the unary ! operation.

impl Ord for Ipv4Addr

fn cmp(&self, other: &Ipv4Addr) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq<IpAddr> for Ipv4Addr

fn eq(&self, other: &IpAddr) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq<Ipv4Addr> for IpAddr

fn eq(&self, other: &Ipv4Addr) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for Ipv4Addr

fn eq(&self, other: &Ipv4Addr) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<IpAddr> for Ipv4Addr

fn partial_cmp(&self, other: &IpAddr) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Ipv4Addr> for IpAddr

fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd for Ipv4Addr

fn partial_cmp(&self, other: &Ipv4Addr) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Step for Ipv4Addr

fn steps_between(_: &Ipv4Addr, _: &Ipv4Addr) -> Option<usize>

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the number of successor steps required to get from start to end.

fn forward_checked(start: Ipv4Addr, count: usize) -> Option<Ipv4Addr>

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the successor of self count times.

fn backward_checked(start: Ipv4Addr, count: usize) -> Option<Ipv4Addr>

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the predecessor of self count times.

unsafe fn forward_unchecked(start: Ipv4Addr, count: usize) -> Ipv4Addr

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the successor of self count times.

unsafe fn backward_unchecked(start: Ipv4Addr, count: usize) -> Ipv4Addr

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the predecessor of self count times.

fn forward(start: Self, count: usize) -> Self

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the successor of self count times.

fn backward(start: Self, count: usize) -> Self

🔬This is a nightly-only experimental API. (step_trait #42168)

Returns the value that would be obtained by taking the predecessor of self count times.

impl Copy for Ipv4Addr

impl Eq for Ipv4Addr

impl StructuralPartialEq for Ipv4Addr

impl TrustedStep for Ipv4Addr