Struct std::ffi::OsString

pub struct OsString { /* fields omitted */ }

A type that can represent owned, mutable platform-native strings, but is cheaply inter-convertible with Rust strings.

The need for this type arises from the fact that:

• On Unix systems, strings are often arbitrary sequences of non-zero bytes, in many cases interpreted as UTF-8.

• On Windows, strings are often arbitrary sequences of non-zero 16-bit values, interpreted as UTF-16 when it is valid to do so.

• In Rust, strings are always valid UTF-8, which may contain zeros.

OsString and OsStr bridge this gap by simultaneously representing Rust and platform-native string values, and in particular allowing a Rust string to be converted into an "OS" string with no cost if possible.

OsString is to &OsStr as String is to &str: the former in each pair are owned strings; the latter are borrowed references.

Creating an OsString

From a Rust string: OsString implements From<String>, so you can use my_string.from to create an OsString from a normal Rust string.

From slices: Just like you can start with an empty Rust String and then push_str &str sub-string slices into it, you can create an empty OsString with the new method and then push string slices into it with the push method.

Extracting a borrowed reference to the whole OS string

You can use the as_os_str method to get an &OsStr from an OsString; this is effectively a borrowed reference to the whole string.

Conversions

See the [module's toplevel documentation about conversions][conversions] for a discussion on the traits which OsString implements for conversions from/to native representations.

Methods

impl OsString

pub fn new() -> OsString

Constructs a new empty OsString.

Examples

use std::ffi::OsString;

let os_string = OsString::new();

pub fn as_os_str(&self) -> &OsStr

Converts to an OsStr slice.

Examples

use std::ffi::{OsString, OsStr};

let os_string = OsString::from("foo");
let os_str = OsStr::new("foo");
assert_eq!(os_string.as_os_str(), os_str);

pub fn into_string(self) -> Result<String, OsString>

Converts the OsString into a String if it contains valid Unicode data.

On failure, ownership of the original OsString is returned.

Examples

use std::ffi::OsString;

let os_string = OsString::from("foo");
let string = os_string.into_string();
assert_eq!(string, Ok(String::from("foo")));

pub fn push<T: AsRef<OsStr>>(&mut self, s: T)

Extends the string with the given &OsStr slice.

Examples

use std::ffi::OsString;

let mut os_string = OsString::from("foo");
os_string.push("bar");
assert_eq!(&os_string, "foobar");

pub fn with_capacity(capacity: usize) -> OsString

Creates a new OsString with the given capacity.

The string will be able to hold exactly capacity length units of other OS strings without reallocating. If capacity is 0, the string will not allocate.

See main OsString documentation information about encoding.

Examples

use std::ffi::OsString;

let mut os_string = OsString::with_capacity(10);
let capacity = os_string.capacity();

// This push is done without reallocating
os_string.push("foo");

assert_eq!(capacity, os_string.capacity());

pub fn clear(&mut self)

Truncates the OsString to zero length.

Examples

use std::ffi::OsString;

let mut os_string = OsString::from("foo");
assert_eq!(&os_string, "foo");

os_string.clear();
assert_eq!(&os_string, "");

pub fn capacity(&self) -> usize

Returns the capacity this OsString can hold without reallocating.

See OsString introduction for information about encoding.

Examples

use std::ffi::OsString;

let mut os_string = OsString::with_capacity(10);
assert!(os_string.capacity() >= 10);

pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more capacity to be inserted in the given OsString.

The collection may reserve more space to avoid frequent reallocations.

Examples

use std::ffi::OsString;

let mut s = OsString::new();
s.reserve(10);
assert!(s.capacity() >= 10);

pub fn reserve_exact(&mut self, additional: usize)

Reserves the minimum capacity for exactly additional more capacity to be inserted in the given OsString. Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore capacity can not be relied upon to be precisely minimal. Prefer reserve if future insertions are expected.

Examples

use std::ffi::OsString;

let mut s = OsString::new();
s.reserve_exact(10);
assert!(s.capacity() >= 10);

pub fn shrink_to_fit(&mut self)

Shrinks the capacity of the OsString to match its length.

Examples

use std::ffi::OsString;

let mut s = OsString::from("foo");

s.reserve(100);
assert!(s.capacity() >= 100);

s.shrink_to_fit();
assert_eq!(3, s.capacity());

pub fn shrink_to(&mut self, min_capacity: usize)

🔬 This is a nightly-only experimental API. (shrink_to)

new API

Shrinks the capacity of the OsString with a lower bound.

The capacity will remain at least as large as both the length and the supplied value.

Panics if the current capacity is smaller than the supplied minimum capacity.

Examples

#![feature(shrink_to)]
use std::ffi::OsString;

let mut s = OsString::from("foo");

s.reserve(100);
assert!(s.capacity() >= 100);

s.shrink_to(10);
assert!(s.capacity() >= 10);
s.shrink_to(0);
assert!(s.capacity() >= 3);

Important traits for Box<I>

impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>

pub fn into_boxed_os_str(self) -> Box<OsStr>

Converts this OsString into a boxed OsStr.

Examples

use std::ffi::{OsString, OsStr};

let s = OsString::from("hello");

let b: Box<OsStr> = s.into_boxed_os_str();

Methods from Deref<Target = OsStr>

pub fn to_str(&self) -> Option<&str>

Yields a &str slice if the OsStr is valid Unicode.

This conversion may entail doing a check for UTF-8 validity.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("foo");
assert_eq!(os_str.to_str(), Some("foo"));

pub fn to_string_lossy(&self) -> Cow<str>

Converts an OsStr to a Cow<str>.

Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

Examples

Calling to_string_lossy on an OsStr with valid unicode:

use std::ffi::OsStr;

let os_str = OsStr::new("foo");
assert_eq!(os_str.to_string_lossy(), "foo");

Had os_str contained invalid unicode, the to_string_lossy call might have returned "fo�".

pub fn to_os_string(&self) -> OsString

Copies the slice into an owned OsString.

Examples

use std::ffi::{OsStr, OsString};

let os_str = OsStr::new("foo");
let os_string = os_str.to_os_string();
assert_eq!(os_string, OsString::from("foo"));

pub fn is_empty(&self) -> bool

Checks whether the OsStr is empty.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert!(os_str.is_empty());

let os_str = OsStr::new("foo");
assert!(!os_str.is_empty());

pub fn len(&self) -> usize

Returns the length of this OsStr.

Note that this does not return the number of bytes in this string as, for example, OS strings on Windows are encoded as a list of u16 rather than a list of bytes. This number is simply useful for passing to other methods like OsString::with_capacity to avoid reallocations.

See OsStr introduction for more information about encoding.

Examples

use std::ffi::OsStr;

let os_str = OsStr::new("");
assert_eq!(os_str.len(), 0);

let os_str = OsStr::new("foo");
assert_eq!(os_str.len(), 3);

Trait Implementations

impl Clone for OsString

fn clone(&self) -> OsString

Returns a copy of the value.

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

Performs copy-assignment from source.

impl From<String> for OsString

fn from(s: String) -> OsString

Performs the conversion.

impl<'a, T: ?Sized + AsRef<OsStr>> From<&'a T> for OsString

fn from(s: &'a T) -> OsString

Performs the conversion.

impl Index<RangeFull> for OsString

type Output = OsStr

The returned type after indexing.

fn index(&self, _index: RangeFull) -> &OsStr

Performs the indexing (container[index]) operation.

impl Deref for OsString

type Target = OsStr

The resulting type after dereferencing.

fn deref(&self) -> &OsStr

Dereferences the value.

impl Default for OsString

fn default() -> OsString

Constructs an empty OsString.

impl Debug for OsString

fn fmt(&self, formatter: &mut Formatter) -> Result

Formats the value using the given formatter.

impl PartialEq for OsString

fn eq(&self, other: &OsString) -> 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 !=.

impl PartialEq<str> for OsString

fn eq(&self, other: &str) -> 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 !=.

impl PartialEq<OsString> for str

fn eq(&self, other: &OsString) -> 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 !=.

impl Eq for OsString

impl PartialOrd for OsString

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

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

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

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

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

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

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

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

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

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

impl PartialOrd<str> for OsString

fn partial_cmp(&self, other: &str) -> 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 Ord for OsString

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

impl Hash for OsString

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

Feeds this value into the given [Hasher].

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

Feeds a slice of this type into the given [Hasher].

impl From<Box<OsStr>> for OsString

fn from(boxed: Box<OsStr>) -> OsString

Performs the conversion.

impl From<OsString> for Box<OsStr>

Important traits for Box<I>

impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>

fn from(s: OsString) -> Box<OsStr>

Performs the conversion.

impl From<OsString> for Arc<OsStr>

fn from(s: OsString) -> Arc<OsStr>

Performs the conversion.

impl From<OsString> for Rc<OsStr>

fn from(s: OsString) -> Rc<OsStr>

Performs the conversion.

impl<'a, 'b> PartialEq<OsStr> for OsString

fn eq(&self, other: &OsStr) -> 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 !=.

impl<'a, 'b> PartialEq<OsString> for OsStr

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialOrd<OsStr> for OsString

fn partial_cmp(&self, other: &OsStr) -> 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<'a, 'b> PartialOrd<OsString> for OsStr

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialEq<&'a OsStr> for OsString

fn eq(&self, other: &&'a OsStr) -> 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 !=.

impl<'a, 'b> PartialEq<OsString> for &'a OsStr

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialOrd<&'a OsStr> for OsString

fn partial_cmp(&self, other: &&'a OsStr) -> 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<'a, 'b> PartialOrd<OsString> for &'a OsStr

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialEq<OsString> for Cow<'a, OsStr>

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialEq<Cow<'a, OsStr>> for OsString

fn eq(&self, other: &Cow<'a, OsStr>) -> 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 !=.

impl<'a, 'b> PartialOrd<OsString> for Cow<'a, OsStr>

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialOrd<Cow<'a, OsStr>> for OsString

fn partial_cmp(&self, other: &Cow<'a, OsStr>) -> 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 Borrow<OsStr> for OsString

fn borrow(&self) -> &OsStr

Immutably borrows from an owned value.

impl AsRef<OsStr> for OsString

fn as_ref(&self) -> &OsStr

Performs the conversion.

impl From<OsString> for PathBuf

fn from(s: OsString) -> PathBuf

Performs the conversion.

impl From<PathBuf> for OsString

fn from(path_buf: PathBuf) -> OsString

Performs the conversion.

impl AsRef<Path> for OsString

fn as_ref(&self) -> &Path

Performs the conversion.

impl<'a, 'b> PartialEq<OsString> for PathBuf

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialEq<PathBuf> for OsString

fn eq(&self, other: &PathBuf) -> 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 !=.

impl<'a, 'b> PartialOrd<OsString> for PathBuf

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialOrd<PathBuf> for OsString

fn partial_cmp(&self, other: &PathBuf) -> 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<'a, 'b> PartialEq<OsString> for Path

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialEq<Path> for OsString

fn eq(&self, other: &Path) -> 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 !=.

impl<'a, 'b> PartialOrd<OsString> for Path

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialOrd<Path> for OsString

fn partial_cmp(&self, other: &Path) -> 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<'a, 'b> PartialEq<OsString> for &'a Path

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialEq<&'a Path> for OsString

fn eq(&self, other: &&'a Path) -> 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 !=.

impl<'a, 'b> PartialOrd<OsString> for &'a Path

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialOrd<&'a Path> for OsString

fn partial_cmp(&self, other: &&'a Path) -> 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<'a, 'b> PartialEq<OsString> for Cow<'a, Path>

fn eq(&self, other: &OsString) -> 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 !=.

impl<'a, 'b> PartialEq<Cow<'a, Path>> for OsString

fn eq(&self, other: &Cow<'a, Path>) -> 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 !=.

impl<'a, 'b> PartialOrd<OsString> for Cow<'a, Path>

fn partial_cmp(&self, other: &OsString) -> 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<'a, 'b> PartialOrd<Cow<'a, Path>> for OsString

fn partial_cmp(&self, other: &Cow<'a, Path>) -> 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 OsStringExt for OsString

fn from_vec(vec: Vec<u8>) -> OsString

This is supported on Unix only.

Creates an [OsString] from a byte vector.

Important traits for Vec<u8>

impl Write for Vec<u8>

fn into_vec(self) -> Vec<u8>

This is supported on Unix only.

Yields the underlying byte vector of this [OsString].

impl OsStringExt for OsString

fn from_wide(wide: &[u16]) -> OsString

This is supported on Windows only.

Creates an OsString from a potentially ill-formed UTF-16 slice of 16-bit code units.