Struct OsStr  Copy item path  1.87.0  · Source  #[repr(transparent)]
pub struct OsStr {
    inner: Slice ,
}Expand description Borrowed reference to an OS string (see OsString ).
This type represents a borrowed reference to a string in the operating system’s preferred
representation.
&OsStr is to OsString  as &str  is to String : the
former in each pair are borrowed references; the latter are owned strings.
See the module’s toplevel documentation about conversions  for a discussion on
the traits which OsStr implements for conversions  from/to native representations.
Coerces into an OsStr slice.
§ Examples 
use  std::ffi::OsStr;
let  os_str = OsStr::new("foo" );Converts a slice of bytes to an OS string slice without checking that the string contains
valid OsStr-encoded data.
The byte encoding is an unspecified, platform-specific, self-synchronizing superset of UTF-8.
By being a self-synchronizing superset of UTF-8, this encoding is also a superset of 7-bit
ASCII.
See the module’s toplevel documentation about conversions  for safe,
cross-platform conversions  from/to native representations.
§ Safety 
As the encoding is unspecified, callers must pass in bytes that originated as a mixture of
validated UTF-8 and bytes from OsStr::as_encoded_bytes  from within the same Rust version
built for the same target platform.  For example, reconstructing an OsStr from bytes sent
over the network or stored in a file will likely violate these safety rules.
Due to the encoding being self-synchronizing, the bytes from OsStr::as_encoded_bytes  can be
split either immediately before or immediately after any valid non-empty UTF-8 substring.
§ Example 
use  std::ffi::OsStr;
let  os_str = OsStr::new("Mary had a little lamb" );
let  bytes = os_str.as_encoded_bytes();
let  words = bytes.split(|b| * b == b' ' );
let  words: Vec<& OsStr> = words.map(|word| {
    unsafe  { OsStr::from_encoded_bytes_unchecked(word) }
}).collect();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" ));Converts an OsStr to a Cow <str >.
Any non-UTF-8 sequences are replaced with
U+FFFD REPLACEMENT CHARACTER .
§ Examples 
Calling to_string_lossy on an OsStr with invalid unicode:
#[cfg(unix)]  {
    use  std::ffi::OsStr;
    use  std::os::unix::ffi::OsStrExt;
    let  source = [0x66 , 0x6f , 0x80 , 0x6f ];
    let  os_str = OsStr::from_bytes(& source[..]);
    assert_eq! (os_str.to_string_lossy(), "fo�o" );
}
#[cfg(windows)]  {
    use  std::ffi::OsString;
    use  std::os::windows::prelude::* ;
    let  source = [0x0066 , 0x006f , 0xD800 , 0x006f ];
    let  os_string = OsString::from_wide(& source[..]);
    let  os_str = os_string.as_os_str();
    assert_eq! (os_str.to_string_lossy(), "fo�o" );
}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" ));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());Returns the length of this OsStr.
Note that this does not  return the number of bytes in the string in
OS string form.
The length returned is that of the underlying storage used by OsStr.
As discussed in the OsString  introduction, OsString  and OsStr
store strings in a form best suited for cheap inter-conversion between
native-platform and Rust string forms, which may differ significantly
from both of them, including in storage size and encoding.
This number is simply useful for passing to other methods, like
OsString::with_capacity  to avoid reallocations.
See the main OsString documentation information about encoding and capacity units.
§ 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 );Converts an OS string slice to a byte slice.  To convert the byte slice back into an OS
string slice, use the OsStr::from_encoded_bytes_unchecked  function.
The byte encoding is an unspecified, platform-specific, self-synchronizing superset of UTF-8.
By being a self-synchronizing superset of UTF-8, this encoding is also a superset of 7-bit
ASCII.
Note: As the encoding is unspecified, any sub-slice of bytes that is not valid UTF-8 should
be treated as opaque and only comparable within the same Rust version built for the same
target platform.  For example, sending the slice over the network or storing it in a file
will likely result in incompatible byte slices.  See OsString  for more encoding details
and std::ffi  for platform-specific, specified conversions.
🔬 This is a nightly-only experimental API. (os_str_slice #118485 ) Takes a substring based on a range that corresponds to the return value of
OsStr::as_encoded_bytes .
The range’s start and end must lie on valid OsStr boundaries.
A valid OsStr boundary is one of:
The start of the string 
The end of the string 
Immediately before a valid non-empty UTF-8 substring 
Immediately after a valid non-empty UTF-8 substring 
 
§ Panics 
Panics if range does not lie on valid OsStr boundaries or if it
exceeds the end of the string.
§ Example 
#![feature(os_str_slice)]
 use  std::ffi::OsStr;
let  os_str = OsStr::new("foo=bar" );
let  bytes = os_str.as_encoded_bytes();
if let  Some (index) = bytes.iter().position(|b| * b == b'=' ) {
    let  key = os_str.slice_encoded_bytes(..index);
    let  value = os_str.slice_encoded_bytes(index + 1 ..);
    assert_eq! (key, "foo" );
    assert_eq! (value, "bar" );
}Converts this string to its ASCII lower case equivalent in-place.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’,
but non-ASCII letters are unchanged.
To return a new lowercased value without modifying the existing one, use
OsStr::to_ascii_lowercase .
§ Examples 
use  std::ffi::OsString;
let  mut  s = OsString::from("GRÜßE, JÜRGEN ❤" );
s.make_ascii_lowercase();
assert_eq! ("grÜße, jÜrgen ❤" , s);Converts this string to its ASCII upper case equivalent in-place.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’,
but non-ASCII letters are unchanged.
To return a new uppercased value without modifying the existing one, use
OsStr::to_ascii_uppercase .
§ Examples 
use  std::ffi::OsString;
let  mut  s = OsString::from("Grüße, Jürgen ❤" );
s.make_ascii_uppercase();
assert_eq! ("GRüßE, JüRGEN ❤" , s);Returns a copy of this string where each character is mapped to its
ASCII lower case equivalent.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’,
but non-ASCII letters are unchanged.
To lowercase the value in-place, use OsStr::make_ascii_lowercase .
§ Examples 
use  std::ffi::OsString;
let  s = OsString::from("Grüße, Jürgen ❤" );
assert_eq! ("grüße, jürgen ❤" , s.to_ascii_lowercase());Returns a copy of this string where each character is mapped to its
ASCII upper case equivalent.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’,
but non-ASCII letters are unchanged.
To uppercase the value in-place, use OsStr::make_ascii_uppercase .
§ Examples 
use  std::ffi::OsString;
let  s = OsString::from("Grüße, Jürgen ❤" );
assert_eq! ("GRüßE, JüRGEN ❤" , s.to_ascii_uppercase());Checks if all characters in this string are within the ASCII range.
§ Examples 
use  std::ffi::OsString;
let  ascii = OsString::from("hello!\n" );
let  non_ascii = OsString::from("Grüße, Jürgen ❤" );
assert! (ascii.is_ascii());
assert! (!non_ascii.is_ascii());Checks that two strings are an ASCII case-insensitive match.
Same as to_ascii_lowercase(a) == to_ascii_lowercase(b),
but without allocating and copying temporaries.
§ Examples 
use  std::ffi::OsString;
assert! (OsString::from("Ferris" ).eq_ignore_ascii_case("FERRIS" ));
assert! (OsString::from("Ferrös" ).eq_ignore_ascii_case("FERRöS" ));
assert! (!OsString::from("Ferrös" ).eq_ignore_ascii_case("FERRÖS" ));Returns an object that implements Display  for safely printing an
OsStr  that may contain non-Unicode data. This may perform lossy
conversion, depending on the platform.  If you would like an
implementation which escapes the OsStr  please use Debug 
instead.
§ Examples 
use  std::ffi::OsStr;
let  s = OsStr::new("Hello, world!" );
println! ("{}" , s.display());Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Immutably borrows from an owned value. 
Read more Performs copy-assignment from 
source. 
Read more 🔬 This is a nightly-only experimental API. (clone_to_uninit #126799 ) Performs copy-assignment from 
self to 
dest. 
Read more Formats the value using the given formatter. 
Read more Returns the “default value” for a type. 
Read more Extends a collection with the contents of an iterator. 
Read more 🔬 This is a nightly-only experimental API. (extend_one #72631 ) Extends a collection with exactly one element.
🔬 This is a nightly-only experimental API. (extend_one #72631 ) Reserves capacity in a collection for the given number of additional elements. 
Read more Copies the string into a newly allocated Arc <OsStr >.
Copies the string into a newly allocated Box <OsStr >.
Copies the string into a newly allocated Rc <OsStr >.
Copies the string into a newly allocated Arc <OsStr >.
Copies the string into a newly allocated Box <OsStr >.
Copies the string into a newly allocated Rc <OsStr >.
Converts a Cow<'a, OsStr> into a Box <OsStr >,
by copying the contents if they are borrowed.
🔬 This is a nightly-only experimental API. (slice_concat_trait #27747 ) The resulting type after concatenation
🔬 This is a nightly-only experimental API. (slice_concat_trait #27747 ) Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more This method returns an ordering between 
self and 
other values if one exists. 
Read more Tests less than (for 
self and 
other) and is used by the 
< operator. 
Read more Tests less than or equal to (for 
self and 
other) and is used by the
<= operator. 
Read more Tests greater than (for 
self and 
other) and is used by the 
>
operator. 
Read more Tests greater than or equal to (for 
self and 
other) and is used by
the 
>= operator. 
Read more The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. 
Read more Uses borrowed data to replace owned data, usually by cloning. 
Read more Tries to convert an &OsStr to a &str.
use  std::ffi::OsStr;
let  os_str = OsStr::new("foo" );
let  as_str = <& str>::try_from(os_str).unwrap();
assert_eq! (as_str, "foo" );The type returned in the event of a conversion error.
Immutably borrows from an owned value. 
Read more Mutably borrows from an owned value. 
Read more