Metadata in std::fs - Rust
Description: Metadata information about a file.

## Metadata

# Struct Metadata

1.0.0 · Source

    pub struct Metadata(/* private fields */);

Expand description

Metadata information about a file.

This structure is returned from the `metadata` or `symlink_metadata` function or method and represents known metadata about a file such as its permissions, size, modification times, etc.

## Implementations§

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### impl Metadata

1.1.0 · Source

#### pub fn file_type(&self) -> FileType

Returns the file type for this metadata.

##### §Examples

    fn main() -> std::io::Result<()> {
        use std::fs;

        let metadata = fs::metadata("foo.txt")?;

        println!("{:?}", metadata.file_type());
        Ok(())
    }

1.0.0 · Source

#### pub fn is_dir(&self) -> bool

Returns `true` if this metadata is for a directory. The result is mutually exclusive to the result of `Metadata::is_file`, and will be false for symlink metadata obtained from `symlink_metadata`.

##### §Examples

    fn main() -> std::io::Result<()> {
        use std::fs;

        let metadata = fs::metadata("foo.txt")?;

        assert!(!metadata.is_dir());
        Ok(())
    }

1.0.0 · Source

#### pub fn is_file(&self) -> bool

Returns `true` if this metadata is for a regular file. The result is mutually exclusive to the result of `Metadata::is_dir`, and will be false for symlink metadata obtained from `symlink_metadata`.

When the goal is simply to read from (or write to) the source, the most reliable way to test the source can be read (or written to) is to open it. Only using `is_file` can break workflows like `diff <( prog_a )` on a Unix-like system for example. See `File::open` or `OpenOptions::open` for more information.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        assert!(metadata.is_file());
        Ok(())
    }

1.58.0 · Source

#### pub fn is_symlink(&self) -> bool

Returns `true` if this metadata is for a symbolic link.

##### §Examples

ⓘ

    use std::fs;
    use std::path::Path;
    use std::os::unix::fs::symlink;

    fn main() -> std::io::Result<()> {
        let link_path = Path::new("link");
        symlink("/origin_does_not_exist/", link_path)?;

        let metadata = fs::symlink_metadata(link_path)?;

        assert!(metadata.is_symlink());
        Ok(())
    }

1.0.0 · Source

#### pub fn len(&self) -> u64

Returns the size of the file, in bytes, this metadata is for.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        assert_eq!(0, metadata.len());
        Ok(())
    }

1.0.0 · Source

#### pub fn permissions(&self) -> Permissions

Returns the permissions of the file this metadata is for.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        assert!(!metadata.permissions().readonly());
        Ok(())
    }

1.10.0 · Source

#### pub fn modified(&self) -> Result<SystemTime>

Returns the last modification time listed in this metadata.

The returned value corresponds to the `mtime` field of `stat` on Unix platforms and the `ftLastWriteTime` field on Windows platforms.

##### §Errors

This field might not be available on all platforms, and will return an `Err` on platforms where it is not available.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        if let Ok(time) = metadata.modified() {
            println!("{time:?}");
        } else {
            println!("Not supported on this platform");
        }
        Ok(())
    }

1.10.0 · Source

#### pub fn accessed(&self) -> Result<SystemTime>

Returns the last access time of this metadata.

The returned value corresponds to the `atime` field of `stat` on Unix platforms and the `ftLastAccessTime` field on Windows platforms.

Note that not all platforms will keep this field update in a file’s metadata, for example Windows has an option to disable updating this time when files are accessed and Linux similarly has `noatime`.

##### §Errors

This field might not be available on all platforms, and will return an `Err` on platforms where it is not available.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        if let Ok(time) = metadata.accessed() {
            println!("{time:?}");
        } else {
            println!("Not supported on this platform");
        }
        Ok(())
    }

1.10.0 · Source

#### pub fn created(&self) -> Result<SystemTime>

Returns the creation time listed in this metadata.

The returned value corresponds to the `btime` field of `statx` on Linux kernel starting from to 4.11, the `birthtime` field of `stat` on other Unix platforms, and the `ftCreationTime` field on Windows platforms.

##### §Errors

This field might not be available on all platforms, and will return an `Err` on platforms or filesystems where it is not available.

##### §Examples

    use std::fs;

    fn main() -> std::io::Result<()> {
        let metadata = fs::metadata("foo.txt")?;

        if let Ok(time) = metadata.created() {
            println!("{time:?}");
        } else {
            println!("Not supported on this platform or filesystem");
        }
        Ok(())
    }

## Trait Implementations§

1.0.0 · Source§

### impl Clone for Metadata

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#### fn clone(&self) -> Metadata

Returns a duplicate of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from `source`. Read more
1.16.0 · Source§

### impl Debug for Metadata

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations§

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### impl Freeze for Metadata

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### impl RefUnwindSafe for Metadata

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### impl Send for Metadata

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### impl Sync for Metadata

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### impl Unpin for Metadata

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### impl UnwindSafe for Metadata

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.