# Struct std::fs::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(())
    }

Run
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#### 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(())
    }

Run
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#### 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(())
    }

Run
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(())
    }

Run
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#### 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(())
    }

Run
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#### 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(())
    }

Run
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(())
    }

Run
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(())
    }

Run
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(())
    }

Run

## Trait Implementations§

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### impl Clone for Metadata

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

Returns a copy of the value. Read more
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#### 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
1.1.0 · source§

### impl MetadataExt for Metadata

Available on Windows only.
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#### fn file_attributes(&self) -> u32

Returns the value of the `dwFileAttributes` field of this metadata. Read more
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#### fn creation_time(&self) -> u64

Returns the value of the `ftCreationTime` field of this metadata. Read more
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#### fn last_access_time(&self) -> u64

Returns the value of the `ftLastAccessTime` field of this metadata. Read more
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#### fn last_write_time(&self) -> u64

Returns the value of the `ftLastWriteTime` field of this metadata. Read more
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#### fn file_size(&self) -> u64

Returns the value of the `nFileSize{High,Low}` fields of this metadata. Read more
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#### fn volume_serial_number(&self) -> Option<u32>

🔬This is a nightly-only experimental API. (`windows_by_handle` #63010)
Returns the value of the `dwVolumeSerialNumber` field of this metadata. Read more
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#### fn number_of_links(&self) -> Option<u32>

🔬This is a nightly-only experimental API. (`windows_by_handle` #63010)
Returns the value of the `nNumberOfLinks` field of this metadata. Read more
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#### fn file_index(&self) -> Option<u64>

🔬This is a nightly-only experimental API. (`windows_by_handle` #63010)
Returns the value of the `nFileIndex{Low,High}` fields of this metadata. Read more
1.1.0 · source§

### impl MetadataExt for Metadata

Available on Linux only.
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#### fn as_raw_stat(&self) -> &stat

👎Deprecated since 1.8.0: other methods of this trait are now preferred
Gain a reference to the underlying `stat` structure which contains the raw information returned by the OS. Read more
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#### fn st_dev(&self) -> u64

Returns the device ID on which this file resides. Read more
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#### fn st_ino(&self) -> u64

Returns the inode number. Read more
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#### fn st_mode(&self) -> u32

Returns the file type and mode. Read more
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#### fn st_nlink(&self) -> u64

Returns the number of hard links to file. Read more
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#### fn st_uid(&self) -> u32

Returns the user ID of the file owner. Read more
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#### fn st_gid(&self) -> u32

Returns the group ID of the file owner. Read more
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#### fn st_rdev(&self) -> u64

Returns the device ID that this file represents. Only relevant for special file. Read more
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#### fn st_size(&self) -> u64

Returns the size of the file (if it is a regular file or a symbolic link) in bytes. Read more
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#### fn st_atime(&self) -> i64

Returns the last access time of the file, in seconds since Unix Epoch. Read more
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#### fn st_atime_nsec(&self) -> i64

Returns the last access time of the file, in nanoseconds since `st_atime`. Read more
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#### fn st_mtime(&self) -> i64

Returns the last modification time of the file, in seconds since Unix Epoch. Read more
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#### fn st_mtime_nsec(&self) -> i64

Returns the last modification time of the file, in nanoseconds since `st_mtime`. Read more
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#### fn st_ctime(&self) -> i64

Returns the last status change time of the file, in seconds since Unix Epoch. Read more
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#### fn st_ctime_nsec(&self) -> i64

Returns the last status change time of the file, in nanoseconds since `st_ctime`. Read more
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#### fn st_blksize(&self) -> u64

Returns the “preferred” block size for efficient filesystem I/O. Read more
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#### fn st_blocks(&self) -> u64

Returns the number of blocks allocated to the file, 512-byte units. Read more
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### impl MetadataExt for Metadata

Available on WASI only.
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#### fn dev(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_dev` field of the internal `filestat_t`
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#### fn ino(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_ino` field of the internal `filestat_t`
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#### fn nlink(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_nlink` field of the internal `filestat_t`
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#### fn size(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_size` field of the internal `filestat_t`
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#### fn atim(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_atim` field of the internal `filestat_t`
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#### fn mtim(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_mtim` field of the internal `filestat_t`
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#### fn ctim(&self) -> u64

🔬This is a nightly-only experimental API. (`wasi_ext` #71213)
Returns the `st_ctim` field of the internal `filestat_t`
1.1.0 · source§

### impl MetadataExt for Metadata

Available on Unix only.
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#### fn dev(&self) -> u64

Returns the ID of the device containing the file. Read more
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#### fn ino(&self) -> u64

Returns the inode number. Read more
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#### fn mode(&self) -> u32

Returns the rights applied to this file. Read more
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#### fn nlink(&self) -> u64

Returns the number of hard links pointing to this file. Read more
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#### fn uid(&self) -> u32

Returns the user ID of the owner of this file. Read more
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#### fn gid(&self) -> u32

Returns the group ID of the owner of this file. Read more
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#### fn rdev(&self) -> u64

Returns the device ID of this file (if it is a special one). Read more
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#### fn size(&self) -> u64

Returns the total size of this file in bytes. Read more
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#### fn atime(&self) -> i64

Returns the last access time of the file, in seconds since Unix Epoch. Read more
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#### fn atime_nsec(&self) -> i64

Returns the last access time of the file, in nanoseconds since `atime`. Read more
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#### fn mtime(&self) -> i64

Returns the last modification time of the file, in seconds since Unix Epoch. Read more
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#### fn mtime_nsec(&self) -> i64

Returns the last modification time of the file, in nanoseconds since `mtime`. Read more
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#### fn ctime(&self) -> i64

Returns the last status change time of the file, in seconds since Unix Epoch. Read more
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#### fn ctime_nsec(&self) -> i64

Returns the last status change time of the file, in nanoseconds since `ctime`. Read more
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#### fn blksize(&self) -> u64

Returns the block size for filesystem I/O. Read more
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#### fn blocks(&self) -> u64

Returns the number of blocks allocated to the file, in 512-byte units. Read more

## Auto Trait Implementations§

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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 Twhere 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 Twhere 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 Twhere 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> 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 Twhere 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 Twhere 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 Twhere 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 Twhere 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.