# Trait MetadataExt

1.1.0 · Source

    pub trait MetadataExt {
        // Required methods
        fn file_attributes(&self) -> u32;
        fn creation_time(&self) -> u64;
        fn last_access_time(&self) -> u64;
        fn last_write_time(&self) -> u64;
        fn file_size(&self) -> u64;
        fn volume_serial_number(&self) -> Option<u32>;
        fn number_of_links(&self) -> Option<u32>;
        fn file_index(&self) -> Option<u64>;
        fn change_time(&self) -> Option<u64>;
    }

Available on Windows only.
Expand description

Windows-specific extensions to `fs::Metadata`.

The data members that this trait exposes correspond to the members of the `BY_HANDLE_FILE_INFORMATION` structure.

## Required Methods§

1.1.0 · Source

#### fn file_attributes(&self) -> u32

Returns the value of the `dwFileAttributes` field of this metadata.

This field contains the file system attribute information for a file or directory. For possible values and their descriptions, see File Attribute Constants in the Windows Dev Center.

##### §Examples

    use std::io;
    use std::fs;
    use std::os::windows::prelude::*;

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

1.1.0 · Source

#### fn creation_time(&self) -> u64

Returns the value of the `ftCreationTime` field of this metadata.

The returned 64-bit value is equivalent to a `FILETIME` struct, which represents the number of 100-nanosecond intervals since January 1, 1601 (UTC). The struct is automatically converted to a `u64` value, as that is the recommended way to use it.

If the underlying filesystem does not support creation time, the returned value is 0.

##### §Examples

    use std::io;
    use std::fs;
    use std::os::windows::prelude::*;

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

1.1.0 · Source

#### fn last_access_time(&self) -> u64

Returns the value of the `ftLastAccessTime` field of this metadata.

The returned 64-bit value is equivalent to a `FILETIME` struct, which represents the number of 100-nanosecond intervals since January 1, 1601 (UTC). The struct is automatically converted to a `u64` value, as that is the recommended way to use it.

For a file, the value specifies the last time that a file was read from or written to. For a directory, the value specifies when the directory was created. For both files and directories, the specified date is correct, but the time of day is always set to midnight.

If the underlying filesystem does not support last access time, the returned value is 0.

##### §Examples

    use std::io;
    use std::fs;
    use std::os::windows::prelude::*;

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

1.1.0 · Source

#### fn last_write_time(&self) -> u64

Returns the value of the `ftLastWriteTime` field of this metadata.

The returned 64-bit value is equivalent to a `FILETIME` struct, which represents the number of 100-nanosecond intervals since January 1, 1601 (UTC). The struct is automatically converted to a `u64` value, as that is the recommended way to use it.

For a file, the value specifies the last time that a file was written to. For a directory, the structure specifies when the directory was created.

If the underlying filesystem does not support the last write time, the returned value is 0.

##### §Examples

    use std::io;
    use std::fs;
    use std::os::windows::prelude::*;

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

1.1.0 · Source

#### fn file_size(&self) -> u64

Returns the value of the `nFileSize` fields of this metadata.

The returned value does not have meaning for directories.

##### §Examples

    use std::io;
    use std::fs;
    use std::os::windows::prelude::*;

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

Source

#### 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.

This will return `None` if the `Metadata` instance was created from a call to `DirEntry::metadata`. If this `Metadata` was created by using `fs::metadata` or `File::metadata`, then this will return `Some`.

Source

#### 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.

This will return `None` if the `Metadata` instance was created from a call to `DirEntry::metadata`. If this `Metadata` was created by using `fs::metadata` or `File::metadata`, then this will return `Some`.

Source

#### fn file_index(&self) -> Option<u64>

🔬This is a nightly-only experimental API. (`windows_by_handle` #63010)

Returns the value of the `nFileIndex` fields of this metadata.

This will return `None` if the `Metadata` instance was created from a call to `DirEntry::metadata`. If this `Metadata` was created by using `fs::metadata` or `File::metadata`, then this will return `Some`.

Source

#### fn change_time(&self) -> Option<u64>

🔬This is a nightly-only experimental API. (`windows_change_time` #121478)

Returns the value of the `ChangeTime` fields of this metadata.

`ChangeTime` is the last time file metadata was changed, such as renames, attributes, etc.

This will return `None` if `Metadata` instance was created from a call to `DirEntry::metadata` or if the `target_vendor` is outside the current platform support for this api.

## Implementors§

1.1.0 · Source§

### impl MetadataExt for Metadata