Enum Disposition 

#[non_exhaustive]
pub enum Disposition {
    CreateNew,
    OpenExisting,
    OpenAlways,
}

The disposition of an open: what it does when the file exists and when it does not.

None of the three changes the contents of a file that exists, so no data access is gated by the choice.

Variant	dwCreationDisposition	File exists	File does not exist
CreateNew	CREATE_NEW	fails, ERROR_FILE_EXISTS	created
OpenExisting	OPEN_EXISTING	opened	fails, ERROR_FILE_NOT_FOUND
OpenAlways	OPEN_ALWAYS	opened	created

A file that an open creates is created empty.

There is deliberately no Default: the options start at OpenExisting, which creates nothing, and a disposition is stated where one is wanted.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

CreateNew

CREATE_NEW: create the file, and fail if it exists.

OpenExisting

OPEN_EXISTING: open the file, and fail if it does not exist.

OpenAlways

OPEN_ALWAYS: open the file if it exists, and create it if it does not.

Trait Implementations

impl Clone for Disposition

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Disposition

impl Debug for Disposition

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

Formats the value using the given formatter.

impl Eq for Disposition

impl Hash for Disposition

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Disposition

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Disposition