Struct io_uring::squeue::Flags

pub struct Flags { /* private fields */ }

Submission flags

Implementations

impl Flags

pub const IO_DRAIN: Self = _

When this flag is specified, the SQE will not be started before previously submitted SQEs have completed, and new SQEs will not be started before this one completes.

pub const IO_LINK: Self = _

When this flag is specified, it forms a link with the next SQE in the submission ring. That next SQE will not be started before this one completes.

pub const IO_HARDLINK: Self = _

Like IO_LINK, but it doesn’t sever regardless of the completion result.

pub const ASYNC: Self = _

Normal operation for io_uring is to try and issue an sqe as non-blocking first, and if that fails, execute it in an async manner.

To support more efficient overlapped operation of requests that the application knows/assumes will always (or most of the time) block, the application can ask for an sqe to be issued async from the start.

pub const BUFFER_SELECT: Self = _

Conceptually the kernel holds a set of buffers organized into groups. When you issue a request with this flag and set buf_group to a valid buffer group ID (e.g. buf_group on Read) then once the file descriptor becomes ready the kernel will try to take a buffer from the group.

If there are no buffers in the group, your request will fail with -ENOBUFS. Otherwise, the corresponding cqueue::Entry::flags will contain the chosen buffer ID, encoded with:

(buffer_id << IORING_CQE_BUFFER_SHIFT) | IORING_CQE_F_BUFFER

You can use buffer_select to take the buffer ID.

The buffer will then be removed from the group and won’t be usable by other requests anymore.

You can provide new buffers in a group with ProvideBuffers.

See also the LWN thread on automatic buffer selection.

pub const SKIP_SUCCESS: Self = _

Don’t post CQE if request succeeded.

pub const fn empty() -> Self

Returns an empty set of flags.

pub const fn all() -> Self

Returns the set containing all flags.

pub const fn bits(&self) -> u8

Returns the raw value of the flags currently stored.

Examples found in repository

src/squeue.rs (line 292)

    pub fn flags(mut self, flags: Flags) -> Entry {
        self.0.flags |= flags.bits();
        self
    }

    /// Set the user data. This is an application-supplied value that will be passed straight
    /// through into the [completion queue entry](crate::cqueue::Entry::user_data).
    #[inline]
    pub fn user_data(mut self, user_data: u64) -> Entry {
        self.0.user_data = user_data;
        self
    }

    /// Set the personality of this event. You can obtain a personality using
    /// [`Submitter::register_personality`](crate::Submitter::register_personality).
    pub fn personality(mut self, personality: u16) -> Entry {
        self.0.personality = personality;
        self
    }
}

impl Sealed for Entry {
    const ADDITIONAL_FLAGS: u32 = 0;
}

impl EntryMarker for Entry {}

impl Clone for Entry {
    fn clone(&self) -> Entry {
        // io_uring_sqe doesn't implement Clone due to the 'cmd' incomplete array field.
        Entry(unsafe { mem::transmute_copy(&self.0) })
    }
}

impl Debug for Entry {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        f.debug_struct("Entry")
            .field("op_code", &self.0.opcode)
            .field("flags", &self.0.flags)
            .field("user_data", &self.0.user_data)
            .finish()
    }
}

impl Entry128 {
    /// Set the submission event's [flags](Flags).
    #[inline]
    pub fn flags(mut self, flags: Flags) -> Entry128 {
        self.0 .0.flags |= flags.bits();
        self
    }

pub const fn from_bits(bits: u8) -> Option<Self>

Convert from underlying bit representation, unless that representation contains bits that do not correspond to a flag.

pub const fn from_bits_truncate(bits: u8) -> Self

Convert from underlying bit representation, dropping any bits that do not correspond to flags.

pub const unsafe fn from_bits_unchecked(bits: u8) -> Self

Convert from underlying bit representation, preserving all bits (even those not corresponding to a defined flag).

Safety

The caller of the bitflags! macro can chose to allow or disallow extra bits for their bitflags type.

The caller of from_bits_unchecked() has to ensure that all bits correspond to a defined flag or that extra bits are valid for this bitflags type.

pub const fn is_empty(&self) -> bool

Returns true if no flags are currently stored.

pub const fn is_all(&self) -> bool

Returns true if all flags are currently set.

pub const fn intersects(&self, other: Self) -> bool

Returns true if there are flags common to both self and other.

pub const fn contains(&self, other: Self) -> bool

Returns true if all of the flags in other are contained within self.

pub fn insert(&mut self, other: Self)

Inserts the specified flags in-place.

pub fn remove(&mut self, other: Self)

Removes the specified flags in-place.

pub fn toggle(&mut self, other: Self)

Toggles the specified flags in-place.

pub fn set(&mut self, other: Self, value: bool)

Inserts or removes the specified flags depending on the passed value.

pub const fn intersection(self, other: Self) -> Self

Returns the intersection between the flags in self and other.

Specifically, the returned set contains only the flags which are present in both self and other.

This is equivalent to using the & operator (e.g. ops::BitAnd), as in flags & other.

pub const fn union(self, other: Self) -> Self

Returns the union of between the flags in self and other.

Specifically, the returned set contains all flags which are present in either self or other, including any which are present in both (see Self::symmetric_difference if that is undesirable).

This is equivalent to using the | operator (e.g. ops::BitOr), as in flags | other.

pub const fn difference(self, other: Self) -> Self

Returns the difference between the flags in self and other.

Specifically, the returned set contains all flags present in self, except for the ones present in other.

It is also conceptually equivalent to the “bit-clear” operation: flags & !other (and this syntax is also supported).

This is equivalent to using the - operator (e.g. ops::Sub), as in flags - other.

pub const fn symmetric_difference(self, other: Self) -> Self

Returns the symmetric difference between the flags in self and other.

Specifically, the returned set contains the flags present which are present in self or other, but that are not present in both. Equivalently, it contains the flags present in exactly one of the sets self and other.

This is equivalent to using the ^ operator (e.g. ops::BitXor), as in flags ^ other.

pub const fn complement(self) -> Self

Returns the complement of this set of flags.

Specifically, the returned set contains all the flags which are not set in self, but which are allowed for this type.

Alternatively, it can be thought of as the set difference between Self::all() and self (e.g. Self::all() - self)

This is equivalent to using the ! operator (e.g. ops::Not), as in !flags.

Trait Implementations

impl Binary for Flags

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

Formats the value using the given formatter.

impl BitAnd<Flags> for Flags

fn bitand(self, other: Self) -> Self

Returns the intersection between the two sets of flags.

type Output = Flags

The resulting type after applying the & operator.

impl BitAndAssign<Flags> for Flags

fn bitand_assign(&mut self, other: Self)

Disables all flags disabled in the set.

impl BitOr<Flags> for Flags

fn bitor(self, other: Flags) -> Self

Returns the union of the two sets of flags.

type Output = Flags

The resulting type after applying the | operator.

impl BitOrAssign<Flags> for Flags

fn bitor_assign(&mut self, other: Self)

Adds the set of flags.

impl BitXor<Flags> for Flags

fn bitxor(self, other: Self) -> Self

Returns the left flags, but with all the right flags toggled.

type Output = Flags

The resulting type after applying the ^ operator.

impl BitXorAssign<Flags> for Flags

fn bitxor_assign(&mut self, other: Self)

Toggles the set of flags.

impl Clone for Flags

fn clone(&self) -> Flags

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Flags

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

Formats the value using the given formatter.

impl Extend<Flags> for Flags

fn extend<T: IntoIterator<Item = Self>>(&mut self, iterator: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl FromIterator<Flags> for Flags

fn from_iter<T: IntoIterator<Item = Self>>(iterator: T) -> Self

Creates a value from an iterator.

impl Hash for Flags

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 LowerHex for Flags

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

Formats the value using the given formatter.

impl Not for Flags

fn not(self) -> Self

Returns the complement of this set of flags.

type Output = Flags

The resulting type after applying the ! operator.

impl Octal for Flags

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

Formats the value using the given formatter.

impl Ord for Flags

fn cmp(&self, other: &Flags) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl PartialEq<Flags> for Flags

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<Flags> for Flags

fn partial_cmp(&self, other: &Flags) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Sub<Flags> for Flags

fn sub(self, other: Self) -> Self

Returns the set difference of the two sets of flags.

type Output = Flags

The resulting type after applying the - operator.

impl SubAssign<Flags> for Flags

fn sub_assign(&mut self, other: Self)

Disables all flags enabled in the set.

impl UpperHex for Flags

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

Formats the value using the given formatter.

impl Copy for Flags

impl Eq for Flags

impl StructuralEq for Flags

impl StructuralPartialEq for Flags