Enum QoSHistoryPolicy

pub enum QoSHistoryPolicy {
    SystemDefault {
        depth: u32,
    },
    KeepLast {
        depth: u32,
    },
    KeepAll,
}

The HISTORY DDS QoS policy.

A subscription internally maintains a queue of messages (called “samples” in DDS) that have not been processed yet by the application, and likewise a publisher internally maintains a queue.

If the history policy is KeepAll, this queue is unbounded, and if it is KeepLast, it is bounded and old values are discarded when the queue is overfull.

The rmw layer may not be able to handle very large queue depths, e.g. greater than i32::MAX. In this case, the functions taking the QoS profile as an argument will return an error.

Compatibility

Publisher	Subscription	Compatible
KeepLast	KeepLast	yes
KeepLast	KeepAll	yes
KeepAll	KeepLast	yes
KeepAll	KeepAll	yes

Variants

SystemDefault

Use the default policy of the RMW layer.

If the default policy is KeepAll, the depth will be ignored.

Fields

depth: u32

The length of the publisher/subscription queue.

KeepLast

Keep only the depth most recent messages.

Fields

depth: u32

The length of the publisher/subscription queue.

KeepAll

Keep all messages, at least until other resource limits are exceeded.

Trait Implementations

impl Clone for QoSHistoryPolicy

fn clone(&self) -> QoSHistoryPolicy

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for QoSHistoryPolicy

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

Formats the value using the given formatter.

impl Ord for QoSHistoryPolicy

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

This method returns an Ordering between self and other.

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

where Self: Sized,

Compares and returns the maximum of two values.

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

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for QoSHistoryPolicy

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl PartialOrd for QoSHistoryPolicy

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl Copy for QoSHistoryPolicy

impl Eq for QoSHistoryPolicy

impl StructuralPartialEq for QoSHistoryPolicy