status.h File Reference

DDS-compatible status type hierarchy for VLink publisher and subscriber callbacks. More...

#include <cstdint>
#include <iostream>
#include <memory>
#include <string>
#include <type_traits>
#include "../base/exception.h"
#include "../base/macros.h"

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Classes
struct	vlink::Status::Base
	Abstract base class for all VLink status event objects. More...
struct	vlink::Status::Unknown
	Placeholder status returned when the transport reports an unrecognised event type. More...

Namespaces
namespace	vlink
namespace	vlink::Status
	DDS-compatible status type enumeration, base class, and type-safe cast utilities.

Typedefs
using	vlink::Status::InstanceHandle = const void*
	Opaque handle type for DDS instance identifiers.
using	vlink::Status::BasePtr = std::shared_ptr<Status::Base>
	Type alias for a shared pointer to a base status event.

Enumerations
enum	vlink::Status::Type : uint8_t {   vlink::Status::kUnknown = 0 , vlink::Status::kPublicationMatched = 1 , vlink::Status::kOfferedDeadlineMissed = 2 , vlink::Status::kOfferedIncompatibleQos = 3 ,   vlink::Status::kLivelinessLost = 4 , vlink::Status::kSubscriptionMatched = 5 , vlink::Status::kRequestedDeadlineMissed = 6 , vlink::Status::kLivelinessChanged = 7 ,   vlink::Status::kSampleRejected = 8 , vlink::Status::kRequestedIncompatibleQos = 9 , vlink::Status::kSampleLost = 10 }
	Discriminator for concrete status event types. More...

Functions
VLINK_EXPORT std::ostream &	vlink::Status::operator<< (std::ostream &ostream, const BasePtr &status) noexcept
	Writes the human-readable description of status to ostream.

Detailed Description

DDS-compatible status type hierarchy for VLink publisher and subscriber callbacks.

The Status namespace defines an event-driven status reporting model that mirrors the DDS status change notification system. When a transport-level event occurs (e.g., a new subscriber appears, a deadline is missed), the middleware creates a concrete Status::Base subclass and delivers it to the registered status callback.

Status types are divided into two groups:

Writer-side (DataWriter / Publisher / Server / Setter):

Type	Triggered when
kPublicationMatched	A matching subscriber appeared or disappeared
kOfferedDeadlineMissed	Writer failed to publish within its declared deadline
kOfferedIncompatibleQos	A subscriber with incompatible QoS was discovered
kLivelinessLost	Writer failed to assert liveliness within its duration

Reader-side (DataReader / Subscriber / Client / Getter):

Type	Triggered when
kSubscriptionMatched	A matching publisher appeared or disappeared
kRequestedDeadlineMissed	Reader did not receive data within its declared deadline
kLivelinessChanged	A writer's liveliness status changed
kSampleRejected	An incoming sample was rejected (resource limit hit)
kRequestedIncompatibleQos	A publisher with incompatible QoS was discovered
kSampleLost	A sample was lost before it could be delivered

Concrete status structs (counters, handles, etc.) are defined in status_detail.h.

Usage

auto sub = vlink::Subscriber<MyMsg>::create("dds://my_topic");
sub->register_status_callback([](vlink::Status::BasePtr status) {
    if (status->get_type() == vlink::Status::kSubscriptionMatched) {
        auto matched = status->as<vlink::Status::SubscriptionMatched>();
        VLOG_I("Matched publishers: ", matched->current_count);
    }
});