Fast DDS  Version 3.0.1
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HistoryQosPolicy Class Reference

Specifies the behavior of the Service in the case where the value of a sample changes (one or more times) before it can be successfully communicated to one or more existing subscribers. More...

#include <QosPolicies.hpp>

Inheritance diagram for HistoryQosPolicy:

Public Member Functions

FASTDDS_EXPORTED_API HistoryQosPolicy ()
 Constructor.
 
virtual FASTDDS_EXPORTED_API ~HistoryQosPolicy ()=default
 Destructor.
 
bool operator== (const HistoryQosPolicy &b) const
 
void clear () override
 Clears the QosPolicy object.
 
- Public Member Functions inherited from Parameter_t
FASTDDS_EXPORTED_API Parameter_t ()
 Constructor without parameters.
 
FASTDDS_EXPORTED_API Parameter_t (ParameterId_t pid, uint16_t length)
 Constructor using a parameter PID and the parameter length.
 
virtual FASTDDS_EXPORTED_API ~Parameter_t ()
 Destructor.
 
bool operator== (const Parameter_t &b) const
 
- Public Member Functions inherited from QosPolicy
 QosPolicy ()
 Constructor without parameters.
 
 QosPolicy (bool send_always)
 Constructor.
 
 QosPolicy (const QosPolicy &b)=default
 Copy Constructor.
 
virtual ~QosPolicy ()=default
 Destructor.
 
bool operator== (const QosPolicy &b) const
 
QosPolicyoperator= (const QosPolicy &b)=default
 
virtual bool send_always () const
 Whether it should always be sent.
 

Public Attributes

HistoryQosPolicyKind kind
 HistoryQosPolicyKind.
By default, KEEP_LAST_HISTORY_QOS.
 
int32_t depth
 History depth.
 
- Public Attributes inherited from Parameter_t
ParameterId_t Pid
 Parameter ID.
By default, PID_PAD.
 
uint16_t length
 Parameter length.
By default, 0.
 
- Public Attributes inherited from QosPolicy
bool hasChanged
 Boolean that indicates if the Qos has been changed with respect to the default Qos.
 

Additional Inherited Members

- Protected Attributes inherited from QosPolicy
bool send_always_
 Boolean that indicates if the Qos has to be sent even if it is not changed.
 

Detailed Description

Specifies the behavior of the Service in the case where the value of a sample changes (one or more times) before it can be successfully communicated to one or more existing subscribers.

This QoS policy controls whether the Service should deliver only the most recent value, attempt to deliver all intermediate values, or do something in between. On the publishing side this policy controls the samples that should be maintained by the DataWriter on behalf of existing DataReader entities. The behavior with regards to a DataReaderentities discovered after a sample is written is controlled by the DURABILITY QoS policy. On the subscribing side it controls the samples that should be maintained until the application “takes” them from the Service.

Note
Immutable Qos Policy

Constructor & Destructor Documentation

◆ HistoryQosPolicy()

FASTDDS_EXPORTED_API HistoryQosPolicy ( )
inline

Constructor.

◆ ~HistoryQosPolicy()

virtual FASTDDS_EXPORTED_API ~HistoryQosPolicy ( )
virtualdefault

Destructor.

Member Function Documentation

◆ clear()

void clear ( )
inlineoverridevirtual

Clears the QosPolicy object.

Implements QosPolicy.

◆ operator==()

bool operator== ( const HistoryQosPolicy b) const
inline

Member Data Documentation

◆ depth

int32_t depth

History depth.


By default, 1. If a value other than 1 is specified, it should be consistent with the settings of the ResourceLimitsQosPolicy.

Warning
Only takes effect if the kind is KEEP_LAST_HISTORY_QOS.

◆ kind

HistoryQosPolicyKind.
By default, KEEP_LAST_HISTORY_QOS.


The documentation for this class was generated from the following file: