Class CSubscriber

Class CSubscriber#

Defined in File ecal_subscriber.h

Inheritance Relationships#

Derived Type#

public eCAL::CMsgSubscriber< T > (Template Class CMsgSubscriber)

Class Documentation#

class CSubscriber#

eCAL subscriber class.

The CSubscriber

class is used to receive topics from matching eCAL publishers.

For receiving the topic payload the subscriber class provides a callback interface and overloaded receive methods.

// create subscriber, topic name "A"
eCAL::CSubscriber sub("A");

//---------------------------------------------------------------------------------------
// receive content with 100 ms timeout as standard string and read receive time stamp
//---------------------------------------------------------------------------------------
std::string rcv_s;
long long time = 0;
size_t rcv_len = sub.Receive(rcv_s, &time, 100);

//---------------------------------------------------------------------------------------
// receive content with a callback functions
//---------------------------------------------------------------------------------------
void OnReceive(const char* topic_name_, const struct eCAL::SReceiveCallbackData* data_)
{
  size_t      size = data_->size;
  const void* data = data_->buf;
  long long   time = data_->time;
}

// add callback
sub.AddReceiveCallback(std::bind(OnReceive, std::placeholders::_1, std::placeholders::_2));

// idle main thread
while(eCAL::Ok())
{
  // sleep 100 ms
  std::this_thread::sleep_for(std::chrono::milliseconds(100));
}

Subclassed by eCAL::CMsgSubscriber< T >

Public Functions

ECAL_API CSubscriber()#: Constructor.

ECAL_API CSubscriber(const std::string &topic_name_, const std::string &topic_type_, const std::string &topic_desc_ = "")#

Constructor.

Deprecated:: Please use the constructor CSubscriber(const std::string& topic_name_, const SDataTypeInformation& topic_info_) instead. This function will be removed in future eCAL versions..

Parameters:

topic_name_ – Unique topic name.
topic_type_ – Type name (optional for type checking).
topic_desc_ – Type description (optional for description checking).

ECAL_API CSubscriber(const std::string &topic_name_, const SDataTypeInformation &topic_info_)#

Constructor.

Parameters:

topic_name_ – Unique topic name.
topic_info_ – Topic information (encoding, type, descriptor)

ECAL_API CSubscriber(const std::string &topic_name_)#

Constructor.

Parameters:: topic_name_ – Unique topic name.

ECAL_API virtual ~CSubscriber()#: Destructor.

ECAL_API CSubscriber(const CSubscriber&) = delete#: CSubscribers are non-copyable.

ECAL_API CSubscriber &operator=(const CSubscriber&) = delete#: CSubscribers are non-copyable.

ECAL_API CSubscriber(CSubscriber &&rhs) noexcept#: CSubscribers are move-enabled.

ECAL_API CSubscriber &operator=(CSubscriber &&rhs) noexcept#: CSubscribers are move-enabled.

ECAL_API bool Create(const std::string &topic_name_, const std::string &topic_type_, const std::string &topic_desc_ = "")#

Creates this object.

Deprecated:: Please use the create method bool Create(const std::string& topic_name_, const STopicInformation& topic_info_) instead. This function will be removed in future eCAL versions.

Parameters:

topic_name_ – Unique topic name.
topic_type_ – Type name (optional for type checking).
topic_desc_ – Type description (optional for description checking).

Returns:

true if it succeeds, false if it fails.

ECAL_API inline bool Create(const std::string &topic_name_)#

Creates this object.

Parameters:: topic_name_ – Unique topic name.
Returns:: True if it succeeds, false if it fails.

ECAL_API bool Create(const std::string &topic_name_, const SDataTypeInformation &topic_info_)#

Creates this object.

Parameters:

topic_name_ – Unique topic name.
topic_info_ – Topic information (encoding, type, descriptor)

Returns:

True if it succeeds, false if it fails.

ECAL_API bool Destroy()#

Destroys this object.

Returns:: true if it succeeds, false if it fails.

ECAL_API bool SetQOS(const QOS::SReaderQOS &qos_)#

Set subscriber quality of service attributes.

Deprecated:: Will be removed in future eCAL versions.

Parameters:: qos_ – Quality of service policies.
Returns:: True if it succeeds, false if it fails.

ECAL_API QOS::SReaderQOS GetQOS()#

Get current subscriber quality of service attributes.

Deprecated:: Will be removed in future eCAL versions.

Returns:: Quality of service attributes.

ECAL_API bool SetID(const std::set<long long> &id_set_)#

Set a set of id’s to prefiltering topics (see CPublisher::SetID).

Parameters:: id_set_ – Set of id’s.
Returns:: True if it succeeds, false if it fails.

ECAL_API bool SetAttribute(const std::string &attr_name_, const std::string &attr_value_)#

Sets subscriber attribute.

This feature is marked as experimental:

Parameters:

attr_name_ – Attribute name.
attr_value_ – Attribute value.

Returns:

True if it succeeds, false if it fails.

ECAL_API bool ClearAttribute(const std::string &attr_name_)#

Removes subscriber attribute.

This feature is marked as experimental:

Parameters:: attr_name_ – Attribute name.
Returns:: True if it succeeds, false if it fails.

ECAL_API size_t Receive(std::string &buf_, long long *time_ = nullptr, int rcv_timeout_ = 0) const#

Receive a message from the publisher.

Deprecated:: Please use the method bool ReceiveBuffer(std::string& buf_, long long* time_ = nullptr, int rcv_timeout_ = 0) instead. This function will be removed in future eCAL versions.

Parameters:

buf_ – [out] Standard string for copying message content.
time_ – [out] Time from publisher in us (default = nullptr).
rcv_timeout_ – Maximum time before receive operation returns (in milliseconds, -1 means infinite).

Returns:

Length of received buffer.

ECAL_API bool ReceiveBuffer(std::string &buf_, long long *time_ = nullptr, int rcv_timeout_ = 0) const#

Receive a message from the publisher (able to process zero length buffer).

Parameters:

buf_ – [out] Standard string for copying message content.
time_ – [out] Time from publisher in us (default = nullptr).
rcv_timeout_ – Maximum time before receive operation returns (in milliseconds, -1 means infinite).

Returns:

True if it succeeds, false if it fails.

ECAL_API bool AddReceiveCallback(ReceiveCallbackT callback_)#

Add callback function for incoming receives.

Parameters:: callback_ – The callback function to add.
Returns:: True if succeeded, false if not.

ECAL_API bool RemReceiveCallback()#

Remove callback function for incoming receives.

Returns:: True if succeeded, false if not.

ECAL_API bool AddEventCallback(eCAL_Subscriber_Event type_, SubEventCallbackT callback_)#

Add callback function for subscriber events.

Parameters:

type_ – The event type to react on.
callback_ – The callback function to add.

Returns:

True if succeeded, false if not.

ECAL_API bool RemEventCallback(eCAL_Subscriber_Event type_)#

Remove callback function for subscriber events.

Parameters:: type_ – The event type to remove.
Returns:: True if succeeded, false if not.

ECAL_API inline bool IsCreated() const#

Query if this object is created.

Returns:: true if created, false if not.

ECAL_API size_t GetPublisherCount() const#

Query the number of publishers.

Returns:: Number of publishers.

ECAL_API std::string GetTopicName() const#

Gets name of the connected topic.

Returns:: The topic name.

ECAL_API std::string GetTypeName() const#

Gets type of the connected topic.

Deprecated:: Please use the method SDataTypeInformation GetDataTypeInformation() instead. You can extract the typename from the SDataTypeInformation variable. This function will be removed in future eCAL versions.

Returns:: The type name.

ECAL_API std::string GetDescription() const#

Gets description of the connected topic.

Deprecated:: Please use the method SDataTypeInformation GetDataTypeInformation() instead. You can extract the descriptor from the SDataTypeInformation variable. This function will be removed in future eCAL versions.

Returns:: The description.

ECAL_API SDataTypeInformation GetDataTypeInformation() const#

Gets description of the connected topic.

Returns:: The topic information.

ECAL_API bool SetTimeout(int timeout_)#

Set the timeout parameter for triggering the timeout callback.

Deprecated:: Will be removed in future eCAL versions.

Parameters:: timeout_ – The timeout in milliseconds.
Returns:: True if succeeded, false if not.

ECAL_API std::string Dump(const std::string &indent_ = "") const#

Dump the whole class state into a string.

Parameters:: indent_ – Indentation used for dump.
Returns:: The dump sting.

Class CSubscriber

Contents

Class CSubscriber#

Inheritance Relationships#

Derived Type#

Class Documentation#