Wrapper class for posix message queue. More...

#include <message_queue.hpp>

Inheritance diagram for iox::posix::MessageQueue:

Collaboration diagram for iox::posix::MessageQueue:

Public Member Functions
	MessageQueue ()

	MessageQueue (const MessageQueue &other)=delete

	MessageQueue (MessageQueue &&other)

MessageQueue &	operator= (const MessageQueue &other)=delete

MessageQueue &	operator= (MessageQueue &&other)

cxx::expected< IpcChannelError >	destroy ()
	close and remove message queue.

cxx::expected< IpcChannelError >	send (const std::string &msg) const
	send a message to queue using std::string. More...

cxx::expected< std::string, IpcChannelError >	receive () const
	receive message from queue using std::string. More...

cxx::expected< std::string, IpcChannelError >	timedReceive (const units::Duration &timeout) const
	try to receive message from queue for a given timeout duration using std::string. Only defined for NON_BLOCKING == false. More...

cxx::expected< IpcChannelError >	timedSend (const std::string &msg, const units::Duration &timeout) const
	try to send a message to the queue for a given timeout duration using std::string

cxx::expected< bool, IpcChannelError >	isOutdated ()

Public Member Functions inherited from DesignPattern::Creation< MessageQueue, IpcChannelError >
	Creation (Creation &&rhs) noexcept

	Creation (const Creation &rhs) noexcept=default

Creation &	operator= (Creation &&rhs) noexcept

Creation &	operator= (const Creation &rhs) noexcept=default

bool	isInitialized () const noexcept
	returns true if the object was constructed successfully, otherwise false

Static Public Member Functions
static cxx::expected< bool, IpcChannelError >	unlinkIfExists (const IpcChannelName_t &name)

Static Public Member Functions inherited from DesignPattern::Creation< MessageQueue, IpcChannelError >
static result_t	create (Targs &&... args) noexcept
	factory method which guarantees that either a working object is produced or an error value describing the error during construction More...

static result_t	verify (MessageQueue &&newObject) noexcept
	verifies if a class was created successfully More...

static iox::cxx::expected< IpcChannelError >	placementCreate (void *const memory, Targs &&... args) noexcept
	factory method which guarantees that either a working object is produced or an error value describing the error during construction More...

Static Public Attributes
static constexpr mqd_t	INVALID_DESCRIPTOR = -1

static constexpr int32_t	ERROR_CODE = -1

static constexpr size_t	SHORTEST_VALID_QUEUE_NAME = 2

static constexpr size_t	NULL_TERMINATOR_SIZE = 1

static constexpr size_t	MAX_MESSAGE_SIZE = 4096

Friends
class	DesignPattern::Creation< MessageQueue, IpcChannelError >
	for calling private constructor in create method

Additional Inherited Members
Public Types inherited from DesignPattern::Creation< MessageQueue, IpcChannelError >
using	CreationPattern_t = Creation< MessageQueue, IpcChannelError >

using	result_t = iox::cxx::expected< MessageQueue, IpcChannelError >

using	errorType_t = IpcChannelError

Protected Attributes inherited from DesignPattern::Creation< MessageQueue, IpcChannelError >
bool	m_isInitialized

IpcChannelError	m_errorValue

Detailed Description

Wrapper class for posix message queue.

Template Parameters

NON_BLOCKING

specifies the type of message queue. A non-blocking message queue will immediately return from a send/receive call if the queue is full/empty. A blocking message has member functions timedSend and timedReceive which allow to specify a maximum timeout duration.

auto mq = posix::MessageQueue<true>::CreateMessageQueue("/MqName123");
if (mq.has_value())
{
    mq->send("important message, bla.");
    // ...
    std::string str;
    mq->receive(str);
}

Constructor & Destructor Documentation

◆ MessageQueue()

iox::posix::MessageQueue::MessageQueue ( )

default constructor. The result is an invalid MessageQueue object which can be reassigned later by using the move constructor.

Member Function Documentation

◆ receive()

cxx::expected<std::string, IpcChannelError> iox::posix::MessageQueue::receive ( ) const

receive message from queue using std::string.

Todo:: zero copy receive with receive(cxx::string&); cxx::string would be the buffer for mq_receive

Returns: number of characters received. In case of an error, returns -1 and msg is empty.

◆ send()

cxx::expected<IpcChannelError> iox::posix::MessageQueue::send ( const std::string & msg ) const

send a message to queue using std::string.

Returns: true if sent without errors, false otherwise

◆ timedReceive()

cxx::expected<std::string, IpcChannelError> iox::posix::MessageQueue::timedReceive ( const units::Duration & timeout ) const

try to receive message from queue for a given timeout duration using std::string. Only defined for NON_BLOCKING == false.

Returns: optional containing the received string. In case of an error, nullopt type is returned.

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

iceoryx_utils/internal/posix_wrapper/message_queue.hpp

Public Member Functions

Static Public Member Functions

Static Public Attributes

Friends