RMsgQueue Class Reference

class RMsgQueue : public RMsgQueueBase

A handle to a message queue.

The templated class provides the behaviour for managing an asynchronous queue of messages, where the template parameter defines the message type.

The class adds a type-checking interface to the basic message queue functionality provided by RMsgQueueBase.

Inherits from

Public Member Functions
TInt CreateGlobal(const TDesC &, TInt, TOwnerType)
TInt CreateLocal(TInt, TOwnerType)
TInt Receive(T &)
voidReceiveBlocking(T &)
TInt Send(const T &)
voidSendBlocking(const T &)
Inherited Functions
RHandleBase::Attributes()const
RHandleBase::BTraceId()const
RHandleBase::Close()
RHandleBase::DoExtendedClose()
RHandleBase::Duplicate(const RThread &,TOwnerType)
RHandleBase::FullName()const
RHandleBase::FullName(TDes &)const
RHandleBase::Handle()const
RHandleBase::HandleInfo(THandleInfo *)
RHandleBase::Name()const
RHandleBase::NotifyDestruction(TRequestStatus &)
RHandleBase::Open(const TFindHandleBase &,TOwnerType)
RHandleBase::OpenByName(const TDesC &,TOwnerType,TInt)
RHandleBase::RHandleBase()
RHandleBase::RHandleBase(TInt)
RHandleBase::SetHandle(TInt)
RHandleBase::SetHandleNC(TInt)
RHandleBase::SetReturnedHandle(TInt)
RHandleBase::SetReturnedHandle(TInt,RHandleBase &)
RMsgQueueBase::CancelDataAvailable()
RMsgQueueBase::CancelSpaceAvailable()
RMsgQueueBase::CreateGlobal(const TDesC &,TInt,TInt,TOwnerType)
RMsgQueueBase::CreateLocal(TInt,TInt,TOwnerType)
RMsgQueueBase::MessageSize()
RMsgQueueBase::NotifyDataAvailable(TRequestStatus &)
RMsgQueueBase::NotifySpaceAvailable(TRequestStatus &)
RMsgQueueBase::Open(RMessagePtr2,TInt,TOwnerType)
RMsgQueueBase::Open(TInt,TOwnerType)
RMsgQueueBase::OpenGlobal(const TDesC &,TOwnerType)
RMsgQueueBase::Receive(TAny *,TInt)
RMsgQueueBase::ReceiveBlocking(TAny *,TInt)
RMsgQueueBase::Send(const TAny *,TInt)
RMsgQueueBase::SendBlocking(const TAny *,TInt)
Inherited Enumerations
RHandleBase:TAttributes
RMsgQueueBase:@43
Inherited Attributes
RHandleBase::iHandle

Member Functions Documentation

CreateGlobal(const TDesC &, TInt, TOwnerType)

TInt CreateGlobal(const TDesC &aName,
TIntaSize,
TOwnerTypeaType = EOwnerProcess
)[inline]

Creates a global message queue, and opens a handle to that message queue.

If the name is non-empty, the message queue is visible to all processes. If the name is empty it cannot be opened or searched for by name, but a handle to it can be passed to another process as a process parameter or via IPC.

The size of each message in the queue is the size of the template parameter type. This must conform to the restrictions imposed on the aMsgLength parameter passed to the base class function RMsgQueueBase::CreateGlobal().

KErrNone if the queue is created sucessfully, otherwise one of the other system wide error codes.

panic

KERN-EXEC 49 if aSize is less than or equal to zero.

panic

KERN-EXEC 48 if the size of the template parameter type is not a multiple of 4 bytes, is less than 4, or is greater than KMaxLength.

RMsgQueueBase::CreateGlobal

KMaxLength

Parameters

const TDesC & aNameThe name to be assigned to the message queue.
TInt aSizeThe number of message 'slots' in the queue. This must be a positive value, i.e. greater than zero.
TOwnerType aType = EOwnerProcessThe type of handle to be created. EOwnerProcess is the default value, if not explicitly specified.

CreateLocal(TInt, TOwnerType)

TInt CreateLocal(TIntaSize,
TOwnerTypeaType = EOwnerProcess
)[inline]

Creates a message queue that is private to the current process, and opens a handle to that message queue.

The size of each message in the queue is the size of the template parameter type. This must conform to the restrictions imposed on the aMsgLength parameter passed to the base class function RMsgQueueBase::CreateLocal().

KErrNone if the queue is created sucessfully, otherwise one of the other system wide error codes.

panic

KERN-EXEC 49 if aSize is less than or equal to zero.

panic

KERN-EXEC 48 if the size of the template parameter type is not a multiple of 4 bytes, is less than 4, or is greater than KMaxLength.

RMsgQueueBase::CreateLocal

KMaxLength

Parameters

TInt aSizeThe number of message 'slots' in the queue. This must be a positive value, i.e. greater than zero.
TOwnerType aType = EOwnerProcessThe type of handle to be created. EOwnerProcess is the default value, if not explicitly specified.

Receive(T &)

TInt Receive(T &aMsg)[inline]

Retrieves the first message in the queue.

The function does not wait (i.e. block), if the queue is empty.

The function is implemented through a call to RMsgQueueBase::Receive().

KErrNone, ifsuccessful; KErrUnderflow, if the queue is empty.

RMsgQueueBase::Receive

Parameters

T & aMsgThe object into which the message is retrieved.

ReceiveBlocking(T &)

voidReceiveBlocking(T &aMsg)[inline]

Retrieves the first message in the queue, and waits if the queue is empty.

The function uses NotifyDataAvailable() to provide the blocking operation. Note it is not possible to cancel a call to ReceiveBlocking().

The function is implemented through a call to RMsgQueueBase::ReceiveBlocking().

RMsgQueueBase::ReceiveBlocking

Parameters

T & aMsgThe object into which the message is retrieved.

Send(const T &)

TInt Send(const T &aMsg)[inline]

Sends a message through this queue.

The function does not wait (i.e. block), if the queue is full.

The function is implemented through a call to RMsgQueueBase::Send().

KErrNone, if successful; KErrOverflow, if queue is full,

RMsgQueueBase::Send

Parameters

const T & aMsgThe message data to be sent.

SendBlocking(const T &)

voidSendBlocking(const T &aMsg)[inline]

Sends a message through this queue, and waits for space to become available if the queue is full.

The function uses NotifySpaceAvailable() to provide the blocking operation. Note that it is not possible to cancel a call to SendBlocking().

The function is implemented through a call to RMsgQueueBase::SendBlocking().

RMsgQueueBase::SendBlocking

Parameters

const T & aMsgThe message data to be sent.