Class RDevice

RDevice

Support

Supported from 5.0

Description

User side handle to an LDD factory object, an instance of a DLogicalDevice derived class.

The LDD factory object is a Kernel side object which is constructed on the Kernel heap when the logical device is opened using User::LoadLogicalDevice(). The handle allows the User side to get information about the logical device.

To use the device, a thread must create and use an instance of an RBusLogicalChannel derived class.

Derivation

RDevice User side handle to an LDD factory object, an instance of a DLogicalDevice derived class RHandleBase A handle to an object

Defined in RDevice:
GetCaps(), IsAvailable(), Open(), Open(), QueryVersionSupported()

Inherited from RHandleBase:
Close(), Duplicate(), Handle(), SetHandle()

See also:

• DLogicalDevice
• User::LoadLogicalDevice()
• RBusLogicalChannel

TInt Open(const TDesC& aName,TOwnerType aType=EOwnerProcess);

Description

Opens a handle to a specifically named LDD factory object.

Parameters

const TDesC& aName The name of the LDD factory object which is to be opened. TOwnerType aType An enumeration whose enumerators define the ownership of this handle. If not explicitly specified, EOwnerProcess is taken as default, and ownership is vested in the current process. Ownership can be vested in the current thread by passing the EOwnerThread enumerator.

Return value

TInt KErrNone, if successful; otherwise one of the other system wide error codes.

TInt Open(const TFindLogicalDevice& aFind,TOwnerType aType=EOwnerProcess);

Description

Opens a handle to an LDD factory object found using a TFindLogicalDevice object.

A TFindLogicalDevice object is used to find all LDD factory objects whose full names match a specified pattern.

Parameters

const TFindLogicalDevice& aFind Used to find LDD factory objects. TOwnerType aType An enumeration whose enumerators define the ownership of this handle. If not explicitly specified, EOwnerProcess is taken as default, and ownership is vested in the current process. Ownership can be vested in the current thread by passing the EOwnerThread enumerator.

Return value

TInt KErrNone, if successful; otherwise one of the other system wide error codes.

See also:

• TFindLogicalDevice

void GetCaps(TDes8& aDes) const;

Description

Gets the capabilities of this device.

A call to this function results in a call to the GetCaps() member function of the Kernel side LDD factory object, an instance of a DLogicalDevice derived class.

Parameters

TDes8& aDes On return, contains information about the capabilities of the device. The caller is responsible for supplying a descriptor with the appropriate maximum length.

Notes:

• The format and meaning of the information returned by this function depends on the logical device. No format is imposed by the function itself.

See also:

• DLogicalDevice::GetCaps()

TBool QueryVersionSupported(const TVersion& aVer) const;

Description

Tests whether the device includes support for the specified version.

A call to this function results in a call to the QueryVersionSupported() member function of the Kernel side LDD factory object, an instance of a DLogicalDevice derived class.

Parameters

const TVersion& aVer The version to be compared against the version of the device.

Return value

TBool True, if the device includes support for the specified version; false otherwise.

Notes:

• The meaning of "support for a version" depends on the device, but the most common interpretation is to assume that a higher version number implies more advanced behaviour than a lower version number.

See also:

• TVersion
• DLogicalDevice::QueryVersionSupported()

TBool IsAvailable(TInt aUnit,const TDesC* aPhysicalDevice,const TDesC* anInfo) const;

Description

Tests whether a unit is supported.

A call to this function results in a call to the IsAvailable() member function of the Kernel side LDD factory object, an instance of a DLogicalDevice derived class.

Parameters

TInt aUnit The unit const TDesC* aPhysicalDevice A pointer to a descriptor containing the name of the PDD; this pointer can be Null. const TDesC* anInfo A pointer to a descriptor containing additional information; this pointer can be Null.

Return value

TBool True, if the unit and the additional information coupled with the name of the PDD is supported; false otherwise.

Notes:

• The meaning of units is not defined by the device driver framework.