CAsyncCallBack Class Reference

#include <e32base.h>

Link against: euser_v5.lib

class CAsyncCallBack : public CAsyncOneShot

Inherits from

Detailed Description

An active object that performs its processing through an associated call back function, and which is only performed once.

Member Attribute Documentation

iCallBack

TCallBack iCallBack[protected]

The callback object that encapsulates the callback function.

Constructor & Destructor Documentation

CAsyncCallBack ( TInt )

IMPORT_CCAsyncCallBack(TIntaPriority)

Constructor taking a priority value.

Specifically, the constructor sets this active object's priority value through a call to the base class constructor in its ctor list.

No call back is set, which means that it must be set subsequently through a call to the Set() function.

See also: CAsyncCallBack::Set

Parameters
aPriorityThe active object priority value. CActive::TPriority defines a standard set of priorities.

CAsyncCallBack ( const TCallBack &, TInt )

IMPORT_CCAsyncCallBack(const TCallBack &aCallBack,
TIntaPriority
)

Constructor taking a priority value and a callback.

Specifically, the constructor:

1. sets this active object's priority value through a call to the base class constructor in its ctor list

2. sets the callback; the function encapsulated by the callback is called when this active object is scheduled to run.

Parameters
aCallBackA reference to a callback object encapsulating a function which is called when this active object is ready to run. The constructor takes a copy of this callback object, which means that it can be safely discarded after construction.
aPriorityThe active object priority value.

~CAsyncCallBack ( )

IMPORT_C~CAsyncCallBack()[virtual]

Destructor.

Member Function Documentation

CallBack ( )

IMPORT_C voidCallBack()

Queues this active object to be run, if it is not already queued.

RunL ( )

voidRunL()[protected, virtual]

Reimplemented from CActive::RunL()

Calls the callback function.

See also: TCallBack::CallBack

Set ( const TCallBack & )

IMPORT_C voidSet(const TCallBack &aCallBack)

Sets the call back.

Parameters
aCallBackA reference to a callback object encapsulating a function which is called when this active object is ready to run.
Panic Codes
E32USER-CBase1 if the active object is currently active.