CILLPollThread

This class is only available in the RT environment. It has been derived from CIThread to ease the creation of a thread that has to execute regularly, using a low level alarm; the period runs independent of the thread. The class must be used to derive an application specific low level poll thread class, or it can be used directly to control a thread object.

Class members

Constructor

Destructor

Create

DoForever

OnPoll

SetPoll

Member variables

The following member variables are only available to the members of the class and its derived classes:

DWORD m_dwUsecs; KNHANDLE m_hAlarm; DWORD m_dwAlarm[KN_ALARM_EVENT_SIZE/4]; BOOLEAN m_bChanged;

CILLPollThread::Constructor

See CIThread::Constructor.

CILLPollThread::Destructor

See CIThread::Destructor. The destructor deletes the alarm, if it had been created already.

CILLPollThread::Create

If the object is already attached, it is first detached. Then this call creates a new RT thread object and attaches it to the object.

Syntax

DWORD CILLPollThread::Create(
    char * pszName, 
    DWORD dwUsecs,
    BYTE byPrio, 
    DWORD dwStack, 
    BOOLEAN bGo
);

Parameters

pszName: Specifies a name that, if not empty, is used to catalog the RT object.
dwUsecs: Indicates the number of usecs per poll period.
byPrio: Indicates the priority for the new thread and must either be zero (this means the best possible priority in the process) or obey this rule: (max priority of process) <= byPrio < 254.
dwStack: Indicates the number of bytes to be reserved for stack space; it should be a multiple of 4 and at least 2048; if omitted, 4096 is used.
bGo: Indicates whether the thread will execute immediately (TRUE) or will be created in suspended state (FALSE); if omitted, TRUE is used. The new thread creates the low level alarm object. The result is a status indicating success or failure.

Status

E_OK: No exceptional conditions occurred.
E_MEM: The current process cannot create a thread as specified with the memory available.
E_LIMIT: Either the calling thread's process already reached its object or thread limit, or the job does not allow the required priority, or the object directory is full.
E_SLOT: You cannot create more RT objects because the GDT's slots are full.
E_PARAM: dwStack contains a value of less than 2048, or the name is too long or is improperly formatted.
E_CONTEXT: The object directory already contains the name being cataloged.

CILLPollThread::DoForever

See CIThread::DoForever. CILLPollThread::DoForever is called by the framework and should never be called explicitly. CILLPollThread::DoForever waits for the alarm event, calls the OnPoll member and returns its result. When overruling this call, do not include a call to the default call.

CILLPollThread::OnPoll

CILLPollThread::OnPoll is called by the framework when a period has passed; it should never be called explicitly. CILLPollThread::OnPoll just returns TRUE. When overruling this call, there is no need to call the default call.

Syntax

BOOLEAN CILLPollThread::OnPoll(void);

Parameters

None. The result must be TRUE to let the thread continue, FALSE to terminate the thread.

CILLPollThread::SetPoll

With this call the poll period can be changed. The new value becomes active in the next period.

Syntax

void CILLPollThread::SetPoll(
    DWORD dwUsecs
);

Parameters

dwUsecs: Indicates the number of usecs per poll period.

Alarms

CreateRtAlarm