Method ITcIoCyclicCaller:AddIoDriver

Reports the ITcIoCyclic interface of a module to a cyclic I/O caller, e.g. a TwinCAT task.

Syntax


virtual HRESULT TCOMAPI AddIoDriver(STcIoCyclicEntry* 
pEntry, ITcIoCyclic* ipDrv, ULONG_PTR context=0, ULONG sortOrder=0)=0;

Parameter

pEntry: (type: STcIoCyclicEntry) pointer to a list item that is inserted into the internal list of the cyclic I/O caller; see also description.

ipDrv: (type: ITcloCyclic) [in] interface pointer used by the cyclic I/O caller.

context: (type: ULONG_PTR) [optional] a context value that is transferred to the ITcIoCyclic::InputUpdate() and ITcIoCyclic::OutputUpdate methods with each call.

sortOrder: (type: ULONG) [optional] the sorting order can be used for controlling the order of execution if various module instances are executed by the same cyclic caller.

Return value

If successful, S_OK ("0") or another positive value will be returned, cf. Return values. Extended messages refer in particular to the column HRESULT in ADS Return Codes.

Description

A TwinCAT module class normally uses a Smart Pointer to refer to the cyclic I/O caller of type ITcIoCyclicCallerPtr. The object ID of the cyclic I/O caller is stored in this Smart Pointer and a reference can be obtained via the TwinCAT object server. In addition, the Smart Pointer class already contains a list item. Therefore the Smart Pointer can be used as the first parameter for the AddIoDriver method.

The following code sample illustrates the login of the ITcIoCyclicCaller interface.

HRESULT hr = S_OK;
if ( m_spIoCyclicCaller.HasOID() )
{
if ( SUCCEEDED_DBG(hr = m_spSrv->TcQuerySmartObjectInterface(m_spIoCyclicCaller)) 
)
{
if ( FAILED(hr = m_spIoCyclicCaller->AddIoDriver(m_spIoCyclicCaller, 
THIS_CAST(ITcIoCyclic))) )
{
m_spIoCyclicCaller = NULL;
    }
 }
}