FW_SafeRelease
This function decrements the reference counter of the object, analogous to ITcUnknown.TcRelease(), and at the same time sets the interface pointer to zero.
Return value
FW_SafeRelease : HRESULT;
Name | Type | Description |
|---|---|---|
FW_SafeRelease | HRESULT | Returns S_OK if the function call was successful. |
Inputs
VAR_INPUT
pipUnk : POINTER TO ITcUknown;
END_VAR
Name | Type | Description |
|---|---|---|
pipUnk | POINTER TO ITcUknown | Specifies the address of the interface pointer to the object. The interface pointer is checked internally for null pointers. |
Example
This function can for example be called in the destructor of the object family, which holds an interface pointer to another object.
METHOD FB_exit : BOOL
VAR_INPUT
bInCopyCode : BOOL; // if TRUE, the exit method is called for exiting an instance that is copied afterwards (online change).
END_VAR
-----------------------------------------------------------------------
IF NOT bInCopyCode THEN // no online change
FW_SafeRelease(ADR(ipItf));
END_IF
Requirements
TwinCAT Version | Hardware | Libraries to be integrated |
|---|---|---|
TwinCAT 3.1, Build 4020 | x86, x64, ARM | Tc3_Module |