SA0046: Possible use of not initialised interface

Detects the use of interfaces that were not initialized before being used

Justification: An interface reference should be checked for <> 0 before it is used. Otherwise an access violation may occur during access.

Importance: High

Example 115. Example

//Declaration of INTERFACE ITF and assigned METH2:
METHOD METH2 : BOOL
VAR_INPUT
    iInput2:INT;
END_VAR

//Declaration of INTERFACE Master_ITF1 and assigned METH:
METHOD METH : BOOL
VAR_INPUT
    iInput:INT;
END_VAR

PROGRAM PLC_PRG
VAR
    instPOU : POU;
    instITF : ITF;
    instMasterITF1 : Master_ITF1;
    instMasterITF2 : Master_ITF2;
    iDummy : INT;
    xDummy : BOOL;
    instNoInitITF : ITF;
    instNoInitITF2 : ITF;
    instNoInitMasterITF1 : Master_ITF1;
    instNoInitMasterITF2 : Master_ITF2;
END_VAR

instITF := instPOU;
xDummy := instITF.METH(iInput := iDummy);    // OK
instMasterITF1 := instPOU;
xDummy := instMasterITF1.METH(iInput := iDummy);    // OK

xDummy := instNoInitITF.METH(iInput := INT#1);    // SA0046
xDummy := instNoInitITF.METH2(iInput2 := INT#2);    // SA0046
xDummy := instNoInitMasterITF1.METH(iInput := INT#3);    // SA0046
iDummy := instNoInitMasterITF2.Prop;    // SA0046

IF instNoInitITF <> 0 THEN
    instNoInitITF.Prop;    // OK, because the interface can't be 0
END_IF

Output in the Messages view:

SA0046: Possible use of not initialised interface 'instNoInitITF'
SA0046: Possible use of not initialised interface 'instNoInitITF'
SA0046: Possible use of not initialised interface 'instNoInitMasterITF1'
SA0046: Possible use of not initialised interface 'instNoInitMasterITF2'