Detects method calls in the FB_Init method of a base function block, which are overwritten by a function block derived
from a base function block
Justification: In these cases, it could be that the variables in the overwritten methods are not initialized in the base FB.
Importance: High
Example
The function block FB_A includes the methods FB_Init and Meth_MyInit. FB_Init calls Meth_MyInit for initialization. The function block FB_B is derived from FB_A. PLC_PRG calls FB_B and therefore uses its mbMyDintB variable before it has been initialized. FB_B.Meth_MyInit overwrites FB_A.Meth_MyInit.
FUNCTION_BLOCK FB_A VAR mbMyDintA : DINT; END_VAR FUNCTION_BLOCK FB_B EXTENDS FB_A VAR mbMyDintB : DINT; END_VAR METHOD FB_Init : BOOL VAR_INPUT bInitRetains:BOOL; bInCopyCode:BOOL; END_VAR VAR diDummy:DINT; // SA0106 END_VAR mbMyDintA := 123; diDummy := Meth_MyInit(); METHOD Meth_MyInit : DINT VAR_INPUT END_VAR mbMyDintB := 123; // access to member of FB_B PROGRAM PLC_PRG VAR g_BInst : FB_B; xVar : BOOL; END_VAR xVar := g_BInst.fb_init(TRUE, TRUE); //this instruction causes the following order of initializations: //FB_A.fb_init //FB_B.Meth_MyInit // SA0106 //FB_B.fb_init //FB_B.Meth_MyInit --> SA0106: Virtual method call 'Meth_MyInit' in FB_INIT