Detects lines of code where the operator ADR is applied for a constant
Justification: Using a pointer to a constant variables overrides the CONSTANT property of the variable. The variable can be changed by means of the pointer without
any notification from the compiler.
Exception: In rare cases, it might be useful to pass a pointer to a constant to a
function. However, you have to make sure that this function does not change the transferred
value. Whenever possible, use VAR_IN_OUT CONSTANT.
Importance: High
When the “replace constants” option is selected in the “Compiler options” of the project settings, the address operator is not permitted for scalar constants (integer, BOOL, REAL) and a complie error is issued. (Constant strings, structures, and arrays always have an address.)
Example
PROGRAM PLC_PRG VAR CONSTANT c_iValue : INT := INT#15; END_VAR VAR poiValue : POINTER TO INT; END_VAR poiValue := ADR(c_iValue); // SA0007 --> SA0007: Address to constant variable 'c_iValue'