SA0009: Unused return values

Detects function, method and property calls in which the return value is not used

Justification: When a function or method returns a return value, you should also evaluate it. The return value often indicates whether or not the function has been executed successfully. If there is no evaluation, then you will not be able to identify later whether the return value was forgotten or if it is actually not needed.

Exception: If a return value is irrelevant for the call, then you should document this and omit the assignment. Error returns should never be ignored.

Importance: Medium

PLCopen rule: CP7 / CP17

FUNCTION Return_BOOL : BOOL
VAR_INPUT
END_VAR
VAR
    xTest : BOOL;
END_VAR

xTest := FALSE;
Return_BOOL := xTest;

PROGRAM PLC_PRG
Return_BOOL();  // SA0009