EXPT block returns a wrong value under certain target system in case of an invalid connection

Symptom:

In case of an invalid connection of the EXPT block with ANY_REAL values (see example), the block should return "Not-a-Number" (NaN). Moreover, the example checks the validity of the ANY_REAL value with the IS_VALID block because the IS_VALID block will return the value FALSE in case of "NaN".
However, this is not the case for the platform "vxWorks x86".

Example for ST-code

FUNCTION_BLOCK ExampleExptInvalid2
  VAR
   resultRealInvalid : REAL;
  END_VAR
 
  resultRealInvalid:= EXPT(IN1 := REAL#-25.0, IN2 := REAL#0.5);
  (* For the built-in PLC, 'resultRealInvalid' evaluates to 'NaN' in the 'Values of Variables* view. *)
  (* But this is not the case for vxWorks x86. *)
  ASSERT(NOT IS_VALID(resultRealInvalid));
 
END_FUNCTION_BLOCK

Workaround: none existing

logi.cals recommends to install and use the most current versions of logi.CAD 3 and the runtime system so that the latest features and problem fixes according to the release notes are provided in the used version.

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