Blackboard Vector Invalid

[CPP]
I want to do a if check that checks if blackboard vector is invalid.
when I UE_LOG it , the value (340282346638528859811704183484516925440.000
,340282346638528859811704183484516925440.000
,340282346638528859811704183484516925440.000)
return.
you think its ok to use this value as the if or there is a better way,
of course invalid would never suppose to happen but just to be sure.