PG_FREE_IF_COPY()

Given the following snippet:

HeapTupleHeader tuple;
Datum temp;
bool isnull;

tuple = PG_GETARG_HEAPTUPLEHEADER(0);
temp = GetAttributeByName(tuple, "data", &isnull);

When using this for a btree operator functions, you need to
PG_FREE_IF_COPY(?,?);

Which of the above parameters need I free?

tuple, or temp,.... Or both?

... John