Confused about erl_free_term

[Ashok P. Nadkarni]

I'm confused about allocation/freeing of terms when using the 
erl_interface library.

Suppose I have code as follows:

t1 = erl_decode(blah blah....);
t2 = erl_hd(t1);

Once I'm done using t1 and t2, do I have to call erl_free_term for both 
t1 and t2 ? Or will calling erl_free_term(t1) also free t2? If I do have 
to call erl_free_term separately for both, could I instead call 
erl_free_compound(t1) to get the same effect?

Thanks in advance,

/Ashok