Availability:C-language interface function
size_t PL_atom_index(atom_t
atom)Extract the index of an atom. This is a relatively small
integer. Atoms are numbered sequentially, starting at one (1). Note that
the sequence may have holes due to atom garbage collection. The released
index may later be reused for a new atom. The index may be used as a
compact identifier for the atom. Extracting the index has no impact on
the lifetime of the atom, i.e., the index is valid as long as the atom_t
is valid.