Availability:C-language interface function
const char* PL_atom_chars(atom_t 
atom)Deprecated. This function returns a pointer to the content represented 
by the atom or blob regardless of its type. New code that uses blobs 
should use the blob functions such as PL_blob_data() 
to get a pointer to the content, the size of the content, and the type 
of the content. Most applications that need to get text from a term_t 
handle should use PL_atom_nchars(), PL_atom_wchars(), 
or PL_atom_mbchars(). 
If it is
known that atom is a classical Prolog text atom, one 
can use PL_atom_nchars() 
to obtain the C string and its length (for ISO-Latin-1 atoms) or PL_atom_wchars() 
to obtain a C wide string (wchar_t).