following functions are available for creating and inspecting atoms:

atom_t PL_new_atom_nchars(size_t len, const char *s)

Create a new atom as PL_new_atom(), but using the given length and characters. If len is (size_t)-1, it is computed from s using strlen(). See PL_new_atom() for error handling.

const char * PL_atom_nchars(atom_t a, size_t *len)

Extract the text and length of an atom. If you do not need the length, pass NULL as the value of len. If PL_atom_nchars() is called for a blob, NULL is returned.