Availability:C-language interface function
int PL_get_string_chars(term_t 
+t, char **s, size_t *len)If t is a string object, store a pointer to a 0-terminated 
C-string in s and the length of the string in len. 
Note that this pointer is invalidated by backtracking, garbage 
collection and stack-shifts, so generally the only safe operations are 
to pass it immediately to a C function that doesn't involve Prolog.