diff --git a/include/SWI-Prolog.h b/include/SWI-Prolog.h
index 54f863bd1..189bee1fe 100755
--- a/include/SWI-Prolog.h
+++ b/include/SWI-Prolog.h
@@ -362,6 +362,7 @@ typedef struct PL_blob_t
 
 extern X_API PL_agc_hook_t PL_agc_hook(PL_agc_hook_t);
 extern X_API char* PL_atom_chars(atom_t);
+extern X_API char* PL_atom_nchars(atom_t, size_t *);
 extern X_API term_t PL_copy_term_ref(term_t);
 extern X_API term_t PL_new_term_ref(void);
 extern X_API term_t PL_new_term_refs(int);
diff --git a/library/yap2swi/yap2swi.c b/library/yap2swi/yap2swi.c
index 76dea181d..a71b6fa5d 100755
--- a/library/yap2swi/yap2swi.c
+++ b/library/yap2swi/yap2swi.c
@@ -265,6 +265,15 @@ X_API char* PL_atom_chars(atom_t a)	 /* SAM check type */
   return RepAtom(SWIAtomToAtom(a))->StrOfAE;
 }
 
+/* SWI: char* PL_atom_chars(atom_t atom)
+   YAP: char* AtomName(Atom) */
+X_API char* PL_atom_nchars(atom_t a, size_t *len)	 /* SAM check type */
+{
+  char *s = RepAtom(SWIAtomToAtom(a))->StrOfAE;
+  *len = strlen(s);
+  return s;
+}
+
 X_API int
 PL_chars_to_term(const char *s, term_t term) { 
   YAP_Term t,error;