diff --git a/C/iopreds.c b/C/iopreds.c
index fc0e5b749..ab1a144a5 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -109,7 +109,6 @@ STATIC_PROTO (Int p_write2, (void));
 STATIC_PROTO (Int p_set_read_error_handler, (void));
 STATIC_PROTO (Int p_get_read_error_handler, (void));
 STATIC_PROTO (Int p_read, (void));
-STATIC_PROTO (Int p_peek, (void));
 STATIC_PROTO (Int p_past_eof, (void));
 STATIC_PROTO (Int p_put, (void));
 STATIC_PROTO (Int p_put_byte, (void));
@@ -1712,105 +1711,6 @@ p_past_eof (void)
   return out;
 }
 
-static Int
-p_peek_byte (void)
-{				/* at_end_of_stream */
-  /* the next character is a EOF */ 
-  int sno = CheckStream (ARG1, Input_Stream_f, "peek/2");
-  StreamDesc *s;
-  Int ocharcount, olinecount, olinepos;
-  Int status;
-  Int ch;
-
-  if (sno < 0)
-    return(FALSE);
-  status = Stream[sno].status;
-  if (!(status & Binary_Stream_f)) {
-    UNLOCK(Stream[sno].streamlock);
-    Yap_Error(PERMISSION_ERROR_INPUT_TEXT_STREAM, ARG1, "peek/2");
-    return(FALSE);
-  }
-  UNLOCK(Stream[sno].streamlock);
-  if (Stream[sno].stream_getc == PlUnGetc) {
-    ch = MkIntTerm(Stream[sno].och);
-    /* sequence of peeks */
-    return Yap_unify_constant(ARG2,ch);
-  }
-  if (status & Eof_Stream_f) {
-    Yap_Error(PERMISSION_ERROR_INPUT_PAST_END_OF_STREAM, ARG1, "peek/2");
-    return(FALSE);
-  }
-  s = Stream+sno;
-  ocharcount = s->charcount;
-  olinecount = s->linecount;
-  olinepos = s->linepos;
-  ch = Stream[sno].stream_getc(sno);
-  s->charcount = ocharcount;
-  s->linecount = olinecount;
-  s->linepos = olinepos;
-  /* buffer the character */
-  s->och = ch;
-  /* mark a special function to recover this character */
-  s->stream_getc = PlUnGetc;
-  s->stream_wgetc = get_wchar;
-  s->stream_gets = DefaultGets;
-  if (CharConversionTable != NULL)
-    s->stream_wgetc_for_read = ISOWGetc;
-  else
-    s->stream_wgetc_for_read = s->stream_wgetc;
-  UNLOCK(s->streamlock);
-  return(Yap_unify_constant(ARG2,MkIntTerm(ch)));
-}
-
-static Int
-p_peek (void)
-{				/* at_end_of_stream */
-  /* the next character is a EOF */ 
-  int sno = CheckStream (ARG1, Input_Stream_f, "peek/2");
-  StreamDesc *s;
-  Int ocharcount, olinecount, olinepos;
-  Int status;
-  Int ch;
-
-  if (sno < 0)
-    return(FALSE);
-  status = Stream[sno].status;
-  if (status & Binary_Stream_f) {
-    UNLOCK(Stream[sno].streamlock);
-    Yap_Error(PERMISSION_ERROR_INPUT_BINARY_STREAM, ARG1, "peek/2");
-    return FALSE;
-  }
-  UNLOCK(Stream[sno].streamlock);
-  if (Stream[sno].stream_getc == PlUnGetc) {
-    ch = MkIntTerm(Stream[sno].och);
-    /* sequence of peeks */
-    return Yap_unify_constant(ARG2,ch);
-  }
-  LOCK(Stream[sno].streamlock);
-  s = Stream+sno;
-  ocharcount = s->charcount;
-  olinecount = s->linecount;
-  olinepos = s->linepos;
-  UNLOCK(Stream[sno].streamlock);
-  ch = get_wchar(sno);
-  LOCK(Stream[sno].streamlock);
-  s->charcount = ocharcount;
-  s->linecount = olinecount;
-  s->linepos = olinepos;
-  /* buffer the character */
-  s->och = ch;
-  /* mark a special function to recover this character */
-  s->stream_getc = PlUnGetc;
-  s->stream_wgetc = get_wchar;
-  s->stream_gets = DefaultGets;
-  if (CharConversionTable != NULL)
-    s->stream_wgetc_for_read = ISOWGetc;
-  else
-    s->stream_wgetc_for_read = s->stream_wgetc;
-  UNLOCK(Stream[sno].streamlock);
-  return(Yap_unify_constant(ARG2,MkIntTerm(ch)));
-}
-
 static Int
 p_has_bom (void)
 {				/* '$set_output'(+Stream,-ErrorMessage)  */
@@ -4192,8 +4092,6 @@ Yap_InitIOPreds(void)
   Yap_InitCPred ("$set_stream_position", 2, p_set_stream_position, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$user_file_name", 2, p_user_file_name, SafePredFlag|SyncPredFlag),
   Yap_InitCPred ("$past_eof", 1, p_past_eof, SafePredFlag|SyncPredFlag),
-  Yap_InitCPred ("$peek", 2, p_peek, SafePredFlag|SyncPredFlag),
-  Yap_InitCPred ("$peek_byte", 2, p_peek_byte, SafePredFlag|SyncPredFlag),
   Yap_InitCPred ("$has_bom", 1, p_has_bom, SafePredFlag);
   Yap_InitCPred ("$stream_representation_error", 2, p_representation_error, SafePredFlag|SyncPredFlag);
   Yap_InitCPred ("$is_same_tty", 2, p_is_same_tty, SafePredFlag|SyncPredFlag|HiddenPredFlag);
diff --git a/pl/boot.yap b/pl/boot.yap
index 28481e6b8..20ff3b1c6 100755
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -1468,3 +1468,16 @@ get_code(C) :-
 	swi_get_code(C).
 get_code(Stream, C) :-
 	swi_get_code(Stream, C).
+
+peek_byte(C) :-
+	swi_peek_byte(C).
+peek_byte(Stream, C) :-
+	swi_peek_byte(Stream, C).
+peek_char(C) :-
+	swi_peek_char(C).
+peek_char(Stream, C) :-
+	swi_peek_char(Stream, C).
+peek_code(C) :-
+	swi_peek_code(C).
+peek_code(Stream, C) :-
+	swi_peek_code(Stream, C).
diff --git a/pl/yio.yap b/pl/yio.yap
index a35ab6a05..56cd08fec 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -124,12 +124,6 @@
 '$check_priority_arg'(X,G) :-
 	'$do_error'(domain_error(write_option,priority(X)),G).
 
-set_input(Stream) :-
-	'$set_input'(Stream).
-	
-set_output(Stream) :-
-	'$set_output'(Stream).
-
 open_pipe_streams(Read, Write) :-
 	(
 	 '$undefined'(pipe(_,_),unix)
@@ -416,49 +410,6 @@ format(T) :-
 
 /* character I/O	*/
 
-peek_byte(V) :-
-	\+ var(V), (\+ integer(V) ; V < -1 ; V > 256), !,
-	'$do_error'(type_error(in_byte,V),get_byte(V)).
-peek_byte(V) :-
-	current_input(S), 
-	'$peek_byte'(S,V).
-
-peek_byte(S,V) :-
-	\+ var(V), (\+ integer(V) ; V < -1 ; V > 256), !,
-	'$do_error'(type_error(in_byte,V),get_byte(S,V)).
-peek_byte(S,V) :-
-	'$peek_byte'(S,V).
-
-peek_char(V) :-
-	\+ var(V),
-	( atom(V)  -> atom_codes(V,[_,_|_]), V \= end_of_file ; true ), !,
-	'$do_error'(type_error(in_character,V),get_char(V)).
-peek_char(V) :-
-	current_input(S),
-	'$peek'(S,I),
-	( I = -1 -> V = end_of_file ; atom_codes(V,[I])).
-
-peek_char(S,V) :-
-	\+ var(V),
-	( atom(V)  -> atom_codes(V,[_,_|_]), V \= end_of_file ; true ), !,
-	'$do_error'(type_error(in_character,V),get_char(S,V)).
-peek_char(S,V) :-
-	'$peek'(S,I),
-	( I = -1 -> V = end_of_file ; atom_codes(V,[I])).
-
-peek_code(S,V) :-
-	\+ var(V), (\+ integer(V)), !,
-	'$do_error'(type_error(in_character_code,V),get_code(S,V)).
-peek_code(S,V) :-
-	'$peek'(S,V).
-
-peek_code(V) :-
-	\+ var(V), (\+ integer(V)), !,
-	'$do_error'(type_error(in_character_code,V),get_code(V)).
-peek_code(V) :-
-	current_input(S),
-	'$peek'(S,V).
-
 put_byte(V) :- var(V), !,
 	'$do_error'(instantiation_error,put_byte(V)).
 put_byte(V) :-