diff --git a/C/c_interface.c b/C/c_interface.c
index a5fbe5638..90ed1d0d0 100644
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -478,7 +478,7 @@ X_API void    STD_PROTO(YAP_EndConsult,(IOSTREAM *));
 X_API Term    STD_PROTO(YAP_Read, (IOSTREAM *));
 X_API void    STD_PROTO(YAP_Write, (Term, IOSTREAM *, int));
 X_API Term    STD_PROTO(YAP_CopyTerm, (Term));
-X_API Term    STD_PROTO(YAP_WriteBuffer, (Term, char *, unsigned int, int));
+X_API int     STD_PROTO(YAP_WriteBuffer, (Term, char *, size_t, int));
 X_API char   *STD_PROTO(YAP_CompileClause, (Term));
 X_API void    STD_PROTO(YAP_PutValue, (Atom,Term));
 X_API Term    STD_PROTO(YAP_GetValue, (Atom));
@@ -2799,8 +2799,8 @@ YAP_CopyTerm(Term t)
   return tn;
 }
 
-X_API Term
-YAP_WriteBuffer(Term t, char *buf, unsigned int sze, int flags)
+X_API int
+YAP_WriteBuffer(Term t, char *buf, size_t sze, int flags)
 {
   BACKUP_MACHINE_REGS();
   t = Yap_TermToString(t, buf, sze, flags);
diff --git a/H/yapio.h b/H/yapio.h
index 56a897b65..590f6933a 100644
--- a/H/yapio.h
+++ b/H/yapio.h
@@ -278,11 +278,11 @@ int   STD_PROTO(Yap_GetCharForSIGINT,(void));
 Int   STD_PROTO(Yap_StreamToFileNo,(Term));
 Term  STD_PROTO(Yap_OpenStream,(FILE *,char *,Term,int));
 Term  STD_PROTO(Yap_StringToTerm,(char *,Term *));
-Term  STD_PROTO(Yap_TermToString,(Term,char *,unsigned int,int));
-int   STD_PROTO(Yap_GetFreeStreamD,(void));
-int   STD_PROTO(Yap_GetFreeStreamDForReading,(void));
+int     Yap_TermToString(Term t, char *s, size_t sz, int flags);
+int     Yap_GetFreeStreamD(void);
+int     Yap_GetFreeStreamDForReading(void);
 
-Term	STD_PROTO(Yap_WStringToList,(wchar_t *));
+Term	Yap_WStringToList(wchar_t *);
 Term	STD_PROTO(Yap_WStringToListOfAtoms,(wchar_t *));
 Atom	STD_PROTO(Yap_LookupWideAtom,(wchar_t *));
 
diff --git a/docs/yap.tex b/docs/yap.tex
index a2fbb7c0e..94ceb0828 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -9651,12 +9651,21 @@ applying the predicate @var{Pred} to all list elements on which
       Calls @var{Pred} on all elements of @code{List} and collects a result in
 @var{X} and @var{Y}.
 
-@item foldl3(:@var{Pred}, +@var{List}, ?@var{X0}, ?@var{X}, ?@var{Y0}, ?@var{Y}, ?@var{Z0}, ?@var{Z})
+@item foldl2(:@var{Pred}, +@var{List}, ?@var{List1}, ?@var{X0}, ?@var{X}, ?@var{Y0}, ?@var{Y})
+@findex foldl2/7
+@snindex foldl2/7
+@cnindex foldl2/7
+      Calls @var{Pred} on all elements of @code{List} and collects a result in
+@var{X} and @var{Y}.
+
+@item foldl3(:@var{Pred}, +@var{List1}, ?@var{List2}, ?@var{X0},
+?@var{X}, ?@var{Y0}, ?@var{Y}, ?@var{Z0}, ?@var{Z})
+
 @findex foldl3/6
 @snindex foldl3/6
 @cnindex foldl3/6
-      Calls @var{Pred} on all elements of @code{List} and collects a result in
-@var{X}, @var{Y} and @var{Z}.
+      Calls @var{Pred} on all elements of @code{List} and collects a
+result in @var{X}, @var{Y} and @var{Z}.
 
 @item scanl(:@var{Pred}, +@var{List}, +@var{V0}, ?@var{Values})
 @findex scanl/4
@@ -17725,14 +17734,15 @@ characters. The term is written according to a mask of the following
 flags in the @code{flag} argument: @code{YAP_WRITE_QUOTED},
 @code{YAP_WRITE_HANDLE_VARS}, @code{YAP_WRITE_USE_PORTRAY},  and @code{YAP_WRITE_IGNORE_OPS}.
 
-@item  @code{void} YAP_WriteBuffer(@code{YAP_Term} @var{t}, @code{char *}
-@var{buff}, @code{unsigned int}
+@item  @code{int} YAP_WriteBuffer(@code{YAP_Term} @var{t}, @code{char *}
+@var{buff}, @code{size_t}
 @var{size}, @code{int} @var{flags})
 @findex  YAP_WriteBuffer/4
 Write a YAP_Term @var{t} to buffer @var{buff} with size @var{size}. The
-term is written according to a mask of the following flags in the
-@code{flag} argument: @code{YAP_WRITE_QUOTED},
-@code{YAP_WRITE_HANDLE_VARS}, and @code{YAP_WRITE_IGNORE_OPS}.
+flag are currently ignored. This function can fail, say, if the term
+cannot be encoded in ISO-LATIN8. The code always uses
+@code{YAP_WRITE_HANDLE_VARS}. You may also use @code{YAP_WRITE_QUOTED},
+and   @code{YAP_WRITE_IGNORE_OPS} together.
 
 @item  @code{void} YAP_InitConsult(@code{int} @var{mode}, @code{char *} @var{filename})
 @findex YAP_InitConsult/2
diff --git a/library/dialect/swi/fli/swi.c b/library/dialect/swi/fli/swi.c
index 687bb8175..fc3cd5a06 100755
--- a/library/dialect/swi/fli/swi.c
+++ b/library/dialect/swi/fli/swi.c
@@ -2868,19 +2868,20 @@ Yap_read_term(term_t t, IOSTREAM *st, term_t *excep, term_t vs)
   return TRUE;
 }
 
-Term
-Yap_TermToString(Term t, char *s, unsigned int sz, int flags)
+int
+Yap_TermToString(Term t, char *s, size_t sz, int flags)
 {
   CACHE_REGS
-  IOSTREAM *stream = Sopen_string(NULL, s, sz, "w");
   int out;
+  unsigned swi_flags;
 
-  if (!stream)
-    return FALSE;
   Yap_StartSlots( PASS_REGS1 );
-  out = PL_write_term(stream, Yap_InitSlot(t PASS_REGS), 1200, 0);
+  swi_flags = CVT_WRITE;
+  if (flags & (YAP_WRITE_QUOTED|YAP_WRITE_IGNORE_OPS)) {
+    swi_flags = CVT_WRITE_CANONICAL;
+  }
+  out = PL_get_nchars(Yap_InitSlot(t PASS_REGS), &sz, &s, swi_flags);
   Yap_CloseSlots( PASS_REGS1 );
-  Sclose(stream);
   return out;
 }