diff --git a/src/harfbuzz-dump-main.c b/src/harfbuzz-dump-main.c
index 7f2ab5bb8..1e8c5e5f2 100644
--- a/src/harfbuzz-dump-main.c
+++ b/src/harfbuzz-dump-main.c
@@ -200,7 +200,7 @@ main (int argc, char **argv)
       if ((error = HB_Done_GSUB_Table (gsub)))
 	croak ("HB_Done_GSUB_Table", error);
     }
-  else if (error != HB_Err_Table_Missing)
+  else if (error != HB_Err_Not_Covered)
     fprintf (stderr, "HB_Load_GSUB_Table %x\n", error);
 
   if (!(error = HB_Load_GPOS_Table (face, &gpos, NULL)))
@@ -210,7 +210,7 @@ main (int argc, char **argv)
       if ((error = HB_Done_GPOS_Table (gpos)))
 	croak ("HB_Done_GPOS_Table", error);
     }
-  else if (error != HB_Err_Table_Missing)
+  else if (error != HB_Err_Not_Covered)
     fprintf (stderr, "HB_Load_GPOS_Table %x\n", error);
 
   printf ("</OpenType>\n");
diff --git a/src/harfbuzz-dump.c b/src/harfbuzz-dump.c
index 4ae548fcc..ed365d8ae 100644
--- a/src/harfbuzz-dump.c
+++ b/src/harfbuzz-dump.c
@@ -97,21 +97,21 @@ DEF_DUMP (LangSys)
     DUMP1("<FeatureIndex>%d</FeatureIndex>\n", LangSys->FeatureIndex[i]);
 }
 
-DEF_DUMP (Script)
+DEF_DUMP (ScriptTable)
 {
   int i;
 
-  RECURSE (DefaultLangSys, LangSys, &Script->DefaultLangSys);
+  RECURSE (DefaultLangSys, LangSys, &ScriptTable->DefaultLangSys);
 
-  DUMP_FUINT (Script, LangSysCount);
+  DUMP_FUINT (ScriptTable, LangSysCount);
 
-  for (i=0; i < Script->LangSysCount; i++)
+  for (i=0; i < ScriptTable->LangSysCount; i++)
     {
       do_indent (stream, indent);
       fprintf (stream, "<LangSysTag>");
-      Print_Tag (Script->LangSysRecord[i].LangSysTag, stream);
+      Print_Tag (ScriptTable->LangSysRecord[i].LangSysTag, stream);
       fprintf (stream, "</LangSysTag>\n");
-      RECURSE_NUM (LangSys, i, LangSys, &Script->LangSysRecord[i].LangSys);
+      RECURSE_NUM (LangSys, i, LangSys, &ScriptTable->LangSysRecord[i].LangSys);
     }
 }
 
@@ -127,7 +127,7 @@ DEF_DUMP (ScriptList)
       fprintf (stream, "<ScriptTag>");
       Print_Tag (ScriptList->ScriptRecord[i].ScriptTag, stream);
       fprintf (stream, "</ScriptTag>\n");
-      RECURSE_NUM (Script, i, Script, &ScriptList->ScriptRecord[i].Script);
+      RECURSE_NUM (Script, i, ScriptTable, &ScriptList->ScriptRecord[i].Script);
     }
 }
 
diff --git a/src/harfbuzz-gdef.c b/src/harfbuzz-gdef.c
index cca0b8c93..041ddd5dd 100644
--- a/src/harfbuzz-gdef.c
+++ b/src/harfbuzz-gdef.c
@@ -21,6 +21,7 @@ static HB_Error  Load_LigCaretList( HB_LigCaretList*  lcl,
 
 static void  Free_AttachList( HB_AttachList*  al );
 static void  Free_LigCaretList( HB_LigCaretList*  lcl );
+
 static void  Free_NewGlyphClasses( HB_GDEFHeader*  gdef );
 
 
@@ -104,7 +105,7 @@ HB_Error  HB_Init_GDEF_Extension( HB_Engine  engine )
 
 
   if ( !_engine )
-    return HB_Err_Invalid_Engine;
+    return ERR(HB_Err_Invalid_Engine);
 
   return  HB_Register_Extension( _engine,
 				 GDEF_ID,
@@ -133,7 +134,7 @@ HB_Error  HB_New_GDEF_Table( HB_GDEFHeader** retptr )
   HB_GDEFHeader*  gdef;
 
   if ( !retptr )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( ALLOC( gdef, sizeof( *gdef ) ) )
     return error;
@@ -164,7 +165,7 @@ HB_Error  HB_Load_GDEF_Table( FT_Face          face,
 
 
   if ( !retptr )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( GOTO_Table( TTAG_GDEF ) )
     return error;
@@ -523,7 +524,7 @@ static HB_Error  Load_CaretValue( HB_CaretValue*  cv,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GDEF_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;
@@ -768,7 +769,7 @@ HB_Error  HB_GDEF_Get_Glyph_Property( HB_GDEFHeader*  gdef,
 
 
   if ( !gdef || !property )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   /* first, we check for mark attach classes */
 
@@ -873,7 +874,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
 
 
   if ( !gdef || !glyph_array || !class_array )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gcd = &gdef->GlyphClassDef;
 
@@ -895,7 +896,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
 
   if ( curr_class >= 5 )
   {
-    error = HB_Err_Invalid_Argument;
+    error = ERR(HB_Err_Invalid_Argument);
     goto Fail4;
   }
 
@@ -916,7 +917,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
       {
 	if ( curr_glyph == 0xFFFF )
 	{
-	  error = HB_Err_Invalid_Argument;
+	  error = ERR(HB_Err_Invalid_Argument);
 	  goto Fail3;
 	}
 	else
@@ -932,7 +933,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
 
       if ( curr_glyph > glyph_array[n] )
       {
-	error = HB_Err_Invalid_Argument;
+	error = ERR(HB_Err_Invalid_Argument);
 	goto Fail3;
       }
 
@@ -942,7 +943,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
 
       if ( curr_class >= 5 )
       {
-	error = HB_Err_Invalid_Argument;
+	error = ERR(HB_Err_Invalid_Argument);
 	goto Fail3;
       }
 
@@ -957,7 +958,7 @@ HB_Error  HB_GDEF_Build_ClassDefinition( HB_GDEFHeader*  gdef,
       {
 	if ( curr_glyph == 0xFFFF )
 	{
-	  error = HB_Err_Invalid_Argument;
+	  error = ERR(HB_Err_Invalid_Argument);
 	  goto Fail3;
 	}
 	else
@@ -1103,7 +1104,7 @@ _HB_GDEF_Add_Glyph_Property( HB_GDEFHeader* gdef,
     break;
 
   default:
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
   }
 
   count = gdef->GlyphClassDef.cd.cd2.ClassRangeCount;
diff --git a/src/harfbuzz-gdef.h b/src/harfbuzz-gdef.h
index 08ff36270..9f9338c8d 100644
--- a/src/harfbuzz-gdef.h
+++ b/src/harfbuzz-gdef.h
@@ -17,9 +17,6 @@
 
 HB_BEGIN_HEADER
 
-#define HB_Err_Invalid_GDEF_SubTable_Format  0x1030
-#define HB_Err_Invalid_GDEF_SubTable         0x1031
-
 
 /* GDEF glyph properties.  Note that HB_GDEF_COMPONENT has no corresponding
  * flag in the LookupFlag field.     */
diff --git a/src/harfbuzz-global.h b/src/harfbuzz-global.h
index 88fe1aa28..9aed8ca8d 100644
--- a/src/harfbuzz-global.h
+++ b/src/harfbuzz-global.h
@@ -30,21 +30,24 @@ typedef signed int HB_Int;
 typedef int HB_Bool;
 
 
-/* compatible with FT_Error */
 typedef enum {
-  HB_Err_Invalid_Argument           = FT_Err_Invalid_Argument,
-  HB_Err_Invalid_Face_Handle        = FT_Err_Invalid_Face_Handle,
-  HB_Err_Invalid_Stream_Operation   = FT_Err_Invalid_Stream_Operation,
-  HB_Err_Empty_Script               = 0x1005,
+  /* no error */
+  HB_Err_Ok                           = 0x0000,
+  HB_Err_Not_Covered                  = 0xFFFF,
 
-  HB_Err_Ok                         = FT_Err_Ok,
-  HB_Err_Not_Covered                = 0x1002,
-  HB_Err_Out_Of_Memory              = FT_Err_Out_Of_Memory,
-  HB_Err_Table_Missing              = FT_Err_Table_Missing,
-  HB_Err_Invalid_SubTable_Format    = 0x1000,
-  HB_Err_Invalid_SubTable           = 0x1001,
-  HB_Err_Too_Many_Nested_Contexts   = 0x1003,
-  HB_Err_No_MM_Interpreter          = 0x1004
+  /* _hb_err() is called whenever returning the following errors,
+   * and in a couple places for HB_Err_Not_Covered too. */
+
+  /* programmer error */
+  HB_Err_Invalid_Argument             = 0x1A66,
+
+  /* font error */
+  HB_Err_Invalid_SubTable_Format      = 0x157F,
+  HB_Err_Invalid_SubTable             = 0x1570,
+  HB_Err_Read_Error                   = 0x6EAD,
+
+  /* system error */
+  HB_Err_Out_Of_Memory                = 0xDEAD
 } HB_Error;
 
 HB_END_HEADER
diff --git a/src/harfbuzz-gpos.c b/src/harfbuzz-gpos.c
index 7ba16410b..71dade7f1 100644
--- a/src/harfbuzz-gpos.c
+++ b/src/harfbuzz-gpos.c
@@ -53,7 +53,7 @@ static HB_Error  default_mmfunc( FT_Face      face,
   HB_UNUSED(metric_id);
   HB_UNUSED(metric_value);
   HB_UNUSED(data);
-  return _hb_err(HB_Err_No_MM_Interpreter);
+  return ERR(HB_Err_Not_Covered); /* ERR() call intended */
 }
 
 
@@ -73,7 +73,7 @@ HB_Error  HB_Load_GPOS_Table( FT_Face          face,
 
 
   if ( !retptr )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( GOTO_Table( TTAG_GPOS ) )
     return error;
@@ -672,7 +672,7 @@ static HB_Error  Load_Anchor( HB_Anchor*  an,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;
@@ -742,7 +742,7 @@ static HB_Error  Get_Anchor( GPOS_Instance*   gpi,
 	return error;
 
       if ( gpi->face->glyph->format != ft_glyph_format_outline )
-	return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+	return ERR(HB_Err_Invalid_SubTable);
 
       ap = an->af.af2.AnchorPoint;
 
@@ -756,7 +756,7 @@ static HB_Error  Get_Anchor( GPOS_Instance*   gpi,
 	goto no_contour_point;
 
       if ( ap >= outline.n_points )
-	return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+	return ERR(HB_Err_Invalid_SubTable);
 
       *x_value = outline.points[ap].x;
       *y_value = outline.points[ap].y;
@@ -908,7 +908,7 @@ static HB_Error  Load_SinglePos( HB_GPOS_SubTable* st,
   FORGET_Frame();
 
   if ( !format )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   cur_offset = FILE_Pos();
   if ( FILE_Seek( new_offset ) ||
@@ -949,7 +949,7 @@ static HB_Error  Load_SinglePos( HB_GPOS_SubTable* st,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;
@@ -1036,7 +1036,7 @@ static HB_Error  Lookup_SinglePos( GPOS_Instance*    gpi,
 
   case 2:
     if ( index >= sp->spf.spf2.ValueCount )
-      return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+      return ERR(HB_Err_Invalid_SubTable);
     error = Get_ValueRecord( gpi, &sp->spf.spf2.Value[index],
 			     sp->ValueFormat, POSITION( buffer->in_pos ) );
     if ( error )
@@ -1044,7 +1044,7 @@ static HB_Error  Lookup_SinglePos( GPOS_Instance*    gpi,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
   }
 
   (buffer->in_pos)++;
@@ -1445,7 +1445,7 @@ static HB_Error  Load_PairPos( HB_GPOS_SubTable* st,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;
@@ -1498,11 +1498,11 @@ static HB_Error  Lookup_PairPos1( GPOS_Instance*       gpi,
 
 
   if ( index >= ppf1->PairSetCount )
-     return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+     return ERR(HB_Err_Invalid_SubTable);
 
   pvr = ppf1->PairSet[index].PairValueRecord;
   if ( !pvr )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   glyph2 = IN_CURGLYPH();
 
@@ -1550,7 +1550,7 @@ static HB_Error  Lookup_PairPos2( GPOS_Instance*       gpi,
 
   c1r = &ppf2->Class1Record[cl1];
   if ( !c1r )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
   c2r = &c1r->Class2Record[cl2];
 
   error = Get_ValueRecord( gpi, &c2r->Value1, format1, POSITION( first_pos ) );
@@ -1622,7 +1622,7 @@ static HB_Error  Lookup_PairPos( GPOS_Instance*    gpi,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   /* if we don't have coverage for the second glyph don't skip it for
@@ -1827,7 +1827,7 @@ static HB_Error  Lookup_CursivePos( GPOS_Instance*    gpi,
   }
 
   if ( index >= cp->EntryExitCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   eer = &cp->EntryExitRecord[index];
 
@@ -2146,7 +2146,7 @@ static HB_Error  Load_MarkBasePos( HB_GPOS_SubTable* st,
   FORGET_Frame();
 
   if (mbp->PosFormat != 1)
-    return _hb_err(HB_Err_Invalid_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
 
   cur_offset = FILE_Pos();
   if ( FILE_Seek( new_offset ) ||
@@ -2293,18 +2293,18 @@ static HB_Error  Lookup_MarkBasePos( GPOS_Instance*    gpi,
   ma = &mbp->MarkArray;
 
   if ( mark_index >= ma->MarkCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   class       = ma->MarkRecord[mark_index].Class;
   mark_anchor = &ma->MarkRecord[mark_index].MarkAnchor;
 
   if ( class >= mbp->ClassCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   ba = &mbp->BaseArray;
 
   if ( base_index >= ba->BaseCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   br          = &ba->BaseRecord[base_index];
   base_anchor = &br->BaseAnchor[class];
@@ -2704,18 +2704,18 @@ static HB_Error  Lookup_MarkLigPos( GPOS_Instance*    gpi,
   ma = &mlp->MarkArray;
 
   if ( mark_index >= ma->MarkCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   class       = ma->MarkRecord[mark_index].Class;
   mark_anchor = &ma->MarkRecord[mark_index].MarkAnchor;
 
   if ( class >= mlp->ClassCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   la = &mlp->LigatureArray;
 
   if ( lig_index >= la->LigatureCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   lat = &la->LigatureAttach[lig_index];
 
@@ -3044,18 +3044,18 @@ static HB_Error  Lookup_MarkMarkPos( GPOS_Instance*    gpi,
   ma1 = &mmp->Mark1Array;
 
   if ( mark1_index >= ma1->MarkCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   class        = ma1->MarkRecord[mark1_index].Class;
   mark1_anchor = &ma1->MarkRecord[mark1_index].MarkAnchor;
 
   if ( class >= mmp->ClassCount )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   ma2 = &mmp->Mark2Array;
 
   if ( mark2_index >= ma2->Mark2Count )
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   m2r          = &ma2->Mark2Record[mark2_index];
   mark2_anchor = &m2r->Mark2Anchor[class];
@@ -3802,7 +3802,7 @@ static HB_Error  Load_ContextPos( HB_GPOS_SubTable* st,
     return Load_ContextPos3( &cp->cpf.cpf3, stream );
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -3933,7 +3933,7 @@ static HB_Error  Lookup_ContextPos2( GPOS_Instance*          gpi,
   pcs = &cpf2->PosClassSet[classes[0]];
   if ( !pcs )
   {
-    error = _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    error = ERR(HB_Err_Invalid_SubTable);
     goto End;
   }
 
@@ -4071,7 +4071,7 @@ static HB_Error  Lookup_ContextPos( GPOS_Instance*    gpi,
 			       flags, context_length, nesting_level );
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -4688,16 +4688,16 @@ static HB_Error  Load_ChainContextPos2( HB_ChainContextPosFormat2*  ccpf2,
   FORGET_Frame();
 
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->BacktrackClassDef, 65535,
-					      backtrack_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       backtrack_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
     goto Fail5;
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->InputClassDef, count,
-					      input_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       input_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
     goto Fail4;
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccpf2->LookaheadClassDef, 65535,
-					      lookahead_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       lookahead_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
     goto Fail3;
 
   ccpf2->ChainPosClassSet   = NULL;
@@ -5028,7 +5028,7 @@ static HB_Error  Load_ChainContextPos( HB_GPOS_SubTable* st,
     return Load_ChainContextPos3( &ccp->ccpf.ccpf3, stream );
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -5241,7 +5241,7 @@ static HB_Error  Lookup_ChainContextPos2(
   cpcs = &ccpf2->ChainPosClassSet[input_classes[0]];
   if ( !cpcs )
   {
-    error = _hb_err(HB_Err_Invalid_GPOS_SubTable);
+    error = ERR(HB_Err_Invalid_SubTable);
     goto End1;
   }
 
@@ -5519,7 +5519,7 @@ static HB_Error  Lookup_ChainContextPos(
 				    nesting_level );
 
   default:
-    return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -5544,7 +5544,7 @@ HB_Error  HB_GPOS_Select_Script( HB_GPOSHeader*  gpos,
 
 
   if ( !gpos || !script_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
@@ -5572,18 +5572,18 @@ HB_Error  HB_GPOS_Select_Language( HB_GPOSHeader*  gpos,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
 
 
   if ( !gpos || !language_index || !req_feature_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -5615,7 +5615,7 @@ HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
   HB_LangSys*        ls;
   HB_UShort*          fi;
@@ -5625,7 +5625,7 @@ HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
 
 
   if ( !gpos || !feature_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
@@ -5634,7 +5634,7 @@ HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
   fr = fl->FeatureRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -5644,7 +5644,7 @@ HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
   else
   {
     if ( language_index >= s->LangSysCount )
-      return HB_Err_Invalid_Argument;
+      return ERR(HB_Err_Invalid_Argument);
 
     ls = &lsr[language_index].LangSys;
   }
@@ -5654,7 +5654,7 @@ HB_Error  HB_GPOS_Select_Feature( HB_GPOSHeader*  gpos,
   for ( n = 0; n < ls->FeatureCount; n++ )
   {
     if ( fi[n] >= fl->FeatureCount )
-      return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+      return ERR(HB_Err_Invalid_SubTable_Format);
 
     if ( feature_tag == fr[fi[n]].FeatureTag )
     {
@@ -5683,7 +5683,7 @@ HB_Error  HB_GPOS_Query_Scripts( HB_GPOSHeader*  gpos,
 
 
   if ( !gpos || !script_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
@@ -5712,18 +5712,18 @@ HB_Error  HB_GPOS_Query_Languages( HB_GPOSHeader*  gpos,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
 
 
   if ( !gpos || !language_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -5756,7 +5756,7 @@ HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
   HB_LangSys*        ls;
   HB_UShort*          fi;
@@ -5766,7 +5766,7 @@ HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
 
 
   if ( !gpos || !feature_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gpos->ScriptList;
   sr = sl->ScriptRecord;
@@ -5775,7 +5775,7 @@ HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
   fr = fl->FeatureRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -5785,7 +5785,7 @@ HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
   else
   {
     if ( language_index >= s->LangSysCount )
-      return HB_Err_Invalid_Argument;
+      return ERR(HB_Err_Invalid_Argument);
 
     ls = &lsr[language_index].LangSys;
   }
@@ -5800,7 +5800,7 @@ HB_Error  HB_GPOS_Query_Features( HB_GPOSHeader*  gpos,
     if ( fi[n] >= fl->FeatureCount )
     {
       FREE( ftl );
-      return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+      return ERR(HB_Err_Invalid_SubTable_Format);
     }
     ftl[n] = fr[fi[n]].FeatureTag;
   }
@@ -5830,7 +5830,7 @@ static HB_Error  GPOS_Do_Glyph_Lookup( GPOS_Instance*    gpi,
   nesting_level++;
 
   if ( nesting_level > HB_MAX_NESTING_LEVEL )
-    return _hb_err(HB_Err_Too_Many_Nested_Contexts);
+    return ERR(HB_Err_Not_Covered); /* ERR() call intended */
 
   lookup_count = gpos->LookupList.LookupCount;
   if (lookup_index >= lookup_count)
@@ -5892,7 +5892,7 @@ _HB_GPOS_Load_SubTable( HB_GPOS_SubTable* st,
     case HB_GPOS_LOOKUP_CONTEXT:	return Load_ContextPos		( st, stream );
     case HB_GPOS_LOOKUP_CHAIN:		return Load_ChainContextPos	( st, stream );
   /*case HB_GPOS_LOOKUP_EXTENSION:	return Load_ExtensionPos	( st, stream );*/
-    default:				return _hb_err(HB_Err_Invalid_GPOS_SubTable_Format);
+    default:				return ERR(HB_Err_Invalid_SubTable_Format);
   }
 }
 
@@ -6010,7 +6010,7 @@ HB_Error  HB_GPOS_Add_Feature( HB_GPOSHeader*  gpos,
   if ( !gpos ||
        feature_index >= gpos->FeatureList.FeatureCount ||
        gpos->FeatureList.ApplyCount == gpos->FeatureList.FeatureCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gpos->FeatureList.ApplyOrder[gpos->FeatureList.ApplyCount++] = feature_index;
 
@@ -6040,7 +6040,7 @@ HB_Error  HB_GPOS_Clear_Features( HB_GPOSHeader*  gpos )
 
 
   if ( !gpos )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gpos->FeatureList.ApplyCount = 0;
 
@@ -6058,7 +6058,7 @@ HB_Error  HB_GPOS_Register_Glyph_Function( HB_GPOSHeader*    gpos,
 					   HB_GlyphFunction  gfunc )
 {
   if ( !gpos )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gpos->gfunc = gfunc;
 
@@ -6072,7 +6072,7 @@ HB_Error  HB_GPOS_Register_MM_Function( HB_GPOSHeader*  gpos,
 					void*            data )
 {
   if ( !gpos )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gpos->mmfunc = mmfunc;
   gpos->data   = data;
@@ -6096,7 +6096,7 @@ HB_Error  HB_GPOS_Apply_String( FT_Face           face,
   int            i, j, lookup_count, num_features;
 
   if ( !face || !gpos || !buffer )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( buffer->in_length == 0 )
     return HB_Err_Not_Covered;
diff --git a/src/harfbuzz-gpos.h b/src/harfbuzz-gpos.h
index 6d8cd8d5a..3563759fe 100644
--- a/src/harfbuzz-gpos.h
+++ b/src/harfbuzz-gpos.h
@@ -18,9 +18,6 @@
 
 HB_BEGIN_HEADER
 
-#define HB_Err_Invalid_GPOS_SubTable_Format  0x1020
-#define HB_Err_Invalid_GPOS_SubTable         0x1021
-
 
 /* Lookup types for glyph positioning */
 
diff --git a/src/harfbuzz-gsub.c b/src/harfbuzz-gsub.c
index ccdb57fc1..fd17a286b 100644
--- a/src/harfbuzz-gsub.c
+++ b/src/harfbuzz-gsub.c
@@ -43,7 +43,7 @@ HB_Error  HB_Load_GSUB_Table( FT_Face          face,
   HB_Lookup*      lo;
 
   if ( !retptr )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( GOTO_Table( TTAG_GSUB ) )
     return error;
@@ -238,7 +238,7 @@ static HB_Error  Load_SingleSubst( HB_GSUB_SubTable* st,
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;
@@ -307,14 +307,14 @@ static HB_Error  Lookup_SingleSubst( HB_GSUBHeader*   gsub,
 
   case 2:
     if ( index >= ss->ssf.ssf2.GlyphCount )
-      return _hb_err(HB_Err_Invalid_GSUB_SubTable);
+      return ERR(HB_Err_Invalid_SubTable);
     value = ss->ssf.ssf2.Substitute[index];
     if ( REPLACE_Glyph( buffer, value, nesting_level ) )
       return error;
     break;
 
   default:
-    return _hb_err(HB_Err_Invalid_GSUB_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
   }
 
   if ( gdef && gdef->NewGlyphClasses )
@@ -504,7 +504,7 @@ static HB_Error  Lookup_MultipleSubst( HB_GSUBHeader*    gsub,
     return error;
 
   if ( index >= ms->SequenceCount )
-    return _hb_err(HB_Err_Invalid_GSUB_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   count = ms->Sequence[index].GlyphCount;
   s     = ms->Sequence[index].Substitute;
@@ -982,7 +982,7 @@ static HB_Error  Lookup_LigatureSubst( HB_GSUBHeader*    gsub,
     return error;
 
   if ( index >= ls->LigatureSetCount )
-     return _hb_err(HB_Err_Invalid_GSUB_SubTable);
+     return ERR(HB_Err_Invalid_SubTable);
 
   lig = ls->LigatureSet[index].Ligature;
 
@@ -1801,7 +1801,7 @@ static HB_Error  Load_ContextSubst( HB_GSUB_SubTable* st,
   case 1:  return Load_ContextSubst1( &cs->csf.csf1, stream );
   case 2:  return Load_ContextSubst2( &cs->csf.csf2, stream );
   case 3:  return Load_ContextSubst3( &cs->csf.csf3, stream );
-  default: return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -1929,7 +1929,7 @@ static HB_Error  Lookup_ContextSubst2( HB_GSUBHeader*          gsub,
   scs = &csf2->SubClassSet[classes[0]];
   if ( !scs )
   {
-    error = _hb_err(HB_Err_Invalid_GSUB_SubTable);
+    error = ERR(HB_Err_Invalid_SubTable);
     goto End;
   }
 
@@ -2056,7 +2056,7 @@ static HB_Error  Lookup_ContextSubst( HB_GSUBHeader*    gsub,
   case 1:  return Lookup_ContextSubst1( gsub, &cs->csf.csf1, buffer, flags, context_length, nesting_level );
   case 2:  return Lookup_ContextSubst2( gsub, &cs->csf.csf2, buffer, flags, context_length, nesting_level );
   case 3:  return Lookup_ContextSubst3( gsub, &cs->csf.csf3, buffer, flags, context_length, nesting_level );
-  default: return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -2676,17 +2676,17 @@ static HB_Error  Load_ChainContextSubst2(
   FORGET_Frame();
 
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccsf2->BacktrackClassDef, 65535,
-					      backtrack_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       backtrack_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
       goto Fail5;
 
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccsf2->InputClassDef, count,
-					      input_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       input_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
       goto Fail4;
   if ( ( error = _HB_OPEN_Load_EmptyOrClassDefinition( &ccsf2->LookaheadClassDef, 65535,
-					      lookahead_offset, base_offset,
-					      stream ) ) != HB_Err_Ok )
+						       lookahead_offset, base_offset,
+						       stream ) ) != HB_Err_Ok )
     goto Fail3;
 
   ccsf2->ChainSubClassSet   = NULL;
@@ -3010,7 +3010,7 @@ static HB_Error  Load_ChainContextSubst( HB_GSUB_SubTable* st,
     case 1:  return Load_ChainContextSubst1( &ccs->ccsf.ccsf1, stream );
     case 2:  return Load_ChainContextSubst2( &ccs->ccsf.ccsf2, stream );
     case 3:  return Load_ChainContextSubst3( &ccs->ccsf.ccsf3, stream );
-    default: return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+    default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -3218,7 +3218,7 @@ static HB_Error  Lookup_ChainContextSubst2( HB_GSUBHeader*               gsub,
   cscs = &ccsf2->ChainSubClassSet[input_classes[0]];
   if ( !cscs )
   {
-    error = _hb_err(HB_Err_Invalid_GSUB_SubTable);
+    error = ERR(HB_Err_Invalid_SubTable);
     goto End1;
   }
 
@@ -3479,7 +3479,7 @@ static HB_Error  Lookup_ChainContextSubst( HB_GSUBHeader*    gsub,
     case 1:  return Lookup_ChainContextSubst1( gsub, &ccs->ccsf.ccsf1, buffer, flags, context_length, nesting_level );
     case 2:  return Lookup_ChainContextSubst2( gsub, &ccs->ccsf.ccsf2, buffer, flags, context_length, nesting_level );
     case 3:  return Lookup_ChainContextSubst3( gsub, &ccs->ccsf.ccsf3, buffer, flags, context_length, nesting_level );
-    default: return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+    default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 }
 
@@ -3508,7 +3508,7 @@ static HB_Error  Load_ReverseChainContextSubst( HB_GSUB_SubTable* st,
   rccs->SubstFormat = GET_UShort();
 
   if ( rccs->SubstFormat != 1 )
-    return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+    return ERR(HB_Err_Invalid_SubTable_Format);
 
   FORGET_Frame();
 
@@ -3783,7 +3783,7 @@ HB_Error  HB_GSUB_Select_Script( HB_GSUBHeader*  gsub,
 
 
   if ( !gsub || !script_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
@@ -3811,18 +3811,18 @@ HB_Error  HB_GSUB_Select_Language( HB_GSUBHeader*  gsub,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
 
 
   if ( !gsub || !language_index || !req_feature_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -3854,7 +3854,7 @@ HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
   HB_LangSys*        ls;
   HB_UShort*          fi;
@@ -3864,7 +3864,7 @@ HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
 
 
   if ( !gsub || !feature_index )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
@@ -3873,7 +3873,7 @@ HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
   fr = fl->FeatureRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -3883,7 +3883,7 @@ HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
   else
   {
     if ( language_index >= s->LangSysCount )
-      return HB_Err_Invalid_Argument;
+      return ERR(HB_Err_Invalid_Argument);
 
     ls = &lsr[language_index].LangSys;
   }
@@ -3893,7 +3893,7 @@ HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
   for ( n = 0; n < ls->FeatureCount; n++ )
   {
     if ( fi[n] >= fl->FeatureCount )
-      return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+      return ERR(HB_Err_Invalid_SubTable_Format);
 
     if ( feature_tag == fr[fi[n]].FeatureTag )
     {
@@ -3922,7 +3922,7 @@ HB_Error  HB_GSUB_Query_Scripts( HB_GSUBHeader*  gsub,
 
 
   if ( !gsub || !script_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
@@ -3951,18 +3951,18 @@ HB_Error  HB_GSUB_Query_Languages( HB_GSUBHeader*  gsub,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
 
 
   if ( !gsub || !language_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -3995,7 +3995,7 @@ HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
 
   HB_ScriptList*     sl;
   HB_ScriptRecord*   sr;
-  HB_Script*         s;
+  HB_ScriptTable*         s;
   HB_LangSysRecord*  lsr;
   HB_LangSys*        ls;
   HB_UShort*          fi;
@@ -4005,7 +4005,7 @@ HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
 
 
   if ( !gsub || !feature_tag_list )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   sl = &gsub->ScriptList;
   sr = sl->ScriptRecord;
@@ -4014,7 +4014,7 @@ HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
   fr = fl->FeatureRecord;
 
   if ( script_index >= sl->ScriptCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   s   = &sr[script_index].Script;
   lsr = s->LangSysRecord;
@@ -4024,7 +4024,7 @@ HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
   else
   {
     if ( language_index >= s->LangSysCount )
-      return HB_Err_Invalid_Argument;
+      return ERR(HB_Err_Invalid_Argument);
 
     ls = &lsr[language_index].LangSys;
   }
@@ -4039,7 +4039,7 @@ HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
     if ( fi[n] >= fl->FeatureCount )
     {
       FREE( ftl );
-      return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+      return ERR(HB_Err_Invalid_SubTable_Format);
     }
     ftl[n] = fr[fi[n]].FeatureTag;
   }
@@ -4067,7 +4067,7 @@ static HB_Error  GSUB_Do_Glyph_Lookup( HB_GSUBHeader* gsub,
   nesting_level++;
 
   if ( nesting_level > HB_MAX_NESTING_LEVEL )
-    return _hb_err(HB_Err_Too_Many_Nested_Contexts);
+    return ERR(HB_Err_Not_Covered); /* ERR() call intended */
 
   lookup_count = gsub->LookupList.LookupCount;
   if (lookup_index >= lookup_count)
@@ -4126,7 +4126,7 @@ _HB_GSUB_Load_SubTable( HB_GSUB_SubTable* st,
     case HB_GSUB_LOOKUP_CHAIN:		return Load_ChainContextSubst		( st, stream );
   /*case HB_GSUB_LOOKUP_EXTENSION:	return Load_ExtensionSubst		( st, stream );*/
     case HB_GSUB_LOOKUP_REVERSE_CHAIN:	return Load_ReverseChainContextSubst	( st, stream );
-    default:				return _hb_err(HB_Err_Invalid_GSUB_SubTable_Format);
+    default:				return ERR(HB_Err_Invalid_SubTable_Format);
   };
 }
 
@@ -4257,7 +4257,7 @@ HB_Error  HB_GSUB_Add_Feature( HB_GSUBHeader*  gsub,
   if ( !gsub ||
        feature_index >= gsub->FeatureList.FeatureCount ||
        gsub->FeatureList.ApplyCount == gsub->FeatureList.FeatureCount )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gsub->FeatureList.ApplyOrder[gsub->FeatureList.ApplyCount++] = feature_index;
 
@@ -4287,7 +4287,7 @@ HB_Error  HB_GSUB_Clear_Features( HB_GSUBHeader*  gsub )
 
 
   if ( !gsub )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gsub->FeatureList.ApplyCount = 0;
 
@@ -4306,7 +4306,7 @@ HB_Error  HB_GSUB_Register_Alternate_Function( HB_GSUBHeader*  gsub,
 					       void*            data )
 {
   if ( !gsub )
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   gsub->altfunc = altfunc;
   gsub->data    = data;
@@ -4325,7 +4325,7 @@ HB_Error  HB_GSUB_Apply_String( HB_GSUBHeader*   gsub,
 
   if ( !gsub ||
        !buffer)
-    return HB_Err_Invalid_Argument;
+    return ERR(HB_Err_Invalid_Argument);
 
   if ( buffer->in_length == 0 )
     return retError;
diff --git a/src/harfbuzz-gsub.h b/src/harfbuzz-gsub.h
index 3f8ed7c06..8caa2ba27 100644
--- a/src/harfbuzz-gsub.h
+++ b/src/harfbuzz-gsub.h
@@ -18,9 +18,6 @@
 
 HB_BEGIN_HEADER
 
-#define HB_Err_Invalid_GSUB_SubTable_Format  0x1010
-#define HB_Err_Invalid_GSUB_SubTable         0x1011
-
 
 /* Lookup types for glyph substitution */
 
diff --git a/src/harfbuzz-impl.c b/src/harfbuzz-impl.c
index 4479cd4b5..1d2b69905 100644
--- a/src/harfbuzz-impl.c
+++ b/src/harfbuzz-impl.c
@@ -36,7 +36,7 @@ _hb_qalloc( HB_UInt   size,
   {
     block = malloc( size );
     if ( !block )
-      error = HB_Err_Out_Of_Memory;
+      error = ERR(HB_Err_Out_Of_Memory);
   }
 
   *perror = error;
@@ -58,7 +58,7 @@ _hb_alloc( HB_UInt   size,
   {
     block = malloc( size );
     if ( !block )
-      error = HB_Err_Out_Of_Memory;
+      error = ERR(HB_Err_Out_Of_Memory);
     else
       memset( (char*)block, 0, (size_t)size );
   }
@@ -78,7 +78,7 @@ _hb_realloc( FT_Pointer  block,
 
   block2 = realloc( block, new_size );
   if ( block2 == NULL && new_size != 0 )
-    error = HB_Err_Out_Of_Memory;
+    error = ERR(HB_Err_Out_Of_Memory);
 
   if ( !error )
     block = block2;
@@ -114,10 +114,10 @@ _hb_stream_seek( HB_Stream stream,
   if ( stream->read )
   {
     if ( stream->read( stream, pos, NULL, 0 ) )
-      error = HB_Err_Invalid_Stream_Operation;
+      error = ERR(HB_Err_Read_Error);
   }
   else if ( pos > (HB_Int)stream->size )
-    error = HB_Err_Invalid_Stream_Operation;
+    error = ERR(HB_Err_Read_Error);
 
   LOG(( "_hb_stream_seek(%ld) -> %d\n", pos, error ));
   return error;
@@ -144,7 +144,7 @@ _hb_stream_frame_enter( HB_Stream stream,
     if ( read_bytes < count )
     {
       FREE( stream->base );
-      error = HB_Err_Invalid_Stream_Operation;
+      error = ERR(HB_Err_Read_Error);
     }
     stream->cursor = stream->base;
     stream->limit  = stream->cursor + count;
@@ -156,7 +156,7 @@ _hb_stream_frame_enter( HB_Stream stream,
     if ( stream->pos >= stream->size        ||
          stream->pos + count > stream->size )
     {
-      error = HB_Err_Invalid_Stream_Operation;
+      error = ERR(HB_Err_Read_Error);
       goto Exit;
     }
 
@@ -204,7 +204,7 @@ _hb_face_goto_table( FT_Face    face,
   if ( !FT_IS_SFNT(face) )
   {
     LOG(( "not a SFNT face !!\n" ));
-    error = HB_Err_Invalid_Face_Handle;
+    error = ERR(HB_Err_Invalid_Argument);
   }
   else
   {
@@ -259,7 +259,7 @@ _hb_face_goto_table( FT_Face    face,
         goto FoundIt;
       }
     }
-    error = HB_Err_Table_Missing;
+    error = HB_Err_Not_Covered;
 
   FoundIt:
     FORGET_Frame();
diff --git a/src/harfbuzz-impl.h b/src/harfbuzz-impl.h
index 353123b2b..3e7ac1c00 100644
--- a/src/harfbuzz-impl.h
+++ b/src/harfbuzz-impl.h
@@ -140,6 +140,8 @@ _hb_face_goto_table( FT_Face    face,
 
 #define  MEM_Copy(dest,source,count)   memcpy( (char*)(dest), (const char*)(source), (size_t)(count) )
 
+#define ERR(err)   _hb_err (err)
+
 
 HB_INTERNAL FT_Pointer
 _hb_alloc( HB_UInt   size,
diff --git a/src/harfbuzz-open.c b/src/harfbuzz-open.c
index dfdaefdfe..5844e7482 100644
--- a/src/harfbuzz-open.c
+++ b/src/harfbuzz-open.c
@@ -68,7 +68,7 @@ static void  Free_LangSys( HB_LangSys*  ls )
 
 /* Script */
 
-static HB_Error  Load_Script( HB_Script*  s,
+static HB_Error  Load_Script( HB_ScriptTable*  s,
 			      HB_Stream    stream )
 {
   HB_Error   error;
@@ -116,7 +116,7 @@ static HB_Error  Load_Script( HB_Script*  s,
 
   if ( s->LangSysCount == 0 && s->DefaultLangSys.FeatureCount == 0 )
   {
-    error = HB_Err_Empty_Script;
+    error = HB_Err_Not_Covered;
     goto Fail2;
   }
 
@@ -160,7 +160,7 @@ Fail2:
 }
 
 
-static void  Free_Script( HB_Script*  s )
+static void  Free_Script( HB_ScriptTable*  s )
 {
   HB_UShort           n, count;
 
@@ -231,7 +231,7 @@ _HB_OPEN_Load_ScriptList( HB_ScriptList* sl,
     error = Load_Script( &sr[sl->ScriptCount].Script, stream );
     if ( error == HB_Err_Ok )
       sl->ScriptCount += 1;
-    else if ( error != HB_Err_Empty_Script )
+    else if ( error != HB_Err_Not_Covered )
       goto Fail;
 
     (void)FILE_Seek( cur_offset );
@@ -243,7 +243,7 @@ _HB_OPEN_Load_ScriptList( HB_ScriptList* sl,
 #if 0
   if ( sl->ScriptCount == 0 )
   {
-    error = _hb_err(HB_Err_Invalid_SubTable);
+    error = ERR(HB_Err_Invalid_SubTable);
     goto Fail;
   }
 #endif
@@ -739,7 +739,7 @@ static HB_Error  Load_Coverage2( HB_CoverageFormat2*  cf2,
 	 ( rr[n].End - rr[n].Start + (long)rr[n].StartCoverageIndex ) >=
 	   0x10000L )
     {
-      error = _hb_err(HB_Err_Invalid_SubTable);
+      error = ERR(HB_Err_Invalid_SubTable);
       goto Fail;
     }
   }
@@ -777,7 +777,7 @@ _HB_OPEN_Load_Coverage( HB_Coverage* c,
   {
   case 1:  return Load_Coverage1( &c->cf.cf1, stream );
   case 2:  return Load_Coverage2( &c->cf.cf2, stream );
-  default: return _hb_err(HB_Err_Invalid_SubTable_Format);
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -905,7 +905,7 @@ _HB_OPEN_Coverage_Index( HB_Coverage* c,
   {
   case 1:  return Coverage_Index1( &c->cf.cf1, glyphID, index );
   case 2:  return Coverage_Index2( &c->cf.cf2, glyphID, index );
-  default: return _hb_err(HB_Err_Invalid_SubTable_Format);
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
@@ -947,7 +947,7 @@ static HB_Error  Load_ClassDef1( HB_ClassDefinition*  cd,
   /* sanity check; we are limited to 16bit integers */
 
   if ( cdf1->StartGlyph + (long)count >= 0x10000L )
-    return _hb_err(HB_Err_Invalid_SubTable);
+    return ERR(HB_Err_Invalid_SubTable);
 
   cdf1->ClassValueArray = NULL;
 
@@ -965,7 +965,7 @@ static HB_Error  Load_ClassDef1( HB_ClassDefinition*  cd,
     cva[n] = GET_UShort();
     if ( cva[n] >= limit )
     {
-      error = _hb_err(HB_Err_Invalid_SubTable);
+      error = ERR(HB_Err_Invalid_SubTable);
       goto Fail;
     }
     d[cva[n]] = TRUE;
@@ -1089,7 +1089,7 @@ _HB_OPEN_Load_ClassDefinition( HB_ClassDefinition* cd,
   {
   case 1:  error = Load_ClassDef1( cd, limit, stream ); break;
   case 2:  error = Load_ClassDef2( cd, limit, stream ); break;
-  default: error = _hb_err(HB_Err_Invalid_SubTable_Format);	break;
+  default: error = ERR(HB_Err_Invalid_SubTable_Format);	break;
   }
 
   if ( error )
@@ -1277,7 +1277,7 @@ _HB_OPEN_Get_Class( HB_ClassDefinition* cd,
   {
   case 1:  return Get_Class1( &cd->cd.cd1, glyphID, klass, index );
   case 2:  return Get_Class2( &cd->cd.cd2, glyphID, klass, index );
-  default: return _hb_err(HB_Err_Invalid_SubTable_Format);
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
   }
 
   return HB_Err_Ok;               /* never reached */
diff --git a/src/harfbuzz-open.h b/src/harfbuzz-open.h
index fd9c11028..d7cc9f01d 100644
--- a/src/harfbuzz-open.h
+++ b/src/harfbuzz-open.h
@@ -50,20 +50,20 @@ struct  HB_LangSysRecord_
 typedef struct HB_LangSysRecord_  HB_LangSysRecord;
 
 
-struct  HB_Script_
+struct  HB_ScriptTable_
 {
   HB_LangSys         DefaultLangSys; /* DefaultLangSys table     */
   HB_UShort           LangSysCount;   /* number of LangSysRecords */
   HB_LangSysRecord*  LangSysRecord;  /* array of LangSysRecords  */
 };
 
-typedef struct HB_Script_  HB_Script;
+typedef struct HB_ScriptTable_  HB_ScriptTable;
 
 
 struct  HB_ScriptRecord_
 {
   HB_UInt    ScriptTag;              /* ScriptTag identifier */
-  HB_Script  Script;                 /* Script table         */
+  HB_ScriptTable  Script;                 /* Script table         */
 };
 
 typedef struct HB_ScriptRecord_  HB_ScriptRecord;