diff --git a/src/hb-aat-map.hh b/src/hb-aat-map.hh
index c914f58d7..d0ee7d672 100644
--- a/src/hb-aat-map.hh
+++ b/src/hb-aat-map.hh
@@ -38,7 +38,7 @@ struct hb_aat_map_t
 
   void init ()
   {
-    memset (this, 0, sizeof (*this));
+    hb_memset (this, 0, sizeof (*this));
     chain_flags.init ();
   }
   void fini () { chain_flags.fini (); }
diff --git a/src/hb-bit-page.hh b/src/hb-bit-page.hh
index 8d910832f..87d0e6143 100644
--- a/src/hb-bit-page.hh
+++ b/src/hb-bit-page.hh
@@ -41,7 +41,7 @@ struct hb_vector_size_t
   elt_t& operator [] (unsigned int i) { return v[i]; }
   const elt_t& operator [] (unsigned int i) const { return v[i]; }
 
-  void clear (unsigned char v = 0) { memset (this, v, sizeof (*this)); }
+  void clear (unsigned char v = 0) { hb_memset (this, v, sizeof (*this)); }
 
   template <typename Op>
   hb_vector_size_t process (const Op& op) const
@@ -116,7 +116,7 @@ struct hb_bit_page_t
       *la |= ~(mask (a) - 1);
       la++;
 
-      memset (la, 0xff, (char *) lb - (char *) la);
+      hb_memset (la, 0xff, (char *) lb - (char *) la);
 
       *lb |= ((mask (b) << 1) - 1);
     }
@@ -132,7 +132,7 @@ struct hb_bit_page_t
       *la &= mask (a) - 1;
       la++;
 
-      memset (la, 0, (char *) lb - (char *) la);
+      hb_memset (la, 0, (char *) lb - (char *) la);
 
       *lb &= ~((mask (b) << 1) - 1);
     }
diff --git a/src/hb-buffer-deserialize-json.hh b/src/hb-buffer-deserialize-json.hh
index 44c802a00..993bb1f69 100644
--- a/src/hb-buffer-deserialize-json.hh
+++ b/src/hb-buffer-deserialize-json.hh
@@ -590,8 +590,8 @@ _resume:
 	case 1:
 #line 38 "hb-buffer-deserialize-json.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 	break;
 	case 5:
diff --git a/src/hb-buffer-deserialize-text.hh b/src/hb-buffer-deserialize-text.hh
index 484171ce5..6b9b4282f 100644
--- a/src/hb-buffer-deserialize-text.hh
+++ b/src/hb-buffer-deserialize-text.hh
@@ -493,8 +493,8 @@ _resume:
 	case 1:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 	break;
 	case 4:
@@ -548,8 +548,8 @@ _resume:
 	case 15:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
@@ -665,8 +665,8 @@ _resume:
 	case 12:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
@@ -678,8 +678,8 @@ _resume:
 	case 14:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
@@ -717,8 +717,8 @@ _resume:
 	case 11:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
@@ -744,8 +744,8 @@ _resume:
 	case 13:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
@@ -875,8 +875,8 @@ _again:
 	case 11:
 #line 38 "hb-buffer-deserialize-text.rl"
 	{
-	memset (&info, 0, sizeof (info));
-	memset (&pos , 0, sizeof (pos ));
+	hb_memset (&info, 0, sizeof (info));
+	hb_memset (&pos , 0, sizeof (pos ));
 }
 #line 51 "hb-buffer-deserialize-text.rl"
 	{
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 44b5dcba3..f3c4cbe14 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -230,7 +230,7 @@ hb_buffer_t::shift_forward (unsigned int count)
      * Ideally, we should at least set Default_Ignorable bits on
      * these, as well as consistent cluster values.  But the former
      * is layering violation... */
-    memset (info + len, 0, (idx + count - len) * sizeof (info[0]));
+    hb_memset (info + len, 0, (idx + count - len) * sizeof (info[0]));
   }
   len += count;
   idx += count;
@@ -299,8 +299,8 @@ hb_buffer_t::clear ()
   out_len = 0;
   out_info = info;
 
-  memset (context, 0, sizeof context);
-  memset (context_len, 0, sizeof context_len);
+  hb_memset (context, 0, sizeof context);
+  hb_memset (context_len, 0, sizeof context_len);
 
   deallocate_var_all ();
   serial = 0;
@@ -345,7 +345,7 @@ hb_buffer_t::add (hb_codepoint_t  codepoint,
 
   glyph = &info[len];
 
-  memset (glyph, 0, sizeof (*glyph));
+  hb_memset (glyph, 0, sizeof (*glyph));
   glyph->codepoint = codepoint;
   glyph->mask = 0;
   glyph->cluster = cluster;
@@ -1432,9 +1432,9 @@ hb_buffer_set_length (hb_buffer_t  *buffer,
 
   /* Wipe the new space */
   if (length > buffer->len) {
-    memset (buffer->info + buffer->len, 0, sizeof (buffer->info[0]) * (length - buffer->len));
+    hb_memset (buffer->info + buffer->len, 0, sizeof (buffer->info[0]) * (length - buffer->len));
     if (buffer->have_positions)
-      memset (buffer->pos + buffer->len, 0, sizeof (buffer->pos[0]) * (length - buffer->len));
+      hb_memset (buffer->pos + buffer->len, 0, sizeof (buffer->pos[0]) * (length - buffer->len));
   }
 
   buffer->len = length;
diff --git a/src/hb-common.cc b/src/hb-common.cc
index daaa7658c..2d548b72f 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -976,7 +976,7 @@ hb_feature_from_string (const char *str, int len,
   }
 
   if (feature)
-    memset (feature, 0, sizeof (*feature));
+    hb_memset (feature, 0, sizeof (*feature));
   return false;
 }
 
@@ -1088,7 +1088,7 @@ hb_variation_from_string (const char *str, int len,
   }
 
   if (variation)
-    memset (variation, 0, sizeof (*variation));
+    hb_memset (variation, 0, sizeof (*variation));
   return false;
 }
 
diff --git a/src/hb-font.cc b/src/hb-font.cc
index 0fb75b785..d12796f74 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -71,7 +71,7 @@ hb_font_get_font_h_extents_nil (hb_font_t         *font HB_UNUSED,
 				hb_font_extents_t *extents,
 				void              *user_data HB_UNUSED)
 {
-  memset (extents, 0, sizeof (*extents));
+  hb_memset (extents, 0, sizeof (*extents));
   return false;
 }
 
@@ -96,7 +96,7 @@ hb_font_get_font_v_extents_nil (hb_font_t         *font HB_UNUSED,
 				hb_font_extents_t *extents,
 				void              *user_data HB_UNUSED)
 {
-  memset (extents, 0, sizeof (*extents));
+  hb_memset (extents, 0, sizeof (*extents));
   return false;
 }
 
@@ -409,7 +409,7 @@ hb_font_get_glyph_extents_nil (hb_font_t          *font HB_UNUSED,
 			       hb_glyph_extents_t *extents,
 			       void               *user_data HB_UNUSED)
 {
-  memset (extents, 0, sizeof (*extents));
+  hb_memset (extents, 0, sizeof (*extents));
   return false;
 }
 
diff --git a/src/hb-font.hh b/src/hb-font.hh
index bb402e23e..6942d99c7 100644
--- a/src/hb-font.hh
+++ b/src/hb-font.hh
@@ -206,14 +206,14 @@ struct hb_font_t
 
   hb_bool_t get_font_h_extents (hb_font_extents_t *extents)
   {
-    memset (extents, 0, sizeof (*extents));
+    hb_memset (extents, 0, sizeof (*extents));
     return klass->get.f.font_h_extents (this, user_data,
 					extents,
 					!klass->user_data ? nullptr : klass->user_data->font_h_extents);
   }
   hb_bool_t get_font_v_extents (hb_font_extents_t *extents)
   {
-    memset (extents, 0, sizeof (*extents));
+    hb_memset (extents, 0, sizeof (*extents));
     return klass->get.f.font_v_extents (this, user_data,
 					extents,
 					!klass->user_data ? nullptr : klass->user_data->font_v_extents);
@@ -342,7 +342,7 @@ struct hb_font_t
   hb_bool_t get_glyph_extents (hb_codepoint_t glyph,
 			       hb_glyph_extents_t *extents)
   {
-    memset (extents, 0, sizeof (*extents));
+    hb_memset (extents, 0, sizeof (*extents));
     return klass->get.f.glyph_extents (this, user_data,
 				       glyph,
 				       extents,
diff --git a/src/hb-graphite2.cc b/src/hb-graphite2.cc
index 4d0e687c7..9e068f8d8 100644
--- a/src/hb-graphite2.cc
+++ b/src/hb-graphite2.cc
@@ -318,7 +318,7 @@ _hb_graphite2_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,
 
 #undef ALLOCATE_ARRAY
 
-  memset (clusters, 0, sizeof (clusters[0]) * buffer->len);
+  hb_memset (clusters, 0, sizeof (clusters[0]) * buffer->len);
 
   hb_codepoint_t *pg = gids;
   clusters[0].cluster = buffer->info[0].cluster;
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 58117113e..3c6688f5c 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -45,7 +45,7 @@ void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_o
 hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
 					  const hb_segment_properties_t &props_)
 {
-  memset (this, 0, sizeof (*this));
+  hb_memset (this, 0, sizeof (*this));
 
   feature_infos.init ();
   for (unsigned int table_index = 0; table_index < 2; table_index++)
diff --git a/src/hb-ot-map.hh b/src/hb-ot-map.hh
index 847d5ca2a..53cf16fd4 100644
--- a/src/hb-ot-map.hh
+++ b/src/hb-ot-map.hh
@@ -89,7 +89,7 @@ struct hb_ot_map_t
 
   void init ()
   {
-    memset (this, 0, sizeof (*this));
+    hb_memset (this, 0, sizeof (*this));
 
     features.init ();
     for (unsigned int table_index = 0; table_index < 2; table_index++)
diff --git a/src/hb-pool.hh b/src/hb-pool.hh
index 95fc5a08e..e4bb64f62 100644
--- a/src/hb-pool.hh
+++ b/src/hb-pool.hh
@@ -58,7 +58,7 @@ struct hb_pool_t
     T* obj = next;
     next = * ((T**) next);
 
-    memset (obj, 0, sizeof (T));
+    hb_memset (obj, 0, sizeof (T));
 
     return obj;
   }
diff --git a/src/hb-uniscribe.cc b/src/hb-uniscribe.cc
index 50f71ce9c..cd95197bb 100644
--- a/src/hb-uniscribe.cc
+++ b/src/hb-uniscribe.cc
@@ -478,7 +478,7 @@ populate_log_font (LOGFONTW  *lf,
 		   hb_font_t *font,
 		   unsigned int font_size)
 {
-  memset (lf, 0, sizeof (*lf));
+  hb_memset (lf, 0, sizeof (*lf));
   lf->lfHeight = - (int) font_size;
   lf->lfCharSet = DEFAULT_CHARSET;