diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 5b1d9764e..9f4d7cb0b 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -369,7 +369,7 @@ hb_ot_layout_get_ligature_carets (hb_font_t      *font,
 				  unsigned int   *caret_count /* IN/OUT */,
 				  hb_position_t  *caret_array /* OUT */)
 {
-  unsigned int result_caret_count = 0;
+  unsigned int result_caret_count = caret_count ? *caret_count : 0;
   unsigned int result = font->face->table.GDEF->table->get_lig_carets (font, direction, glyph, start_offset, &result_caret_count, caret_array);
   if (result)
   {