diff --git a/src/OT/glyf/SubsetGlyph.hh b/src/OT/glyf/SubsetGlyph.hh
index 79c7f7dd2..c21fee80b 100644
--- a/src/OT/glyf/SubsetGlyph.hh
+++ b/src/OT/glyf/SubsetGlyph.hh
@@ -86,7 +86,7 @@ struct SubsetGlyph
        * harmless instructions, since that's what they will be
        * interpreted as. */
 
-      memset (p, 0x7A /* TrueType instruction ROFF; harmless */, end - p);
+      hb_memset (p, 0x7A /* TrueType instruction ROFF; harmless */, end - p);
       p += end - p;
       dest_glyph = hb_bytes_t (dest_glyph.arrayZ, p - (char *) dest_glyph.arrayZ);