diff --git a/src/fileio.c b/src/fileio.c
index b7c86af..779a0d6 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4328,7 +4328,7 @@
 
 	use_crypt_method = buf->b_p_cm;  /* select pkzip or blowfish */
 
-	memset(header, 0, sizeof(header));
+	vim_memset(header, 0, sizeof(header));
 	vim_strncpy(header, (char_u *)crypt_magic[use_crypt_method],
 							     CRYPT_MAGIC_LEN);