diff --git a/ext/date/php_date.c b/ext/date/php_date.c
index 31cb41adfdf..3d203eb2275 100644
--- a/ext/date/php_date.c
+++ b/ext/date/php_date.c
@@ -1694,7 +1694,7 @@ PHPAPI void php_strftime(INTERNAL_FUNCTION_PARAMETERS, int gmt)
 	/* VS2012 strftime() returns number of characters, not bytes.
 		See VC++11 bug id 766205. */
 	if (real_len > 0) {
-		real_len = strlen(buf);
+		real_len = buf->len;
 	}
 #endif