diff --git a/man2/sysctl.2 b/man2/sysctl.2
index 65f79516d..161060490 100644
--- a/man2/sysctl.2
+++ b/man2/sysctl.2
@@ -154,7 +154,7 @@ main(void)
     size_t osnamelth;
     int name[] = { CTL_KERN, KERN_OSTYPE };
 
-    memset(&args, 0, sizeof(struct __sysctl_args));
+    memset(&args, 0, sizeof(args));
     args.name = name;
     args.nlen = sizeof(name)/sizeof(name[0]);
     args.oldval = osname;