Also: in the example EOVERFLOW is probably better than ENOMEM.

lib/libc/stdlib/malloc.3

@@ -1,4 +1,4 @@
-.\" $NetBSD: malloc.3,v 1.32 2010/04/30 07:14:15 jruoho Exp $
+.\" $NetBSD: malloc.3,v 1.33 2010/04/30 07:16:35 jruoho Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -96,7 +96,7 @@ If
 must be used, be sure to test for overflow:
 .Bd -literal -offset indent
 if (size && number > SIZE_MAX / size) {
-	errno = ENOMEM;
+	errno = EOVERFLOW;
 	err(EXIT_FAILURE, "overflow");
 }
 .Ed