local host does not see broadcast on OS X

[Dar Scott]

I have a small sockets stack that listens on a UDP port (accept) and 
sends datagrams to that port on an IP address.  If the address is 
broadcast, the behavior is not consistent among platforms tested.  This 
applies whether the broadcast is general (255.255.255.255) or subnet 
specific (for example, 10.99.255.255)

If the local computer is included in the broadcast specification (which 
it always is in the general broadcast), the datagram is received on 
Windows XP and on Mac OS 9.2.  But it is not on OS X.

To my thinking the OS X behavior is goofy.  Now it comes to my mind 
that maybe that behavior, goofy or not, is traditional on unix.  (Maybe 
some folks would think it very irreverent to describe TCP/IP behavior 
as goofy on a descendent of BSD unix.)

Anybody know what is up here?  Does this happen on linux, too?

Dar Scott