UNIX Sockets - Broadcasting - Broadcast address

UNIX Sockets - Broadcasting - Broadcast address

[Kay M]

I have written a client program that connects to the local broadcast address 
and reads datagrams that are produced by a server. It works on my linux (no 
internet) machine. But on my PC under CYGWIN the binding of the socket to 
the Broadcast Address give an error EADDRNOAVAIL.

I tried both 127.255.255.255 and also INADDR_BROADCAST. If I change 
broadcast address to 127.255.255.254, then server and client both work  
under Cygwin, but that isnt Broadcasting address though.

Can anyone help /explain ?

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Re: UNIX Sockets - Broadcasting - Broadcast address

[Corinna Vinschen]

On Tue, Dec 11, 2001 at 03:21:13AM +0000, Kay M wrote:
> I have written a client program that connects to the local broadcast address 
> and reads datagrams that are produced by a server. It works on my linux (no 
> internet) machine. But on my PC under CYGWIN the binding of the socket to 
> the Broadcast Address give an error EADDRNOAVAIL.

You're getting the error from the underlying WinSock DLL.  I don't
understand what you're doing, though.  If the server is sending
UDP broadcast messages on your subnet, where do you `connect'???
With UDP you just call readfrom() and wait for a package.  There's
nothing you could connect to or listen on.  And the subnet's
broadcast address isn't a legal address for a machine anyway.

Corinna

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Corinna Vinschen                  Please, send mails regarding Cygwin to
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