Receiving UDP datagrams?

Hello,
I have a C library I've been using for a while which allows text
messages to be embedded unto UDP datagrams and sent from one
application to another over a local Ethernet. I've used it for several
years with no problems.
At the moment, I'm trying to take one of the application which uses
this library, and send some of its results over the network to a
Labview application. I've been trying to start by looking at the
udpex.lib example VI's, and loading the Spray Receiver VI.
I figured that if I set the Spray Receiver's port number to the same
port as I'm broadcasting messages to, then I should see the messages
that are being passed around. However, I don't- the receiver always
times out. Similarly, if I use the Spray Sende
r to broadcast to the
same port as I'm listening to, I would expect to receive a datagram in
my C code, but nothing appears.
Running the Spray Sender and Spray Receiver VI's together seems to
work fine- I see the messages bouncing back and forth between them.
I'm pretty sure I have the port numbers and other parameters set
appropriately, but I'm stumped as to why I'm getting no indications of
messages passing back and forth between the Labview and C sides. Can
anyone suggest anything to look for, particularly something that might
help someone who (at least, thinks) knows the win32 UDP well, but is
just getting started with LabView?
Thanks,
Les Elkins
Spatial Inttegrated Systems, Inc.

Dennis Knutson wrote in message news:<[email protected]>...
> All I can say is that I once used the LabVIEW VIs to connect to a UDP
> write written in Visual Basic just by using the UDP Open and UDP Read
> functions. I looked back at my old code and saw that the only thing I
> did was change the max size and timeout values. I don't know about
> Spray Sender or Spray Receiver VIs. Where did you find them?
The Spray Sender and Spray Receiver VI's are examples for an Application
Note on TCP/IP and UDP. I don't have the full title at hand, but the note
is referenced in the UDP section of the manual.
This certainly looks like something that should 'just work', but I'm not there yet...
Thanks,
Les Elkins

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Posting
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[Time delta from previous displayed frame: 0.000000000 seconds]
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[Coloring Rule String: udp]
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.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
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Address: ae:4e:20:00:01:00 (ae:4e:20:00:01:00)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
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Internet Protocol Version 4, Src: 192.168.1.50 (192.168.1.50), Dst: 192.168.1.255 (192.168.1.255)
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0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Capable Transport) (0x00)
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Identification: 0x0032 (50)
Flags: 0x00
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..0. .... = More fragments: Not set
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Checksum: 0xafd1 [validation disabled]
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0000 34 34 34 34 34 34 444444
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I am running out of my ideas, if anyone could help, with any idea, please do. I am not sure if this feature is dropped in win7 or not.

Hi,
From your description, you may gather the network monitor traces to ensure which part lost UDP broadcast packets.
Thank you.
Best regards,
Stevens Song
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