* Amir:
>Can anyone explain to me the difference between these two declarations
>Comm.SendMsg[AM_MSG];
>Comm.ReceiveMsg[AM_MSG];
>
>and
>
>Comm.SendMsg;
>Comm.ReceiveMsg;
>
>I cannot comprehend why the former declaration is needed.

TinyOS uses the "Active Message" abstraction. Which just means that
every message carries with it an 8 bit value used to identify its type
(sort of like a protocol number on ethernet or a port number in TCP).
When you use Comm.SendMsg[AM_MSG], the messages you send will be marked
as type AM_MSG. Similarly, Comm.ReceiveMsg[AM_MSG] will only pass
messages of type AM_MSG. AM_MSG should be an enum constant or a macro of
an 8 bit value.

Regards,
Alexander

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