You need to get deeply with the Kernigan and Ritchie 'C' Programming Manual.
If you are not familaiar with C you are basically Stuff Out of Luck with TOS.
In general:
type* name; // declares a pointer to a variable of type.
type _name; // another variable, the '_' may make it less visible
name = &something; // sets the pointer to the address of "something"
name = (type*)else; // casts (forces) "else" to be a type*
The TOS_Msg stucts are defined in tos/types/AM.h, unless of course
you are NOT using mica2 or the UART, in which case they may be defined
in a tos/platform/[platform]/AM.h file...And, no, that is not part
of the 'C' definition, but rather a consequence of 'C''s propensity
to encourage you to shoot yourself until you lose consciousness.
Pong message structs can probably be found in a *.h ('*' is not a
pointer in this case, thank the Unix gods...) file somewhere in
the vicinity of the pong app directory.
MS
Wu Nick wrote:
> Deal, all
> I am not very familiar with the nesC and C language. So I got some
> problem with the source code. For example, in the PingPong application
> which under the apps file. I know about how the PingPong app works, so I
> can guess what the meaning for each event and command. But some parts of
> the source code I don’t explicit understand, especially for the part
> which is about packet transmission. I append apart of source code on the
> back (I put a # mark in the front, and write my Q on the back). Have
> anyone can kindly explain that for me? Please help me out of this
> Best regards,
> Wu
>
> implementation {
> # TOS_Msg m_msg; // using TOS_Msg structure from
> AM.h, naming m_msg, right?
> # TOS_MsgPtr p_msg; // where is TOS_MsgPtr from? #
> PongMsg_t* pongmsg; // the * symbol
> in here is a pointer?
> command result_t StdControl.init() {
>
> # pongmsg = (PongMsg_t*)m_msg.data; // no
> idea for this!!
> # p_msg = &m_msg; //what is
> the & mean?
> }
>
> event result_t Timer.fired() {
>
> # if (call SendMsg.send(TOS_BCAST_ADDR, sizeof(PongMsg_t), p_msg))
> { } // this command will check for????
>
> }
>
> event TOS_MsgPtr ReceiveMsg.receive( TOS_MsgPtr msg ) {
> # PongMsg_t* _pongmsg; // what is the different between
> pongmsg and _pongmsg???
>
> # _pongmsg = (PongMsg_t*)msg->data; //where is the data
> structure from???
>
> if( _pongmsg->src != TOS_LOCAL_ADDRESS ) {
> pongmsg->src = _pongmsg->src;
> pongmsg->src_rssi = rssival;
> pongmsg->src_lqi = _pongmsg->src_lqi;
> pongmsg->dest = TOS_LOCAL_ADDRESS;
> pongmsg->dest_lqi = battval;
> # call SendMsg.send(_pongmsg->src, sizeof(PongMsg_t),
> p_msg); // what does the parameter p_msg define for??? } else {
> // send to UART
> call Leds.yellowToggle();
> pongmsg->src = _pongmsg->src;
> pongmsg->src_rssi = _pongmsg->src_rssi;
> pongmsg->src_lqi = _pongmsg->src_lqi;
> pongmsg->dest = _pongmsg->dest;
> pongmsg->dest_rssi = rssival;
> pongmsg->dest_lqi = _pongmsg->dest_lqi;
> call SendMsg.send(TOS_UART_ADDR, sizeof(PongMsg_t), p_msg);
> }
> # return msg; // the return value msg is for what?
> }
>
> _________________________________________________________________
> 信箱不夠大？MSN Hotmail Plus：讓你的 Hotmail 信箱容量增加 1000 倍
> http://join.msn.com/?pgmarket=zh-tw
> _______________________________________________
> Tinyos-help mailing list
> [email protected]
> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
_______________________________________________
Tinyos-help mailing list
[email protected]
https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
