Are you running this on a simulator or a real mote?
I think there was an answer to part of your problem
a day or two ago: you may need to use the "packed"
attribute in your structure definition to prevent
types from being padded to fit some processor's
idea of their boundaries. I think, but am not
sure right now, that our real micro-controllers
do not use padding, but a PC may.
Also having a pointer in a message is, well, pointless.
You need to have the actual data array in the struct
itself because the sending code doesn't de-ref the
pointer to get to your data. But to answer the question,
I think pointers are 2 bytes on the controllers and
4 bytes on Win32.
To your subsequent question about variable length messages:
All TOS messages are variable length, only the number of
bytes specified in the send call are sent from the user's
packet pointer. Your problem is that you have a fixed field
"nx_uint32_t mac;" _after_ the variable length data portion
so you will always have to send the full data[nn] in order
to get to it. If you can change the order of the fields you
can then just specify a sub-length of data for each send.
MS
Omar Cheikhrouhou (yahoo) wrote:
> In fact, i use the following structure to exchange message between node
> on network.
>
>
>
> typedef struct riseg_msg{
>
> nx_uint8_t type; /*the type of the riseg message*/
>
> uint8_t *data;
>
> nx_uint32_t mac; /* the mac field, present in all riseg message */
>
> } riseg_msg_t;
>
>
>
>
>
> /*Default size=19 bytes*/
>
> typedef struct join_key_msg{
>
>
>
> nx_uint16_t next; /* the address of the next hop in the ring */
>
> nx_uint8_t gid; /* the group identity */
>
> uint8_t key[KEY_SIZE]; /*the group key. Default size=16 bytes*/
>
>
>
> } join_key_msg_t;
>
>
>
> riseg_msg_t *risegMsgSent;
>
>
>
> However, when I print the size of message I get 12 instead of 9 (1+4+4).
>
> ====output using printf=========================
>
> sizeof(riseg_msg_t):12, sizeof(join_key_msg_t):19
>
> sizeof(riseg_msg_t->type):1, sizeof(riseg_msg_t->data):4,
> sizeof(riseg_msg_t->mac):4
>
> sizeof(risegMsgSent):4, sizeof(*risegMsgSent):12,
>
>
>
> I do not understand.
>
>
>
> Can anybody explain to me why 12? What is the size of pointer in TinyOS?
>
>
>
> Thanks in advance,
>
>
>
> *De :* Prabhakar Misra [mailto:misra.pra...@gmail.com]
> *Envoyé :* jeudi 8 juillet 2010 21:22
> *À :* Omar Cheikhrouhou (yahoo)
> *Objet :* Re: [Tinyos-help] problem sending message
>
>
>
> Hi,
> Your problem is a bit vague, may be you could be a bit more exact.
> Is the sending being done over a radio or something??
>
> On Thu, Jul 8, 2010 at 1:31 PM, Omar Cheikhrouhou (yahoo)
> <enis01a...@yahoo.fr <mailto:enis01a...@yahoo.fr>> wrote:
>
> When i send two succesive message in telosb mote I got that the second
> packet has as value the first one when I print its value in senddone and
> receive.
>
> Do you have any explication for this problem…
>
>
> _______________________________________________
> Tinyos-help mailing list
> Tinyos-help@millennium.berkeley.edu
> <mailto:Tinyos-help@millennium.berkeley.edu>
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>
>
>
>
> --
> Regards,
> Prabhakar Misra,
> Senior Undergraduate,
> Department of Computer Science and Enginnering.
> Indian Institute of Technology Kanpur,
> India.
>
>
> ------------------------------------------------------------------------
>
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