Re: [Bluez-devel] reading response on bluetooth socket

["Mayank Batra" <mayankbatra@gmail.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2526 bytes --]

Hi Goetz,

On 6/25/06, Götz Issel <g.issel@fh-wolfenbuettel.de> wrote:
>
> After having set up a rfcommm connection from my notebook to a mobile
> phone I
> need to get the response data from the mobile device. I can read from the
> socket using 'recv()' but if no data is there at thaht moment this will
> block
> the process or pause my program. What I need to do is get a signal on
> 'data
> available' on the socket for reading or a non blocking read. I heard there
> is
> a function 'select()' .. but it does not seem to work or I don't
> understand
> it. It needs to be as simple as possible.


This is correct. A read() will block your thread completely.
You have two options:
- Write from one thread and read from another (Doesn't sound interesting!)
- Use select

This is what I have now:
>
> // init + declare variables
>        fd_set readFds;
>        struct timeval timeout;
>        struct sockaddr_rc addr = { 0 };
>        int rfcomm_sock, status;
>
> // allocate a socket
>         rfcomm_sock = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
>
> // set the connection parameters (who to connect to)
>        addr.rc_family = AF_BLUETOOTH;
>        addr.rc_channel = (uint8_t) dest_channel;
>        str2ba( dest, &addr.rc_bdaddr );
>
> // connect to server, here mobile phone
>         status = connect(rfcomm_sock, (struct sockaddr *)&addr,
> sizeof(addr));
>
>        timeout.tv_sec=5;
>        timeout.tv_usec=0;
>        FD_ZERO(&readFds);
>        FD_SET(rfcomm_socket, &readFds);
>        if (select(rfcommsocket + 1, &readFds, NULL, NULL, &timeout) == 0)
>        {
>                printf("timed out");
>        }
>        else
>                printf("data ready for read");


Ahh, I assume that rfcomm_sock, rfcomm_socket and rfcommsocket refer to the
same thing.
God! did the above code ever compile??

Try the following code snippet which works for me:
fd_set readfds;
FD_ZERO(&readfds);
FD_SET(rfcomm_sock, &readfds);
while(1) {
  int ready = select(FD_SETSIZE, &readfds, 0, 0, 0);
  if(ready == 0)
   continue;
  if(ready == -1 && errno != EINTR)
   break;
  if(FD_ISSET(rfcomm_sock, &readfds)) {
    /* You've got something on rfcomm_sock, perform a read */
   int size = 1024;
   size = read(rfcomm_sock, &buf, 1024);//buf is a char array declared
somewhere
   /* Now, you have got the data in buf, parse it for the SAP header and
send a response if required */
  }
}


Hope that helps.

Regards,
Mayank

[-- Attachment #1.2: Type: text/html, Size: 4109 bytes --]

[-- Attachment #2: Type: text/plain, Size: 299 bytes --]

Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

[-- Attachment #3: Type: text/plain, Size: 164 bytes --]

_______________________________________________
Bluez-devel mailing list
Bluez-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bluez-devel