Re: [Bluez-users] rfcomm question 3

[Marco Trudel <mtrudel@gmx.ch>]

Hello Michael

Maybe this helps:

---- start code snippet ----
// handle the includes yourself

#define CHANNEL 4
#define QUEUE 10

int main()
{
	int sock, client;
	socklen_t alen;
	struct sockaddr_rc addr;

	addr.rc_family = AF_BLUETOOTH;
	bacpy(&addr.rc_bdaddr, BDADDR_ANY);
	addr.rc_channel = htobs(CHANNEL);
	alen = sizeof(addr);

	// request a socket from the operating system
	if((sock = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM)) < 0)
	{
		printf("socket(...) failed");
		exit(1);
	}

	// bind the socket to the system
	if(bind(sock, (struct sockaddr *)&addr, alen) < 0)
	{
		printf("bind(...) failed\n");
		exit(2);
	}

	// set the socket into listen mode. handle 10 (QUEUE) connections.
	if(listen(sock, QUEUE) < 0)
	{
		printf("listen(...) failed\n");
		exit(3);
	}

	// wait for the next connection or serve the next in the queue
	while(client = accept(sock, (struct sockaddr *)&addr, &alen))
	{
		char remoteAddr[18];
		ba2str(&addr.rc_bdaddr, remoteAddr);
		printf("connection from %s:\n", remoteAddr);

		// send a "hello from server" to client
		char out[] = "hello from server";
		send(client, out, strlen(out), 0);
		printf("> %s\n", out);

		// read the answer
		char buffer[101]; // buffer size 100, 1 for '\0'
		int noReadChars = recv(client, buffer, sizeof(buffer)-1, 0);
		buffer[noReadChars] = '\0'; // here the received answer ends
		printf("< %s\n", buffer);

		// now close the connection
		close(client);
	}

	close(sock);
	return 0;
}
---- code snippet end ----

If you start this sample the machine listens on rfcomm channel 4 for
incoming connections. you can now connect with a mobile phone.

If you now search for "c socket programming" on google, you'll be able to
fully understand this code snippet and be able to change it to do what you
want.


regards
Marco


Ka Kin Cheung wrote:
> Hi all users!
>     Sorry, but I have to say that I have knowledge about C, but I don't 
> have so much knowledge about socket programming. And I would like to 
> point out that what I find hard is just to let my main program to listen 
> to what bluetooth mobile device wishes to connect to PC, and then let 
> the program run even though no bluetooth device is connecting with the 
> PC i.e. let PC to be server. Anyway, thank you very much for all of your 
> advices. Sorry for any misunderstanding.
>     By the way, C is the main programming language of my project, so it 
> is not possible for me to use one language more. But I thank Marco for 
> advice.
>     And I wish to ask question here. I've heard that rfcom_bind can do 
> something similar those things do in rctest.c, but until now, I can't 
> find any detail about rfcomm_bind, even in this mail-list or in web. So, 
> if anyone knows, please kindly inform me here and I'll use it once I 
> understand what it does. Sorry for impolite reply but I am eager to 
> learn more about this. Thank you very much!
> Michael
> *//*
> 
>     Hello Ka Kin Cheung
> 
>     It looks like you haven't that much c or socket programming
>     knowledge. So
>     if you try to learn c, socket programming, compiling, bluetooth
>     programming
>     and all relatet topics in one step, that's pretty hard.
> 
>     What about Java? JSR 82?
>     It's fully documentated and you find a lot of samples if you ask
>     google...
> 
>     Take a look at this:
>     http://sourceforge.net/projects/avetanabt/
>     (It is available for windows as well.)
> 
>     And a good general programming rule (specially for c/c++):
>     Do not use gcc if you haven't already understand what your code's
>     supposed
>     to do.
> 
> 
>     regards
>     Marco
> 
> 
>     Ka Kin Cheung wrote:
>      > Hi all,
>      > I've added -lbluetooth in the command, and it successes. But when I
>      > run the program, the program terminates and doesn't wait for any
>     mobile
>      > terminal involving into the program. What is the problem about my
>      > program? And need I really link the header files in
>     bluez-libs/include?
>      > If so, should I include like this "bluez-libs-2.14/include/xx.h"?
>     But
>      > the /usr/include contains the files. So I wish to know why if it
>     is so.
>      > Here is the syntax of my program.
>      > int main (int argc, char **argv)
>      > {
>      > ...
>      > int no_connection;
>      > ...
>      > printf("\E[H\E[J");
>      > printf ("Bluetooth infrared converter\n\n");
>      > printf ("Doing initializations !\n");
>      > no_connection=0;
>      > do_listen(recv_mode);
>      > ...
>      > while (1)
>      > {
>      > no_connection++;
>      > printf("Now %d mobile terminal(s) is(are) using this program\n");
>      > sprintf (command, "at+cscs=i\"8859-1\"\r");
>      > ret_code = put_command (command, answer, sizeof (answer), 5, 0);
>      > sprintf (command, "AT*EAM=\"Bt-IrConverter\"\r");
>      > ret_code = put_command (command, answer, sizeof (answer), 5, 0);
>      > submenu_selected = 0;
>      > while (!submenu_selected)
>      > {
>      > ....
>      > Thanks very much.
>      > Michael
>      >
>      > */Alain Volmat /* wrote:
>      >
>      > Hi Michael,
>      >
>      > ba2str is a function provided by bluez-libs. Linking your
>      > program against the bluez-lib might solve your problem.
>      >
>      > add -lbluetooth to your command line.
>      >
>      > Alain
>      >
>      > * Ka Kin Cheung [Thu, 3 Feb 2005 at 18:50 +0800]
>      >
>      > > Hi all users!
>      > > I first give a thank to Alain Volmat that points
>      > > out my fault and confusion about rctest.c. Then I put
>      > > the parts do_listen and recv_mode in my main porgram.
>      > > But when I compile, strange things occur.....
>      > > As my program is MySQL C API, I have to compile
>      > > with "gcc -c -I/usr/include/mysql XX.c", and it is no
>      > > problem. But when I type "gcc -o XX XX.o
>     & gt; > -L/usr/lib/mysql -lmysqlclient", following occurs:
>      > > bic_midterm.o(.text+0x1c0a): In function `do_listen':
>      > > : undefined reference to `ba2str'
>      > > collect2: ld returned 1 exit status
>      > > I checked with rctest.c, but there is not a function
>      > > for ba2str. On the other hand, tv2fl can be accepted
>      > > as there is a function in rctest.c. Here are the
>      > > include files in my main program.
>      > > #ifdef HAVE_CONFIG_H
>      > > #include
>      > > #endif
>      > >
>      > >
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > >
>      > >
>      > > #include
>      > > include
>      > > #include
>      > > ; #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > >
>      > > #include
>      > >
>      > >
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > > #include
>      > >
>      > >
>      > > #include
>      > > Let's see if there is any function that is missing. If
>      > > there is no function missing, where can I find the
>      > > ba2str function? I believe that if ba2str function can
>      > > be found declared, the program can be run. Thank you
>      > > very much for your kindness.
>      > > Michael
>      > >
>      > >
>      >
>     _______________________________________________________________________
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