liblo-devel Mailing List for LibLO

Hi Fernando,

I assume that you are talking about fetching the passed values out from a
received message in the message handler. The values are each passed in a
union.

Here is one of my message handlers (sorry if it doesn't format well in an
email):


//	Callback handler for "/request/write <id> <node> <location>
<parameter size> <parameter ID> <parameter format> <value>"
//				or			 <id> <node>
<location> <parameter name> <parameter format> <value>"
int		handler_reqwrite(const char *path, const char *types, lo_arg
**argv, int argc, lo_message msg, void *user_data)
{
	if ( *(types+3) == 'i')
// if the forth parameter is a size and not a name . . .
		if ( argv[2]->i == -1 )
// and if the location is ram and not a flash page . . .
			requestWrite( (void*)argv[0]->i, argv[1]->i,
argv[3]->i, argv[4]->i, argv[5]->i, argv[6]);
		else
			requestWriteFlash( (void*)argv[0]->i, argv[1]->i,
argv[3]->i, argv[4]->i, argv[5]->i, argv[6]);
	else
// if the forth parameter is a name and not a size . . .
		if ( argv[2]->i == -1 )
// and if the location is ram and not a flash page . . .
			requestWriteByName( (void*)argv[0]->i, argv[1]->i,
&argv[3]->s, argv[4]->i, argv[5]);
		else
			requestWriteFlashByName( (void*)argv[0]->i,
argv[1]->i, &argv[3]->s, argv[4]->i, argv[5]);
	return 0;
}


Each 'lo_arg' type is a union of all of the OSC types and each 'argv' is a
pointer to a union. As an example, if the second value passed was an 'int',
then I would access it as:

	int size = argv[1]->i ;

and if it was a string (which is actually a character-pointer, so we have a
pointer to a pointer):

	char* name = &argv[1]->s ;

Of course, the 'types' parameter would tell you the true type of the
parameter so that you can access it correctly, and I have caused
segmentation faults when I made the wrong assumption of the type.

Is that what you needed? Let me know if you would like anything else. I have
a ton of code now.

Mark



-----Original Message-----
From: Fernando Carello [mailto:fca...@gm...]
Sent: Sunday, February 28, 2021 9:00 AM
To: liblo development list
Subject: Re: [liblo] how to connect to a liblo TCP OSC server?


Hello,
I've successfully tested liblo in C, writing both client and server
implementations.

Now I'm faced with a maybe silly problem...

I can compose an OSC message from native C types using
lo_message_new() and appropriate
lo_message_add_* methods.

But, how may I convert OSC arguments from lo_arg to native C types?

Thanks!
Fernando


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Hello,
I've successfully tested liblo in C, writing both client and server
implementations.

Now I'm faced with a maybe silly problem...

I can compose an OSC message from native C types using
lo_message_new() and appropriate
lo_message_add_* methods.

But, how may I convert OSC arguments from lo_arg to native C types?

Thanks!
Fernando