[PD] puredata external tutorial

[IOhannes m zmölnig]

hi,

On 07/23/2014 03:02 AM, dougall wrote:
> Hi,
> 
> Thanks for your great tutorial on writing Puredata externals.  It had me up
> and running in no time.

great to hear

> 
> I found a small bug.The pan~ example code doesn't assign the pan_tilde_free
> function pointer in the pan_tilde_setup function.  It is explained clearly
> in the document but the example code itself doesn't match.

thanks, i'll fix it asap.

> 
> Perhaps you can answer a question for me.  I've been writing some externals
> to read data from analog sensors on an i2c device.  I have a separate
> thread and use sys_lock() and sys_unlock() to output to the data to pd from
> inside the thread.  Is this best practice?  I've seen a number of different
> approaches to this situation.


first of all, the best place to ask such questions is the pd-dev
mailinglist [1].

imho, the best practice is:
- setup a clock-callback that converts the data from your representation
to an atom-list and then outputs the data.
- in your reading thread trigger the clock in a protected way:

   sys_lock();
   clock_delay(x->x_clock, 0);
   sys_unlock();

- this will call the clock asap within the main thread of Pd.

fmadsr
IOhannes





[1] http://lists.puredata.info/listinfo/pd-dev


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