[PD-dev] help setting signal input via arg

[Christof Ressi]

CLASS_SIGNALMAININ expects the variable to be t_float, but x_cf is 
declared as a double! The compiler happily accepts it and you get 
garbage at runtime! In this particular case, Pd would read the lower 
half of the double and interpret it as a float.

Actually, there are ways to check the type and prevent such errors. I 
just opened a ticket on GitHub: 
https://github.com/pure-data/pure-data/issues/2142

---

As a side note:

In gendyn_new() you seem to hardcode x_cf to 440 Hz:

https://github.com/porres/pd-else/blob/653c23eb7ee0f50799dd2732f0a258fb389726b9/Code_source/Compiled/audio/gendyn~.c#L238C5-L238C19

I guess what you actually want to do is the following (after parsing the 
flags):

x->x_cf = atom_getfloatarg(0, argc, argv);

But maybe you only did this for testing purposes.

Christof

On 22.11.2023 21:27, Alexandre Torres Porres wrote:
> Hi, this is embarrassing, after coding so many objects that can easily 
> set a signal input via an argument, like an oscillator whose signal 
> input sets frequency and you can also set it via an argument (just 
> like [osc~]), I can't see what's wrong with this code I'm workin on 
> right now.
>
> I am adapting else/gendyn~ to take center frequency so it works more 
> like an oscillator and I am setting it via an argument or loading a 
> default value, and I can see it is printed fine and loaded 
> correctly at "new".
>
> It goes into a x->x_cf variable that is also loaded at setup as 
> via CLASS_MAINSIGNALIN(gendyn_class, t_gendyn, x_cf);
>
> but in the perform routine this becomes "0" for some weird reason I 
> cannot understand, so I have to give it a float or a signal into the 
> inlet so it actually works.
>
> I can't see what's wrong, for me it's exactly the same as other 
> objects from my library, like [saw~], for instance.
>
> Code live in 
> https://github.com/porres/pd-else/blob/master/Code_source/Compiled/audio/gendyn~.c
>
> I wonder if any wizard out there can spot the mistake I just can't 
> seem to grab for the life of me
>
> thanks
>
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