[PD-dev] trying to understand class_new

[Christof Ressi]

Don't worry too much about *vp for now. The fault actually occurs in 
m_class.c:506.

Do you use PDINSTANCE?

Also, you can check stm32f4xx_it.c:90 to see what kind of error you're 
getting.

How much memory do you have available?

Christof

On 22.03.2020 17:15, Boštjan Jerko wrote:
> I’m attaching images from debugger. The strange thing is that type1 is 
> A_DEFFLOAT, but *vp is still A_NULL. Guess I need to work (at least) 
> on that.
> That way the loop doesn’t even get started.
> So one image shows values of type1 and *vp and the other is stack.
>
> I’m using stm32f429 and Segger programmer with their Ozone debugger.
>
> B.
>
>
>
>> On 22 Mar 2020, at 11:52, Christof Ressi <info at christofressi.com 
>> <mailto:info at christofressi.com>> wrote:
>>
>>> and then in function class_new vp is empty so while (*vp) doesn’t go 
>>> through it
>> What do you mean by "empty", when exactly is "vp" empty and how did 
>> you test?
>>
>> "vp" is initially set to "type1", which in the case of pdint_setup() 
>> is "A_DEFFLOAT". So it would be very strange if "vp" was initially 
>> empty in the case pdint_setup(). The while loop sets "vp" to the next 
>> vararg and increments the pointer until it encounters "A_NULL" (= 0). 
>> So finally, "*vp" will always be 0, if that is what you mean by empty.
>>
>> Or did you mean "vp" itself is NULL? This would be even stranger, 
>> because it points to the stack.
>>
>> Do your run the code in a debugger? If yes, post the stack trace. If 
>> not, well, use a debugger :-)
>>
>> BTW, which device are you using?
>>
>> Christof
>>
>> On 22.03.2020 09:13, Boštjan Jerko wrote:
>>> Hi Christof,
>>>
>>> the problem is that I don’t really know what happens but it goes 
>>> something like that:
>>>
>>> calling pd_init -> pd_init_systems -> conf_init -> 
>>> x_connective_setup -> pdint_setup
>>>
>>> and then in function class_new vp is empty so while (*vp) doesn’t go 
>>> through it and after exiting class_new the microcontroller stops 
>>> with a hard error.
>>> So maybe the question is really - should the vp be empty and if not 
>>> - why is that happening?
>>>
>>> B.
>>>
>>>> On 21 Mar 2020, at 13:58, Christof Ressi <info at christofressi.com 
>>>> <mailto:info at christofressi.com>> wrote:
>>>>
>>>> Hi,
>>>>
>>>>> The code compiles but I get the error when running in the 
>>>>> pdint_setup where pdint_new in class_new breaks with an error.
>>>>> My idea is to first try to understand the code hence my question:
>>>> I think first you should post the error you get ;-) Maybe the 
>>>> problem is trivially solved without having to look at  code for 
>>>> class_new() at all.
>>>>> What does class_new do?
>>>> It creates a new Pd class (t_pd). The class contains all the 
>>>> methods and some metadata. It also registers a creator function in 
>>>> pd_objectmaker, which is the factory object for all classes.
>>>>
>>>> When you type "[foo 0]" you really send a message "obj <x> <y> foo 
>>>> 0" to the canvas, which in turn sends a message "foo 0" to 
>>>> pd_objectmaker, which finally returns a newly created instance 
>>>> (given that it can find a creator method for "foo").
>>>>
>>>> But again, I think the problem is likely trivial and those 
>>>> implementation details shouldn't concern you, unless you want to 
>>>> learn about Pd internals, of course :-)
>>>>
>>>> Christof
>>>>
>>>> On 21.03.2020 13:20, Boštjan Jerko wrote:
>>>>> Hi,
>>>>>
>>>>> I’m trying to port libpd to stm32. I don’t need gui so working 
>>>>> only on connecting pd script to the output (which is DAC from 
>>>>> stm32 in my case).
>>>>> The code compiles but I get the error when running in the 
>>>>> pdint_setup where pdint_new in class_new breaks with an error.
>>>>> My idea is to first try to understand the code hence my question:
>>>>> What does class_new do?
>>>>>
>>>>> My guess is connecting puredata command with a function in C. Am I 
>>>>> correct or completely missing the point?
>>>>>
>>>>> Thanks.
>>>>>
>>>>> B.
>>>>>
>>>>>
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>>>>> https://lists.puredata.info/listinfo/pd-dev
>>>>
>>>>
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>>
>>
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