[PD] Strange behavior using custom external
Robert Esler
robert at urbanstew.org
Sun Mar 2 08:21:23 CET 2014
Thanks for the advice on the setup function. I spent a few hours debugging and seemed to have fixed the problem. Though it is still mysterious to me why the memory corruption was happening the way it did, I traced it down to how I had declared my C++ object. Initially, I had declared my object in a single function and sent data to the Pd class struct. Such as:
static myObject n;
x->someInt = n.someFunction();
I moved my C++ object declaration to the Pd class struct as a pointer then allocated its memory in the _new() function and deallocating in the _free() function.
This seems to have cleaned up the memory from my C++ object, since I need the initial instance of the object to last the lifetime of the Pd object. Though oddly, this didn't work the first time, I also had to do the same procedure with a std::vector<double> declaration too. Since then the error has not occurred again. Below is my class struct now.
Not sure why declaring my C++ object or the vector as a pointer is necessary but clearly it worked.
Thanks again for everyone's help.
static t_class *rhynamo_class;
typedef struct _rhynamo {
t_object x_obj;
t_clock *x_clock;
t_outlet *l_out;
std::vector<double> *delay;
_attributes A;
int x_hit;
int x_increment;
double x_delay;
Rhythm *rhythm;
} t_rhynamo;
On Feb 28, 2014, at 8:45 AM, Charles Z Henry <czhenry at gmail.com> wrote:
> You can make these changes (one from IOhannes and two of my suggestions in-line below) and see if the error is gone. My guess is: probably not. I didn't see any glaring problems that would cause memory corruption.
>
> Could you also show us your rhynamo_set(symbol, float) function? Does the error occur *only* after the set function gets used?
>
> If for some reason, these small changes do fix your issue, just back up and make one change at a time, and check if you can reproduce the error each time. I'd be interested to know what actually causes it.
>
>
> On Thu, Feb 27, 2014 at 6:13 PM, GCC <robert at urbanstew.org> wrote:
> Below is my setup method. This object generates rhythmic phrases so it accesses the time scheduler in Pd as per the code [metro] or [delay], and outputs a bang. Perhaps this could be where it goes wrong?
> Thanks for your time and help.
> -Rob
> -----------
> void rhynamo_setup(void) {
>
>
> rhynamo_class = class_new(gensym("rhynamo"),
> (t_newmethod)rhynamo_new,
> (t_method)delay_free, sizeof(t_rhynamo),
> CLASS_DEFAULT,
> A_GIMME, 0);
>
> post("[rhynamo] a rhythmic generator v .02 : by Robert Esler 2014");
>
> class_addbang (rhynamo_class, rhynamo_bang);
> class_addfloat(rhynamo_class, (t_method)rhynamo_generate);
> class_addsymbol(rhynamo_class, (t_method)rhynamo_set);
>
> ^--I don't think you need the addsymbol line. The rhynamo_set function access is provided by the next addmethod line, immediately below.
>
> class_addmethod(rhynamo_class,
> (t_method)rhynamo_set, gensym("set"), A_DEFSYMBOL, A_DEFFLOAT, 0);
> class_addmethod(rhynamo_class,
> (t_method)rhynamo_generate, gensym("generate"), A_FLOAT, 0);
>
> ^--This line should have A_DEFFLOAT instead of A_FLOAT.
>
>
>
>
> class_sethelpsymbol(rhynamo_class, gensym("help-rhynamo"));
>
>
> }
> -------------
>
> Date: Thu, 27 Feb 2014 14:15:05 -0600
> From: Charles Z Henry <czhenry at gmail.com>
> Subject: Re: [PD] Strange behavior using custom external
> To: Robert Esler <robert at urbanstew.org>
> Cc: pd-list <pd-list at iem.at>
> Message-ID:
> <CAPfmNOFA_cprs4Ux0Yg1YY7hFsgrpt79B+FeLj5kzf1FRD0R4Q at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> The difference probably indicates that something is going on in your
> _setup() function. Once you've loaded a class in a patch, it stays in
> memory. If you close the patch, and open another patch without the class,
> you may still see the effects---but if you close pd, and reopen without
> using the class, you should not see the effects at all.
>
> The backtrace shows a seg fault from calls in "binbuf_eval", which is the
> code related to parsing and loading a patch. You might just have passed a
> struct as an argument, where it's expected to be an element of that struct.
>
> Although.... pointer type mismatches will definitely throw a compiler
> warning you should have seen already. Would you post the _setup() function?
>
> Chuck
>
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