[PD-dev] Trouble with memory+pointers

[Ed Kelly]

Splendid! It doesn't crash any more. It doesn't work either, but at least I'm in more familiar debugging territory! Thanks.

I used a x->firstl, x->firstr and x->firstx variables that were tested and set, so that the first time each list is initialized, the first thing that happens is e.g.
x->masking.maskl = getbytes(n * sizeof(t_atom));
 and then the freebytes is used the second, third, fourth etc times.

Cheers,
Ed

Martin Peach <martin.peach at sympatico.ca> wrote: Ed Kelly wrote:
> Hi devs,
>
> I'm trying to rewrite some of my externals to be a bit more 
> effe\icient, clear up after themselves and generally work more 
> smoothly. I started with maskxor, because I really need this to work 
> for the ICMC, and it's not working properly in certain situations.
>
> So I borrowed some code from zexy/src/drip.c and rewrote it. It 
> compiled OK, but crashes PD. Can anyone tell me what is wrong with my 
> code, and how to fix it?
>
I guess because you don't initialize the pointers the first time. Your 
maskxor_new has:
 
  SETFLOAT(&x->masking.maskr[0], 0);
  SETFLOAT(&x->masking.maskl[0], 0);
  SETFLOAT(&x->masking.maskxor[0], 0);
...but x->masking.maskr etc. don't yet point to anything, they were 
declared as:
t_atom *maskxor, *maskl, *maskr;
...but not given any value. If it doesn't crash right there it will do 
so when you try to free the pointers:
  if (x->masking.maskl) {
    freebytes(x->masking.maskl, x->lengthl * sizeof(t_atom));
    x->masking.maskl = 0;
    x->lengthl = 0;
  }
Martin

> Best,
> Ed
>
>
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