hi,

free(x_biases_array) doesn't seem to work

i'm not to good at C but you are missing the correct path ("nameofthestruct"->"nameofthevarible"). like

free(x->x_biases_array).

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Mensaje telepatico asistido por maquinas.

On 22/02/2024 06:19, Alexandros Drymonitis wrote:

I have a data structure with a symbol and an array of symbols that store array names defined as:

t_symbol **x_weights_arrays;
t_symbol *x_biases_array;

When I'm done with them, I want to free the memory, but calling free(x_biases_array) doesn't seem to work, and once called, as soon as I try to do something else in Pd (like unlock the patch and choose an object), Pd crashes.

I have narrowed down the error to freeing these symbols, and I'm sure the crash is not caused by something else. I scanned m_pd.h to see if there is a function to free t_symbol memory, but didn't seem to find anything. This might be something obvious for C-savvy people, but I'm not one, so any advice is welcome.

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Pd-dev mailing list Pd-dev@lists.iem.at https://lists.puredata.info/listinfo/pd-dev

Hi,

Pd symbols are immutable and permanent. `gensym("foo")` looks if the symbol "foo" already exists; if yes, it just returns it, otherwise it creates a new symbol, adds it to the global symbol table and finally returns it.

You must never attempt to free a symbol!

t_symbol **x_weights_arrays;
t_symbol *x_biases_array;

Here you must only free `x_weights_array`, which is an array of `t_symbol*`, but not the `t_symbol*` elements themselves.

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Side note: since symbols are unique and persistent, they can be compared *by address*. In other words, two symbols are equal if they have the same address. This is different from ordinary C-strings which may reside at different memory locations and thus need to be compared with `strcmp()` (or equivalent functions).

Christof

On 22.02.2024 10:19, Alexandros Drymonitis wrote:

I have a data structure with a symbol and an array of symbols that store array names defined as:

t_symbol **x_weights_arrays;
t_symbol *x_biases_array;

When I'm done with them, I want to free the memory, but calling free(x_biases_array) doesn't seem to work, and once called, as soon as I try to do something else in Pd (like unlock the patch and choose an object), Pd crashes.

I have narrowed down the error to freeing these symbols, and I'm sure the crash is not caused by something else. I scanned m_pd.h to see if there is a function to free t_symbol memory, but didn't seem to find anything. This might be something obvious for C-savvy people, but I'm not one, so any advice is welcome.

---

Pd-dev mailing list Pd-dev@lists.iem.at https://lists.puredata.info/listinfo/pd-dev

Am 22. Februar 2024 10:19:27 MEZ schrieb Alexandros Drymonitis adrcki@gmail.com:

I have a data structure with a symbol and an array of symbols that store array names defined as:

t_symbol **x_weights_arrays;
t_symbol *x_biases_array;

When I'm done with them, I want to free the memory, but calling free(x_biases_array) doesn't seem to work, and once called, as soon as I try to do something else in Pd (like unlock the patch and choose an object), Pd crashes.

Never free symbols. A symbol is created by `gensym` and owned by Pd.

mfg.sfg.jfd IOhannes