Gabriele Lanaro, 18.04.2010 22:19:
> I've a C where some relationship between "object" exists, like this
> pseudocode:
>
> c_structA {
> c_structB *bstructs;
> }
>
> c_structB ...
>
> I've defined some methods to handle the memory management of these
> structures:
>
> new_c_structA
> new_c_strucB
> free_c_structA
> free_c_structB
>
> And also other functions (mehods) like:
> c_structA_append(c_structA *a, c_structB *b)
>
>
> I've to wrap these structures in cython but I encounter some problems with
> the reference counting and the garbage collector.
>
>
> class A:
> cdef c_structA *this
>
> def append(self, b):
> c_structA_append(self.this, b.this)
>
> class B:
> ...
>
>
> My problem is in particular, when I call append from the class A, the
> reference count of b doesn't increment (since the aggregation is done in C),
> so b is garbage collected and I lost any reference of c_structB (b.this)
> causing a segfault when accessing it. One solution would be for example
> this:
>
> def append(self, b):
> c_structA_append(self.this, b.this)
> self.blist.append(b)
>
> However it seems to be a dirty solution
Not at all.
> Are there any best practice to handle this kind of situations?
You have two choices: let A handle all the memory allocation, or keep a
Python reference from A to the B instances it references. You were not very
explicit about the meaning and the relationship of the two structs, so
depending on what they do and why they do it, either of the two solutions
can be better.
Stefan
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