preserving state across external functions calls

> Hi,
> I have a question about a correct way of preserving state/some
> information across pg functions call
> Let's imagine following example:
>
> External C functions:
>
> FUNCTION_INIT_SOMETHING     - allocates a memory, returns some kind of
> handle
> FUNCTION_DO_SOMETHING      - use allocated memory
> FUNCTION_FREE_SOMETHING  - deallocate using handle
>
> and of cause general idea is automatic deallocation at the and of
> session scope
> Thank you.
>
>
>