[Csnd-dev] opcode deinit

Hi all,

I have been thinking that we could regularise the opcode api by adding an (optional) deinit field
in OENTRY. 

At the moment, opcodes requiring deinit need to explicitly register a callback with Csound. While this
works, it seems a bit awkward. 

Since we have already removed the use for the “a” function field in the OENTRY, I thought we may
be able to reuse it for this purpose. For example,

 OENTRY o = { “name”, S(STATE), 0,  3,  "a",  “aki", init_func, perf_func, deinit_func};

Not all opcode need this, but for the ones who do, this seems a more natural way to set it up.

The current deinit routine for an instrument is:

/* call the opcode deinitialisation routines of an instrument instance */
/* called from deact() in insert.c */
int csoundDeinitialiseOpcodes(CSOUND *csound, INSDS *ip)
{
    int err = 0;

    while (ip->nxtd != NULL) {
      opcodeDeinit_t  *dp = (opcodeDeinit_t*) ip->nxtd;
      err |= dp->func(csound, dp->p);
      ip->nxtd = (void*) dp->nxt;
      free(dp);
    }
    return err;
}

and we would possibly modify it to be something simple like this:

int csoundDeinitialiseOpcodes(CSOUND *csound, INSDS *ip)
{
   int err = 0;
   OPDS dds = (OPDS *) ip;
   while ((dds = dds->nxtp) != NULL) 
    err |= (*dds->dopadr)(csound, dds);
   return err;
}

or thereabouts. 

Any thoughts?
========================
Prof. Victor Lazzarini
Maynooth University
Ireland