#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include "ppport.h"

#include <pthread.h>
static PerlInterpreter *orig_perl=NULL;
static PerlInterpreter *cb_perl=NULL;

SV* cb_ptr = NULL;

void InvokeCB ()
{
   static int val = 0;
   val++;
   dTHX;
   dSP;
   ENTER;
   SAVETMPS;
   PUSHMARK(SP);
   SV * sv = cb_ptr;
   if (my_perl != orig_perl)
   {
      CLONE_PARAMS clone_param;
      clone_param.stashes = NULL;
      clone_param.flags = CLONEf_COPY_STACKS | CLONEf_KEEP_PTR_TABLE;
      clone_param.proto_perl = cb_perl;
      sv = sv_dup(sv, &clone_param);
   }

   XPUSHs(sv_2mortal(newSViv(val)));

   PUTBACK;
   call_sv(sv, G_DISCARD);

   FREETMPS;
   LEAVE;
}

void * BGThread(void * dontcare)
{
   PERL_SET_CONTEXT(orig_perl);
   cb_perl = perl_clone(orig_perl, CLONEf_COPY_STACKS | CLONEf_KEEP_PTR_TABLE);
   PERL_SET_CONTEXT(cb_perl);
   while (1)
   {
      sleep(5);
      InvokeCB();
   }
}

MODULE = myModule               PACKAGE = myModule

int
RegisterCB (SV *SubRef)
    CODE:
       pthread_t tid;
       pthread_create(&tid, NULL, BGThread, NULL);
       orig_perl = PERL_GET_CONTEXT;
       cb_ptr = newSVsv(SubRef);
       SvSHARE(cb_ptr);
       RETVAL = 1;
    OUTPUT:
       RETVAL