phpthreads - hints anyone...

Im looking at adding threading to php, (for the cgi/cli stuff).. The story so far: I've created an extension which diverts all zend_execute calls into the extension -> phpthreads_execute. this function is a copy of zend_execute with a few modifications - to copy & restore things like EG(active_symbol_table); - to malloc lock and unlock the execute loop and release on each opcode. I've started testing the phpthreads_create($callback); - it appears to work ok, execept it segfaults on completion.. - trying to reduce refcounts somewhere. The fireup code looks something like this.. void phpthreads_create(void *ptr) {

       zval myretval;
       zval *callback = (zval *) ptr;
            if (!call_user_function( EG(function_table), NULL, callback, &myretval, 0, NULL TSRMLS_CC ))  {
               zend_error(E_ERROR, "Problem Starting thread with callback");
       }
             pthread_exit(NULL);
            }

/* {{{ proto string phpthreads_thread(string function) Return a string to confirm that the module is compiled in */ PHP_FUNCTION(phpthreads_create) {

           zval *callback;
       pthread_t thread;
           if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z", &callback) == FAILURE) {
         return;
     }
       pthread_create( &thread, NULL, (void *) phpthreads_create, (void*) callback);
       RETURN_TRUE;

} and the backtrace of the simple threaded test looks like this.. 0x08128f08 in _zval_ptr_dtor (zval_ptr=0x81b5ce8) at /usr/src/php/php4/Zend/zend_execute_API.c:275

275             (*zval_ptr)->refcount--;

(gdb) bt #0 0x08128f08 in _zval_ptr_dtor (zval_ptr=0x81b5ce8) at /usr/src/php/php4/Zend/zend_execute_API.c:275 #1 0x424ceba2 in ?? () #2 0x424c7c92 in ?? () #3 0x08130588 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /usr/src/php/php4/Zend/zend.c:810 #4 0x08110abd in php_execute_script (primary_file=0x40006c71) at /usr/src/php/php4/main/main.c:1398 #5 0x08110138 in php_module_shutdown () at /usr/src/php/php4/main/main.c:1058 #6 0x2e325f43 in ?? () does anyone want to suggest what might be missing - is it worth putting this into pecl - and does someone what to lend a hand?? regards alan