// This code works wellchar uniqueid[256];char *tmp = NULL;ast_cdr_getvar(chan->cdr, "uniqueid",&tmp, uniqueid,sizeof(uniqueid), 0);ast_log(LOG_DEBUG, "UNIQUEID: '%s'\n",uniqueid);// This code prints out all variable defined for current channelprintf("\n\nDUMPING VARIABLES\n");struct ast_var_t *variables;struct varshead *headp;headp=&chan->varshead;AST_LIST_TRAVERSE(headp,variables,entries) { printf("%s -> %s\n", ast_var_name(variables),ast_var_value(variables));}// This code doesn't print anything at all, why?// I wan't to print all variables from CDRprintf("DUMPING CDR VARIABLES:\n");headp = &(chan->cdr)->varshead;AST_LIST_TRAVERSE(headp, variables, entries) { printf("%s -> %s\n", ast_var_name(variables), ast_var_value(variables));}printf("\n\n");