dtrace discuss - Nov 2007 - How to implement "%a" in C program?

Hi all,

Here is a fragment dtrace script, I included it in my C program.
static const char *g_prog "sdt:::callout-start"
"{"
"        @callouts[((callout_t *)arg0)->c_func] = count();"
"}"

I know
"printa("%40a %10 at d\n", @callout)"
will print "module`symbol-name" and count.

But how to achieve this in C program in libdtrace?
Is there any existing examples?

I''ve read intrstat.c. I know I can get the name of
 "stringof(`devnamesp[this->devi->devi_major].dn_name)"
by
{
  dtrace_agggdata_t *data;
  dtrace_recdesc_t *nrec;
  name = data->dtada_data + nrec->dtrd_offset;
}

Is there any docs about libdtrace programming?

Many thanks,
-Aubrey