How do you print an associative array in DTrace?

Question

The question pretty much sums it up. "dtrace 'print an associative array'" has exactly one google hit and the similar searches are equally useless.

EDIT:

If I were to use an aggregation, I'm not aware that I'd still be able to remove entries. My application requires that I be able to do things like:

file_descriptors[0] = "stdin"
file_descriptors[3] = "service.log"

...
...


file_descriptors[3] = 0

...
...

# should print only those entries that have not been cleared.
print_array(file_descriptors)

I know that you can clear an entire aggregation, but what about a single entry?

UPDATE:

Since I'm doing this in OS X and my application is to track all of the file descriptors that have been opened by a particular process, I was able to have an array of 256 pathnames, thusly:

syscall::open*:entry
/execname == $1/
{
    self->path = copyinstr(arg0);
}

syscall::open*:return
/execname == $1/
{    
    opened[arg0] = self->path;
}

syscall::close*:entry
/execname == $1/
{
    opened[arg0] = 0;
}

tick-10sec
{
    printf("  0:  %s\n", opened[0]);
}

The above probe repeated 255 more times...

It sucks. I'd really like to have something better.

Answer 1

Is this the link Google found? Because the advice seems pretty sound:

I think the effect you're looking for should be achieved by using an aggregation rather than an array. So you'd actually do something like:

@requests[remote_ip,request] = count();

... and then:

profile:::tick-10sec
{
    /* print all of the requests */
    printa(@requests);

    /* Nuke the requests aggregation */
    trunc(@requests);
}

Answer 2

Use an associative array and sum(1) and sum(-1) instead of count().