=proto
int duk_is_thread(duk_context *ctx, int index);

=stack
[ ... val! ... ]

=summary
<p>Returns 1 if value at <code>index</code> is an object and is a Duktape
thread (coroutine), otherwise returns 0.  If <code>index</code> is invalid,
also returns 0.</p>

=example
if (duk_is_thread(ctx, -3)) {
    /* ... */
}

=tags
stack