/*
 *  call-seq:
 *     thr.group   => thgrp or nil
 *
 *  Returns the <code>ThreadGroup</code> which contains <i>thr</i>, or nil if
 *  the thread is not a member of any group.
 *
 *     Thread.main.group   #=> #<ThreadGroup:0x4029d914>
 */

VALUE
rb_thread_group(VALUE thread)
{
    rb_thread_t *th;
    VALUE group;
    GetThreadPtr(thread, th);
    group = th->thgroup;

    if (!group) {
        group = Qnil;
    }
    return group;
}