set truth(1) yes
set truth(0) no
package require Thread
set id [ thread::id ]
set tid [
	thread::create {
		while 1 {
			for { set i 0 } { $i < 9999999 } { incr i } {}
			update
		}
	}
]
after 1000
puts "Does thread exist? $truth([ thread::exists $tid])"
#puts "catch return is '[ catch { thread::send $tid { return } } results options ]'"
#puts "results is '$results'"
#puts "options is '$options'"
thread::release -wait $tid
while { [ thread::exists $tid ] } {
	puts "waiting"
	after 1000
}
puts "Does thread still exist? $truth([ thread::exists $tid])"
