keep track of the parent of a ruby thread.rb

ruby_thread_parent.rb

T0 = Thread.main

t1 = Thread.new(Thread.current) { |x| Thread.current[:parent] = x; sleep 1_00_000; }
t2 = Thread.new(Thread.current) { |x| Thread.current[:parent] = x; sleep 1_00_000; }

(t1[:parent] == t2[:parent]) && (t1[:parent] == T0)

__END__

# to find out the parent of a thread, ie. was spawned by which thread 
# we do not do:
t1 = Thread.new() { |x| Thread.current[:parent] = Thread.current; sleep 1_00_000; } 
as inside the block the value of 'Thread.current' can change
# GOTCHA: potential memory-leak as we are storing the reference to the thread, the thread will not be reclaimed by GC, if the thread creating is nested.
# can use it to keep track of and to restrict nesting, by comparing t1[:parent] == T0
# http://www.tutorialspoint.com/ruby/ruby_multithreading.htm
The class method Thread.current returns the Thread object that represents the current thread. This allows threads to manipulate themselves. The class method Thread.main returns the Thread object that represents the main thread.this is the initial thread of execution that began when the Ruby program was started.