# Handle to the program's main thread
	fun main_thread: MainThread
	do
		var cache = main_thread_cache
		if cache != null then return cache

		main_thread_mutex.lock

		# Recheck if cache has been updated since lock has been unlocked/locked
		cache = main_thread_cache
		if cache != null then
			main_thread_mutex.unlock
			return cache
		end

		# Create a `MainThread` exactly once
		var thread = new MainThread
		thread.native = sys.native_pthread_self
		main_thread_cache = thread

		main_thread_mutex.unlock
		return thread
	end