Issue #5958 has been updated by Masaki Matsushita.


=begin
Without ThreadGroup#join, we have to get list of threads and join each thread in the ThreadGroup.

 thgrp = ThreadGroup.new
 
 3.times do |i|
   thgrp.add(Thread.new{ sleep i+1 })
 end
 
 thgrp.list.each(&:join)

Moreover, it is confusing to set limit on joining in the situation.

 class ThreadGroup
   def join(delay=nil)
     if delay
       limit = Time.now + delay
       if self.list.all?{|th| th.join(limit - Time.now.to_f) }
         return self
       else
         return nil
       end
     else
       self.list.each(&:join)
       return self
     end
   end
 end

ThreadGroup#join enables to join threads as a unit of ThreadGroup.
I think ThreadGroup will be more useful if it provides methods to manipulate its own threads like this.
=end
----------------------------------------
Feature #5958: ThreadGroup#join
https://bugs.ruby-lang.org/issues/5958

Author: Masaki Matsushita
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 


=begin
I propose the method ThreadGroup#join.
Calling thread waits all threads in receiving threadgroup.

 thgrp = ThreadGroup.new
 thgrp.add(Thread.new{ sleep 1 })
 thgrp.join #=> #<ThreadGroup:0x007ff257d6d098>

Time limit to run the threads in the threadgroup can be specified.
If the time limit expires, nil will be returned.

 thgrp = ThreadGroup.new
 thgrp.add(Thread.new{})
 thgrp.add(Thread.new{ sleep })
 thgrp.join(0.1) #=> nil

I think it is useful to wait grouped threads together.
=end


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