If I have the following code :
threads = [] (1..5).each do |i| threads << Thread.new { `process x#{i}.bin` } end threads.each do |t| t.join # i'd like to get the output of the process command now. end What do I have to do to get the output of the process command? How could I create a custom thread so that I can accomplish this?
The script
threads = [] (1..5).each do |i| threads << Thread.new { Thread.current[:output] = `echo Hi from thread ##{i}` } end threads.each do |t| t.join puts t[:output] end illustrates how to accomplish what you need. It has the benefit of keeping the output with the thread that generated it, so you can join and get the output of each thread at any time. When run, the script prints
Hi from thread #1 Hi from thread #2 Hi from thread #3 Hi from thread #4 Hi from thread #5
puts t.value
Hi Hi Hi from thread #1 from...
I found it simpler to use collect to collect the Threads into a list, and use thread.value to join and return the value from the thread - this trims it down to:
#!/usr/bin/env ruby threads = (1..5).collect do |i| Thread.new { `echo Hi from thread ##{i}` } end threads.each do |t| puts t.value end When run, this produces:
Hi from thread #1 Hi from thread #2 Hi from thread #3 Hi from thread #4 Hi from thread #5 
Thread.current[:output] is that there is no way to have a timeout using value.This is a simple, and interesting way to use Thread#value:
a, b, c = [ Thread.new { "something" }, Thread.new { "something else" }, Thread.new { "what?" } ].map(&:value) a # => "something" b # => "something else" c # => "what?" 
join because value does that internally.
a, (b, c), d = Just use Thread#value:
threads = (1..5).collect do |i| Thread.new { `echo x#{i}.bin` } end threads.each do |t| puts t.value end You should use the Queue class. Each thread should put its result in the queue, and the main thread should fetch it from there. Notice that using that approach, results my be in a order different from thread creation order in the queue.
