From: Hal Fulton <hal9000@...>
Date: 2004-06-04T13:43:44+09:00
Subject: playing with popen again

Why doesn't this work?

prog1 calls prog2... the latter starts by writing a line, then reading
a line. The former reads first, then writes.

It hangs indefinitely. When I kill prog1, it appears that I interrupted
a gets on each side.

What am I doing that's stupid?

Thanks,
Hal


# prog1
io = IO.popen("ruby prog2.rb","r+")
str = io.gets
puts "got: #{str}"
io.puts "junk"

str = io.gets
puts "got: #{str}"
io.puts "junk"

str = io.gets
puts "got: #{str}"
io.puts "junk"


#!/usr/local/bin/ruby
# prog2
puts "This is prompt 1"
gets
puts "This is 2nd prompt"
gets
puts "3rd/final prompt"
gets


$ ruby prog1.rb   # and then ctl-C
prog1.rb:2:in `gets': Interrupt from prog1.rb:2
prog2.rb:3:in `gets': Interrupt from prog2.rb:3