From: jeremy@... Date: 2016-05-17T00:20:00+00:00 Subject: [ruby-core:75532] [Ruby trunk Bug#9082] popen3 hangs when stderr gets lots of output Issue #9082 has been updated by Jeremy Kemper. Note you can use `Open3.capture3` to safely read stdout and stderr without doing `popen3` + `IO.select` yourself. Internally, this uses separate threads to read stderr & stdout and to wait for the child process to finish: https://github.com/ruby/ruby/blob/1ec544695fa02d714180ef9c34e755027b6a2103/lib/open3.rb#L257-L273 ---------------------------------------- Bug #9082: popen3 hangs when stderr gets lots of output https://bugs.ruby-lang.org/issues/9082#change-58649 * Author: Rodrigo Rosenfeld Rosas * Status: Rejected * Priority: Normal * Assignee: * ruby -v: ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux] * Backport: ---------------------------------------- Create this program test.rb: STDERR.puts "some error line\n" * 10_000 Then, try this: ruby -r open3 -e "Open3.popen3('ruby test.rb'){|i,o,e,t|i.close;o.read}" For this particular case, if I do "e.read" before "o.read" it works. But for my real case involving the "tidy" command with lots of warnings in the stderr it will freeze even if I call "e.read". Since I don't really need this output, I'm using popen2 and redirecting stderr to /dev/null, so this is not urgent, but I thought you'd like to know about this. Also, if you replace 10_000 with 1_000 above it also works here. -- https://bugs.ruby-lang.org/ Unsubscribe: