[MacRuby-devel] MacRuby with Subprocesses

[Matt Aimonetti]

I have to respectfully agree that open3 is easier to use, however it doesn't
offer some of the more advanced features offered by NSTask.

I also found out why you are seeing a segfault, the arguments should be
passed in an array, try:

framework "foundation"
task = NSTask.launchedTaskWithLaunchPath("/bin/ls", arguments:["-l"])
p task.isRunning
p task.standardOutput

# keep the run loop running
NSRunLoop.currentRunLoop.runUntilDate(NSDate.distantFuture)

This code works for me.

- Matt


On Wed, Nov 3, 2010 at 9:12 AM, Matt Massicotte <massicotte at apple.com>wrote:

> I respectfully disagree :)
>
> NSTask is a huge pain and will result in dramatically more code in the
> simple cases.  Open3 is much easier to work with, and we can only dream of a
> solution as simple as backticks in Cocoa.  It becomes less of an issue if
> you are executing long-running processes and do not want to block on their
> completion.
>
> All that said, using the Cocoa implementations is definitely generally
> preferred.  But, if Ruby offers something that Cocoa either doesn't or
> doesn't do well, you should:
>
> - use the one that best fits your problem
> - file a bug so the Cocoa version can be improved
>
> Matt
>
> On Nov 3, 2010, at 9:00 AM, Matt Aimonetti wrote:
>
> > NSTask is the way to go, I used it in many cases, including some examples
> in my O'Reilly book:
> > http://macruby.labs.oreilly.com/ch04.html#_tasks_subprocesses
> >
> > You can also look at this more complex example:
> >
> >
> https://github.com/mattetti/couchdbx-app/tree/master/macruby_version/CouchDBX/
> >
> > The wrappers might be interesting to look at to see how I'm hiding some
> of the complexity.
> >
> > - Matt
> >
> > Sent from my iPhone
> >
> > On Nov 3, 2010, at 7:31, Louis-Philippe <default at spiralix.org> wrote:
> >
> >> Hi all,
> >>
> >> I'm looking  around MacRuby to find a way to run a subprocess and
> monitor it, here is what I tried:
> >>
> >> NSTask:
> >>
> >> framework "foundation"
> >> task = NSTask.launchedTaskWithLaunchPath("/bin/ls", arguments:"-l")
> >> p task.isRunning
> >> p task.standardOutput
> >>
> >> => Segmentation fault
> >>
> >> Open4:
> >>
> >> require 'rubygems'
> >> require 'popen4'
> >> status = POpen4::popen4('irb') { |stdout,stderr,stdin,pid|
> >>  stdin.puts "a = 1"
> >>  stdin.puts "a == 1"
> >>  stdin.close
> >>  puts "pid: #{pid}"
> >>  puts "stdout: #{stdout.read.strip}"
> >>  puts "stderr: #{stderr.read.strip}"
> >> }
> >> puts "status: #{status.inspect}"
> >> puts "exitstatus: #{status.exitstatus}"
> >>
> >> =>
> /Library/Frameworks/MacRuby.framework/Versions/0.7/usr/lib/ruby/Gems/1.9.2/gems/open4-1.0.1/lib/open4.rb:15:in
> `open4:': fork() function is unimplemented on this machine
> (NotImplementedError)
> >>      from
> /Library/Frameworks/MacRuby.framework/Versions/0.7/usr/lib/ruby/Gems/1.9.2/gems/POpen4-0.1.4/lib/popen4.rb:75:in
> `popen4:'
> >>      from
> /Users/lpperron/Documents/lllaptop/git_repos/Redis/testResque/testOpen4.rb:3:in
> `<main>'
> >>
> >> Open3:
> >>
> >> require 'open3'
> >> puts "starting..."
> >> Open3.popen3('irb') { |stdin,stdout,stderr|
> >>  stdin.puts "a = 1"
> >>  stdin.puts "a == 1"
> >>  stdin.close
> >>
> >>  puts "stdout: #{stdout.read.strip}"
> >>  puts "stderr: #{stderr.read.strip}"
> >> }
> >>
> >> => starting...
> >>
> >> So...  NSTask segfaults...  Open4 cannot work because of unimplemented
> 'fork' in MacRuby and Open3 hangs?
> >> Anybody has an other solution to launch and monitor a subprocess?
> >>
> >> Thanks!
> >>
> >> L-P
> >> _______________________________________________
> >> MacRuby-devel mailing list
> >> MacRuby-devel at lists.macosforge.org
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