From: Adam Shelly <adam.shelly@...>
Date: 2008-08-15T03:24:47+09:00
Subject: Re: Starting new process on Windows!

On 8/14/08, Glen Holcomb <damnbigman@gmail.com> wrote:
> On Thu, Aug 14, 2008 at 8:38 AM, Mateusz Tybura <wujciol@gmail.com> wrote:
> > Glen Holcomb wrote:
> > > Is there an easy/clean way to start a new process in Windows that will
> > > execute just a section of code?  I've tried win32-process but it spawns
> > > a new version of the entire script which doesn't help in my situation.
> >
> > Try to use ruby threads. Example
> > ...
>
>  I'm having an
> issue where it appears that some combination of wx-ruby, win32ole, and the
> garbage collector are causing my app to hang.  I was hoping to execute the
> win32ole code in a separate process in hopes of avoiding the hanging
> problem.

My first thought was you could make your own fork-like functionality.
But after I cooked up an example, I realized that the simpler thing
might be to just extract the section of code in question to a separate
script, and launch that in a new process with `start
separate_script.rb input_data`
Just in case it's useful, here's my initial solution:
-Adam
--------
require 'win32ole'
Datafile = "fork.dump"
done = false
do_ole = ARGV.shift
data,result=0,0

def oleprocess data
  excel = WIN32OLE.new("excel.application") #your ole app here!
  workbook = excel.Workbooks.Add();
  excel.Range("a1")['Value'] = data;
  excel.Range("a2")['Value'] = "=a1*a1";
  result = excel.Range("a2")['Value']
  excel.ActiveWorkbook.Close(0);
  excel.Quit();
  result
end

if (do_ole == "-o")
  p "in new process"
  File.open(Datafile,"rb"){|fp|data = Marshal.load(fp)}
  result = oleprocess(data)
  File.open(Datafile,"wb"){|fp|Marshal.dump(result,fp)}
  exit
else
  data = 42  #initial_processing_here.  data could be arbitrarily complex
  File.open(Datafile,"wb"){|fp|Marshal.dump(data,fp)}
  timestamp = File.mtime(Datafile)
  p "launching new process"
  system("start ruby #{__FILE__} -o")
  until done
    print '.'; sleep(0.1) #do gui stuff and other work here while you
are waiting...
    if (File.mtime(Datafile) > timestamp) #other process is done
      File.open(Datafile,"rb"){|fp|result = Marshal.load(fp)}
      puts "\nsquare of #{data} is #{result}"
      done = true
    end
  end
end