From: Joel VanderWerf <vjoel@...>
Date: 2007-04-06T04:21:03+09:00
Subject: Re: Forking and copying variables

Gary Wright wrote:
> 
> On Apr 5, 2007, at 2:54 PM, Joel VanderWerf wrote:
>> The source for win32/process makes it clear what is going on:
>>
>>       cmd = 'ruby -I "' + $LOAD_PATH.join(File::PATH_SEPARATOR) << '" "'
>>       cmd << File.expand_path($PROGRAM_NAME) << '" ' << ARGV.join(' ')
>>       cmd << ' child#' << @child_pids.length.to_s
>>
>>       startinfo = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
>>       startinfo = startinfo.pack('LLLLLLLLLLLLSSLLLL')
>>       procinfo  = [0,0,0,0].pack('LLLL')
>>
>>       rv = CreateProcess(0, cmd, 0, 0, 1, 0, 0, 0, startinfo, procinfo)
>>
>> It runs the same ruby script again in another process. It's not really 
>> fork in the unix sense.
> 
> Thanks for clarifying things Joel.  As I said, I'm not a Windows guy...
> 
> Seems like a bad choice to use the name 'fork' for this behavior.
> It is more like a fork/exec of the original script (in Unix
> terminology).  It would make more sense to me to have Process.fork
> fail with an exception on Windows and come up with a different name
> for this Windows-only behavior.
> 
> The pseudo-portability of Ruby code has always seemed a bit odd to
> me.  Obviously this sort of issue comes up with File IO, OS services,
> process and thread semantics and so on.
> 
> I almost wish that the differences were more obvious via the class
> structure rather than methods of the same class having different
> semantics on different platforms.

I agree with all of the above. What the win32 fork does is useful in its 
own way, and it might even be useful to have something on unix/linux 
that has the same semantics (fork/exec original script). But it needs a 
different name...

-- 
        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407