From: Gary Wright <gwtmp01@...>
Date: 2007-04-06T04:13:09+09:00
Subject: Re: Forking and copying variables


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.



Gary Wright