[plt-scheme] set environment variables in subprocess

At the OS level, execve() or CreateProcess() lets you provide
environment variables for the new process, instead of just using the
current process's settings. So, we could extend `subprocess' to avoid
`putenv' collisions, but that support is not currently available.

At Wed, 13 Jan 2010 19:12:08 -0600, Robby Findler wrote:
> I guess you'd have to serialize the actual creation of the processes,
> or use yet another process to first set its own variables than exec
> the cgi program.
> 
> Robby
> 
> 2010/1/13 YC <yinso.chen at gmail.com>:
> >
> > On Wed, Jan 13, 2010 at 4:00 PM, David Brown <plt at davidb.org> wrote:
> >>
> >> On Wed, Jan 13, 2010 at 03:07:59PM -0800, YC wrote:
> >>
> >>> is there a way to set the environment variables for the subprocess?  
> Looking
> >>> at http://docs.plt-scheme.org/reference/subprocess.html it was not clear 
> how
> >>> this can be accomplished.
> >>
> >> The 'subprocess' call calls execv on Unix/Linux, so you would have to
> >> set it in the current process before the subprocess is created, which
> >> you could do with 'putenv'.
> >
> > Thanks Jay & Dave.  setenv & putenv modifies the current process's 
> environment variable, so it sounds like if you want to spawn multiple 
> subprocesses in multi-threaded fashion you will have some sort of contention 
> if you are setting more than one environment variables. The example I am 
> thinking about is spawning CGI processes, where the headers are written into 
> the environment variables.
> >
> > Are there other ways or is my concern moot?  Thanks,
> > yc
> >
> >
> >
> >
> >
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