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Re: AttributeError: 'module' object has no attribute 'fork'

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On Friday, August 8, 2014 10:49:27 AM UTC+5:30, Rustom Mody wrote:
> On Thursday, August 7, 2014 10:26:56 PM UTC+5:30, Steven D'Aprano wrote:
> > Roy Smith wrote:

> > >  Peter Otten  wrote:
> > >> os.fork()
> > >> Fork a child process.
> > >> ...
> > >> Availability: Unix.
> > >> """
> > >> You are using the wrong operating system ;)
> > > To be honest, this could be considered a buglet in the os module.  It
> > > really should raise:
> > > NotImplementedError("fork() is only available on unix")
> > > or perhaps even, as Peter suggests:
> > > NotImplementedError("You are using the wrong operating system")
> > > either of those would be better than AttributeError.

> > I disagree. How would you tell if fork is implemented? With the current
> > behaviour, telling whether fork is implemented or not is simple:

> > is_implemented = hasattr(os, "fork")

> > With your suggestion:

> > try:
> >     pid = os.fork()
> > except NotImplementedError:
> >     is_implemented = False
> > else:
> >     if pid == 0:
> >         # In the child process.
> >         os._exit(0)  # Unconditionally exit, right now, no excuses.
> >     is_implemented = True

> > which is not obvious, simple or cheap.

> Surely I am missing something but why not check os.fork before 
> checking os.fork() ?

> Something along these lines

> >>> try:
> ...   os.fork
> ... except AttributeError:
> ...   ii = False
> ... else:
> ...   ii = True

> Of course more appropriate would be something along the lines:
> catch AttributeError and re-raise NotImplementedError

Thinking about this a bit more I see that NotImplemented is under RuntimeError.
Probably a subclass of AttributeError -- PortabilityError?? Cant think of a
good name -- is what is desired

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AttributeError: 'module' object has no attribute 'fork' Satish ML <satishmlwizpro@gmail.com> - 2014-08-06 23:44 -0700
  Re: AttributeError: 'module' object has no attribute 'fork' Peter Otten <__peter__@web.de> - 2014-08-07 09:00 +0200
    Re: AttributeError: 'module' object has no attribute 'fork' Roy Smith <roy@panix.com> - 2014-08-07 07:49 -0400
      Re: AttributeError: 'module' object has no attribute 'fork' Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-08 02:56 +1000
        Re: AttributeError: 'module' object has no attribute 'fork' Rustom Mody <rustompmody@gmail.com> - 2014-08-07 22:19 -0700
          Re: AttributeError: 'module' object has no attribute 'fork' Rustom Mody <rustompmody@gmail.com> - 2014-08-07 22:35 -0700
          Re: AttributeError: 'module' object has no attribute 'fork' Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-08 15:48 +1000
            Re: AttributeError: 'module' object has no attribute 'fork' Rustom Mody <rustompmody@gmail.com> - 2014-08-08 00:17 -0700
              Re: AttributeError: 'module' object has no attribute 'fork' Chris Angelico <rosuav@gmail.com> - 2014-08-08 17:32 +1000

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