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Date: Mon, 20 Sep 2004 13:09:51 -0400 (EDT)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: Dave Korn <dk AT artimi DOT com>
cc: cygwin AT cygwin DOT com
Subject: RE: [APPS] ping python maintainer (and others) - Launching cygwin apps from cmd.exe vs. softlinks in /bin
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Message-ID: <Pine.GSO.4.61.0409201305320.29980@slinky.cs.nyu.edu>
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On Mon, 20 Sep 2004, Dave Korn wrote:

> > -----Original Message-----
> > From: Igor Pechtchanski
> > Sent: 20 September 2004 17:07
>
> > >   Using a non-symbolic link works for me; "ln /bin/python2.3.exe
> > > /bin/cmd-invokable-python.exe" gets me something I can
> > invoke from either
> > > DOS/cmd or bash/sh.
> >
> > Alternatively, you could Google for "vi.bat site:cygwin.com"
> > and apply the same technique to python.
>
>   Fair enough, but what I really want is something that doesn't require my
> makefiles to have to discriminate between what kind of python exe is first
> in the path;

If you use just "python", and the .bat is first in the path, it'll be
picked up.

> I want them to be equipotent, and I don't want to have to
> install things that aren't standard; I want a makefile that can be invoked
> from either cmd.exe or bash, that can run on a system that has either cygwin
> python or win32 python or both installed, that isn't sensitive to which one
> comes in which order in $PATH, and that doesn't require anything extra to be
> installed.  But I guess I could always use a makefile rule to create
> python.bat in the objdir I'm building in.... hmm.  That might have been a
> bit simpler than my current solution, which uses a fairly gross makefile
> hack to search $PATH and some default install locations for any instances of
> python.exe, then discards any which live in a ".../bin/.." subdir to try and
> eliminate the cygwin version!

You could also just create a python.bat in /bin, and cmd.exe will find
that, while Cygwin will use a symlink.

> > c) the code in spawn.cc currently treats any file with a .exe
> > extension specially, and passes it on to CreateProcess without looking
> > into it any more than that.  It could, technically, check whether the
> > file is an old-style symlink, and do the right thing in that case --
> > as always, <http://cygwin.com/acronyms/#PTC>.
>
>   LOL, I don't really think it's within my abilities to come up with a patch
> for spawn.cc that modifies the behaviour of cmd.exe.......

While CGF was obviously joking about the pty/tty "fix", my suggestion was
only half-humorous.  Look in spawn.cc around line 442...  FWIW, you won't
be fixing the behavior of cmd.exe, you'll be fixing the behavior of
Cygwin1.dll when a .exe program is invoked (before it's passed to Windows
via CreateProcess, i.e., the current action for .exe's and some others is
to *not* look inside the file to check whether it's a script or a
symlink).
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_		pechtcha AT cs DOT nyu DOT edu
ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"Happiness lies in being privileged to work hard for long hours in doing
whatever you think is worth doing."  -- Dr. Jubal Harshaw

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