From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Reuben Thomas Newsgroups: gmane.emacs.bugs Subject: bug#17036: Continuation for Emacs: invoking a process on exit? 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charset=ISO-8859-1 On 19 March 2014 16:51, Eli Zaretskii wrote: > > Date: Wed, 19 Mar 2014 13:19:28 +0000 > > From: Reuben Thomas > > Cc: Andreas Schwab , 17036@debbugs.gnu.org > > > > On 19 March 2014 13:10, Stefan wrote: > > > > > > I could imagine a `restart-emacs' command having some small utility. > > > > > > Could the w32 build support something like POSIX's `exec'? > > > > > > Windows has execvp... > http://msdn.microsoft.com/en-us/library/3xw6zy53.aspx > > Don't believe the sales people. MS's execvp is buggy, and even if we > forget about those bugs, it won't do what is expected here: it won't > keep the file descriptors open in the original process still open in > the overlaid process. That's because there's no 'exec' system call on > Windows, so execvp is _emulated_: the original process simply invokes > the new one as its child process, and then immediately exits. > That's good enough for restart-emacs. > So the answer to Stefan is: no, this cannot be done on Windows, not > without some custom code to let the re-executed Emacs inherit all of > the file descriptors which were open in the original Emacs process. > It's fine for what i had in mind, namely Emacs simply launching another command with arguments, much as a Lisp callcc. This could be documented as a limitation on Windows. -- http://rrt.sc3d.org --089e01160d0ef3a82604f4fc2295 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
On 1= 9 March 2014 16:51, Eli Zaretskii <eliz@gnu.org> wrote:
> Date: Wed, 19 Mar 2014 13:19:28 +0000
> From: Reuben Thomas <rrt@sc3d.org>
> Cc: Andreas Schwab <schwab= @linux-m68k.org>, 17036@deb= bugs.gnu.org
>
> On 19 March 2014 13:10, Stefan <monnier@iro.umontreal.ca> wrote:
>
> > > I could imagine a `restart-emacs' command having some sm= all utility.
> >
> > Could the w32 build support something like POSIX's `exec'= ?
>
>
> Windows has execvp... http://msdn.microsoft.com/en-us/l= ibrary/3xw6zy53.aspx

Don't believe the sales people. =A0MS's execvp is buggy, and even i= f we
forget about those bugs, it won't do what is expected here: it won'= t
keep the file descriptors open in the original process still open in
the overlaid process. =A0That's because there's no 'exec' s= ystem call on
Windows, so execvp is _emulated_: the original process simply invokes
the new one as its child process, and then immediately exits.

That's good enough for restart-emacs.
<= div>=A0
So the answer to Stefan is: no, this cannot be done on Windows, not
without some custom code to let the re-executed Emacs inherit all of
the file descriptors which were open in the original Emacs process.

It's fine for w= hat i had in mind, namely Emacs simply launching another command with argum= ents, much as a Lisp callcc. This could be documented as a limitation on Wi= ndows.

--
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