Waiting for Asynchronous Process

Waiting for Asynchronous Process

[Eric]

Suppose I'm writing a function that will compile 4 files (A, B, C, and
D). The first three can compile in any order, but D must come last.
I want the user to have a responsive Emacs while the compilations are
going on.

I could do (call-process "theCompiler" .... "A")
               (call-process "theCompiler" .... "B") ...
but then Emacs is "frozen" until all files are compiled.

I could do (start-process ...), but then I can't seem to wait for the
processes to all exit without causing Emacs to hang.

I know that ELisp doesn't do multithreading. Is it possible to do what
I want without creating a separate script outside of Emacs?

Re: Waiting for Asynchronous Process

[David Kastrup]

Eric <etklaus@gmail.com> writes:

> Suppose I'm writing a function that will compile 4 files (A, B, C, and
> D). The first three can compile in any order, but D must come last.
> I want the user to have a responsive Emacs while the compilations are
> going on.
>
> I could do (call-process "theCompiler" .... "A")
>                (call-process "theCompiler" .... "B") ...
> but then Emacs is "frozen" until all files are compiled.
>
> I could do (start-process ...), but then I can't seem to wait for the
> processes to all exit without causing Emacs to hang.
>
> I know that ELisp doesn't do multithreading. Is it possible to do what
> I want without creating a separate script outside of Emacs?

(info "(elisp) Sentinels")

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

Re: Waiting for Asynchronous Process

[Eric]

On Aug 25, 5:20 pm, David Kastrup <d...@gnu.org> wrote:
> Eric <etkl...@gmail.com> writes:
> > Suppose I'm writing a function that will compile 4 files (A, B, C, and
> > D). The first three can compile in any order, but D must come last.
> > I want the user to have a responsive Emacs while the compilations are
> > going on.
>
> > I could do (call-process "theCompiler" .... "A")
> >                (call-process "theCompiler" .... "B") ...
> > but then Emacs is "frozen" until all files are compiled.
>
> > I could do (start-process ...), but then I can't seem to wait for the
> > processes to all exit without causing Emacs to hang.
>
> > I know that ELisp doesn't do multithreading. Is it possible to do what
> > I want without creating a separate script outside of Emacs?
>
> (info "(elisp) Sentinels")
>
> --
> David Kastrup, Kriemhildstr. 15, 44793 Bochum

That did it. All I needed to do was hit next once more in the manual
and I would have reached the chapter on Sentinels.
Thanks for the help!

Re: Waiting for Asynchronous Process

[Colin S. Miller]

Eric wrote:
> Suppose I'm writing a function that will compile 4 files (A, B, C, and
> D). The first three can compile in any order, but D must come last.
> I want the user to have a responsive Emacs while the compilations are
> going on.
> 
> I could do (call-process "theCompiler" .... "A")
>                (call-process "theCompiler" .... "B") ...
> but then Emacs is "frozen" until all files are compiled.
> 
> I could do (start-process ...), but then I can't seem to wait for the
> processes to all exit without causing Emacs to hang.
> 
> I know that ELisp doesn't do multithreading. Is it possible to do what
> I want without creating a separate script outside of Emacs?

BTW,
"make -j" from M-x compile will do this, if you are using a Unix-based system.

HTH,
Colin S. Miller

-- 
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