Re: buffering of process output

[storm@cua.dk (Kim F. Storm)]

I have tried your example on gnu/linux, and I can confirm your
findings for CVS emacs under X.  (I don't have 20.7)

But if I try your example with 'emacs -nw', then CVS emacs runs
smoothly too.  Wierd!!!

It seems that the difference in buffering in X vs. -nw is in the call
to emacs_read, i.e. in the call to read.  But 20.7 seems to do exactly
the same calls.

I have yet to find a sensible explanation why CVS emacs buffers output
differently with X.
 
So I wonder if X somehow causes read from a pipe to buffer things
differently [line buffering perhaps] (or the pipe to be setup
differently)?

I also tried to do (set-buffer-multibyte nil) before call-process:

- CVS emacs under X becomes much worse (seems to have to collect 16K
  output before updating)

- CVS emacs -nw still runs smoothly.

So unibyte/multibyte also kicks in somehow...

Ideas anyone ??


Kazu Yamamoto (山本和彦) <kazu@iijlab.net> writes:

> Emacs 21 has a different behavior of buffering of process output from
> Emacs 20.7.
>
> Evaluate the following in the *scratch* buffer
>
> 	(call-process "ping" nil t t "localhost")
>
> On Emacs 20.7, each line is smoothly inserted every second.
>
> On Emacs 21.3.50, however, insertion is awkward.
>
> --Kazu
>
> ----
> In GNU Emacs 21.3.50.1 (i386-unknown-netbsdelf1.6T, X toolkit, Xaw3d scroll bars)
>  of 2003-07-16 on caster.iij.ad.jp
> configured using `configure '--without-xim' '--prefix=/usr/local/emacs21' 'CFLAGS=-I/usr/pkg/include' 'CPPFLAGS=-I/usr/pkg/include -L/usr/pkg/lib' 'LDFLAGS=-R/usr/pkg/lib -L/usr/pkg/lib -R/usr/X11R6/lib -L/usr/X11R6/lib''
>

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk