Re: where does fvwm get its xterm icon?

[David Wright <deblis@lionunicorn.co.uk>]

On Mon 24 Sep 2018 at 14:26:48 (+0200), Nicolas George wrote:
> David Wright (2018-09-22):
> > (Actually .xsession here.) That may well be, and it does work to get
> > the xterms placed on the correct positions, but it also has downsides
> > which I can avoid while xtoolwait continues to work (even with its
> > bug).
> > 
> > 1) The xterms' arguments, and (for some of them) the commands they run,
> >    are computed in the shell script that is ~/.xsession. While some of
> >    these might be simple to perform in fvwm-ese, not all of them are,
> >    and I'm not particularly well versed in fvwm-ese. I'm reasonably
> >    competent in bash dialect shell-ese however.
> 
> You can call a shell script from Fvwm, of course. With a little
> creativity, you can even call .xsession or .xinitrc itself and arrange
> to have the same init code for environment and stuff but execute pre-WM
> commands when it is truly the init script and post-WM commands
> otherwise.

That sort of back and forth gets quite complicated quite quickly.
Starting a WM and then starting a bunch of xterms is a procedure that
shellese is suited for. Setting up 20+ pieces of code to be called
from the WM for each xterm (so that WM's Waits can be placed between
the calls) is crazy. Writing a shell script, but in fvwmese, is horrible.
And writing a WM init.hook file in advance of starting the WM is just an
extra body of code to maintain.

> > 2) I get a log of all the .xsession operations in .xsession-errors,
> >    whereas the logging done by fvwm is almost all generated by the
> >    Echo commands I inserted.
> 
> If you get Echo commands in .xsession-errors, that means Fvwm's output
> is connected to it, and then all commands started by Fvwm will too.

Not here (the first line is the init function call which creates 23 xterms):

[fvwm][Echo]: Reading /home/david/.fvwm/init.hook Last edited 2018-09-22
[fvwm][FlocaleGetFontSet]: (-adobe-helvetica-bold-r-*-*-12-*) Missing font charsets:
ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, KOI8-R, ISO8859-7, ISO8859-9, ISO8859-13, ISO8859-14, ISO8859-15, JISX0208.1983-0, KSC5601.1987-0, GB2312.1980-0, JISX0201.1976-0
[fvwm][Echo]: Reading /home/david/.fvwm/post.hook Last edited 2017-04-14
[fvwm][Echo]: Reading /home/david/.fvwm/last-post.hook-wren-0 Last edited 2018-09-22
[fvwm][Echo]: none done
[fvwm][Echo]: Initialised myvar to 0
[MyButtons][FlocaleGetFontSet]: (fixed) Missing font charsets:
ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, KOI8-R, ISO8859-7, ISO8859-9, ISO8859-13, ISO8859-14, ISO8859-15, JISX0208.1983-0, KSC5601.1987-0, GB2312.1980-0, JISX0201.1976-0, ISO10646-1
[FvwmPager][FlocaleGetFontSet]: (-*-times-medium-r-*-*-*-80-*-*-*-*-*-*) Missing font charsets:
ISO8859-3, ISO8859-4, ISO8859-5, KOI8-R, ISO8859-7, ISO8859-9, ISO8859-13, ISO8859-14, JISX0208.1983-0, KSC5601.1987-0, GB2312.1980-0, JISX0201.1976-0
[fvwm][Echo]: Started MyBit

Does fvwm have an equivalent of bash's   set -x   ?
If it were to, would .fvwm's stderr get overwhelmed by output from
every window operation and mouse-click?

> > 3) There's still a race between the xterms when started from InitFunction.
> >    Although their placements are correct, they are mapped at their
> >    locations in a random order instead of deterministically. This
> >    randomises the PIDs and PTSs of their shells, which is less
> >    convenient for seeing who's running what at a glance.
> 
> You may need to enforce the order with your favorite tool, but starting
> from Fvwm's InitFunction will reduce concurrency and therefore make
> things slightly more efficient. And I believe Fvwm is capable of doing
> the wait itself, which would be even more efficient.

It can indeed. Inserting a Wait after each xterm does the job and
tests on my slowest machine (to make timing things easier) shows
that it saves 1–2 seconds in 38; just not worth the trouble.

> Also, relying on the numbers of PIDs and PTYs is really not reliable,
> irregardless of how you start your xterms.

No reliance, just convenience.

> (Also, I had to wonder for a few seconds about why your xterms have
> Presentation Time Stamps, but that is just because I have spent a
> significant part of the week-end surrounded by multimedia jargon.)

Yes, for some reason  ps ax (or -ef)  calls them pts rather than pty.

Cheers,
David.