bug#36296: 26.2; cannot-suspend value on MS Win & resume description

bug#36296: 26.2; cannot-suspend value on MS Win & resume description

[Sebastian Urban]

Hello,

on MS Windows (official build) variable `cannot-suspend' has value
`nil', while according to this thread on help-gnu-emacs:
https://lists.gnu.org/archive/html/help-gnu-emacs/2019-0/msg00259.html
probably should have value `t'.  Although there is a line in
documentation of suspend-emacs ``If `cannot-suspend' is non-nil, or if
the system doesn't support job control, run a subshell instead.'', so
it suppose to work even with `nil' and it does for me (both 26.2 and
emacs-27.0.50-snapshot-2019-06-08-i686), but as Ó. Fuentes wrote in
the thread above:

> I tried C-z on MSWindows and it does not run a subshell. The console
> blinks but nothing else happens. I'm using a development version,
> though.

So maybe set it to `t' for MS Windows to be sure it'll work?


And the second part, as I wrote in mentioned thread:

> But also, maybe a line about this in the Emacs manual?  I mean if we
> have `%emacs' in the manual, so why not a line about times when there
> is no job control, which leads to subshell and for example `exit' as
> a way out back to Emacs.  Maybe just putting "or `exit'" next to
> `%emacs' would be sufficient (I'm just guessing here).


S. U.


In GNU Emacs 26.2 (build 1, i686-w64-mingw32)
  of 2019-04-13 built on CIRROCUMULUS
Repository revision: fd1b34bfba8f3f6298df47c8e10b61530426f749
Windowing system distributor 'Microsoft Corp.', version 6.1.7601

Configured using:
  'configure --without-dbus --host=i686-w64-mingw32
  --without-compress-install 'CFLAGS=-O2 -static -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS THREADS LCMS2

Important settings:
   value of $LANG: PLK
   locale-coding-system: cp1250

Major mode: Fundamental

Minor modes in effect:
   delete-selection-mode: t
   tooltip-mode: t
   global-eldoc-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   buffer-read-only: t
   line-number-mode: t
   transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils elec-pair holidays hol-loaddefs diary-lib
diary-loaddefs cal-menu calendar cal-loaddefs delsel cus-start cus-load
finder-inf info tex-site package easymenu epg-config url-handlers
url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache url-vars seq byte-opt gv bytecomp byte-compile cconv
cl-loaddefs cl-lib time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads w32notify w32 lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 8 131313 13875)
  (symbols 24 23589 1)
  (miscs 20 77 174)
  (strings 16 39533 1354)
  (string-bytes 1 1080439)
  (vectors 12 16419)
  (vector-slots 4 555364 4396)
  (floats 8 55 62)
  (intervals 28 289 10)
  (buffers 536 14))

bug#36296: 26.2; cannot-suspend value on MS Win & resume description

[Sebastian Urban]

This is just a reminder, because "This bug report was last modified 45
days ago."

bug#36296: 26.2; cannot-suspend value on MS Win & resume description

[Lars Ingebrigtsen]

Sebastian Urban <mrsebastianurban@gmail.com> writes:

> on MS Windows (official build) variable `cannot-suspend' has value
> `nil', while according to this thread on help-gnu-emacs:
> https://lists.gnu.org/archive/html/help-gnu-emacs/2019-0/msg00259.html
> probably should have value `t'.

PROBLEMS says:

*** C-z just refreshes the screen instead of suspending Emacs.

You are probably using a shell that doesn't support job control, even
though the system itself is capable of it.  Either use a different shell,
or set the variable 'cannot-suspend' to a non-nil value.

--------

I'm not very familiar with how this works under Windows, but from the
text there, it sounds like it depends on the shell, so Emacs can't
really default the variable to t just based on the OS?  Or is this
always the case on Windows (that `C-z' doesn't work?)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#36296: 26.2; cannot-suspend value on MS Win & resume description

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Sat, 30 Jan 2021 11:06:40 +0100
> Cc: 36296@debbugs.gnu.org
> 
> Sebastian Urban <mrsebastianurban@gmail.com> writes:
> 
> > on MS Windows (official build) variable `cannot-suspend' has value
> > `nil', while according to this thread on help-gnu-emacs:
> > https://lists.gnu.org/archive/html/help-gnu-emacs/2019-0/msg00259.html
> > probably should have value `t'.
> 
> PROBLEMS says:
> 
> *** C-z just refreshes the screen instead of suspending Emacs.
> 
> You are probably using a shell that doesn't support job control, even
> though the system itself is capable of it.  Either use a different shell,
> or set the variable 'cannot-suspend' to a non-nil value.
> 
> --------
> 
> I'm not very familiar with how this works under Windows, but from the
> text there, it sounds like it depends on the shell, so Emacs can't
> really default the variable to t just based on the OS?  Or is this
> always the case on Windows (that `C-z' doesn't work?)

IMNSHO, this is a subtle bug on MS-Windows that needs to be
investigated and fixed; the code looked okay to me last time I looked.
I don't have time to work on it, and the feature is very unimportant
on MS-Windows, so volunteers and patches are welcome, but documenting
this as a "feature" is IMO not TRT.

bug#36296: 26.2; cannot-suspend value on MS Win & resume description

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> IMNSHO, this is a subtle bug on MS-Windows that needs to be
> investigated and fixed; the code looked okay to me last time I looked.
> I don't have time to work on it, and the feature is very unimportant
> on MS-Windows, so volunteers and patches are welcome, but documenting
> this as a "feature" is IMO not TRT.

OK, I'll just leave this bug report open.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no