Document problems with ISO-8859 fonts which actually include only

[gnu-emacs] / etc / PROBLEMS

This file describes various problems that have been encountered
in compiling, installing and running GNU Emacs.

* Some accented ISO-8859-1 characters or umlauts are displayed as | or _.

Try other font set sizes (S-mouse-1).  If the problem persists with
other sizes as well, your text is corrupted, probably through software
that is not 8-bit clean.  If the problem goes away with another font
size, it's probably because some fonts pretend to be ISO-8859-1 fonts
when they are really ASCII fonts. In particular the schumacher-clean
fonts have this bug in some versions of X.

To see what glyphs are included in a font, use `xfd', like this:

  xfd -fn -schumacher-clean-medium-r-normal--12-120-75-75-c-60-iso8859-1

If this shows only ASCII glyphs, the font is indeed the source of the
problem.

The solution is to remove the corresponding lines from the appropriate
`fonts.alias' file, then run `mkfontdir' in that directory, and then run
`xset fp rehash'.

* Large file support is disabled on HP-UX.  See the comments in
src/s/hpux10.h.

* Crashes when displaying uncompressed GIFs with version
libungif-4.1.0 are resolved by using version libungif-4.1.0b1.

* The W3 package (either from from the CVS sources or the last
release) currently (2000-12-14) doesn't run properly with Emacs 21 and
needs work.

* On AIX, if linking fails because libXbsd isn't found, check if you
are compiling with the system's `cc' and CFLAGS containing `-O5'.  If
so, you have hit a compiler bug.  Please make sure to re-configure
Emacs so that it isn't compiled with `-O5'.

* The PSGML package uses the obsolete variables
`before-change-function' and `after-change-function', which are no
longer used by Emacs.  These changes to PSGML 1.2.1 fix that.

--- psgml-edit.el       1999/12/17 10:55:07     1.1
+++ psgml-edit.el       1999/12/17 11:36:37
@@ -263,4 +263,4 @@
                                        ; inhibit-read-only
-       (before-change-function nil)
-       (after-change-function nil))
+       (before-change-functions nil)
+       (after-change-functions nil))
     (setq selective-display t)
@@ -1474,3 +1474,3 @@
        (buffer-read-only nil)
-       (before-change-function nil)
+       (before-change-functions nil)
        (markup-index                   ; match-data index in tag regexp
@@ -1526,3 +1526,3 @@
 (defun sgml-expand-shortref-to-text (name)
-  (let (before-change-function
+  (let (before-change-functions
        (entity (sgml-lookup-entity name (sgml-dtd-entities sgml-dtd-info))))
@@ -1543,3 +1543,3 @@
        (re-found nil)
-       before-change-function)
+       before-change-functions)
     (goto-char sgml-markup-start)
@@ -1576,3 +1576,3 @@
     (goto-char (sgml-element-end element)) 
-    (let ((before-change-function nil))
+    (let ((before-change-functions nil))
       (sgml-normalize-content element only-one)))
--- psgml-other.el      1999/12/17 10:40:02     1.1
+++ psgml-other.el      1999/12/17 11:30:43
@@ -32,2 +32,3 @@
 (require 'easymenu)
+(eval-when-compile (require 'cl))
 
@@ -61,4 +62,9 @@
                   (let ((submenu
-                         (subseq entries 0 (min (length entries)
-                                                sgml-max-menu-size))))
+;;;                      (subseq entries 0 (min (length entries)
+;;;                                             sgml-max-menu-size))
+                         (let ((new (copy-sequence entries)))
+                           (setcdr (nthcdr (1- (min (length entries)
+                                                    sgml-max-menu-size))
+                                           new) nil)
+                           new)))
                     (setq entries (nthcdr sgml-max-menu-size entries))
@@ -113,7 +119,10 @@
       (let ((inhibit-read-only t)
-           (after-change-function nil) ; obsolete variable
-           (before-change-function nil) ; obsolete variable
            (after-change-functions nil)
-           (before-change-functions nil))
-       (put-text-property start end 'face face)))
+           (before-change-functions nil)
+           (modified (buffer-modified-p))
+           (buffer-undo-list t)
+           deactivate-mark)
+       (put-text-property start end 'face face)
+       (when (and (not modified) (buffer-modified-p))
+          (set-buffer-modified-p nil))))
      (t
--- psgml-parse.el      1999/12/17 10:32:45     1.1
+++ psgml-parse.el      2000/12/05 17:12:34
@@ -40,2 +40,4 @@
 
+(eval-when-compile (require 'cl))
+
 \f
@@ -2474,8 +2476,8 @@
       (setq sgml-scratch-buffer nil))
-    (when after-change-function                ;***
-      (message "OOPS: after-change-function not NIL in scratch buffer %s: %s"
+    (when after-change-functions               ;***
+      (message "OOPS: after-change-functions not NIL in scratch buffer %s: %S"
               (current-buffer)
-              after-change-function)
-      (setq before-change-function nil
-           after-change-function nil))
+              after-change-functions)
+      (setq before-change-functions nil
+           after-change-functions nil))
     (setq sgml-last-entity-buffer (current-buffer))
@@ -2846,6 +2848,5 @@
   "Set initial state of parsing"
-  (make-local-variable 'before-change-function)
-  (setq before-change-function 'sgml-note-change-at)
-  (make-local-variable 'after-change-function)
-  (setq after-change-function 'sgml-set-face-after-change)
+  (set (make-local-variable 'before-change-functions) '(sgml-note-change-at))
+  (set (make-local-variable 'after-change-functions)
+       '(sgml-set-face-after-change))
   (sgml-set-active-dtd-indicator (sgml-dtd-doctype dtd))
@@ -3887,7 +3888,7 @@
 
-  (unless before-change-function
-    (message "WARN: before-change-function has been lost, restoring (%s)"
+  (unless before-change-functions
+    (message "WARN: before-change-functions has been lost, restoring (%s)"
             (current-buffer))
-    (setq before-change-function 'sgml-note-change-at)
-    (setq after-change-function 'sgml-set-face-after-change)
+    (setq before-change-functions '(sgml-note-change-at))
+    (setq after-change-functions '(sgml-set-face-after-change))
     )

* On systems with shared libraries you might encounter run-time errors
from the dynamic linker telling you that it is unable to find some
shared libraries, for instance those for Xaw3d or image support.
These errors mean Emacs has been linked with a library whose shared
library is not in the default search path of the dynamic linker.

On many systems, it is possible to set LD_LIBRARY_PATH in your
environment to specify additional directories where shared libraries
can be found.

Other systems allow to set LD_RUN_PATH in a similar way, but before
Emacs is linked.  With LD_RUN_PATH set, the linker will include a
specified run-time search path in the executable.

Please refer to the documentation of your dynamic linker for details.

* On Solaris 2.7, building Emacs with WorkShop Compilers 5.0 98/12/15
C 5.0 failed, apparently with non-default CFLAGS, most probably due to
compiler bugs.  Using Sun Solaris 2.7 Sun WorkShop 6 update 1 C
release was reported to work without problems.  It worked OK on
another system with Solaris 8 using apparently the same 5.0 compiler
and the default CFLAGS.

* On Windows 95/98/ME, subprocesses do not terminate properly.

This is a limitation of the Operating System, and can cause problems
when shutting down Windows. Ensure that all subprocesses are exited
cleanly before exiting Emacs. For more details, see the FAQ at
ftp://ftp.gnu.org/gnu/windows/emacs/doc/index.html

* Mail sent through Microsoft Exchange in some encodings appears to be
mangled and is not seen correctly in Rmail or Gnus.  We don't know
exactly what happens, but it isn't an Emacs problem in cases we've
seen.

* On OSF/Dec Unix/Tru64/<whatever it is this year> under X locally or
remotely, M-SPC acts as a `compose' key with strange results.  See
keyboard(5).

Changing Alt_L to Meta_L fixes it:
% xmodmap -e 'keysym Alt_L = Meta_L Alt_L'
% xmodmap -e 'keysym Alt_R = Meta_R Alt_R'  

* Error "conflicting types for `initstate'" compiling with GCC on Irix 6.

Install GCC 2.95 or a newer version, and this problem should go away.
It is possible that this problem results from upgrading the operating
system without reinstalling GCC; so you could also try reinstalling
the same version of GCC, and telling us whether that fixes the problem.

* On Solaris 7, Emacs gets a segmentation fault when starting up using X.

This results from Sun patch 107058-01 (SunOS 5.7: Patch for
assembler) if you use GCC version 2.7 or later.
To work around it, either install patch 106950-03 or later,
or uninstall patch 107058-01, or install the GNU Binutils.
Then recompile Emacs, and it should work.

* With X11R6.4, public-patch-3, Emacs crashes at startup.

Reportedly this patch in X fixes the problem.

    --- xc/lib/X11/imInt.c~     Wed Jun 30 13:31:56 1999
    +++ xc/lib/X11/imInt.c      Thu Jul  1 15:10:27 1999
    @@ -1,4 +1,4 @@
    -/* $TOG: imInt.c /main/5 1998/05/30 21:11:16 kaleb $ */
    +/* $TOG: imInt.c /main/5 1998/05/30 21:11:16 kaleb $  */
     /******************************************************************

                Copyright 1992, 1993, 1994 by FUJITSU LIMITED
    @@ -166,8 +166,8 @@
     _XimMakeImName(lcd)
         XLCd      lcd;
     {
    -    char* begin;
    -    char* end;
    +    char* begin = NULL;
    +    char* end = NULL;
         char* ret;
         int    i = 0;
         char* ximmodifier = XIMMODIFIER;
    @@ -182,7 +182,11 @@
         }
         ret = Xmalloc(end - begin + 2);
         if (ret != NULL) {
    -           (void)strncpy(ret, begin, end - begin + 1);
    +   if (begin != NULL) {
    +             (void)strncpy(ret, begin, end - begin + 1);
    +        } else {
    +     ret[0] = '\0';
    +   }
            ret[end - begin + 1] = '\0';
         }
         return ret;


* Emacs crashes on Irix 6.5 on the SGI R10K, when compiled with GCC.
  
This seems to be fixed in GCC 2.95.

* Emacs crashes in utmpname on Irix 5.3.

This problem is fixed in Patch 3175 for Irix 5.3.
It is also fixed in Irix versions 6.2 and up.

* On Solaris, CTRL-t is ignored by Emacs when you use
the fr.ISO-8859-15 locale (and maybe other related locales).

You can fix this by editing the file:

        /usr/openwin/lib/locale/iso8859-15/Compose
        
Near the bottom there is a line that reads:

        Ctrl<t> <quotedbl> <Y>                  : "\276"        threequarters

that should read:

        Ctrl<T> <quotedbl> <Y>                  : "\276"        threequarters

Note the lower case <t>.  Changing this line should make C-t work.

* Emacs on Digital Unix 4.0 fails to build, giving error message
     Invalid dimension for the charset-ID 160

This is due to a bug or an installation problem in GCC 2.8.0.
Installing a more recent version of GCC fixes the problem.

* Buffers from `with-output-to-temp-buffer' get set up in Help mode.

Changes in Emacs 20.4 to the hooks used by that function cause
problems for some packages, specifically BBDB.  See the function's
documentation for the hooks involved.  BBDB 2.00.06 fixes the problem.

* Under X, C-v and/or other keys don't work.

These may have been intercepted by your window manager.  In
particular, AfterStep 1.6 is reported to steal C-v in its default
configuration.  Various Meta keys are also likely to be taken by the
configuration of the `feel'.  See the WM's documentation for how to
change this.

* When using Exceed, fonts sometimes appear too tall.

When the display is set to an Exceed X-server and fonts are specified
(either explicitly with the -fn option or implicitly with X resources)
then the fonts may appear "too tall".  The actual character sizes are
correct but there is too much vertical spacing between rows,  which 
gives the appearance of "double spacing".  

To prevent this,  turn off the Exceed's "automatic font substitution"
feature (in the font part of the configuration window).

* Failure in unexec while dumping emacs on Digital Unix 4.0

This problem manifests itself as an error message

    unexec: Bad address, writing data section to ...

The user suspects that this happened because his X libraries
were built for an older system version,

    ./configure --x-includes=/usr/include --x-libraries=/usr/shlib

made the problem go away.

* No visible display on mips-sgi-irix6.2 when compiling with GCC 2.8.1.

This problem went away after installing the latest IRIX patches
as of 8 Dec 1998.

The same problem has been reported on Irix 6.3.

* As of version 20.4, Emacs doesn't work properly if configured for
the Motif toolkit and linked against the free LessTif library.  The
next Emacs release is expected to work with LessTif.

* Emacs gives the error, Couldn't find per display information.

This can result if the X server runs out of memory because Emacs uses
a large number of fonts.  On systems where this happens, C-h h is
likely to cause it.

We do not know of a way to prevent the problem.

* Emacs makes HPUX 11.0 crash.

This is a bug in HPUX; HPUX patch PHKL_16260 is said to fix it.

* Emacs crashes during dumping on the HPPA machine (HPUX 10.20).

This seems to be due to a GCC bug; it is fixed in GCC 2.8.1.

* The Hyperbole package causes *Help* buffers not to be displayed in
Help mode due to setting `temp-buffer-show-hook' rather than using
`add-hook'.  Using `(add-hook 'temp-buffer-show-hook
'help-mode-maybe)' after loading Hyperbole should fix this.

* Versions of the PSGML package earlier than 1.0.3 (stable) or 1.1.2
(alpha) fail to parse DTD files correctly in Emacs 20.3 and later.
Here is a patch for psgml-parse.el from PSGML 1.0.1 and, probably,
earlier versions.

--- psgml-parse.el      1998/08/21 19:18:18     1.1
+++ psgml-parse.el      1998/08/21 19:20:00
@@ -2383,7 +2383,7 @@ (defun sgml-push-to-entity (entity &opti
       (setq sgml-buffer-parse-state nil))
     (cond
      ((stringp entity)                 ; a file name
-      (save-excursion (insert-file-contents entity))
+      (insert-file-contents entity)
       (setq default-directory (file-name-directory entity)))
      ((consp (sgml-entity-text entity)) ; external id?
       (let* ((extid (sgml-entity-text entity))

* Running TeX from AUXTeX package with Emacs 20.3 gives a Lisp error
about a read-only tex output buffer.

This problem appeared for AUC TeX version 9.9j and some earlier
versions.  Here is a patch for the file tex-buf.el in the AUC TeX
package.

diff -c auctex/tex-buf.el~ auctex/tex-buf.el
*** auctex/tex-buf.el~  Wed Jul 29 18:35:32 1998
--- auctex/tex-buf.el   Sat Sep  5 15:20:38 1998
***************
*** 545,551 ****
        (dir (TeX-master-directory)))
      (TeX-process-check file)          ; Check that no process is running
      (setq TeX-command-buffer (current-buffer))
!     (with-output-to-temp-buffer buffer)
      (set-buffer buffer)
      (if dir (cd dir))
      (insert "Running `" name "' on `" file "' with ``" command "''\n")
- --- 545,552 ----
        (dir (TeX-master-directory)))
      (TeX-process-check file)          ; Check that no process is running
      (setq TeX-command-buffer (current-buffer))
!     (let (temp-buffer-show-function temp-buffer-show-hook)
!       (with-output-to-temp-buffer buffer))
      (set-buffer buffer)
      (if dir (cd dir))
      (insert "Running `" name "' on `" file "' with ``" command "''\n")

* On Irix 6.3, substituting environment variables in file names
in the minibuffer gives peculiar error messages such as

   Substituting nonexistent environment variable ""

This is not an Emacs bug; it is caused by something in SGI patch
003082 August 11, 1998.

* After a while, Emacs slips into unibyte mode.

The VM mail package, which is not part of Emacs, sometimes does
  (standard-display-european t)
That should be changed to 
  (standard-display-european 1 t)

* Installing Emacs gets an error running `install-info'.

You need to install a recent version of Texinfo; that package
supplies the `install-info' command.

* Emacs does not recognize the AltGr key, on HPUX.

To fix this, set up a file ~/.dt/sessions/sessionetc with executable
rights, containing this text:

--------------------------------
xmodmap 2> /dev/null - << EOF
keysym Alt_L = Meta_L
keysym Alt_R = Meta_R
EOF

xmodmap - << EOF
clear mod1
keysym Mode_switch = NoSymbol
add mod1 = Meta_L
keysym Meta_R = Mode_switch
add mod2 = Mode_switch
EOF
--------------------------------

* Emacs compiled with DJGPP for MS-DOS/MS-Windows cannot access files
in the directory with the special name `dev' under the root of any
drive, e.g. `c:/dev'.

This is an unfortunate side-effect of the support for Unix-style
device names such as /dev/null in the DJGPP runtime library.  A
work-around is to rename the problem directory to another name.

* M-SPC seems to be ignored as input.

See if your X server is set up to use this as a command
for character composition.

* Emacs startup on GNU/Linux systems (and possibly other systems) is slow.

This can happen if the system is misconfigured and Emacs can't get the
full qualified domain name, FQDN.  You should have your FQDN in the
/etc/hosts file, something like this:

127.0.0.1       localhost
129.187.137.82  nuc04.t30.physik.tu-muenchen.de nuc04

The way to set this up may vary on non-GNU systems.

* Garbled display on non-X terminals when Emacs runs on Digital Unix 4.0.

So far it appears that running `tset' triggers this problem (when TERM
is vt100, at least).  If you do not run `tset', then Emacs displays
properly.  If someone can tell us precisely which effect of running
`tset' actually causes the problem, we may be able to implement a fix
in Emacs.

* When you run Ispell from Emacs, it reports a "misalignment" error.

This can happen if you compiled Ispell to use ASCII characters only
and then try to use it from Emacs with non-ASCII characters,
specifically Latin-1.  The solution is to recompile Ispell with
Latin-1 support.

This can also happen if the version of Ispell installed on your
machine is old.

* On Linux-based GNU systems using libc versions 5.4.19 through
5.4.22, Emacs crashes at startup with a segmentation fault.

This problem happens if libc defines the symbol __malloc_initialized.
One known solution is to upgrade to a newer libc version.  5.4.33 is
known to work.

* On Windows, you cannot use the right-hand ALT key and the left-hand
CTRL key together to type a Control-Meta character.

This is a consequence of a misfeature beyond Emacs's control.

Under Windows, the AltGr key on international keyboards generates key
events with the modifiers Right-Alt and Left-Ctrl.  Since Emacs cannot
distinguish AltGr from an explicit Right-Alt and Left-Ctrl
combination, whenever it sees Right-Alt and Left-Ctrl it assumes that
AltGr has been pressed.

* Under some Windows X-servers, Emacs' display is incorrect 

The symptoms are that Emacs does not completely erase blank areas of the
screen during scrolling or some other screen operations (e.g., selective
display or when killing a region).  M-x recenter will cause the screen
to be completely redisplayed and the "extra" characters will disappear.

This is known to occur under Exceed 6, and possibly earlier versions as
well.  The problem lies in the X-server settings.

There are reports that you can solve the problem with Exceed by
running `Xconfig' from within NT, choosing "X selection", then
un-checking the boxes "auto-copy X selection" and "auto-paste to X
selection".

Of this does not work, please inform bug-gnu-emacs@gnu.org.  Then
please call support for your X-server and see if you can get a fix.
If you do, please send it to bug-gnu-emacs@gnu.org so we can list it
here.

* On Solaris 2, Emacs dumps core when built with Motif.

The Solaris Motif libraries are buggy, at least up through Solaris 2.5.1.
Install the current Motif runtime library patch appropriate for your host.
(Make sure the patch is current; some older patch versions still have the bug.)
You should install the other patches recommended by Sun for your host, too.
You can obtain Sun patches from ftp://sunsolve.sun.com/pub/patches/;
look for files with names ending in `.PatchReport' to see which patches
are currently recommended for your host.

On Solaris 2.6, Emacs is said to work with Motif when Solaris patch
105284-12 is installed, but fail when 105284-15 is installed.
105284-18 might fix it again.

* On Solaris 2.6 and 7, the Compose key does not work.

This is a bug in Motif in Solaris.  Supposedly it has been fixed for
the next major release of Solaris.  However, if someone with Sun
support complains to Sun about the bug, they may release a patch.
If you do this, mention Sun bug #4188711.

One workaround is to use a locale that allows non-ASCII characters.
For example, before invoking emacs, set the LC_ALL environment
variable to "en_US" (American English).  The directory /usr/lib/locale
lists the supported locales; any locale other than "C" or "POSIX"
should do.

pen@lysator.liu.se says (Feb 1998) that the Compose key does work
if you link with the MIT X11 libraries instead of the Solaris X11
libraries.

* Emacs does not know your host's fully-qualified domain name.

You need to configure your machine with a fully qualified domain name,
either in /etc/hosts, /etc/hostname, the NIS, or wherever your system
calls for specifying this.

If you cannot fix the configuration, you can set the Lisp variable
mail-host-address to the value you want.

* Error 12 (virtual memory exceeded) when dumping Emacs, on UnixWare 2.1

Paul Abrahams (abrahams@acm.org) reports that with the installed
virtual memory settings for UnixWare 2.1.2, an Error 12 occurs during
the "make" that builds Emacs, when running temacs to dump emacs.  That
error indicates that the per-process virtual memory limit has been
exceeded.  The default limit is probably 32MB.  Raising the virtual
memory limit to 40MB should make it possible to finish building Emacs.

You can do this with the command `ulimit' (sh) or `limit' (csh).
But you have to be root to do it.

According to Martin Sohnius, you can also retune this in the kernel:

    # /etc/conf/bin/idtune SDATLIM 33554432         ## soft data size limit
    # /etc/conf/bin/idtune HDATLIM 33554432         ## hard "
    # /etc/conf/bin/idtune SVMMSIZE unlimited       ## soft process size limit
    # /etc/conf/bin/idtune HVMMSIZE unlimited       ## hard "
    # /etc/conf/bin/idbuild -B

(He recommends you not change the stack limit, though.)
These changes take effect when you reboot.

* Redisplay using X11 is much slower than previous Emacs versions.

We've noticed that certain X servers draw the text much slower when
scroll bars are on the left.  We don't know why this happens.  If this
happens to you, you can work around it by putting the scroll bars
on the right (as they were in Emacs 19).

Here's how to do this:

  (set-scroll-bar-mode 'right)

If you're not sure whether (or how much) this problem affects you,
try that and see how much difference it makes.  To set things back
to normal, do

  (set-scroll-bar-mode 'left)

* Under X11, some characters appear as hollow boxes.

Each X11 font covers just a fraction of the characters that Emacs
supports.  To display the whole range of Emacs characters requires
many different fonts, collected into a fontset.

If some of the fonts called for in your fontset do not exist on your X
server, then the characters that have no font appear as hollow boxes.
You can remedy the problem by installing additional fonts.

The intlfonts distribution includes a full spectrum of fonts that can
display all the characters Emacs supports.

* Under X11, some characters appear improperly aligned in their lines.

You may have bad X11 fonts; try installing the intlfonts distribution.

* Certain fonts make each line take one pixel more than it "should".

This is because these fonts contain characters a little taller
than the font's nominal height.  Emacs needs to make sure that
lines do not overlap.

* You request inverse video, and the first Emacs frame is in inverse
video, but later frames are not in inverse video.

This can happen if you have an old version of the custom library in
your search path for Lisp packages.  Use M-x list-load-path-shadows to
check whether this is true.  If it is, delete the old custom library.

* In FreeBSD 2.1.5, useless symbolic links remain in /tmp or other
directories that have the +t bit.

This is because of a kernel bug in FreeBSD 2.1.5 (fixed in 2.2).
Emacs uses symbolic links to implement file locks.  In a directory
with +t bit, the directory owner becomes the owner of the symbolic
link, so that it cannot be removed by anyone else.

If you don't like those useless links, you can let Emacs not to using
file lock by adding #undef CLASH_DETECTION to config.h.

* When using M-x dbx with the SparcWorks debugger, the `up' and `down'
commands do not move the arrow in Emacs.

You can fix this by adding the following line to `~/.dbxinit':

 dbxenv output_short_file_name off

* Emacs says it has saved a file, but the file does not actually
appear on disk.

This can happen on certain systems when you are using NFS, if the
remote disk is full.  It is due to a bug in NFS (or certain NFS
implementations), and there is apparently nothing Emacs can do to
detect the problem.  Emacs checks the failure codes of all the system
calls involved in writing a file, including `close'; but in the case
where the problem occurs, none of those system calls fails.

* "Compose Character" key does strange things when used as a Meta key.

If you define one key to serve as both Meta and Compose Character, you
will get strange results.  In previous Emacs versions, this "worked"
in that the key acted as Meta--that's because the older Emacs versions
did not try to support Compose Character.  Now Emacs tries to do
character composition in the standard X way.  This means that you
must pick one meaning or the other for any given key.

You can use both functions (Meta, and Compose Character) if you assign
them to two different keys.

* Emacs gets a segmentation fault at startup, on AIX4.2.

If you are using IBM's xlc compiler, compile emacs.c
without optimization; that should avoid the problem.

* movemail compiled with POP support can't connect to the POP server.

Make sure that the `pop' entry in /etc/services, or in the services
NIS map if your machine uses NIS, has the same port number as the
entry on the POP server.  A common error is for the POP server to be
listening on port 110, the assigned port for the POP3 protocol, while
the client is trying to connect on port 109, the assigned port for the
old POP protocol.

* Emacs crashes in x-popup-dialog.

This can happen if the dialog widget cannot find the font it wants to
use.  You can work around the problem by specifying another font with
an X resource--for example, `Emacs.dialog*.font: 9x15' (or any font that
happens to exist on your X server).

* Emacs crashes when you use Bibtex mode.

This happens if your system puts a small limit on stack size.  You can
prevent the problem by using a suitable shell command (often `ulimit')
to raise the stack size limit before you run Emacs.

Patches to raise the stack size limit automatically in `main'
(src/emacs.c) on various systems would be greatly appreciated.

* Emacs crashes with SIGBUS or SIGSEGV on HPUX 9 after you delete a frame.

We think this is due to a bug in the X libraries provided by HP.  With
the alternative X libraries in /usr/contrib/mitX11R5/lib, the problem
does not happen.

* Emacs crashes with SIGBUS or SIGSEGV on Solaris after you delete a frame.

We suspect that this is a similar bug in the X libraries provided by
Sun.  There is a report that one of these patches fixes the bug and
makes the problem stop:

105216-01 105393-01 105518-01 105621-01 105665-01 105615-02 105216-02
105667-01 105401-08 105615-03 105621-02 105686-02 105736-01 105755-03
106033-01 105379-01 105786-01 105181-04 105379-03 105786-04 105845-01
105284-05 105669-02 105837-01 105837-02 105558-01 106125-02 105407-01

Another person using a newer system (kernel patch level Generic_105181-06)
suspects that the bug was fixed by one of these more recent patches:

106040-07  SunOS 5.6: X Input & Output Method patch
106222-01  OpenWindows 3.6: filemgr (ff.core) fixes
105284-12  Motif 1.2.7: sparc Runtime library patch

* Problems running Perl under Emacs on Windows NT/95.

`perl -de 0' just hangs when executed in an Emacs subshell.
The fault lies with Perl (indirectly with Windows NT/95).

The problem is that the Perl debugger explicitly opens a connection to
"CON", which is the DOS/NT equivalent of "/dev/tty", for interacting
with the user.

On Unix, this is okay, because Emacs (or the shell?) creates a
pseudo-tty so that /dev/tty is really the pipe Emacs is using to
communicate with the subprocess.

On NT, this fails because CON always refers to the handle for the
relevant console (approximately equivalent to a tty), and cannot be
redirected to refer to the pipe Emacs assigned to the subprocess as
stdin.

A workaround is to modify perldb.pl to use STDIN/STDOUT instead of CON.

For Perl 4:

    *** PERL/LIB/PERLDB.PL.orig Wed May 26 08:24:18 1993
    --- PERL/LIB/PERLDB.PL      Mon Jul 01 15:28:16 1996
    ***************
    *** 68,74 ****
          $rcfile=".perldb";
      }
      else {
    !     $console = "con";
          $rcfile="perldb.ini";
      }

    --- 68,74 ----
          $rcfile=".perldb";
      }
      else {
    !     $console = "";
          $rcfile="perldb.ini";
      }


    For Perl 5:
    *** perl/5.001/lib/perl5db.pl.orig  Sun Jun 04 21:13:40 1995
    --- perl/5.001/lib/perl5db.pl       Mon Jul 01 17:00:08 1996
    ***************
    *** 22,28 ****
          $rcfile=".perldb";
      }
      elsif (-e "con") {
    !     $console = "con";
          $rcfile="perldb.ini";
      }
      else {
    --- 22,28 ----
          $rcfile=".perldb";
      }
      elsif (-e "con") {
    !     $console = "";
          $rcfile="perldb.ini";
      }
      else {

* Problems running DOS programs on Windows NT versions earlier than 3.51.

Some DOS programs, such as pkzip/pkunzip will not work at all, while
others will only work if their stdin is redirected from a file or NUL.

When a DOS program does not work, a new process is actually created, but
hangs.  It cannot be interrupted from Emacs, and might need to be killed
by an external program if Emacs is hung waiting for the process to
finish.  If Emacs is not waiting for it, you should be able to kill the
instance of ntvdm that is running the hung process from Emacs, if you
can find out the process id.

It is safe to run most DOS programs using call-process (eg. M-! and
M-|) since stdin is then redirected from a file, but not with
start-process since that redirects stdin to a pipe.  Also, running DOS
programs in a shell buffer prompt without redirecting stdin does not
work.

* Problems on MS-DOG if DJGPP v2.0 is used to compile Emacs:

There are two DJGPP library bugs which cause problems:

  * Running `shell-command' (or `compile', or `grep') you get
    `Searching for program: permission denied (EACCES), c:/command.com';
  * After you shell to DOS, Ctrl-Break kills Emacs.

To work around these bugs, you can use two files in the msdos
subdirectory: `is_exec.c' and `sigaction.c'.  Compile them and link
them into the Emacs executable `temacs'; then they will replace the
incorrect library functions.

* When compiling with DJGPP on Windows 95, Make fails for some targets
like make-docfile.

This can happen if long file name support (the setting of environment
variable LFN) when Emacs distribution was unpacked and during
compilation are not the same.  See the MSDOG section of INSTALL for
the explanation of how to avoid this problem.

* Emacs compiled for MSDOS cannot find some Lisp files, or other
run-time support files, when long filename support is enabled.
(Usually, this problem will manifest itself when Emacs exits
immediately after flashing the startup screen, because it cannot find
the Lisp files it needs to load at startup.  Redirect Emacs stdout
and stderr to a file to see the error message printed by Emacs.)

This can happen if the Emacs distribution was unzipped without LFN
support, thus causing long filenames to be truncated to the first 6
characters and a numeric tail that Windows 95 normally attaches to it.
You should unzip the files again with a utility that supports long
filenames (such as djtar from DJGPP or InfoZip's UnZip program
compiled with DJGPP v2).  The MSDOG section of the file INSTALL
explains this issue in more detail.

* Emacs compiled with DJGPP complains at startup:

  "Wrong type of argument: internal-facep, msdos-menu-active-face"

This can happen if you define an environment variable `TERM'.  Emacs
on MSDOS uses an internal terminal emulator which is disabled if the
value of `TERM' is anything but the string "internal".  Emacs then
works as if its terminal were a dumb glass teletype that doesn't
support faces.  To work around this, arrange for `TERM' to be
undefined when Emacs runs.  The best way to do that is to add an
[emacs] section to the DJGPP.ENV file which defines an empty value for
`TERM'; this way, only Emacs gets the empty value, while the rest of
your system works as before.

* On Windows 95, Alt-f6 does not get through to Emacs.

This character seems to be trapped by the kernel in Windows 95.
You can enter M-f6 by typing ESC f6.

* Typing Alt-Shift has strange effects on Windows 95.

This combination of keys is a command to change keyboard layout.  If
you proceed to type another non-modifier key before you let go of Alt
and Shift, the Alt and Shift act as modifiers in the usual way.

* `tparam' reported as a multiply-defined symbol when linking with ncurses.

This problem results from an incompatible change in ncurses, in
version 1.9.9e approximately.  This version is unable to provide a
definition of tparm without also defining tparam.  This is also
incompatible with Terminfo; as a result, the Emacs Terminfo support
does not work with this version of ncurses.

The fix is to install a newer version of ncurses, such as version 4.2.

* Strange results from format %d in a few cases, on a Sun.

Sun compiler version SC3.0 has been found to miscompile part of
editfns.c.  The workaround is to compile with some other compiler such
as GCC.

* Output from subprocess (such as man or diff) is randomly truncated
on GNU/Linux systems.

This is due to a kernel bug which seems to be fixed in Linux version
1.3.75.

* Error messages `internal facep []' happen on GNU/Linux systems.

There is a report that replacing libc.so.5.0.9 with libc.so.5.2.16
caused this to start happening.  People are not sure why, but the
problem seems unlikely to be in Emacs itself.  Some suspect that it
is actually Xlib which won't work with libc.so.5.2.16.

Using the old library version is a workaround.

* On Solaris, Emacs crashes if you use (display-time).

This can happen if you configure Emacs without specifying the precise
version of Solaris that you are using.

* Emacs dumps core on startup, on Solaris.

Bill Sebok says that the cause of this is Solaris 2.4 vendor patch
102303-05, which extends the Solaris linker to deal with the Solaris
Common Desktop Environment's linking needs.  You can fix the problem
by removing this patch and installing patch 102049-02 instead.
However, that linker version won't work with CDE.

Solaris 2.5 comes with a linker that has this bug.  It is reported that if
you install all the latest patches (as of June 1996), the bug is fixed.
We suspect the crucial patch is one of these, but we don't know
for certain.

        103093-03: [README] SunOS 5.5: kernel patch (2140557 bytes) 
        102832-01: [README] OpenWindows 3.5: Xview Jumbo Patch (4181613 bytes) 
        103242-04: [README] SunOS 5.5: linker patch (595363 bytes)

(One user reports that the bug was fixed by those patches together
with patches 102980-04, 103279-01, 103300-02, and 103468-01.)

If you can determine which patch does fix the bug, please tell
bug-gnu-emacs@gnu.org.

Meanwhile, the GNU linker links Emacs properly on both Solaris 2.4 and
Solaris 2.5.

* Emacs dumps core if lisp-complete-symbol is called, on Solaris.

If you compile Emacs with the -fast or -xO4 option with version 3.0.2
of the Sun C compiler, Emacs dumps core when lisp-complete-symbol is
called.  The problem does not happen if you compile with GCC.

* "Cannot find callback list" messages from dialog boxes on HPUX, in
Emacs built with Motif.

This problem resulted from a bug in GCC 2.4.5.  Newer GCC versions
such as 2.7.0 fix the problem.

* On Irix 6.0, make tries (and fails) to build a program named unexelfsgi

A compiler bug inserts spaces into the string "unexelfsgi . o"
in src/Makefile.  Edit src/Makefile, after configure is run,
find that string, and take out the spaces.

Compiler fixes in Irix 6.0.1 should eliminate this problem.

* "out of virtual swap space" on Irix 5.3

This message occurs when the system runs out of swap space due to too
many large programs running.  The solution is either to provide more
swap space or to reduce the number of large programs being run.  You
can check the current status of the swap space by executing the
command `swap -l'.

You can increase swap space by changing the file /etc/fstab.  Adding a
line like this:

/usr/swap/swap.more     swap    swap    pri=3 0 0

where /usr/swap/swap.more is a file previously created (for instance
by using /etc/mkfile), will increase the swap space by the size of
that file.  Execute `swap -m' or reboot the machine to activate the
new swap area.  See the manpages for `swap' and `fstab' for further
information.

The objectserver daemon can use up lots of memory because it can be
swamped with NIS information.  It collects information about all users
on the network that can log on to the host.

If you want to disable the objectserver completely, you can execute
the command `chkconfig objectserver off' and reboot.  That may disable
some of the window system functionality, such as responding CDROM
icons.

You can also remove NIS support from the objectserver.  The SGI `admin'
FAQ has a detailed description on how to do that; see question 35
("Why isn't the objectserver working?").  The admin FAQ can be found at
ftp://viz.tamu.edu/pub/sgi/faq/.

* With certain fonts, when the cursor appears on a character, the
character doesn't appear--you get a solid box instead.

One user on a Linux-based GNU system reported that this problem went
away with installation of a new X server.  The failing server was
XFree86 3.1.1.  XFree86 3.1.2 works.

* On SunOS 4.1.3, Emacs unpredictably crashes in _yp_dobind_soft.

This happens if you configure Emacs specifying just `sparc-sun-sunos4'
on a system that is version 4.1.3.  You must specify the precise
version number (or let configure figure out the configuration, which
it can do perfectly well for SunOS).

* On SunOS 4, Emacs processes keep going after you kill the X server
(or log out, if you logged in using X).

Someone reported that recompiling with GCC 2.7.0 fixed this problem.

* On AIX 4, some programs fail when run in a Shell buffer
with an error message like   No terminfo entry for "unknown".

On AIX, many terminal type definitions are not installed by default.
`unknown' is one of them.  Install the "Special Generic Terminal
Definitions" to make them defined.

* On SunOS, you get linker errors
   ld: Undefined symbol 
      _get_wmShellWidgetClass
      _get_applicationShellWidgetClass

The fix to this is to install patch 100573 for OpenWindows 3.0
or link libXmu statically.

* On AIX 4.1.2, linker error messages such as
  ld: 0711-212 SEVERE ERROR: Symbol .__quous, found in the global symbol table
        of archive /usr/lib/libIM.a, was not defined in archive member shr.o.

This is a problem in libIM.a.  You can work around it by executing
these shell commands in the src subdirectory of the directory where
you build Emacs:

    cp /usr/lib/libIM.a .
    chmod 664 libIM.a
    ranlib libIM.a

Then change -lIM to ./libIM.a in the command to link temacs (in
Makefile).

* Unpredictable segmentation faults on Solaris 2.3 and 2.4.

A user reported that this happened in 19.29 when it was compiled with
the Sun compiler, but not when he recompiled with GCC 2.7.0.

We do not know whether something in Emacs is partly to blame for this.

* Emacs exits with "X protocol error" when run with an X server for
Windows.

A certain X server for Windows had a bug which caused this.
Supposedly the newer 32-bit version of this server doesn't have the
problem.

* Emacs crashes at startup on MSDOS.

Some users report that Emacs 19.29 requires dpmi memory management,
and crashes on startup if the system does not have it.  We don't yet
know why this happens--perhaps these machines don't have enough real
memory, or perhaps something is wrong in Emacs or the compiler.
However, arranging to use dpmi support is a workaround.

You can find out if you have a dpmi host by running go32 without
arguments; it will tell you if it uses dpmi memory.  For more
information about dpmi memory, consult the djgpp FAQ.  (djgpp
is the GNU C compiler as packaged for MSDOS.)

Compiling Emacs under MSDOS is extremely sensitive for proper memory
configuration.  If you experience problems during compilation, consider
removing some or all memory resident programs (notably disk caches)
and make sure that your memory managers are properly configured.  See
the djgpp faq for configuration hints.

* A position you specified in .Xdefaults is ignored, using twm.

twm normally ignores "program-specified" positions.
You can tell it to obey them with this command in your `.twmrc' file:

  UsePPosition  "on"            #allow clients to request a position

* Compiling lib-src says there is no rule to make test-distrib.c.

This results from a bug in a VERY old version of GNU Sed.  To solve
the problem, install the current version of GNU Sed, then rerun
Emacs's configure script.

* Compiling wakeup, in lib-src, says it can't make wakeup.c.

This results from a bug in GNU Sed version 2.03.  To solve the
problem, install the current version of GNU Sed, then rerun Emacs's
configure script.

* On Sunos 4.1.1, there are errors compiling sysdep.c.

If you get errors such as

    "sysdep.c", line 2017: undefined structure or union
    "sysdep.c", line 2017: undefined structure or union
    "sysdep.c", line 2019: nodename undefined

This can result from defining LD_LIBRARY_PATH.  It is very tricky
to use that environment variable with Emacs.  The Emacs configure
script links many test programs with the system libraries; you must
make sure that the libraries available to configure are the same
ones available when you build Emacs.

* The right Alt key works wrong on German HP keyboards (and perhaps
other non-English HP keyboards too).

This is because HPUX defines the modifiers wrong in X.  Here is a
shell script to fix the problem; be sure that it is run after VUE
configures the X server.

    xmodmap 2> /dev/null - << EOF
    keysym Alt_L = Meta_L
    keysym Alt_R = Meta_R
    EOF

    xmodmap - << EOF
    clear mod1
    keysym Mode_switch = NoSymbol
    add mod1 = Meta_L
    keysym Meta_R = Mode_switch
    add mod2 = Mode_switch
    EOF

* The Emacs window disappears when you type M-q.

Some versions of the Open Look window manager interpret M-q as a quit
command for whatever window you are typing at.  If you want to use
Emacs with that window manager, you should try to configure the window
manager to use some other command.   You can disable the
shortcut keys entirely by adding this line to ~/.OWdefaults:

    OpenWindows.WindowMenuAccelerators: False

* Emacs does not notice when you release the mouse.

There are reports that this happened with (some) Microsoft mice and
that replacing the mouse made it stop.

* Trouble using ptys on IRIX, or running out of ptys.

The program mkpts (which may be in `/usr/adm' or `/usr/sbin') needs to
be set-UID to root, or non-root programs like Emacs will not be able
to allocate ptys reliably.

* On Irix 5.2, unexelfsgi.c can't find cmplrs/stsupport.h.

The file cmplrs/stsupport.h was included in the wrong file set in the
Irix 5.2 distribution.  You can find it in the optional fileset
compiler_dev, or copy it from some other Irix 5.2 system.  A kludgy
workaround is to change unexelfsgi.c to include sym.h instead of
syms.h.

* Slow startup on Linux-based GNU systems.

People using systems based on the Linux kernel sometimes report that
startup takes 10 to 15 seconds longer than `usual'.

This is because Emacs looks up the host name when it starts.
Normally, this takes negligible time; the extra delay is due to
improper system configuration.  This problem can occur for both
networked and non-networked machines.

Here is how to fix the configuration.  It requires being root.

** Networked Case

First, make sure the files `/etc/hosts' and `/etc/host.conf' both
exist.  The first line in the `/etc/hosts' file should look like this
(replace HOSTNAME with your host name):

    127.0.0.1      HOSTNAME

Also make sure that the `/etc/host.conf' files contains the following
lines:

    order hosts, bind 
    multi on

Any changes, permanent and temporary, to the host name should be
indicated in the `/etc/hosts' file, since it acts a limited local
database of addresses and names (e.g., some SLIP connections
dynamically allocate ip addresses).

** Non-Networked Case

The solution described in the networked case applies here as well.
However, if you never intend to network your machine, you can use a
simpler solution: create an empty `/etc/host.conf' file.  The command
`touch /etc/host.conf' suffices to create the file.  The `/etc/hosts'
file is not necessary with this approach.

* On Solaris 2.4, Dired hangs and C-g does not work.  Or Emacs hangs
forever waiting for termination of a subprocess that is a zombie.

casper@fwi.uva.nl says the problem is in X11R6.  Rebuild libX11.so
after changing the file xc/config/cf/sunLib.tmpl.  Change the lines

    #if ThreadedX
    #define SharedX11Reqs -lthread
    #endif

to:

    #if OSMinorVersion < 4
    #if ThreadedX
    #define SharedX11Reqs -lthread
    #endif
    #endif

Be sure also to edit x/config/cf/sun.cf so that OSMinorVersion is 4
(as it should be for Solaris 2.4).  The file has three definitions for
OSMinorVersion: the first is for x86, the second for SPARC under
Solaris, and the third for SunOS 4.  Make sure to update the
definition for your type of machine and system.

Then do `make Everything' in the top directory of X11R6, to rebuild
the makefiles and rebuild X.  The X built this way work only on
Solaris 2.4, not on 2.3.

For multithreaded X to work it is necessary to install patch
101925-02 to fix problems in header files [2.4].  You need
to reinstall gcc or re-run just-fixinc after installing that
patch.

However, Frank Rust <frust@iti.cs.tu-bs.de> used a simpler solution:
he changed
    #define ThreadedX          YES
to
    #define ThreadedX          NO
in sun.cf and did `make World' to rebuild X11R6.  Removing all
`-DXTHREAD*' flags and `-lthread' entries from lib/X11/Makefile and
typing 'make install' in that directory also seemed to work.

* With M-x enable-flow-control, you need to type C-\ twice
  to do incremental search--a single C-\ gets no response.

This has been traced to communicating with your machine via kermit,
with C-\ as the kermit escape character.  One solution is to use
another escape character in kermit.  One user did

   set escape-character 17

in his .kermrc file, to make C-q the kermit escape character.

* The Motif version of Emacs paints the screen a solid color.

This has been observed to result from the following X resource:

   Emacs*default.attributeFont: -*-courier-medium-r-*-*-*-140-*-*-*-*-iso8859-*

That the resource has this effect indicates a bug in something, but we
do not yet know what.  If it is an Emacs bug, we hope someone can
explain what the bug is so we can fix it.  In the mean time, removing
the resource prevents the problem.

* Emacs gets hung shortly after startup, on Sunos 4.1.3.

We think this is due to a bug in Sunos.  The word is that
one of these Sunos patches fixes the bug:

100075-11  100224-06  100347-03  100482-05  100557-02  100623-03  100804-03  101080-01
100103-12  100249-09             100496-02  100564-07  100630-02  100891-10  101134-01
100170-09  100296-04  100377-09  100507-04  100567-04  100650-02  101070-01  101145-01
100173-10  100305-15  100383-06  100513-04  100570-05  100689-01  101071-03  101200-02
100178-09  100338-05  100421-03  100536-02  100584-05  100784-01  101072-01  101207-01

We don't know which of these patches really matter.  If you find out
which ones, please inform bug-gnu-emacs@gnu.org.

* Emacs aborts while starting up, only when run without X.

This problem often results from compiling Emacs with GCC when GCC was
installed incorrectly.  The usual error in installing GCC is to
specify --includedir=/usr/include.  Installation of GCC makes
corrected copies of the system header files.  GCC is supposed to use
the corrected copies in preference to the original system headers.
Specifying --includedir=/usr/include causes the original system header
files to be used.  On some systems, the definition of ioctl in the
original system header files is invalid for ANSI C and causes Emacs
not to work.

The fix is to reinstall GCC, and this time do not specify --includedir
when you configure it.  Then recompile Emacs.  Specifying --includedir
is appropriate only in very special cases and it should *never* be the
same directory where system header files are kept.

* On Solaris 2.x, GCC complains "64 bit integer types not supported"

This suggests that GCC is not installed correctly.  Most likely you
are using GCC 2.7.2.3 (or earlier) on Solaris 2.6 (or later); this
does not work without patching.  To run GCC 2.7.2.3 on Solaris 2.6 or
later, you must patch fixinc.svr4 and reinstall GCC from scratch as
described in the Solaris FAQ
<http://www.wins.uva.nl/pub/solaris/solaris2.html>.  A better fix is
to upgrade to GCC 2.8.1 or later.

* The Compose key on a DEC keyboard does not work as Meta key.

This shell command should fix it:

  xmodmap -e 'keycode 0xb1 = Meta_L'

* Regular expressions matching bugs on SCO systems.

On SCO, there are problems in regexp matching when Emacs is compiled
with the system compiler.  The compiler version is "Microsoft C
version 6", SCO 4.2.0h Dev Sys Maintenance Supplement 01/06/93; Quick
C Compiler Version 1.00.46 (Beta).  The solution is to compile with
GCC.

* On Sunos 4, you get the error ld: Undefined symbol __lib_version.

This is the result of using cc or gcc with the shared library meant
for acc (the Sunpro compiler).  Check your LD_LIBRARY_PATH and delete
/usr/lang/SC2.0.1 or some similar directory.

* You can't select from submenus (in the X toolkit version).

On certain systems, mouse-tracking and selection in top-level menus
works properly with the X toolkit, but neither of them works when you
bring up a submenu (such as Bookmarks or Compare or Apply Patch, in
the Files menu).

This works on most systems.  There is speculation that the failure is
due to bugs in old versions of X toolkit libraries, but no one really
knows.  If someone debugs this and finds the precise cause, perhaps a
workaround can be found.

* Unusable default font on SCO 3.2v4.

The Open Desktop environment comes with default X resource settings
that tell Emacs to use a variable-width font.  Emacs cannot use such
fonts, so it does not work.

This is caused by the file /usr/lib/X11/app-defaults/ScoTerm, which is
the application-specific resource file for the `scoterm' terminal
emulator program.  It contains several extremely general X resources
that affect other programs besides `scoterm'.  In particular, these
resources affect Emacs also:

        *Font: -*-helvetica-medium-r-*--12-*-p-*
        *Background:                    scoBackground
        *Foreground:                    scoForeground

The best solution is to create an application-specific resource file for
Emacs, /usr/lib/X11/sco/startup/Emacs, with the following contents:

        Emacs*Font:     -*-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-1
        Emacs*Background:       white
        Emacs*Foreground:       black

(These settings mimic the Emacs defaults, but you can change them to
suit your needs.)  This resource file is only read when the X server
starts up, so you should restart it by logging out of the Open Desktop
environment or by running `scologin stop; scologin start` from the shell
as root.  Alternatively, you can put these settings in the
/usr/lib/X11/app-defaults/Emacs resource file and simply restart Emacs,
but then they will not affect remote invocations of Emacs that use the
Open Desktop display.

These resource files are not normally shared across a network of SCO
machines; you must create the file on each machine individually.

* rcs2log gives you the awk error message "too many fields".

This is due to an arbitrary limit in certain versions of awk.
The solution is to use gawk (GNU awk).

* Emacs is slow using X11R5 on HP/UX.

This happens if you use the MIT versions of the X libraries--it
doesn't run as fast as HP's version.  People sometimes use the version
because they see the HP version doesn't have the libraries libXaw.a,
libXmu.a, libXext.a and others.  HP/UX normally doesn't come with
those libraries installed.  To get good performance, you need to
install them and rebuild Emacs.

* Loading fonts is very slow.

You might be getting scalable fonts instead of precomputed bitmaps.
Known scalable font directories are "Type1" and "Speedo".  A font
directory contains scalable fonts if it contains the file
"fonts.scale".

If this is so, re-order your X windows font path to put the scalable
font directories last.  See the documentation of `xset' for details.

With some X servers, it may be necessary to take the scalable font
directories out of your path entirely, at least for Emacs 19.26.
Changes in the future may make this unnecessary.

* On AIX 3.2.4, releasing Ctrl/Act key has no effect, if Shift is down.

Due to a feature of AIX, pressing or releasing the Ctrl/Act key is
ignored when the Shift, Alt or AltGr keys are held down.  This can
lead to the keyboard being "control-locked"--ordinary letters are
treated as control characters.

You can get out of this "control-locked" state by pressing and
releasing Ctrl/Act while not pressing or holding any other keys.

* display-time causes kernel problems on ISC systems.

Under Interactive Unix versions 3.0.1 and 4.0 (and probably other
versions), display-time causes the loss of large numbers of STREVENT 
cells.  Eventually the kernel's supply of these cells is exhausted.
This makes emacs and the whole system run slow, and can make other 
processes die, in particular pcnfsd.
        
Other emacs functions that communicate with remote processes may have 
the same problem.  Display-time seems to be far the worst.

The only known fix: Don't run display-time.

* On Solaris, C-x doesn't get through to Emacs when you use the console.

This is a Solaris feature (at least on Intel x86 cpus).  Type C-r
C-r C-t, to toggle whether C-x gets through to Emacs.

* Error message `Symbol's value as variable is void: x', followed by
  segmentation fault and core dump.

This has been tracked to a bug in tar!  People report that tar erroneously
added a line like this at the beginning of files of Lisp code:

   x FILENAME, N bytes, B tape blocks

If your tar has this problem, install GNU tar--if you can manage to
untar it :-).

* Link failure when using acc on a Sun.

To use acc, you need additional options just before the libraries, such as

   /usr/lang/SC2.0.1/values-Xt.o -L/usr/lang/SC2.0.1/cg87 -L/usr/lang/SC2.0.1

and you need to add -lansi just before -lc.

The precise file names depend on the compiler version, so we
cannot easily arrange to supply them.

* Link failure on IBM AIX 1.3 ptf 0013.

There is a real duplicate definition of the function `_slibc_free' in
the library /lib/libc_s.a (just do nm on it to verify).  The
workaround/fix is:

    cd /lib
    ar xv libc_s.a NLtmtime.o
    ar dv libc_s.a NLtmtime.o

* Undefined symbols _dlopen, _dlsym and/or _dlclose on a Sun.

If you see undefined symbols _dlopen, _dlsym, or _dlclose when linking
with -lX11, compile and link against the file mit/util/misc/dlsym.c in
the MIT X11R5 distribution.  Alternatively, link temacs using shared
libraries with s/sunos4shr.h.  (This doesn't work if you use the X
toolkit.)

If you get the additional error that the linker could not find
lib_version.o, try extracting it from X11/usr/lib/X11/libvim.a in
X11R4, then use it in the link.

* Error messages `Wrong number of arguments: #<subr where-is-internal>, 5'

This typically results from having the powerkey library loaded.
Powerkey was designed for Emacs 19.22.  It is obsolete now because
Emacs 19 now has this feature built in; and powerkey also calls
where-is-internal in an obsolete way.

So the fix is to arrange not to load powerkey.

* In Shell mode, you get a ^M at the end of every line.

This happens to people who use tcsh, because it is trying to be too
smart.  It sees that the Shell uses terminal type `unknown' and turns
on the flag to output ^M at the end of each line.  You can fix the
problem by adding this to your .cshrc file:

    if ($?EMACS) then
        if ($EMACS == "t") then
            unset edit 
            stty  -icrnl -onlcr -echo susp ^Z
        endif
    endif

* An error message such as `X protocol error: BadMatch (invalid
parameter attributes) on protocol request 93'.

This comes from having an invalid X resource, such as
   emacs*Cursor:   black
(which is invalid because it specifies a color name for something
that isn't a color.)

The fix is to correct your X resources.

* Undefined symbols when linking on Sunos 4.1 using --with-x-toolkit.

If you get the undefined symbols _atowc _wcslen, _iswprint, _iswspace,
_iswcntrl, _wcscpy, and _wcsncpy, then you need to add -lXwchar after
-lXaw in the command that links temacs.

This problem seems to arise only when the international language
extensions to X11R5 are installed.

* Typing C-c C-c in Shell mode kills your X server.

This happens with Linux kernel 1.0 thru 1.04, approximately.  The workaround is
to define SIGNALS_VIA_CHARACTERS in config.h and recompile Emacs.
Newer Linux kernel versions don't have this problem.

* src/Makefile and lib-src/Makefile are truncated--most of the file missing.

This can happen if configure uses GNU sed version 2.03.  That version
had a bug.  GNU sed version 2.05 works properly.

* Slow startup on X11R6 with X windows.

If Emacs takes two minutes to start up on X11R6, see if your X
resources specify any Adobe fonts.  That causes the type-1 font
renderer to start up, even if the font you asked for is not a type-1
font.

One way to avoid this problem is to eliminate the type-1 fonts from
your font path, like this:

        xset -fp /usr/X11R6/lib/X11/fonts/Type1/

* Pull-down menus appear in the wrong place, in the toolkit version of Emacs.

An X resource of this form can cause the problem:

   Emacs*geometry:      80x55+0+0

This resource is supposed to apply, and does apply, to the menus
individually as well as to Emacs frames.  If that is not what you
want, rewrite the resource.

To check thoroughly for such resource specifications, use `xrdb
-query' to see what resources the X server records, and also look at
the user's ~/.Xdefaults and ~/.Xdefaults-* files.

* --with-x-toolkit version crashes when used with shared libraries.

On some systems, including Sunos 4 and DGUX 5.4.2 and perhaps others,
unexec doesn't work properly with the shared library for the X
toolkit.  You might be able to work around this by using a nonshared
libXt.a library.  The real fix is to upgrade the various versions of
unexec and/or ralloc.  We think this has been fixed on Sunos 4
and Solaris in version 19.29.

* `make install' fails on install-doc with `Error 141'.

This happens on Ultrix 4.2 due to failure of a pipeline of tar
commands.  We don't know why they fail, but the bug seems not to be in
Emacs.  The workaround is to run the shell command in install-doc by
hand.

* --with-x-toolkit option configures wrong on BSD/386.

This problem is due to bugs in the shell in version 1.0 of BSD/386.
The workaround is to edit the configure file to use some other shell,
such as bash.

* Subprocesses remain, hanging but not zombies, on Sunos 5.3.

A bug in Sunos 5.3 causes Emacs subprocesses to remain after Emacs
exits.  Sun patch # 101415-02 is part of the fix for this, but it only
applies to ptys, and doesn't fix the problem with subprocesses
communicating through pipes.

* Mail is lost when sent to local aliases.

Many emacs mail user agents (VM and rmail, for instance) use the
sendmail.el library.  This library can arrange for mail to be
delivered by passing messages to the /usr/lib/sendmail (usually)
program .  In doing so, it passes the '-t' flag to sendmail, which
means that the name of the recipient of the message is not on the
command line and, therefore, that sendmail must parse the message to
obtain the destination address.

There is a bug in the SunOS4.1.1 and SunOS4.1.3 versions of sendmail.
In short, when given the -t flag, the SunOS sendmail won't recognize
non-local (i.e. NIS) aliases.  It has been reported that the Solaris
2.x versions of sendmail do not have this bug.  For those using SunOS
4.1, the best fix is to install sendmail V8 or IDA sendmail (which
have other advantages over the regular sendmail as well).  At the time
of this writing, these official versions are available:

 Sendmail V8 on ftp.cs.berkeley.edu in /ucb/sendmail:
   sendmail.8.6.9.base.tar.Z (the base system source & documentation)
   sendmail.8.6.9.cf.tar.Z   (configuration files)
   sendmail.8.6.9.misc.tar.Z (miscellaneous support programs)
   sendmail.8.6.9.xdoc.tar.Z (extended documentation, with postscript)

 IDA sendmail on vixen.cso.uiuc.edu in /pub:
   sendmail-5.67b+IDA-1.5.tar.gz

* On AIX, you get this message when running Emacs:

    Could not load program emacs
    Symbol smtcheckinit in csh is undefined
    Error was: Exec format error

or this one:

    Could not load program .emacs
    Symbol _system_con in csh is undefined
    Symbol _fp_trapsta in csh is undefined
    Error was: Exec format error

These can happen when you try to run on AIX 3.2.5 a program that was
compiled with 3.2.4.  The fix is to recompile.

* On AIX, you get this compiler error message:

    Processing include file ./XMenuInt.h
        1501-106: (S) Include file X11/Xlib.h not found.

This means your system was installed with only the X11 runtime i.d
libraries.  You have to find your sipo (bootable tape) and install
X11Dev... with smit.

* You "lose characters" after typing Compose Character key.

This is because the Compose Character key is defined as the keysym
Multi_key, and Emacs (seeing that) does the proper X11
character-composition processing.  If you don't want your Compose key
to do that, you can redefine it with xmodmap.

For example, here's one way to turn it into a Meta key:

    xmodmap -e "keysym Multi_key = Meta_L"

If all users at your site of a particular keyboard prefer Meta to
Compose, you can make the remapping happen automatically by adding the
xmodmap command to the xdm setup script for that display.

* 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.

* Watch out for .emacs files and EMACSLOADPATH environment vars

These control the actions of Emacs.
~/.emacs is your Emacs init file.
EMACSLOADPATH overrides which directories the function
"load" will search.

If you observe strange problems, check for these and get rid
of them, then try again.

* After running emacs once, subsequent invocations crash.

Some versions of SVR4 have a serious bug in the implementation of the
mmap () system call in the kernel; this causes emacs to run correctly
the first time, and then crash when run a second time.

Contact your vendor and ask for the mmap bug fix; in the mean time,
you may be able to work around the problem by adding a line to your
operating system description file (whose name is reported by the
configure script) that reads:
#define SYSTEM_MALLOC
This makes Emacs use memory less efficiently, but seems to work around
the kernel bug.

* Inability to send an Alt-modified key, when Emacs is communicating
directly with an X server.

If you have tried to bind an Alt-modified key as a command, and it
does not work to type the command, the first thing you should check is
whether the key is getting through to Emacs.  To do this, type C-h c
followed by the Alt-modified key.  C-h c should say what kind of event
it read.  If it says it read an Alt-modified key, then make sure you
have made the key binding correctly.

If C-h c reports an event that doesn't have the Alt modifier, it may
be because your X server has no key for the Alt modifier.  The X
server that comes from MIT does not set up the Alt modifier by
default.

If your keyboard has keys named Alt, you can enable them as follows:

    xmodmap -e 'add mod2 = Alt_L'
    xmodmap -e 'add mod2 = Alt_R'

If the keyboard has just one key named Alt, then only one of those
commands is needed.  The modifier `mod2' is a reasonable choice if you
are using an unmodified MIT version of X.  Otherwise, choose any
modifier bit not otherwise used.

If your keyboard does not have keys named Alt, you can use some other
keys.  Use the keysym command in xmodmap to turn a function key (or
some other 'spare' key) into Alt_L or into Alt_R, and then use the
commands show above to make them modifier keys.

Note that if you have Alt keys but no Meta keys, Emacs translates Alt
into Meta.  This is because of the great importance of Meta in Emacs.

* `Pid xxx killed due to text modification or page I/O error'

On HP/UX, you can get that error when the Emacs executable is on an NFS
file system.  HP/UX responds this way if it tries to swap in a page and
does not get a response from the server within a timeout whose default
value is just ten seconds.

If this happens to you, extend the timeout period.

* `expand-file-name' fails to work on any but the machine you dumped Emacs on.

On Ultrix, if you use any of the functions which look up information
in the passwd database before dumping Emacs (say, by using
expand-file-name in site-init.el), then those functions will not work
in the dumped Emacs on any host but the one Emacs was dumped on.

The solution?  Don't use expand-file-name in site-init.el, or in
anything it loads.  Yuck - some solution.

I'm not sure why this happens; if you can find out exactly what is
going on, and perhaps find a fix or a workaround, please let us know.
Perhaps the YP functions cache some information, the cache is included
in the dumped Emacs, and is then inaccurate on any other host.

* On some variants of SVR4, Emacs does not work at all with X.

Try defining BROKEN_FIONREAD in your config.h file.  If this solves
the problem, please send a bug report to tell us this is needed; be
sure to say exactly what type of machine and system you are using.

* Linking says that the functions insque and remque are undefined.

Change oldXMenu/Makefile by adding insque.o to the variable OBJS.

* Emacs fails to understand most Internet host names, even though
the names work properly with other programs on the same system.
* Emacs won't work with X-windows if the value of DISPLAY is HOSTNAME:0.
* GNUs can't make contact with the specified host for nntp.

This typically happens on Suns and other systems that use shared
libraries.  The cause is that the site has installed a version of the
shared library which uses a name server--but has not installed a
similar version of the unshared library which Emacs uses.

The result is that most programs, using the shared library, work with
the nameserver, but Emacs does not.

The fix is to install an unshared library that corresponds to what you
installed in the shared library, and then relink Emacs.

On SunOS 4.1, simply define HAVE_RES_INIT.

If you have already installed the name resolver in the file libresolv.a,
then you need to compile Emacs to use that library.  The easiest way to
do this is to add to config.h a definition of LIBS_SYSTEM, LIBS_MACHINE
or LIB_STANDARD which uses -lresolv.  Watch out!  If you redefine a macro
that is already in use in your configuration to supply some other libraries,
be careful not to lose the others.

Thus, you could start by adding this to config.h:

#define LIBS_SYSTEM -lresolv

Then if this gives you an error for redefining a macro, and you see that
the s- file defines LIBS_SYSTEM as -lfoo -lbar, you could change config.h
again to say this:

#define LIBS_SYSTEM -lresolv -lfoo -lbar

* On a Sun running SunOS 4.1.1, you get this error message from GNU ld:

    /lib/libc.a(_Q_sub.o): Undefined symbol __Q_get_rp_rd referenced from text segment 

The problem is in the Sun shared C library, not in GNU ld.

The solution is to install Patch-ID# 100267-03 from Sun.

* Self documentation messages are garbled.

This means that the file `etc/DOC-...' doesn't properly correspond
with the Emacs executable.  Redumping Emacs and then installing the
corresponding pair of files should fix the problem.

* Trouble using ptys on AIX.

People often install the pty devices on AIX incorrectly.
Use `smit pty' to reinstall them properly.

* Shell mode on HP/UX gives the message, "`tty`: Ambiguous".

christos@theory.tn.cornell.edu says:

The problem is that in your .cshrc you have something that tries to
execute `tty`. If you are not running the shell on a real tty then 
tty will print "not a tty". Csh expects one word in some places, 
but tty is giving it back 3.

The solution is to add a pair of quotes around `tty` to make it a single
word: 

if (`tty` == "/dev/console") 

should be changed to:

if ("`tty`" == "/dev/console") 

Even better, move things that set up terminal sections out of .cshrc
and into .login.

* Using X Windows, control-shift-leftbutton makes Emacs hang.

Use the shell command `xset bc' to make the old X Menu package work.

* Emacs running under X Windows does not handle mouse clicks.
* `emacs -geometry 80x20' finds a file named `80x20'.

One cause of such problems is having (setq term-file-prefix nil) in
your .emacs file.  Another cause is a bad value of EMACSLOADPATH in
the environment.

* Emacs gets error message from linker on Sun.

If the error message says that a symbol such as `f68881_used' or
`ffpa_used' or `start_float' is undefined, this probably indicates
that you have compiled some libraries, such as the X libraries, 
with a floating point option other than the default.

It's not terribly hard to make this work with small changes in
crt0.c together with linking with Fcrt1.o, Wcrt1.o or Mcrt1.o.
However, the easiest approach is to build Xlib with the default
floating point option: -fsoft.

* Emacs fails to get default settings from X Windows server.

The X library in X11R4 has a bug; it interchanges the 2nd and 3rd
arguments to XGetDefaults.  Define the macro XBACKWARDS in config.h to
tell Emacs to compensate for this.

I don't believe there is any way Emacs can determine for itself
whether this problem is present on a given system.

* Keyboard input gets confused after a beep when using a DECserver
  as a concentrator.

This problem seems to be a matter of configuring the DECserver to use
7 bit characters rather than 8 bit characters.

* M-x shell persistently reports "Process shell exited abnormally with code 1".

This happened on Suns as a result of what is said to be a bug in Sunos
version 4.0.x.  The only fix was to reboot the machine. 

* Programs running under terminal emulator do not recognize `emacs'
  terminal type.

The cause of this is a shell startup file that sets the TERMCAP
environment variable.  The terminal emulator uses that variable to
provide the information on the special terminal type that Emacs
emulates.

Rewrite your shell startup file so that it does not change TERMCAP
in such a case.  You could use the following conditional which sets
it only if it is undefined.

    if ( ! ${?TERMCAP} ) setenv TERMCAP ~/my-termcap-file

Or you could set TERMCAP only when you set TERM--which should not
happen in a non-login shell.

* X Windows doesn't work if DISPLAY uses a hostname.

People have reported kernel bugs in certain systems that cause Emacs
not to work with X Windows if DISPLAY is set using a host name.  But
the problem does not occur if DISPLAY is set to `unix:0.0'.  I think
the bug has to do with SIGIO or FIONREAD.

You may be able to compensate for the bug by doing (set-input-mode nil nil).
However, that has the disadvantage of turning off interrupts, so that
you are unable to quit out of a Lisp program by typing C-g.

The easy way to do this is to put 

  (setq x-sigio-bug t)

in your site-init.el file.

* Problem with remote X server on Suns.

On a Sun, running Emacs on one machine with the X server on another
may not work if you have used the unshared system libraries.  This
is because the unshared libraries fail to use YP for host name lookup.
As a result, the host name you specify may not be recognized.

* Shell mode ignores interrupts on Apollo Domain

You may find that M-x shell prints the following message:

   Warning: no access to tty; thus no job control in this shell...

This can happen if there are not enough ptys on your system.
Here is how to make more of them.

    % cd /dev
    % ls pty*
    # shows how many pty's you have. I had 8, named pty0 to pty7)
    % /etc/crpty 8
    # creates eight new pty's

* Fatal signal in the command  temacs -l loadup inc dump

This command is the final stage of building Emacs.  It is run by the
Makefile in the src subdirectory, or by build.com on VMS.

It has been known to get fatal errors due to insufficient swapping
space available on the machine.

On 68000's, it has also happened because of bugs in the
subroutine `alloca'.  Verify that `alloca' works right, even
for large blocks (many pages).

* test-distrib says that the distribution has been clobbered
* or, temacs prints "Command key out of range 0-127"
* or, temacs runs and dumps emacs, but emacs totally fails to work.
* or, temacs gets errors dumping emacs

This can be because the .elc files have been garbled.  Do not be
fooled by the fact that most of a .elc file is text: these are
binary files and can contain all 256 byte values.

In particular `shar' cannot be used for transmitting GNU Emacs.
It typically truncates "lines".  What appear to be "lines" in
a binary file can of course be of any length.  Even once `shar'
itself is made to work correctly, `sh' discards null characters
when unpacking the shell archive.

I have also seen character \177 changed into \377.  I do not know
what transfer means caused this problem.  Various network
file transfer programs are suspected of clobbering the high bit.

If you have a copy of Emacs that has been damaged in its
nonprinting characters, you can fix them:

 1) Record the names of all the .elc files.
 2) Delete all the .elc files.
 3) Recompile alloc.c with a value of PURESIZE twice as large.
     (See puresize.h.)  You might as well save the old alloc.o.
 4) Remake emacs.  It should work now.
 5) Running emacs, do Meta-x byte-compile-file repeatedly
  to recreate all the .elc files that used to exist.
  You may need to increase the value of the variable
  max-lisp-eval-depth to succeed in running the compiler interpreted
  on certain .el files.  400 was sufficient as of last report.
 6) Reinstall the old alloc.o (undoing changes to alloc.c if any)
  and remake temacs.
 7) Remake emacs.  It should work now, with valid .elc files.

* temacs prints "Pure Lisp storage exhausted"

This means that the Lisp code loaded from the .elc and .el
files during  temacs -l loadup inc dump  took up more
space than was allocated.

This could be caused by
 1) adding code to the preloaded Lisp files
 2) adding more preloaded files in loadup.el
 3) having a site-init.el or site-load.el which loads files.
   Note that ANY site-init.el or site-load.el is nonstandard;
   if you have received Emacs from some other site
   and it contains a site-init.el or site-load.el file, consider
   deleting that file.
 4) getting the wrong .el or .elc files
   (not from the directory you expected).
 5) deleting some .elc files that are supposed to exist.
   This would cause the source files (.el files) to be
   loaded instead.  They take up more room, so you lose.
 6) a bug in the Emacs distribution which underestimates
   the space required.

If the need for more space is legitimate, change the definition
of PURESIZE in puresize.h.

But in some of the cases listed above, this problem is a consequence
of something else that is wrong.  Be sure to check and fix the real
problem.

* Changes made to .el files do not take effect.

You may have forgotten to recompile them into .elc files.
Then the old .elc files will be loaded, and your changes
will not be seen.  To fix this, do M-x byte-recompile-directory
and specify the directory that contains the Lisp files.

Emacs should print a warning when loading a .elc file which is older
than the corresponding .el file.

* The dumped Emacs crashes when run, trying to write pure data.

Two causes have been seen for such problems.

1) On a system where getpagesize is not a system call, it is defined
as a macro.  If the definition (in both unexec.c and malloc.c) is wrong,
it can cause problems like this.  You might be able to find the correct
value in the man page for a.out (5).

2) Some systems allocate variables declared static among the
initialized variables.  Emacs makes all initialized variables in most
of its files pure after dumping, but the variables declared static and
not initialized are not supposed to be pure.  On these systems you
may need to add "#define static" to the m- or the s- file.

* Compilation errors on VMS.

You will get warnings when compiling on VMS because there are
variable names longer than 32 (or whatever it is) characters.
This is not an error.  Ignore it.

VAX C does not support #if defined(foo).  Uses of this construct
were removed, but some may have crept back in.  They must be rewritten.

There is a bug in the C compiler which fails to sign extend characters
in conditional expressions.  The bug is:
        char c = -1, d = 1;
        int i;

        i = d ? c : d;
The result is i == 255;  the fix is to typecast the char in the
conditional expression as an (int).  Known occurrences of such
constructs in Emacs have been fixed.

* rmail gets error getting new mail

rmail gets new mail from /usr/spool/mail/$USER using a program
called `movemail'.  This program interlocks with /bin/mail using
the protocol defined by /bin/mail.

There are two different protocols in general use.  One of them uses
the `flock' system call.  The other involves creating a lock file;
`movemail' must be able to write in /usr/spool/mail in order to do
this.  You control which one is used by defining, or not defining,
the macro MAIL_USE_FLOCK in config.h or the m- or s- file it includes.
IF YOU DON'T USE THE FORM OF INTERLOCKING THAT IS NORMAL ON YOUR
SYSTEM, YOU CAN LOSE MAIL!

If your system uses the lock file protocol, and fascist restrictions
prevent ordinary users from writing the lock files in /usr/spool/mail,
you may need to make `movemail' setgid to a suitable group such as
`mail'.  You can use these commands (as root):

        chgrp mail movemail
        chmod 2755 movemail

If your system uses the lock file protocol, and fascist restrictions
prevent ordinary users from writing the lock files in /usr/spool/mail,
you may need to make `movemail' setgid to a suitable group such as
`mail'.  To do this,  use the following commands (as root) after doing the
make install.

        chgrp mail movemail
        chmod 2755 movemail

Installation normally copies movemail from the build directory to an
installation directory which is usually under /usr/local/lib.  The
installed copy of movemail is usually in the directory
/usr/local/lib/emacs/VERSION/TARGET.  You must change the group and
mode of the installed copy; changing the group and mode of the build
directory copy is ineffective.

* Emacs spontaneously displays "I-search: " at the bottom of the screen.

This means that Control-S/Control-Q (XON/XOFF) "flow control" is being
used.  C-s/C-q flow control is bad for Emacs editors because it takes
away C-s and C-q as user commands.  Since editors do not output long
streams of text without user commands, there is no need for a
user-issuable "stop output" command in an editor; therefore, a
properly designed flow control mechanism would transmit all possible
input characters without interference.  Designing such a mechanism is
easy, for a person with at least half a brain.

There are three possible reasons why flow control could be taking place:

  1) Terminal has not been told to disable flow control
  2) Insufficient padding for the terminal in use
  3) Some sort of terminal concentrator or line switch is responsible

First of all, many terminals have a set-up mode which controls whether
they generate XON/XOFF flow control characters.  This must be set to
"no XON/XOFF" in order for Emacs to work.  Sometimes there is an
escape sequence that the computer can send to turn flow control off
and on.  If so, perhaps the termcap `ti' string should turn flow
control off, and the `te' string should turn it on.

Once the terminal has been told "no flow control", you may find it
needs more padding.  The amount of padding Emacs sends is controlled
by the termcap entry for the terminal in use, and by the output baud
rate as known by the kernel.  The shell command `stty' will print
your output baud rate; `stty' with suitable arguments will set it if
it is wrong.  Setting to a higher speed causes increased padding.  If
the results are wrong for the correct speed, there is probably a
problem in the termcap entry.  You must speak to a local Unix wizard
to fix this.  Perhaps you are just using the wrong terminal type.

For terminals that lack a "no flow control" mode, sometimes just
giving lots of padding will prevent actual generation of flow control
codes.  You might as well try it.

If you are really unlucky, your terminal is connected to the computer
through a concentrator which sends XON/XOFF flow control to the
computer, or it insists on sending flow control itself no matter how
much padding you give it.  Unless you can figure out how to turn flow
control off on this concentrator (again, refer to your local wizard),
you are screwed!  You should have the terminal or concentrator
replaced with a properly designed one.  In the mean time, some drastic
measures can make Emacs semi-work.

You can make Emacs ignore C-s and C-q and let the operating system
handle them.  To do this on a per-session basis, just type M-x
enable-flow-control RET.  You will see a message that C-\ and C-^ are
now translated to C-s and C-q.  (Use the same command M-x
enable-flow-control to turn *off* this special mode.  It toggles flow
control handling.)

If C-\ and C-^ are inconvenient for you (for example, if one of them
is the escape character of your terminal concentrator), you can choose
other characters by setting the variables flow-control-c-s-replacement
and flow-control-c-q-replacement.  But choose carefully, since all
other control characters are already used by emacs.

IMPORTANT: if you type C-s by accident while flow control is enabled,
Emacs output will freeze, and you will have to remember to type C-q in
order to continue.

If you work in an environment where a majority of terminals of a
certain type are flow control hobbled, you can use the function
`enable-flow-control-on' to turn on this flow control avoidance scheme
automatically.  Here is an example:

(enable-flow-control-on "vt200" "vt300" "vt101" "vt131")

If this isn't quite correct (e.g. you have a mixture of flow-control hobbled
and good vt200 terminals), you can still run enable-flow-control
manually.

I have no intention of ever redesigning the Emacs command set for the
assumption that terminals use C-s/C-q flow control.  XON/XOFF flow
control technique is a bad design, and terminals that need it are bad
merchandise and should not be purchased.  Now that X is becoming
widespread, XON/XOFF seems to be on the way out.  If you can get some
use out of GNU Emacs on inferior terminals, more power to you, but I
will not make Emacs worse for properly designed systems for the sake
of inferior systems.

* Control-S and Control-Q commands are ignored completely.

For some reason, your system is using brain-damaged C-s/C-q flow
control despite Emacs's attempts to turn it off.  Perhaps your
terminal is connected to the computer through a concentrator
that wants to use flow control.

You should first try to tell the concentrator not to use flow control.
If you succeed in this, try making the terminal work without
flow control, as described in the preceding section.

If that line of approach is not successful, map some other characters
into C-s and C-q using keyboard-translate-table.  The example above
shows how to do this with C-^ and C-\.

* Control-S and Control-Q commands are ignored completely on a net connection.

Some versions of rlogin (and possibly telnet) do not pass flow
control characters to the remote system to which they connect.
On such systems, emacs on the remote system cannot disable flow
control on the local system.

One way to cure this is to disable flow control on the local host
(the one running rlogin, not the one running rlogind) using the
stty command, before starting the rlogin process.  On many systems,
"stty start u stop u" will do this.

Some versions of tcsh will prevent even this from working.  One way
around this is to start another shell before starting rlogin, and
issue the stty command to disable flow control from that shell.

If none of these methods work, the best solution is to type
M-x enable-flow-control at the beginning of your emacs session, or
if you expect the problem to continue, add a line such as the
following to your .emacs (on the host running rlogind):

(enable-flow-control-on "vt200" "vt300" "vt101" "vt131")

See the entry about spontaneous display of I-search (above) for more
info.

* Screen is updated wrong, but only on one kind of terminal.

This could mean that the termcap entry you are using for that
terminal is wrong, or it could mean that Emacs has a bug handing
the combination of features specified for that terminal.

The first step in tracking this down is to record what characters
Emacs is sending to the terminal.  Execute the Lisp expression
(open-termscript "./emacs-script") to make Emacs write all
terminal output into the file ~/emacs-script as well; then do
what makes the screen update wrong, and look at the file
and decode the characters using the manual for the terminal.
There are several possibilities:

1) The characters sent are correct, according to the terminal manual.

In this case, there is no obvious bug in Emacs, and most likely you
need more padding, or possibly the terminal manual is wrong.

2) The characters sent are incorrect, due to an obscure aspect
 of the terminal behavior not described in an obvious way
 by termcap.

This case is hard.  It will be necessary to think of a way for
Emacs to distinguish between terminals with this kind of behavior
and other terminals that behave subtly differently but are
classified the same by termcap; or else find an algorithm for
Emacs to use that avoids the difference.  Such changes must be
tested on many kinds of terminals.

3) The termcap entry is wrong.

See the file etc/TERMS for information on changes
that are known to be needed in commonly used termcap entries
for certain terminals.

4) The characters sent are incorrect, and clearly cannot be
 right for any terminal with the termcap entry you were using.

This is unambiguously an Emacs bug, and can probably be fixed
in termcap.c, tparam.c, term.c, scroll.c, cm.c or dispnew.c.

* Output from Control-V is slow.

On many bit-map terminals, scrolling operations are fairly slow.
Often the termcap entry for the type of terminal in use fails
to inform Emacs of this.  The two lines at the bottom of the screen
before a Control-V command are supposed to appear at the top after
the Control-V command.  If Emacs thinks scrolling the lines is fast,
it will scroll them to the top of the screen.

If scrolling is slow but Emacs thinks it is fast, the usual reason is
that the termcap entry for the terminal you are using does not
specify any padding time for the `al' and `dl' strings.  Emacs
concludes that these operations take only as much time as it takes to
send the commands at whatever line speed you are using.  You must
fix the termcap entry to specify, for the `al' and `dl', as much
time as the operations really take.

Currently Emacs thinks in terms of serial lines which send characters
at a fixed rate, so that any operation which takes time for the
terminal to execute must also be padded.  With bit-map terminals
operated across networks, often the network provides some sort of
flow control so that padding is never needed no matter how slow
an operation is.  You must still specify a padding time if you want
Emacs to realize that the operation takes a long time.  This will
cause padding characters to be sent unnecessarily, but they do
not really cost much.  They will be transmitted while the scrolling
is happening and then discarded quickly by the terminal.

Most bit-map terminals provide commands for inserting or deleting
multiple lines at once.  Define the `AL' and `DL' strings in the
termcap entry to say how to do these things, and you will have
fast output without wasted padding characters.  These strings should
each contain a single %-spec saying how to send the number of lines
to be scrolled.  These %-specs are like those in the termcap
`cm' string.

You should also define the `IC' and `DC' strings if your terminal
has a command to insert or delete multiple characters.  These
take the number of positions to insert or delete as an argument.

A `cs' string to set the scrolling region will reduce the amount
of motion you see on the screen when part of the screen is scrolled.

* Your Delete key sends a Backspace to the terminal, using an AIXterm.

The solution is to include in your .Xdefaults the lines:

   *aixterm.Translations: #override <Key>BackSpace: string(0x7f)
   aixterm*ttyModes: erase ^?

This makes your Backspace key send DEL (ASCII 127).

* You type Control-H (Backspace) expecting to delete characters.

Put `stty dec' in your .login file and your problems will disappear
after a day or two.

The choice of Backspace for erasure was based on confusion, caused by
the fact that backspacing causes erasure (later, when you type another
character) on most display terminals.  But it is a mistake.  Deletion
of text is not the same thing as backspacing followed by failure to
overprint.  I do not wish to propagate this confusion by conforming
to it.

For this reason, I believe `stty dec' is the right mode to use,
and I have designed Emacs to go with that.  If there were a thousand
other control characters, I would define Control-h to delete as well;
but there are not very many other control characters, and I think
that providing the most mnemonic possible Help character is more
important than adapting to people who don't use `stty dec'.

If you are obstinate about confusing buggy overprinting with deletion,
you can redefine Backspace in your .emacs file:
  (global-set-key "\b" 'delete-backward-char)
You can probably access  help-command  via f1.

* Editing files through RFS gives spurious "file has changed" warnings.
It is possible that a change in Emacs 18.37 gets around this problem,
but in case not, here is a description of how to fix the RFS bug that
causes it.

    There was a serious pair of bugs in the handling of the fsync() system
    call in the RFS server.

    The first is that the fsync() call is handled as another name for the
    close() system call (!!).  It appears that fsync() is not used by very
    many programs; Emacs version 18 does an fsync() before closing files
    to make sure that the bits are on the disk.

    This is fixed by the enclosed patch to the RFS server.

    The second, more serious problem, is that fsync() is treated as a
    non-blocking system call (i.e., it's implemented as a message that
    gets sent to the remote system without waiting for a reply).  Fsync is
    a useful tool for building atomic file transactions.  Implementing it
    as a non-blocking RPC call (when the local call blocks until the sync
    is done) is a bad idea; unfortunately, changing it will break the RFS
    protocol.  No fix was supplied for this problem.

    (as always, your line numbers may vary)

    % rcsdiff -c -r1.2 serversyscall.c
    RCS file: RCS/serversyscall.c,v
    retrieving revision 1.2
    diff -c -r1.2 serversyscall.c
    *** /tmp/,RCSt1003677   Wed Jan 28 15:15:02 1987
    --- serversyscall.c     Wed Jan 28 15:14:48 1987
    ***************
    *** 163,169 ****
            /*
             * No return sent for close or fsync!
             */
    !       if (syscall == RSYS_close || syscall == RSYS_fsync)
                    proc->p_returnval = deallocate_fd(proc, msg->m_args[0]);
            else
            {
    --- 166,172 ----
            /*
             * No return sent for close or fsync!
             */
    !       if (syscall == RSYS_close)
                    proc->p_returnval = deallocate_fd(proc, msg->m_args[0]);
            else
            {

* Vax C compiler bugs affecting Emacs.

You may get one of these problems compiling Emacs:

   foo.c line nnn: compiler error: no table entry for op STASG
   foo.c: fatal error in /lib/ccom

These are due to bugs in the C compiler; the code is valid C.
Unfortunately, the bugs are unpredictable: the same construct
may compile properly or trigger one of these bugs, depending
on what else is in the source file being compiled.  Even changes
in header files that should not affect the file being compiled
can affect whether the bug happens.  In addition, sometimes files
that compile correctly on one machine get this bug on another machine.

As a result, it is hard for me to make sure this bug will not affect
you.  I have attempted to find and alter these constructs, but more
can always appear.  However, I can tell you how to deal with it if it
should happen.  The bug comes from having an indexed reference to an
array of Lisp_Objects, as an argument in a function call:
  Lisp_Object *args;
  ...
   ... foo (5, args[i], ...)...
putting the argument into a temporary variable first, as in
  Lisp_Object *args;
  Lisp_Object tem;
  ...
   tem = args[i];
   ... foo (r, tem, ...)...
causes the problem to go away.
The `contents' field of a Lisp vector is an array of Lisp_Objects,
so you may see the problem happening with indexed references to that.

* 68000 C compiler problems

Various 68000 compilers have different problems.
These are some that have been observed.

** Using value of assignment expression on union type loses.
This means that  x = y = z;  or  foo (x = z);  does not work
if x is of type Lisp_Object.

** "cannot reclaim" error.

This means that an expression is too complicated.  You get the correct
line number in the error message.  The code must be rewritten with
simpler expressions.

** XCONS, XSTRING, etc macros produce incorrect code.

If temacs fails to run at all, this may be the cause.
Compile this test program and look at the assembler code:

struct foo { char x; unsigned int y : 24; };

lose (arg)
     struct foo arg;
{
  test ((int *) arg.y);
}

If the code is incorrect, your compiler has this problem.
In the XCONS, etc., macros in lisp.h you must replace (a).u.val with
((a).u.val + coercedummy) where coercedummy is declared as int.

This problem will not happen if the m-...h file for your type
of machine defines NO_UNION_TYPE.  That is the recommended setting now.

* C compilers lose on returning unions

I hear that some C compilers cannot handle returning a union type.
Most of the functions in GNU Emacs return type Lisp_Object, which is
defined as a union on some rare architectures.

This problem will not happen if the m-...h file for your type
of machine defines NO_UNION_TYPE.