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

* 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.

* On HPUX 9.05 and 9.06, C-c and C-z are not turned off in the terminal driver.

This seems to be due to a bug in HPUX.  A workaround is to start Emacs
after first setting the "susp" (suspend job) and "dsusp" (delayed
suspend job) control characters temporarily to a character that you
are not likely to type (such as C-_), and set them back after Emacs
exits.  The following script should do it:

	#!/bin/sh
	stty susp '^_' dsusp '^_'
	emacs ${1+"$@"}
	stty susp '^Z' dsusp '^Z'

* 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/app-defaults/Emacs, with the following contents:

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

(or whatever other defaults you prefer).

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 documentatoin 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 fromcontained in
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 on Linux 1.0 thru 1.04, approximately.  The workaround is
to define SIGNALS_VIA_CHARACTERS in config.h and recompile Emacs.
Newer Linux versions don't have this problem.

* On AIX, the Ctrl/Act key interacts strangely with Shift.

This is an AIX feature: Ctrl/Act with Shift is used for switching
virtual terminals.

* 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.  We hope volunteers will do this.

* `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 xemacs, but xemacs totally fails to work.
* or, temacs gets errors dumping xemacs

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.
     You might as well save the old alloc.o.
 4) Remake xemacs.  It should work now.
 5) Running xemacs, 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 xemacs.  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 (xemacs) 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.

(Exception: if you configure with --run-in-place, then the build
directory is also the installation directory; there is only one
copy of movemail, and that is the one to change.)

* 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 may then wish to put the function  help-command  on some
other key.  I leave to you the task of deciding which key.

* 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.

