[chise/xemacs-chise.git.1] / PROBLEMS

                                                  -*- mode:outline -*-

This file describes various problems that have been encountered
in compiling, installing and running XEmacs.  It has been updated for
XEmacs 21.5.

This file is rather large, but we have tried to sort the entries by
their respective relevance for XEmacs, but may have not succeeded
completely in that task.  The file is divided into four parts:

 - Problems with building XEmacs
 - Problems with running XEmacs
 - Compatibility problems
 - Mule issues

Use `C-c C-f' to move to the next equal level of outline, and
`C-c C-b' to move to previous equal level.  `C-h m' will give more
info about the Outline mode.

Also, Try finding the things you need using one of the search commands
XEmacs provides (e.g. `C-s').

General advice:

    WATCH OUT for your init file! (~/.xemacs/init.el or ~/.emacs)  If
    you observe strange problems, invoke XEmacs with the `-vanilla'
    option and see if you can repeat the problem.

    Note that most of the problems described here manifest at RUN
    time, even those described as BUILD problems.  It is quite unusual
    for a released XEmacs to fail to build.  So a "build problem"
    requires you to tweak the build environment, then rebuild XEmacs.
    A "runtime problem" is one that can be fixed by proper
    configuration of the existing build.  Compatibility problems and
    Mule issues are generally runtime problems, but are treated
    separately for convenience.


* Problems with building XEmacs
===============================

** General

    Much general information is in INSTALL.  If it's covered in
    INSTALL, we don't repeat it here.

*** How do I configure to get the buffer tabs/progress bars?

These features depend on support for "native widgets".  Use the
--with-widgets option to configure.  Configuration of widgets is
automatic for "modern" toolkits (MS Windows, GTK, and Motif), but if
you are using Xt and the Athena widgets, you will probably want to
specify a "3d" widget set.  See configure --usage, and don't forget to
install the corresponding development libraries.

*** I know I have libfoo installed, but configure doesn't find it.

Typical of Linux systems with package managers.  To link with a shared
library, you only need the shared library.  To compile objects that
link with it, you need the headers---and distros don't provide them with
the libraries.  You need the additional "development" package, too.

*** When using gcc, you get the error message "undefined symbol __fixunsdfsi".
When using gcc, you get the error message "undefined symbol __main".

This means that you need to link with the gcc library.  It may be called
"gcc-gnulib" or "libgcc.a"; figure out where it is, and define LIB_GCC in
config.h to point to it.

It may also work to use the GCC version of `ld' instead of the standard one.

*** Excessive optimization with pgcc can break XEmacs

It has been reported on some systems that compiling with -O6 can lead
to XEmacs failures.  The workaround is to use a lower optimization
level.  -O2 and -O4 have been tested extensively.

All of this depends heavily on the version of pgcc and the version
of libc.  Snapshots near the release of pgcc-1.0 have been tested
extensively and no sign of breakage has been seen on systems using
glibc-2.

*** 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.

*** When compiling with X11, you get "undefined symbol _XtStrings".

This means that you are trying to link emacs against the X11r4 version of
libXt.a, but you have compiled either Emacs or the code in the lwlib
subdirectory with the X11r5 header files.  That doesn't work.

Remember, you can't compile lwlib for r4 and emacs for r5, or vice versa.
They must be in sync.

*** 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".  (this does not apply to GNU shar, which
uses uuencode to encode binary files.)

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

 make all-elc

This will rebuild all the needed .elc files.

** Intel Architecture General

*** Don't use -O2 or -O3 with Cygwin 1.0, CodeFusion-99070 or gcc 2.7.2 on x86
without also using `-fno-strength-reduce'.

gcc will generate incorrect code otherwise.  This bug is present in at
least 2.6.x and 2.7.[0-2].  This bug has been fixed in GCC 2.7.2.1 and
later.  This bug is O/S independent, but is limited to x86 architectures.

This problem is known to be fixed in egcs (or pgcc) 1.0 or later.

Unfortunately, later releases of Cygnus-released compilers (not the
Net-released ones) have a bug with the same `problem signature'.

If you're lucky, you'll get an error while compiling that looks like:

event-stream.c:3189: internal error--unrecognizable insn:
(insn 256 14 15 (set (reg/v:SI 24)
        (minus:SI (reg/v:SI 25)
            (const_int 2))) -1 (insn_list 11 (nil))
    (nil))
    0       0 [main]

If you're unlucky, your code will simply execute incorrectly.

*** Don't use -O2 with gcc 2.7.2 under Intel architectures without also
using `-fno-caller-saves'.

gcc will generate incorrect code otherwise.  This bug is still
present in gcc 2.7.2.3.  There have been no reports to indicate the
bug is present in egcs 1.0 (or pgcc 1.0) or later.  This bug is O/S
independent, but limited to x86 architectures.

This problem is known to be fixed in egcs (or pgcc) 1.0 or later.

*** `compress' and `uncompress' not found and XFree86

XFree86 installs a very old version of libz.a by default ahead of where
more modern version of libz might be installed.  This will cause problems
when attempting to link against libMagick.  The fix is to remove the old
libz.a in the X11 binary directory.


** Motif

Motif is the X11 version of the Gnus torture test: if there's a way to
crash, Motif will find it.  With the open source release of Motif, it
seems like a good idea to collect all Motif-related issues in one
place.

You should also look in your OS's section, as it may not be Motif's
fault.

*** XEmacs visibly repaints itty-bitty rectangles very slowly.

This should only be visible on a slow X connection (ISDN, maybe T1).

At least some versions of Motif apparently do not implement
XtExposeCompressMaximal properly, so it is disabled.  If you wish to
experiment, you can remove the #ifdef LWLIB_NEEDS_MOTIF at line 238
(or so) of src/EmacsFrame.c, leaving only the line

    /* compress_exposure        */      XtExposeCompressMaximal | XtExposeNoRegion,

and recompile.  This enables exposure compression, giving a 10:1 or
better speedup for some users.  However, on some Motif platforms (Red
Hat Linux 9.0 and Solaris 2.8, at least), this causes XEmacs to hang
while displaying the progress bar (eg, in font-lock).  A workaround
for that problem is to setq `progress-feedback-use-echo-area' to `t'.

*** XEmacs crashes on exit (#1).

The backtrace is something like:

    (gdb) where
    #0  0xfeb9a480 in _libc_kill () from /usr/lib/libc.so.1
    #1  0x000b0388 in fatal_error_signal ()
    #2  <signal handler called>
    #3  YowIter (ht=0xb, id=0x0, v=0x74682074, client=0x47e3c0)
        at ImageCache.c:1159
    #4  0xff26cc5c in _LTHashTableForEachItem (ht=0x4725e8,
        iter=0xff26dda0 <YowIter>, ClientData=0x47e3c0) at Hash.c:671
    #5  0xff2a4664 in destroy (w=0x496550) at Screen.c:352
    #6  0xfef92118 in Phase2Destroy () from /usr/openwin/lib/libXt.so.4
    #7  0xfef91940 in Recursive () from /usr/openwin/lib/libXt.so.4
    #8  0xfef91e44 in XtPhase2Destroy () from /usr/openwin/lib/libXt.so.4
    #9  0xfef91ae8 in _XtDoPhase2Destroy () from /usr/openwin/lib/libXt.so.4
    #10 0xfef918cc in XtDestroyWidget () from /usr/openwin/lib/libXt.so.4
    #11 0xfef91438 in CloseDisplay () from /usr/openwin/lib/libXt.so.4
    #12 0xfef91394 in XtCloseDisplay () from /usr/openwin/lib/libXt.so.4
    #13 0x0025b8b0 in x_delete_device ()
    #14 0x000940b0 in delete_device_internal ()
    #15 0x000806a0 in delete_console_internal ()

This is known to happen with Lesstif version 0.93.36.  Similar
backtraces have also been observed on HP/UX and Solaris.  There is a
patch for Lesstif.  (This is not a solution; it just stops the crash.
It may or may not be harmless, but "it works for the author".)

Note that this backtrace looks a lot like the one in the next item.
However, this one is invulnerable to the Solaris patches mentioned there.

Frank McIngvale <frankm@hiwaay.net> says:

    Ok, 0.93.34 works, and I tracked down the crash to a section
    marked "experimental" in 0.93.36. Patch attached, "works for me".

diff -u -r lesstif-0.93.36/lib/Xm/ImageCache.c lesstif-0.93.36-mod/lib/Xm/ImageCache.c
--- lesstif-0.93.36/lib/Xm/ImageCache.c 2002-08-05 14:53:24.000000000 -0500
+++ lesstif-0.93.36-mod/lib/Xm/ImageCache.c     2002-11-11 11:13:12.000000000 -0600
@@ -1166,5 +1166,4 @@
        DEBUGOUT(_LtDebug0(__FILE__, NULL, "_LtImageCacheScreenDestroy (XmGetPixmapByDepth) %p\n",
                s));
 
-       (void) _LTHashTableForEachItem(PixmapCache, YowIter, (XtPointer)s);
 }

*** XEmacs crashes on exit (#2)

Especially frequent with multiple frames.  Crashes that produce C
backtraces like this:

#0  0xfec9a118 in _libc_kill () from /usr/lib/libc.so.1
#1  0x77f48 in fatal_error_signal (sig=11)
    at /codes/rpluim/xemacs-21.4/src/emacs.c:539
#2  <signal handler called>
#3  0xfee929f4 in XFindContext () from /usr/openwin/lib/libX11.so.4
#4  0xfee92930 in XFindContext () from /usr/openwin/lib/libX11.so.4
#5  0xff297e54 in DisplayDestroy () from /usr/dt/lib/libXm.so.4
#6  0xfefbece0 in XtCallCallbackList () from /usr/openwin/lib/libXt.so.4
#7  0xfefc486c in XtPhase2Destroy () from /usr/openwin/lib/libXt.so.4
#8  0xfefc45d0 in _XtDoPhase2Destroy () from /usr/openwin/lib/libXt.so.4
#9  0xfefc43b4 in XtDestroyWidget () from /usr/openwin/lib/libXt.so.4
#10 0x15cf9c in x_delete_device (d=0x523f00)

are caused by buggy Motif libraries.  Installing the following patches
has been reported to solve the problem on Solaris 2.7:

107081-40 107656-07

For information (although they have not been confirmed to work), the
equivalent patches for Solaris 2.8 are:

108940-33 108652-25

*** On HP-UX 11.0 XEmacs causes excessive X11 errors when running.
    (also appears on AIX as reported in comp.emacs.xemacs)

Marcus Thiessel <marcus@xemacs.org>

  Unfortunately, XEmacs releases prior to 21.0 don't work with
  Motif2.1. It will compile but you will get excessive X11 errors like

  xemacs: X Error of failed request:  BadGC (invalid GC parameter)

  and finally XEmacs gets killed. A workaround is to use the
  Motif1.2_R6 libraries. You can the following line to your call to
  configure:

     --x-libraries="/usr/lib/Motif1.2_R6 -L/usr/lib/X11R6"

  Make sure /usr/lib/Motif1.2_R6/libXm.sl is a link to
  /usr/lib/Motif1.2_R6/libXm.3.

*** On HP-UX 11.0: Object "" does not have windowed ancestor

Marcus Thiessel <marcus@xemacs.org>

  XEmacs dies without core file and reports:

    Error: Object "" does not have windowed ancestor.

  This is a bug. Please apply the patch PHSS_19964 (check if
  superseded). The other alternative is to link with Motif1.2_R6 (see
  previous item).

*** Motif dialog boxes lose on Irix.

Larry Auton <lda@control.att.com> writes:
Beware of not specifying

        --with-dialogs=athena

if it builds with the motif dialogs [boom!] you're a dead man.


** AIX
*** IBM compiler fails: "The character # is not a valid C source character."

Most recently observed in 21.5.9, due to USE_KKCC ifdefs (they just
happen to tickle the implementation).

Valdis Kletnieks says:

  The problem is that IBM defines a *MACRO* called 'memcpy', and we
  have stuck a #ifdef/#endif inside the macro call.  As a workaround,
  try adding '-U__STR__' to your CFLAGS - this will cause string.h to
  not do a #define for strcpy() to __strcpy() - it uses this for
  automatic inlining support.

  (For the record, the same issue affects a number of other functions
  defined in string.h - basically anything the compiler knows how to
  inline.)

*** On AIX 4.3, you must specify --with-dialogs=athena with configure

*** The libXt shipped with AIX 4.3 up to 4.3.2 is broken.  This causes
    xemacs -nw to fail in various ways.  The official APAR is this:

APAR NUMBER: <IX89470>            RESOLVED AS: PROGRAM ERROR

ABSTRACT:
<IX89470>: LIBXT.A INCORRECT HANDLING OF EXCEPTIONS IN XTAPPADDINPUT

    The solution is to install X11.base.lib at version >=4.3.2.5.

*** 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.

*** 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).

*** Excessive optimization on AIX 4.2 can lead to compiler failure.

Valdis.Kletnieks@vt.edu writes:
  At least at the b34 level, and the latest-and-greatest IBM xlc
  (3.1.4.4), there are problems with -O3.  I haven't investigated
  further.


** SunOS/Solaris
*** Don't use -O2 with gcc 2.8.1 and egcs 1.0 under SPARC architectures
without also using `-fno-schedule-insns'.

gcc will generate incorrect code otherwise, typically resulting in
crashes in the function skip-syntax-backward.

*** Don't use gcc-2.95.2 with -mcpu=ultrasparc on Solaris 2.6.

gcc will assume a 64-bit operating system, even though you've
merely told it to assume a 64-bit instruction set.

*** Dumping error when using GNU binutils / GNU ld on a Sun.

Errors similar to the following:

   Dumping under the name xemacs unexec():
   dldump(/space/rpluim/xemacs-obj/src/xemacs): ld.so.1: ./temacs:
   fatal: /space/rpluim/xemacs-obj/src/xemacs: unknown dynamic entry:
   1879048176

are caused by using GNU ld.  There are several workarounds available:

In XEmacs 21.2 or later, configure using the new portable dumper
(--pdump).

Alternatively, you can link using the Sun version of ld, which is
normally held in /usr/ccs/bin.  This can be done by one of:

- building gcc with these configure flags:
  configure --with-ld=/usr/ccs/bin/ld --with-as=/usr/ccs/bin/as

- adding -B/usr/ccs/bin/ to CFLAGS used to configure XEmacs
  (Note: The trailing '/' there is significant.)

- uninstalling GNU ld.

The Solaris2 FAQ claims:

    When you install gcc, don't make the mistake of installing
    GNU binutils or GNU libc, they are not as capable as their
    counterparts you get with Solaris 2.x.

*** 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.

*** Problems finding X11 libraries on Solaris with Openwindows

Some users have reported problems in this area.  The reported solution
is to define the environment variable OPENWINHOME, even if you must set
it to `/usr/openwin'.

*** Sed problems on Solaris 2.5

There have been reports of Sun sed truncating very lines in the
Makefile during configuration.  The workaround is to use GNU sed or,
even better, think of a better way to generate Makefile, and send us a
patch. :-)

*** On Solaris 2 I get undefined symbols from libcurses.a.

You probably have /usr/ucblib/ on your LD_LIBRARY_PATH.  Do the link with
LD_LIBRARY_PATH unset.  Generally, avoid using any ucb* stuff when
building XEmacs.

*** On Solaris 2 I cannot make alloc.o, glyphs.o or process.o.

The SparcWorks C compiler may have difficulty building those modules
with optimization level -xO4.  Try using only "-fast" optimization
for just those modules.  (Or use gcc).

*** Solaris 2.3 /bin/sh coredumps during configuration.

This only occurs if you have LANG != C.  This is a known bug with
/bin/sh fixed by installing Patch-ID# 101613-01.  Or, you can use
bash, as a workaround.

*** 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 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.

*** Undefined symbols when linking on Sunos 4.1.

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.

*** 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.

*** SunOS 4.1.2: undefined symbol _get_wmShellWidgetClass

  Apparently the version of libXmu.so.a that Sun ships is hosed: it's missing
  some stuff that is in libXmu.a (the static version).  Sun has a patch for
  this, but a workaround is to use the static version of libXmu, by changing
  the link command from "-lXmu" to "-Bstatic -lXmu -Bdynamic".  If you have
  OpenWindows 3.0, ask Sun for these patches:
    100512-02       4.1.x OpenWindows 3.0 libXt Jumbo patch
    100573-03       4.1.x OpenWindows 3.0 undefined symbols with shared libXmu

*** Random other SunOS 4.1.[12] link errors.

  The X headers and libraries that Sun ships in /usr/{include,lib}/X11 are
  broken.  Use the ones in /usr/openwin/{include,lib} instead.

** Linux

See also Intel Architecture General, above.

*** egcs-1.1 on Alpha Linux

There have been reports of egcs-1.1 not compiling XEmacs correctly on
Alpha Linux.  There have also been reports that egcs-1.0.3a is O.K.

*** Under Linux, you get "too many arguments to function `getpgrp'".

You have probably installed LessTiff under `/usr/local' and `libXm.so'
could not be found when linking `getpgrp()' test program, making XEmacs
think that `getpgrp()' takes an argument. Try adding `/usr/local/lib'
in `/etc/ld.so.conf' and run `ldconfig'. Then run XEmacs's `configure'
again.  As with all problems of this type, reading the config.log file
generated from configure and seeing the log of how the test failed can
prove enlightening.

*** `Error: No ExtNode to pop!' on Linux systems with Lesstif.

This error message has been observed with lesstif-0.75a.  It does not
appear to cause any harm.

*** xemacs: can't resolve symbol '__malloc_hook'

This is a Linux problem where you've compiled the XEmacs binary on a libc
5.4 with version higher than 5.4.19 and attempted to run the binary against
an earlier version.  The solution is to upgrade your old library.

** IRIX

*** More coredumping in Irix (6.5 known to be vulnerable)

No fix is known yet.  Here's the best information we have:

Valdis Kletnieks <Valdis.Kletnieks@vt.edu> writes:

  Were xemacs and [any 3rd party, locally-compiled] libraries [you use]
  all compiled with the same ABI ( -o32, -n32, -64) and
  mips2/mips3/mips4 flags, and are they appropriate for the machine in
  question?  I know the IP30 implies an Octane, so it should be an R10K
  chipset and above such nonsense, but I've seen the most astoundingly
  bizzare crashes when somebody managed to compile with -mips4 and get
  it to run on an R4400 or R5K system. ;)

  Also, since you're using gcc, try re-running fixincludes and *then*
  rebuilding xemacs and [any] libraries - mismatched headers can do that
  sort of thing to you with little or no clue what's wrong (often you
  get screwed when one routine does an malloc(sizeof(foo_struct)) and
  passes the result to something that things foo_struct is a bit bigger,
  trashing memory....

Here's typical crash backtrace.  With --pdump, this occurs usually at
startup under X windows and xemacs -nw at least starts, while without
--pdump a similar crash is observed during build.

#0  0x0fa460b8 in kill () at regcomp.c:637
637     regcomp.c: No such file or directory.
        in regcomp.c
(gdb) where
#0  0x0fa460b8 in kill () at regcomp.c:637
#1  0x10087f34 in fatal_error_signal ()
(gdb) quit

This is confusing because there is no such file in the XEmacs
distribution.  This is seen on (at least) the following configurations:

uname -a: IRIX64 oct202 6.5 01091821 IP30
XEmacs 21.4.9 "Informed Management" configured for `mips-sgi-irix6.5'.
XEmacs 21.5-b9 "brussels sprouts"  configured for `mips-sgi-irix6.5'.

*** On Irix 6.5, the MIPSpro compiler gets an internal compiler error

The MIPSpro Compiler (at least version 7.2.1) can't seem to handle the
union type properly, and fails to compile src/glyphs.c.  To avoid this
problem, always build ---use-union-type=no (but that's the default, so
you should only see this problem if you're an XEmacs maintainer).

*** Linking with -rpath on IRIX.

Darrell Kindred <dkindred@cmu.edu> writes:
There are a couple of problems [with use of -rpath with Irix ld], though:

  1. The ld in IRIX 5.3 ignores all but the last -rpath
     spec, so the patched configure spits out a warning
     if --x-libraries or --site-runtime-libraries are
     specified under irix 5.x, and it only adds -rpath
     entries for the --site-runtime-libraries.  This bug was
     fixed sometime between 5.3 and 6.2.

  2. IRIX gcc 2.7.2 doesn't accept -rpath directly, so
     it would have to be prefixed by -Xlinker or "-Wl,".
     This would be fine, except that configure compiles with
        ${CC-cc} $CFLAGS $LDFLAGS ...
     rather than quoting $LDFLAGS with prefix-args, like
     src/Makefile does.  So if you specify --x-libraries
     or --site-runtime-libraries, you must use --use-gcc=no,
     or configure will fail.

*** On Irix 6.3, the SGI ld quits with segmentation fault when linking temacs

This occurs if you use the SGI linker version 7.1.  Installing the
patch SG0001872 fixes this 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.

*** 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.

*** Coredumping in Irix 6.2

Pete Forman <gsez020@compo.bedford.waii.com> writes:
A problem noted by myself and others (I've lost the references) was
that XEmacs coredumped when the cut or copy toolbar buttons were
pressed.  This has been fixed by loading the SGI patchset (Feb 98)
without having to recompile XEmacs.

My versions are XEmacs 20.3 (problem first noted in 19.15) and IRIX
6.2, compiled using -n32.  I'd guess that the relevant individual
patch was "SG0002580: multiple fixes for X libraries".  SGI recommends
that the complete patch set be installed rather than parts of it.

** Digital UNIX/OSF/VMS
*** On Digital UNIX, the DEC C compiler might have a problem compiling
some files.

In particular, src/extents.c and src/faces.c might cause the DEC C
compiler to abort.  When this happens: cd src, compile the files by
hand, cd .., and redo the "make" command.  When recompiling the files by
hand, use the old C compiler for the following versions of Digital UNIX:
  - V3.n: Remove "-migrate" from the compile command.
  - V4.n: Add "-oldc" to the compile command.

A related compiler bug has been fixed by the DEC compiler team.  The
new versions of the compiler should run fine.

*** Under some versions of OSF XEmacs runs fine if built without
optimization but will crash randomly if built with optimization.

Using 'cc -g' is not sufficient to eliminate all optimization.  Try
'cc -g -O0' instead.

*** Compilation errors on VMS.

Sorry, XEmacs does not work under VMS.  You might consider working on
the port if you really want to have XEmacs work under VMS.

** HP-UX
*** On HPUX, the HP C compiler might have a problem compiling some files
with optimization.

Richard Cognot <cognot@ensg.u-nancy.fr> writes:

  Had to drop once again to level 2 optimization, at least to
  compile lstream.c. Otherwise, I get a "variable is void: \if"
  problem while dumping (this is a problem I already reported
  with vanilla hpux 10.01 and 9.07, which went away after
  applying patches for the C compiler). Trouble is I still
  haven't found the same patch for hpux 10.10, and I don't
  remember the patch numbers. I think potential XEmacs builders
  on HP should be warned about this.

*** I don't have `xmkmf' and `imake' on my HP.

  You can get these standard X tools by anonymous FTP to
  hpcvaaz.cv.hp.com.  Essentially all X programs need these.

*** On HP-UX, problems with make

Marcus Thiessel <marcus@xemacs.org>

  Some releases of XEmacs (e.g. 20.4) require GNU make to build
  successfully. You don't need GNU make when building 21.x.

*** On HP-UX 9.05 XEmacs won't compile or coredump during the build.

Marcus Thiessel <marcus@xemacs.org>

  This might be a sed problem. For your own safety make sure to use
  GNU sed while dumping XEmacs.


** SCO OpenServer
*** Native cc on SCO OpenServer 5 is now OK.  Icc may still throw you
a curve.  Here is what Robert Lipe <robertl@arnet.com> says:

Unlike XEmacs 19.13, building with the native cc on SCO OpenServer 5
now produces a functional binary.   I will typically build this
configuration for COFF with:

        /path_to_xemacs_source/configure --with-gcc=no \
          --site-includes=/usr/local/include --site-libraries=/usr/local/lib \
          --with-xpm --with-xface --with-sound=nas

This version now supports ELF builds.  I highly recommend this to
reduce the in-core footprint of XEmacs.  This is now how I compile
all my test releases.  Build it like this:

        /path_to_XEmacs_source/configure --with-gcc=no \
          --site-includes=/usr/local/include --site-libraries=/usr/local/lib \
          --with-xpm --with-xface --with-sound=nas --dynamic

The compiler known as icc [ supplied with the OpenServer 5 Development
System ] generates a working binary, but it takes forever to generate
XEmacs.  ICC also whines more about the code than /bin/cc does.  I do
believe all its whining is legitimate, however.    Note that you do
have to 'cd src ; make  LD=icc' to avoid linker errors.

The way I handle the build procedure is:

        /path_to_XEmacs_source/configure --with-gcc=no \
          --site-includes=/usr/local/include --site-libraries=/usr/local/lib \
          --with-xpm --with-xface --with-sound=nas --dynamic --compiler="icc"

NOTE I have the xpm, xface, and audio libraries and includes in
        /usr/local/lib, /usr/local/include.  If you don't have these,
        don't include the "--with-*" arguments in any of my examples.

In previous versions of XEmacs, you had to override the defaults while
compiling font-lock.o and extents.o when building with icc.  This seems
to no longer be true, but I'm including this old information in case it
resurfaces.  The process I used was:

        make -k
        [ procure pizza, beer, repeat ]
        cd src
        make CC="icc -W0,-mP1COPT_max_tree_size=3000" font-lock.o extents.o
        make LD=icc

If you want sound support, get the tls566 supplement from
ftp.sco.com:/TLS or any of its mirrors.  It works just groovy
with XEmacs.

The M-x manual-entry is known not to work.  If you know Lisp and would
like help in making it work, e-mail me at <robertl@dgii.com>.
(UNCHECKED for 19.15 -- it might work).

In earlier releases, gnuserv/gnuclient/gnudoit would open a frame
just fine, but the client would lock up and the server would
terminate when you used C-x # to close the frame.   This is now
fixed in XEmacs.

In etc/ there are two files of note. emacskeys.sco and emacsstrs.sco.
The comments at the top of emacskeys.sco describe its function, and
the emacstrs.sco is a suitable candidate for /usr/lib/keyboard/strings
to take advantage of the keyboard map in emacskeys.sco.

Note: Much of the above entry is probably not valid for XEmacs 21.0
and later.

** Windows

*** XEmacs complains "No such file or directory, diff"

or "ispell" or other commands that seem related to whatever you just
tried to do.

There are a large number of common (in the sense that "everyone has
these, really") Unix utilities that are not provided with XEmacs.  The
GNU Project's implementations are available for Windows in the the
Cygwin distribution (http://www.cygwin.com/), which also provides a
complete Unix emulation environment (and thus makes ports of Unix
utilities nearly trivial).  Another implementation is that from MinGW
(http://www.mingw.org/msys.shtml).

*** Weird crashes in pdump load or shortly after pdump load.

This can happen with incremental linking.  Check if you have set
SUPPORT_EDIT_AND_CONTINUE to non-zero in config.inc, which must allow
incremental linking to be enabled (otherwise it's disabled).  Either turn
this off, execute `nmake -f xemacs.mak clean', or manually remove
`temacs.exe' and `xemacs.exe'.

** Cygwin

See also Intel Architecture General, above.

*** Signal 11 when building or running a dumped XEmacs.

This appears to happen when using the traditional dumping mechanism and
the system malloc.  Andy Piper writes:

  Traditional dumping on Cygwin relies on using gmalloc (there are specific
  hacks in our version of gmalloc to support this), I suspect using sysmalloc
  is the problem.

Try configuring with pdump or without system malloc.

*** In general use etc/check_cygwin_setup.sh to trap environment problems.

The script etc/check_cygwin_setup.sh will attempt to detect whether
you have a suitable environment for building.  This script may not work
correctly if you are using ash instead of bash (see below).

*** Syntax errors running configure scripts, make failing with exit code 127
    in inexplicable situations, etc.

[[ This may be because you are using the default Cygwin shell, under old
versions of Cygwin.  The default Cygwin shell (/bin/sh.exe) is ash, which
appears to work in most circumstances but has some weird failure modes.
You may need to replace the symlink with bash.exe. ]] This doesn't appear
to affect Cygwin any longer, and /bin/sh.exe is no longer a symlink in
any case.

*** Lots of compile errors, esp. on lines containing macro definitions
    terminated by backslashes.

Your partition holding the source files is mounted binary.  It needs
to be mounted text. (This will not screw up any binary files because
the Cygwin utilities specify explicitly whether they want binary or
text mode when working with source vs. binary files, which overrides
the mount type.) To fix this, you just need to run the appropriate
mount command once -- afterwards, the settings are remembered in the
registry.

*** Errors from make like /c:not found.

Make sure you set the environment variable MAKE_MODE to UNIX in your
.bashrc, Control Panel (Windows 2000/NT), or AUTOEXEC.BAT (Windows
98/95).

*** The info files will not build.

makeinfo that ships with old versions of Cygwin doesn't work.
Upgrade to the latest Cygwin version.

*** XEmacs hangs while attempting to rebuild the .elc files.

Check to make sure you're not configuring with rel-alloc.  The relocating
allocator does not currently work under Cygwin due to bugs in Cygwin's
mmap().

*** Trying to build with X, but X11 not detected.

This is usually because xmkmf is not in your path or because you are
using the default Cygwin shell. (See above.)


* Problems with running XEmacs
==============================
** General

*** XEmacs consistently crashes in a particular strange place.

One known case is on Red Hat Linux, compiled with GCC, attempting to
render PNG images.  The problem is that XEmacs code is not compliant
with ANSI rules about aliasing.  Adding -fno-strict-aliasing to CFLAGS
may help (or the equivalent for your compiler).  (Some versions of
XEmacs may already do this automatically, but if you specify CFLAGS or
--cflags yourself, you will have to add this flag by hand.)

If you diagnose this bug for some other symptoms or systems, please
let us know (if you can send mail from the affected system, use M-x
report-xemacs-bug) so we can update this entry.

*** 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.

Note that you will get a warning when loading a .elc file that is
older than the corresponding .el file.

*** VM appears to hang in large folders.

This is normal (trust us) when upgrading to VM-6.22 from earlier
versions.  Let VM finish what it is doing and all will be well.

*** Starting with 21.4.x, killing text is absurdly slow.

See FAQ Q3.10.6.  Should be available on the web near
http://www.xemacs.org/faq/xemacs-faq.html#SEC160.

*** Whenever I try to retrieve a remote file, I have problems.

A typical error: FTP Error: USER request failed; 500 AUTH not understood.
Thanks to giacomo boffi <giacomo.boffi@polimi.it> on comp.emacs.xemacs:

   tell your ftp client to not attempt AUTH authentication (or do not
   use FTP servers that don't understand AUTH)

and notes that you need to add an element (often "-u") to
`efs-ftp-program-args'.  Use M-x customize-variable, and verify the
needed flag with `man ftp' or other local documentation.

*** gnuserv is running, some clients can connect, but others cannot.

The code in gnuslib.c respects the value of TMPDIR.  If the server and
the client have different values in their environment, you lose.
One program known to set TMPDIR and manifest this problem is exmh.
You can defeat the use of TMPDIR by unsetting USE_TMPDIR at the top of
gnuserv.h at build time.

** General Unix

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

Emacs has traditionally used Control-H for help; unfortunately this
interferes with its use as Backspace on TTY's.  As of XEmacs 21,
XEmacs looks at the "erase" setting of TTY structures and maps C-h to
backspace when erase is set to C-h.  This is sort of a special hack,
but it makes it possible for you to use the standard:

    stty erase ^H

to get your backspace key to erase characters.  The erase setting is
recorded in the Lisp variable `tty-erase-char', which you can use to
tune the settings in your .emacs.

A major drawback of this is that when C-h becomes backspace, it no
longer invokes help.  In that case, you need to use f1 for help, or
bind another key.  An example of the latter is the following code,
which moves help to Meta-? (ESC ?):

    (global-set-key "\M-?" 'help-command)

*** At startup I get a warning on stderr about missing charsets:
 
    Warning: Missing charsets in String to FontSet conversion
 
You need to specify appropriate charsets for your locale (usually the
value of the LANG environment variable) in .Xresources.  See
etc/Emacs.ad for the relevant resources (mostly menubar fonts and
fontsets).  Do not edit this file, it's purely informative.

If you have no satisfactory fonts for iso-8859-1, XEmacs will crash.

It looks like XFree86 4.x (the usual server on Linux and *BSD) has
some braindamage where .UTF-8 locales will always generate this
message, because the XFree86 (font)server doesn't know that UTF-8 will
use the ISO10646-1 font registry (or a Cmap or something).

If you are not using a .UTF-8 locale and see this warning for a
character set not listed in the default in Emacs.ad, please let
xemacs-beta@xemacs.org know about it, so we can add fonts to the
appropriate fontsets and stifle this warning.  (Unfortunately it's
buried in Xlib, so we can't easily get rid of it otherwise.)

*** Mail agents (VM, Gnus, rmail) cannot get new mail

rmail and VM get 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'.  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.

*** Things which should be bold or italic (such as the initial
copyright notice) are not.

The fonts of the "bold" and "italic" faces are generated from the font
of the "default" face; in this way, your bold and italic fonts will
have the appropriate size and family.  However, emacs can only be
clever in this way if you have specified the default font using the
XLFD (X Logical Font Description) format, which looks like

        *-courier-medium-r-*-*-*-120-*-*-*-*-*-*

if you use any of the other, less strict font name formats, some of
which look like:

                lucidasanstypewriter-12
and             fixed
and             9x13

then emacs won't be able to guess the names of the "bold" and "italic"
versions.  All X fonts can be referred to via XLFD-style names, so you
should use those forms.  See the man pages for X(1), xlsfonts(1), and
xfontsel(1).

*** 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.

*** Reading and writing files is very very slow.

Try evaluating the form (setq lock-directory nil) and see if that helps.
There is a problem with file-locking on some systems (possibly related
to NFS) that I don't understand.  Please send mail to the address
xemacs-beta@xemacs.org if you figure this one out.

*** When emacs starts up, I get lots of warnings about unknown keysyms.

If you are running the prebuilt binaries, the Motif library expects to find
certain thing in the XKeysymDB file.  This file is normally in /usr/lib/X11/
or in /usr/openwin/lib/.  If you keep yours in a different place, set the
environment variable $XKEYSYMDB to point to it before starting emacs.  If
you still have the problem after doing that, perhaps your version of X is
too old.  There is a copy of the MIT X11R5 XKeysymDB file in the emacs `etc'
directory.  Try using that one.

*** My X resources used to work, and now some of them are being ignored.

Check the resources in .../etc/Emacs.ad (which is the same as the file
sample.Xresources).  Perhaps some of the default resources built in to
emacs are now overriding your existing resources.  Copy and edit the
resources in Emacs.ad as necessary.

*** I have focus problems when I use `M-o' to switch to another screen
without using the mouse.

The focus issues with a program like XEmacs, which has multiple
homogeneous top-level windows, are very complicated, and as a result,
most window managers don't implement them correctly.

The R4/R5 version of twm (and all of its descendants) had buggy focus
handling.  Sufficiently recent versions of tvtwm have been fixed.  In
addition, if you're using twm, make sure you have not specified
"NoTitleFocus" in your .tvtwmrc file.  The very nature of this option
makes twm do some illegal focus tricks, even with the patch.

It is known that olwm and olvwm are buggy, and in different ways.  If
you're using click-to-type mode, try using point-to-type, or vice
versa.

In older versions of NCDwm, one could not even type at XEmacs windows.
This has been fixed in newer versions (2.4.3, and possibly earlier).

(Many people suggest that XEmacs should warp the mouse when focusing
on another screen in point-to-type mode.  This is not ICCCM-compliant
behavior.  Implementing such policy is the responsibility of the
window manager itself, it is not legal for a client to do this.)

*** 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.

*** TTY redisplay is slow.

XEmacs has fairly new TTY redisplay support (beginning from 19.12),
which doesn't include some basic TTY optimizations -- like using
scrolling regions to move around blocks of text.  This is why
redisplay on the traditional terminals, or over slow lines can be very
slow.

If you are interested in fixing this, please let us know at
<xemacs-beta@xemacs.org>.

*** 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, terminfo.c, tparam.c, cm.c, redisplay-tty.c,
redisplay-output.c, or redisplay.c.

*** My buffers are full of \000 characters or otherwise corrupt.

Some compilers have trouble with gmalloc.c and ralloc.c; try recompiling
without optimization.  If that doesn't work, try recompiling with
SYSTEM_MALLOC defined, and/or with REL_ALLOC undefined.

*** A position you specified in .Xresources 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 clents to request a position

*** 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.

*** 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.

*** 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.

*** Once you pull down a menu from the menubar, it won't go away.

It has been claimed that this is caused by a bug in certain very old
(1990?)  versions of the twm window manager.  It doesn't happen with
recent vintages, or with other window managers.

*** Emacs ignores the "help" key when running OLWM.

OLWM grabs the help key, and retransmits it to the appropriate client
using XSendEvent.  Allowing emacs to react to synthetic events is a
security hole, so this is turned off by default.  You can enable it by
setting the variable x-allow-sendevents to t.  You can also cause fix
this by telling OLWM to not grab the help key, with the null binding
"OpenWindows.KeyboardCommand.Help:".

*** 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.

*** The popup menu appears at the bottom/right of my screen.

You probably have something like the following in your ~/.Xresources

        Emacs.geometry:         81x56--9--1

Use the following instead

        Emacs*EmacsFrame.geometry:              81x56--9--1

*** When I try to use the PostgreSQL functions, I get a message about
undefined symbols.

The only known case in which this happens is if you are using gcc, you
configured with --error-checking=all and --with-modules, and you
compiled with no optimization.  If you encounter this problem in any
other situation, please inform xemacs-beta@xemacs.org.

This problem stems from a gcc bug.  With no optimization, functions
declared `extern inline' sometimes are not completely compiled away.  An
undefined symbol with the function's name is put into the resulting
object file.  In this case, when the postgresql module is loaded, the
linker is unable to resolve that symbol, so the module load fails.  The
workaround is to recompile the module with optimization turned on.  Any
optimization level, including -Os, appears to work.

*** 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.  Try using a different
shell.

** MacOS/X, Darwin
*** XEmacs crashes on MacOS within font-lock, or when dealing
with large compilation buffers, or in other regex applications.

The default stack size under MacOS/X is rather small (512k as opposed
to Solaris 8M), hosing the regexp code, which uses alloca()
extensively, overflowing the stack when complex regexps are used.
Workarounds:

1) Increase your stack size, using `ulimit -s 8192' or a (t)csh
   equivalent;

2) Recompile regex.c with REGEX_MALLOC defined.

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

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

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

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

*** 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 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.

*** Trouble using ptys on AIX.

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


** SunOS/Solaris
*** 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

*** When Emacs tries to ring the bell, you get an error like

        audio: sst_open: SETQSIZE" Invalid argument
        audio: sst_close: SETREG MMR2, Invalid argument

you have probably compiled using an ANSI C compiler, but with non-ANSI
include files.  In particular, on Suns, the file
/usr/include/sun/audioio.h uses the _IOW macro to define the constant
AUDIOSETQSIZE.  _IOW in turn uses a K&R preprocessor feature that is
now explicitly forbidden in ANSI preprocessors, namely substitution
inside character constants.  All ANSI C compilers must provide a
workaround for this problem.  Lucid's C compiler is shipped with a new
set of system include files.  If you are using GCC, there is a script
called fixincludes that creates new versions of some system include
files that use this obsolete feature.

*** On Solaris 2.6, XEmacs dumps core when exiting.

This happens if you're XEmacs is running on the same machine as the X
server, and the optimized memory transport has been turned on by
setting the environment variable XSUNTRANSPORT.  The crash occurs
during the call to XCloseDisplay.

If this describes your situation, you need to undefine the
XSUNTRANSPORT environment variable.

*** 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.

*** 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 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.

*** 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).

*** 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

*** 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

*** With process-connection-type set to t, each line of subprocess
output is terminated with a ^M, making ange-ftp and GNUS not work.

On SunOS systems, this problem has been seen to be a result of an
incomplete installation of gcc 2.2 which allowed some non-ANSI
compatible include files into the compilation.  In particular this
affected virtually all ioctl() calls.


** Linux
*** XEmacs crashes on startup, in make-frame.

Typically the Lisp backtrace includes

   make-frame(nil #<x-device on ":0.0" 0x2558>)

somewhere near the top.  The problem is due to an improvement in GNU
ld that sorts the ELF reloc sections in the executable, giving
dramatic speedups in startup for large executables.  It also confuses
the traditional unexec code in XEmacs, leading to the core dump.  The
solution is to use the --pdump or --ldflags='-z nocombreloc' options
to configure.  Recent 21.4 and 12.5 autodetect this in configure.

Red Hat and SuSE (at least) distributed a prerelease version of ld
(versions around 2.11.90.x.y) where autodetection is impossible.  The
recommended procedure is to upgrade to binutils >= 2.12 and rerun
configure.  Otherwise you must apply the flags by hand.  --pdump is
recommended.

*** I want XEmacs to use the Alt key, not the XXX key, for Meta commands

For historical reasons, XEmacs looks for a Meta key, then an Alt key.
It binds Meta commands to the X11 modifier bit attached to the first
of these it finds.  On PCs, the Windows key is often assigned the Meta
bit, but many desktop environments go to great lengths to get all apps
to use the Alt key, and reserve the Windows key to (sensibly enough)
the window manager.

One correct way to implement this was suggested on comp.emacs.xemacs
(by Kilian Foth and in more detail by Michael Piotrowski): unmap the
Meta modifier using xmodmap or xkb, and then map the Meta/Windows key
to the Super or Hyper keysym and an appropriate mod bit.  XEmacs will
not find the Meta keysym, and default to using the Alt key for Meta
keybindings.  Typically few applications use the (X11) Meta modifier;
it is tedious but not too much so to teach the ones you need to use
Super instead of Meta.  There may be further useful hints in the
discussion of keymapping on non-Linux platforms.

*** The color-gcc wrapper

This wrapper colorizes the error messages from gcc.  By default XEmacs
does not interpret the escape sequences used to generate colors,
resulting in a cluttered, hard-to-read buffer.  You can remove the
wrapper, or defeat the wrapper colorization in Emacs process buffers
by editing the "nocolor" attribute in /etc/colorgccrc:

$ diff -u /etc/colorgccrc.old /etc/colorgccrc
--- /etc/colorgccrc.old Tue Dec 26 02:17:46 2000
+++ /etc/colorgccrc     Tue Dec 26 02:15:48 2000
@@ -34,1 +34,1 @@
-nocolor: dumb
+nocolor: dumb emacs

If you want colorization in your Emacs buffers, you may get good
results from the ansi-color.el library:

http://www.geocities.com/kensanata/color-emacs.html#ansicolors

This is written for the mainline GNU Emacs but the author has made
efforts to adapt it to XEmacs.  YMMV.

*** Slow startup on Linux.

People using systems based on the Linux kernel sometimes report that
startup takes 10 to 15 seconds longer than `usual'.  There are two
problems, one older, one newer.

**** Old problem: IPv4 host lookup

On older systems, 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.  (Recent Linux distros usually have
this configuration correct "out of the box".)  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      localhost 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.

**** New problem: IPv6 CNAME lookup

A newer problem is due to XEmacs changing to use the modern
getaddrinfo() interface from the older gethostbyname() interface.  The
solution above is insufficient, because getaddrinfo() by default tries
to get IPv6 information for localhost.  This always involves a dns
lookup to get the CNAME, and the strategies above don't work.  It then
falls back to IPv4 behavior.  This is good[tm] according the people at
WIDE who know about IPv6.

***** Robust network case

Configure your network so that there are no nameservers configured
until the network is actually running.  getaddrinfo() will not try to
access a nameserver that isn't configured.

***** Flaky network case

If you have a flaky modem or DSL connection that can be relied on only
to go down whenever you want to bring XEmacs up, you need to force
IPv4 behavior.  Explicitly setting DISPLAY=127.0.0.1:0.0 (or whatever
is appropriate) works in most cases.

If you cannot or do not want to do that, you can hard code IPv4
behavior in src/process-unix.c.  This is bad[tm], on your own head be
it.  Use the configure option `--with-ipv6-cname=no'.

*** Mandrake

The Mandrake Linux distribution is attempting to comprehensively
update the user interface, and make it consistent across
applications.  This is very difficult, and will occasionally cause
conflicts with applications like Emacs with their own long-established
interfaces.  Known issues specific to Mandrake or especially common:

Some versions of XEmacs (21.1.9 is known) distributed with Mandrake
were patched to make the Meta and Alt keysyms synonymous.  These
normally work as expected in the Mandrake environment.  However,
custom-built XEmacsen (including all 21.2 betas) will "inexplicably"
not respect the "Alt-invokes-Meta-commands" convention.  See "I want
XEmacs to use the Alt key" below.

The color-gcc wrapper (see below) is in common use on the Mandrake
platform.

*** You get crashes in a non-C locale with Linux GNU Libc 2.0.

Internationalization was not the top priority for GNU Libc 2.0.
As of this writing (1998-12-28) you may get crashes while running
XEmacs in a non-C locale.  For example, `LC_ALL=en_US xemacs' crashes
while `LC_ALL=C xemacs' runs fine.  This happens for example with GNU
libc 2.0.7.  Installing libintl.a and libintl.h built from gettext
0.10.35 and re-building XEmacs solves the crashes.  Presumably soon
everyone will upgrade to GNU Libc 2.1 and this problem will go away.

*** `C-z', or `M-x suspend-emacs' hangs instead of suspending.

If you build with `gpm' support on Linux, you cannot suspend XEmacs
because gpm installs a buggy SIGTSTP handler.  Either compile with
`--with-gpm=no', or don't suspend XEmacs on the Linux console until
this bug is fixed.

*** 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 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.

** IRIX
*** On Irix, I don't see the toolbar icons and I'm getting lots of
entries in the warnings buffer.

SGI ships a really old Xpm library in /usr/lib which does not work at
all well with XEmacs.  The solution is to install your own copy of the
latest version of Xpm somewhere and then use the --site-includes and
--site-libraries flags to tell configure where to find it.

*** 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.

*** Beware of the default image & graphics library on Irix

Richard Cognot <cognot@ensg.u-nancy.fr> writes:

You *have* to compile your own jpeg lib. The one delivered with SGI
systems is a C++ lib, which apparently XEmacs cannot cope with.


** Digital UNIX/OSF/VMS/Ultrix
*** XEmacs crashes on Digital Unix within font-lock, or when dealing
with large compilation buffers, or in other regex applications.

The default stack size under Digital Unix is rather small (2M as
opposed to Solaris 8M), hosing the regexp code, which uses alloca()
extensively, overflowing the stack when complex regexps are used.
Workarounds:

1) Increase your stack size, using `ulimit -s 8192' or a (t)csh
   equivalent;

2) Recompile regex.c with REGEX_MALLOC defined.

*** The `Alt' key doesn't behave as `Meta' when running DECwindows.

The default DEC keyboard mapping has the Alt keys set up to generate the
keysym `Multi_key', which has a meaning to xemacs which is distinct from that
of the `Meta_L' and `Meta-R' keysyms.  A second problem is that certain keys
have the Mod2 modifier attached to them for no adequately explored reason.
The correct fix is to pass this file to xmodmap upon starting X:

        clear mod2
        keysym Multi_key = Alt_L
        add mod1 = Alt_L
        add mod1 = Alt_R

*** 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'

*** `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.


** HP-UX
*** I get complaints about the mapping of my HP keyboard at startup,
but I haven't changed anything.

The default HP keymap is set up to have Mod1 assigned to two different keys:
Meta_L and Mode_switch (even though there is not actually a Mode_switch key on
the keyboard -- it uses an "imaginary" keycode.)  There actually is a reason
for this, but it's not a good one.  The correct fix is to execute this command
upon starting X:

        xmodmap -e 'remove mod1 = Mode_switch'

*** On HP-UX, you get "poll: Interrupted system call" message in the
window where XEmacs was launched.

Richard Cognot <cognot@ensg.u-nancy.fr> writes:

  I get a very strange problem when linking libc.a dynamically: every
  event (mouse, keyboard, expose...) results in a "poll: Interrupted
  system call" message in the window where XEmacs was
  launched. Forcing a static link of libc.a alone by adding
  /usr/lib/libc.a at the end of the link line solves this. Note that
  my 9.07 build of 19.14b17 and my (old) build of 19.13 both exhibit
  the same behavior. I've tried various hpux patches to no avail. If
  this problem cannot be solved before the release date, binary kits
  for HP *must* be linked statically against libc, otherwise this
  problem will show up. (This is directed at whoever will volunteer
  for this kit, as I won't be available to do it, unless 19.14 gets
  delayed until mid-june ;-). I think this problem will be an FAQ soon
  after the release otherwise.

Note: The above entry is probably not valid for XEmacs 21.0 and
later.

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

This is because HP-UX 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


*** XEmacs dumps core at startup when native audio is used.  Native
audio does not work with recent versions of HP-UX.

Under HP-UX 10.20 and later (e.g., HP-UX 11.XX), with native audio
enabled, the dumped XEmacs binary ("xemacs") core dumps at startup if
recent versions of the libAlib.sl audio shared library is used.  Note
that "temacs" will run, but "xemacs" will dump core.  This, of course,
causes the XEmacs build to fail.  If GNU malloc is enabled, a stack
trace will show XEmacs to have crashed in the "first" call to malloc().

This bug currently exists in all versions of XEmacs, when the undump
mechanism is used.  It is not known if using the experimental portable
dumper will allow native audio to work.

**** Cause:

Recent versions of the HP-UX 10.20 (and later) audio shared library (in
/opt/audio/lib), pulls in the libdce shared library, which pulls in a
thread (libcma) library.  This prevents the HP-UX undump() routine (in
unexhp9k800.c) from properly working.  What's happening is that some
initialization routines are being called in the libcma library, *BEFORE*
main() is called, and these initialization routines are calling
malloc().  Unfortunately, in order for the undumper to work, XEmacs must
adjust (move upwards) the sbrk() value *BEFORE* the first call to
malloc(); if malloc() is called before XEmacs has properly adjusted sbrk
(which is what is happening), dumped memory that is being used by
XEmacs, is improperly re-allocated for use by malloc() and the dumped
memory is corrupted.  This causes XEmacs to die an horrible death.

It is believed that versions of the audio library past December 1998
will trigger this problem.  Under HP-UX 10.20, you probably have to
install audio library patches to encounter this.  It's probable that
recent "fresh, out-of-the-box" HP-UX 11.XX workstations also have this
problem.  For HP-UX 10.20, it's believed that audio patch PHSS_17121 (or
a superceeding one, like PHSS_17554, PHSS_17971, PHSS_18777, PHSS_21481,
or PHSS_21662, etc.) will trigger this.

To check if your audio library will cause problems for XEmacs, run
"chatr /opt/audio/lib/libAlib.sl".  If "libdce" appears in the displayed
shared library list, XEmacs will probably encounter problems if audio is
enabled.

**** Workaround:

Don't enable native audio.  Re-run configure without native audio
support.

If your site supports it, try using NAS (Network Audio Support).

Try using the experimental portable dumper.  It may work, or it may
not.


*** `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.

*** 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.


** SCO
*** 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.


** Windows
*** Conflicts with FSF NTEmacs

Depending on how it is installed, FSF NTEmacs may setup various EMACS*
variables in your environment.  The presence of these variables may
cause XEmacs to fail at startup, cause you to see corrupted
doc-strings, or cause other random problems.

You should remove these variables from your environment.  These
variables are not required to run FSF NTEmacs if you start it by
running emacs.bat.

*** XEmacs can't find my init file

XEmacs looks for your init in your "home" directory -- either in
`~/.xemacs/init.el' or `~/.emacs'.  XEmacs decides that your "home"
directory is, in order of preference:
        
- The value of the HOME environment variable, if the variable exists.
- The value of the registry entry SOFTWARE\XEmacs\XEmacs\HOME,
  if it exists.
- The value of the HOMEDRIVE and HOMEPATH environment variables, if
  these variables both exist.
- C:\.

To determine what XEmacs thinks your home directory is, try opening
a file in the `~' directory, and you should see its expansion in the
modeline.  If this doesn't work, type ESC : (user-home-directory).

*** XEmacs can't find any packages

XEmacs looks for your packages in subdirectories of a directory which
is set at compile-time (see `config.inc'), and whose default is
`C:\Program Files\XEmacs'.  XEmacs also looks in `~/.xemacs', where
`~' refers to your home directory (see previous entry).  The variable
`configure-package-path' holds the actual path that was compiled into
your copy of XEmacs.

The compile-time default location can be overridden by the EMACSPACKAGEPATH
environment variable or by the SOFTWARE\XEmacs\XEmacs\EMACSPACKAGEPATH
registry entry.  You should check that these variables, if they exist,
point to the actual location of your package tree.

*** XEmacs doesn't die when shutting down Windows 95 or 98

When shutting down Windows 95 or 98 you may see a dialog that says
  "xemacs / You must quit this program before you quit Windows".
It is safe to
  "Click OK to quit the program and Windows",
but you won't be offered a chance to save any modified XEmacs buffers.

*** Key bindings

The C-z, C-x, C-c, and C-v keystrokes have traditional uses in both
emacs and Windows programs. XEmacs binds these keys to their
traditional emacs uses, and provides Windows 3.x style bindings for
the Cut, Copy and Paste functions.

        Function        XEmacs binding
        --------        --------------
        Undo            C-_
        Cut             Sh-Del
        Copy            C-Insert
        Paste           Sh-Insert

You can rebind keys to make XEmacs more Windows-compatible; for
example, to bind C-z to undo:

       (global-set-key [(control z)] 'undo)

Rebindind C-x and C-c is trickier because by default these are prefix
keys in XEmacs. See the "Key Bindings" node in the XEmacs manual.

*** Behavior of selected regions

Use the pending-del package to enable the standard Windows behavior of
self-inserting deletes region.

*** Limitations on the use of the AltGr key.

In some locale and OS combinations you can't generate M-AltGr-key or
C-M-AltGr-key sequences at all.

To generate C-AltGr-key or C-M-AltGr-key sequences you must use the
right-hand Control key and you must press it *after* AltGr.

These limitations arise from fundamental problems in the way that the
win32 API reports AltGr key events. There isn't anything that XEmacs
can do to work round these problems that it isn't already doing.

You may want to create alternative bindings if any of the standard
XEmacs bindings require you to use some combination of Control or Meta
and AltGr.

*** Limited support for subprocesses under Windows 9x

Attempting to use call-process to run a 16bit program gives a
"Spawning child process: Exec format error". For example shell-command
fails under Windows 95 and 98 if you use command.com or any other
16bit program as your shell.

XEmacs may incorrectly quote your call-process command if it contains
double quotes, backslashes or spaces.

start-process and functions that rely on it are supported under Windows 95,
98 and NT. However, starting a 16bit program that requires keyboard input
may cause XEmacs to hang or crash under Windows 95 and 98, and will leave
the orphaned 16bit program consuming all available CPU time.

Sending signals to subprocesses started by call-process or by
start-process fails with a "Cannot send signal to process" error under
Windows 95 and 98. As a side effect of this, quitting XEmacs while it
is still running subprocesses causes it to crash under Windows 95 and
98.


** Cygwin
*** Signal 11 when building or running a dumped XEmacs.

See the section on Cygwin above, under building.

*** XEmacs fails to start because cygXpm-noX4.dll was not found.

Andy Piper <andy@xemacs.org> sez:

    cygXpm-noX4 is part of the cygwin distribution under libraries or
    graphics, but is not installed by default. You need to run the
    cygwin setup again and select this package.

*** Subprocesses do not work.

You do not have "tty" in your CYGWIN environment variable.  This must
be set in your autoexec.bat (win95) or the system properties (winnt)
as it must be read before the cygwin DLL initializes.

*** ^G does not work on hung subprocesses.

This is a known problem. It can be remedied by defining BROKEN_SIGIO
in src/s/cygwin.h, however this currently leads to instability in XEmacs.
(#### is this still true?)

*** Errors from make like `/c:not found' when running `M-x compile'.

Make sure you set the environment variable MAKE_MODE to UNIX in your
init file (.xemacs/init.el), Control Panel (Windows 2000/NT), or
AUTOEXEC.BAT (Windows 98/95).

*** There are no images in the toolbar buttons.

You need version 4.71 of commctrl.dll which does not ship with windows
95. You can get this by installing IE 4.0 or downloading it from the
microsoft website.


* Compatibility problems (with Emacs 18, GNU Emacs, or previous XEmacs/lemacs)
==============================================================================

*** "Symbol's value as variable is void: unread-command-char".
 "Wrong type argument: arrayp, #<keymap 143 entries>"
 "Wrong type argument: stringp, [#<keypress-event return>]"

There are a few incompatible changes in XEmacs, and these are the
symptoms.  Some of the emacs-lisp code you are running needs to be
updated to be compatible with XEmacs.

The code should not treat keymaps as arrays (use `define-key', etc.),
should not use obsolete variables like `unread-command-char' (use
`unread-command-events').  Many (most) of the new ways of doing things
are compatible in GNU Emacs and XEmacs.

Modern Emacs packages (Gnus, VM, W3, efs, etc) are written to support
GNU Emacs and XEmacs.  We have provided modified versions of several
popular emacs packages (dired, etc) which are compatible with this
version of emacs.  Check to make sure you have not set your load-path
so that your private copies of these packages are being found before
the versions in the lisp directory.

Make sure that your load-path and your $EMACSLOADPATH environment
variable are not pointing at an Emacs18 lisp directory.  This will
cripple emacs.

** Some packages that worked before now cause the error
Wrong type argument: arrayp, #<face ... >

Code which uses the `face' accessor functions must be recompiled with
xemacs 19.9 or later.  The functions whose callers must be recompiled
are: face-font, face-foreground, face-background,
face-background-pixmap, and face-underline-p.  The .elc files
generated by version 19.9 will work in 19.6 and 19.8, but older .elc
files which contain calls to these functions will not work in 19.9.

** Signaling: (error "Byte code stack underflow (byte compiler bug), pc 38")

This error is given when XEmacs 20 is compiled without MULE support
but is attempting to load a .elc which requires MULE support.  The fix
is to rebytecompile the offending file.

** Signaling: (wrong-type-argument ...) when loading mail-abbrevs

The is seen when installing the Insidious Big Brother Data Base (bbdb)
which includes an outdated copy of mail-abbrevs.el.  Remove the copy
that comes with bbdb and use the one that comes with XEmacs.


* MULE issues
=============

** A reminder: XEmacs/Mule work does not currently receive *any*
funding, and all work is done by volunteers.  If you think you can
help, please contact the XEmacs maintainers.

** XEmacs/Mule doesn't support TTY's satisfactorily.

This is a major problem, which we plan to address in a future release
of XEmacs.  Basically, XEmacs should have primitives to be told
whether the terminal can handle international output, and which
locale.  Also, it should be able to do approximations of characters to
the nearest supported by the locale.

** Internationalized (Asian) Isearch doesn't work.

Currently, Isearch doesn't directly support any of the input methods
that are not XIM based (like egg, canna and quail) (and there are
potential problems with XIM version too...).  If you're using egg
there is a workaround.  Hitting <RET> right after C-s to invoke
Isearch will put Isearch in string mode, where a complete string can
be typed into the minibuffer and then processed by Isearch afterwards.
Since egg is now supported in the minibuffer using string mode you can
now use egg to input your Japanese, Korean or Chinese string, then hit
return to send that to Isearch and then use standard Isearch commands
from there.

** Using egg and mousing around while in 'fence' mode screws up my
buffer.

Don't do this. The fence modes of egg and canna are currently very
modal, and messing with where they expect point to be and what they
think is the current buffer is just asking for trouble. If you're
lucky they will realize that something is awry, and simply delete the
fence, but worst case can trash other buffers too. We've tried to
protect against this where we can, but there still are many ways to
shoot yourself in the foot. So just finish what you are typing into
the fence before reaching for the mouse.

** Not all languages in Quail are supported like Devanagari and Indian
languages, Lao and Tibetan.

Quail requires more work and testing.  Although it has been ported to
XEmacs, it works really well for Japanese and for the European
languages.

** Right-to-left mode is not yet implemented, so languages like
Arabic, Hebrew and Thai don't work.

Getting this right requires more work.  It may be implemented in a
future XEmacs version, but don't hold your breath.  If you know
someone who is ready to implement this, please let us know.

** We need more developers and native language testers.  It's extremely
difficult (and not particularly productive) to address languages that
nobody is using and testing.

** The kWnn and cWnn support for Chinese and Korean needs developers
and testers.  It probably doesn't work.

** There are no `native XEmacs' TUTORIALs for any Asian languages,
including Japanese.  FSF Emacs and XEmacs tutorials are quite similar,
so it should be sufficient to skim through the differences and apply
them to the Japanese version.

** We only have localized menus translated for Japanese, and the
Japanese menus are developing bitrot (the Mule menu appears in
English).

** XIM is untested for any language other than Japanese.