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1.1 root 1: This file describes various problems that have been encountered
2: in compiling, installing and running GNU Emacs.
3:
4: * If you have trouble building Emacs in Solaris, it is likely to be
5: that you've put /usr/ucb ahead of /usr/ccs/bin in PATH. Try changing
6: that for building Emacs. (The problem may really come from
7: /usr/ucb/ld.)
8:
9: * M-x manual command does not work on Solaris when you specify a
10: manual section number. You can make it work by setting manual-program
11: to "/usr/ucb/man".
12:
13: * On some variants of SVR4, Emacs does not work at all with X.
14:
15: Try defining BROKEN_FIONREAD in your config.h file. If this solves
16: the problem, please send a bug report to tell us this is needed; be
17: sure to say exactly what type of machine and system you are using.
18:
19: * On some MIPS systems, division by zero crashes Emacs.
20:
21: Some operating systems on MIPS machines give SIGTRAP for division by
22: zero instead of the usual signals. The only real solution is to fix
23: the system to give a proper signal.
24:
25: In the meantime, you can change init_data in data.c if you wish.
26: Change it to handle SIGTRAP as well as SIGFPE. But this will have a
27: great disadvantage: you will not be able to run Emacs under a
28: debugger. I think crashing on division by zero is a lesser problem.
29:
30: * Linking says that the functions insque and remque are undefined.
31:
32: Change oldXMenu/Makefile by adding insque.o to the variable OBJS.
33:
34: * Emacs fails to understand most Internet host names, even though
35: the names work properly with other programs on the same system.
36:
37: This typically happens on Suns and other systems that use shared
38: libraries. The cause is that the site has installed a version of the
39: shared library which uses a name server--but has not installed a
40: similiar version of the unshared library which Emacs uses.
41:
42: The result is that most programs, using the shared library, work with
43: the nameserver, but Emacs does not.
44:
45: The fix is to install an unshared library that corresponds to what you
46: installed in the shared library, and then relink Emacs.
47:
48: * On a Sun running SunOS 4.1.1, you get this error message from GNU ld:
49:
50: /lib/libc.a(_Q_sub.o): Undefined symbol __Q_get_rp_rd referenced from text segment
51:
52: The problem is in the Sun shared C library, not in GNU ld.
53:
54: The solution is to install Patch-ID# 100267-03 from Sun.
55:
56: * Self documentation messages are garbled.
57:
58: This means that the file `etc/DOC-...' doesn't properly correspond
59: with the Emacs executable. Redumping Emacs and then installing the
60: corresponding pair of files should fix the problem.
61:
62: * M-x shell immediately responds "Process shell exited abnormally with code 1".
63:
64: This is often due to inability to run the program `env'.
65: This should be in the `etc' subdirectory of the directory
66: where Emacs is installed, and it should be marked executable.
67:
68: * Trouble using ptys on AIX.
69:
70: People often instll the pty devices on AIX incorrectly.
71: Use `smit pty' to reinstall them properly.
72:
73: * Shell mode on HP/UX gives the message, "`tty`: Ambiguous".
74:
75: [email protected] says:
76:
77: The problem is that in your .cshrc you have something that tries to
78: execute `tty`. If you are not running the shell on a real tty then
79: tty will print "not a tty". Csh expects one word in some places,
80: but tty is giving it back 3.
81:
82: The solution is to add a pair of quotes around `tty` to make it a single
83: word:
84:
85: if (`tty` == "/dev/console")
86:
87: should be changed to:
88:
89: if ("`tty`" == "/dev/console")
90:
91: Even better, move things that set up terminal sections out of .cshrc
92: and into .login.
93:
94: * Using X Windows, control-shift-leftbutton makes Emacs hang.
95:
96: Use the shell command `xset bc' to make the old X Menu package work.
97:
98: * Emacs running under X Windows does not handle mouse clicks.
99: * `emacs -geometry 80x20' finds a file named `80x20'.
100:
101: One cause of such problems is having (setq term-file-prefix nil) in
102: your .emacs file. Another cause is a bad value of EMACSLOADPATH in
103: the environment.
104:
105: * Emacs gets error message from linker on Sun.
106:
107: If the error message says that a symbol such as `f68881_used' or
108: `ffpa_used' or `start_float' is undefined, this probably indicates
109: that you have compiled some libraries, such as the X libraries,
110: with a floating point option other than the default.
111:
112: It's not terribly hard to make this work with small changes in
113: crt0.c together with linking with Fcrt1.o, Wcrt1.o or Mcrt1.o.
114: However, the easiest approach is to build Xlib with the default
115: floating point option: to decide at run time what hardware is
116: available.
117:
118: * Emacs fails to get default settings from X Windows server.
119:
120: The X library in X11R4 has a bug; it interchanges the 2nd and 3rd
121: arguments to XGetDefaults. Define the macro XBACKWARDS in config.h to
122: tell Emacs to compensate for this.
123:
124: I don't believe there is any way Emacs can determine for itself
125: whether this problem is present on a given system.
126:
127: * Keyboard input gets confused after a beep when using a DECserver
128: as a concentrator.
129:
130: This problem seems to be a matter of configuring the DECserver to use
131: 7 bit characters rather than 8 bit characters.
132:
133: * M-x shell persistently reports "Process shell exited abnormally with code 1".
134:
135: This happened on Suns as a result of what is said to be a bug in Sunos
136: version 4.0.x. The only fix was to reboot the machine.
137:
138: * Programs running under terminal emulator do not recognize `emacs'
139: terminal type.
140:
141: The cause of this is a shell startup file that sets the TERMCAP
142: environment variable. The terminal emulator uses that variable to
143: provide the information on the special terminal type that Emacs
144: emulates.
145:
146: Rewrite your shell startup file so that it does not change TERMCAP
147: in such a case. You could use the following conditional which sets
148: it only if it is undefined.
149:
150: if ( ! ${?TERMCAP} ) setenv TERMCAP ~/my-termcap-file
151:
152: Or you could set TERMCAP only when you set TERM--which should not
153: happen in a non-login shell.
154:
155: * Error compiling sysdep.c, "sioctl.h: no such file or directory".
156:
157: Among USG systems with TIOCGWINSZ, some require sysdep.c to include
158: the file sioctl.h; on others, sioctl.h does not exist. We don't know
159: how to distinguish these two kind of systems, so currently we try to
160: include sioctl.h on all of them. If this #include gets an error, just
161: delete it.
162:
163: * X Windows doesn't work if DISPLAY uses a hostname.
164:
165: People have reported kernel bugs in certain systems that cause Emacs
166: not to work with X Windows if DISPLAY is set using a host name. But
167: the problem does not occur if DISPLAY is set to `unix:0.0'. I think
168: the bug has to do with SIGIO or FIONREAD.
169:
170: You may be able to compensate for the bug by doing (set-input-mode nil nil).
171: However, that has the disadvantage of turning off interrupts, so that
172: you are unable to quit out of a Lisp program by typing C-g.
173:
174: The easy way to do this is to put
175:
176: (setq x-sigio-bug t)
177:
178: in your site-init.el file.
179:
180: * Problem with remote X server on Suns.
181:
182: On a Sun, running Emacs on one machine with the X server on another
183: may not work if you have used the unshared system libraries. This
184: is because the unshared libraries fail to use YP for host name lookup.
185: As a result, the host name you specify may not be recognized.
186:
187: * Watch out for .emacs files and EMACSLOADPATH environment vars
188:
189: These control the actions of Emacs.
190: ~/.emacs is your Emacs init file.
191: EMACSLOADPATH overrides which directories the function
192: "load" will search.
193:
194: If you observe strange problems, check for these and get rid
195: of them, then try again.
196:
197: * Shell mode ignores interrupts on Apollo Domain
198:
199: You may find that M-x shell prints the following message:
200:
201: Warning: no access to tty; thus no job control in this shell...
202:
203: This can happen if there are not enough ptys on your system.
204: Here is how to make more of them.
205:
206: % cd /dev
207: % ls pty*
208: # shows how many pty's you have. I had 8, named pty0 to pty7)
209: % /etc/crpty 8
210: # creates eight new pty's
211:
212: * Fatal signal in the command temacs -l loadup inc dump
213:
214: This command is the final stage of building Emacs. It is run by the
215: Makefile in the src subdirectory, or by build.com on VMS.
216:
217: It has been known to get fatal errors due to insufficient swapping
218: space available on the machine.
219:
220: On 68000's, it has also happened because of bugs in the
221: subroutine `alloca'. Verify that `alloca' works right, even
222: for large blocks (many pages).
223:
224: * test-distrib says that the distribution has been clobbered
225: * or, temacs prints "Command key out of range 0-127"
226: * or, temacs runs and dumps xemacs, but xemacs totally fails to work.
227: * or, temacs gets errors dumping xemacs
228:
229: This can be because the .elc files have been garbled. Do not be
230: fooled by the fact that most of a .elc file is text: these are
231: binary files and can contain all 256 byte values.
232:
233: In particular `shar' cannot be used for transmitting GNU Emacs.
234: It typically truncates "lines". What appear to be "lines" in
235: a binary file can of course be of any length. Even once `shar'
236: itself is made to work correctly, `sh' discards null characters
237: when unpacking the shell archive.
238:
239: I have also seen character \177 changed into \377. I do not know
240: what transfer means caused this problem. Various network
241: file transfer programs are suspected of clobbering the high bit.
242:
243: The only verified ways to transfer GNU Emacs are `tar', kermit (in
244: binary mode on Unix), and rcp or internet ftp between two Unix systems,
245: or chaosnet cftp using raw mode.
246:
247: If you have a copy of Emacs that has been damaged in its
248: nonprinting characters, you can fix them:
249:
250: 1) Record the names of all the .elc files.
251: 2) Delete all the .elc files.
252: 3) Recompile alloc.c with a value of PURESIZE twice as large.
253: You might as well save the old alloc.o.
254: 4) Remake xemacs. It should work now.
255: 5) Running xemacs, do Meta-x byte-compile-file repeatedly
256: to recreate all the .elc files that used to exist.
257: You may need to increase the value of the variable
258: max-lisp-eval-depth to succeed in running the compiler interpreted
259: on certain .el files. 400 was sufficient as of last report.
260: 6) Reinstall the old alloc.o (undoing changes to alloc.c if any)
261: and remake temacs.
262: 7) Remake xemacs. It should work now, with valid .elc files.
263:
264: * temacs prints "Pure Lisp storage exhausted"
265:
266: This means that the Lisp code loaded from the .elc and .el
267: files during temacs -l loadup inc dump took up more
268: space than was allocated.
269:
270: This could be caused by
271: 1) adding code to the preloaded Lisp files
272: 2) adding more preloaded files in loadup.el
273: 3) having a site-init.el or site-load.el which loads files.
274: Note that ANY site-init.el or site-load.el is nonstandard;
275: if you have received Emacs from some other site
276: and it contains a site-init.el or site-load.el file, consider
277: deleting that file.
278: 4) getting the wrong .el or .elc files
279: (not from the directory you expected).
280: 5) deleting some .elc files that are supposed to exist.
281: This would cause the source files (.el files) to be
282: loaded instead. They take up more room, so you lose.
283: 6) a bug in the Emacs distribution which underestimates
284: the space required.
285:
286: If the need for more space is legitimate, change the definition
287: of PURESIZE in config.h.
288:
289: But in some of the cases listed above, this problem is a consequence
290: of something else that is wrong. Be sure to check and fix the real
291: problem.
292:
293: * Changes made to .el files do not take effect.
294:
295: You may have forgotten to recompile them into .elc files.
296: Then the old .elc files will be loaded, and your changes
297: will not be seen. To fix this, do M-x byte-recompile-directory
298: and specify the directory that contains the Lisp files.
299:
300: * The dumped Emacs (xemacs) crashes when run, trying to write pure data.
301:
302: Two causes have been seen for such problems.
303:
304: 1) On a system where getpagesize is not a system call, it is defined
305: as a macro. If the definition (in both unexec.c and malloc.c) is wrong,
306: it can cause problems like this. You might be able to find the correct
307: value in the man page for a.out (5).
308:
309: 2) Some systems allocate variables declared static among the
310: initialized variables. Emacs makes all initialized variables in most
311: of its files pure after dumping, but the variables declared static and
312: not initialized are not supposed to be pure. On these systems you
313: may need to add "#define static" to the m- or the s- file.
314:
315: * Compilation errors on VMS.
316:
317: You will get warnings when compiling on VMS because there are
318: variable names longer than 32 (or whatever it is) characters.
319: This is not an error. Ignore it.
320:
321: VAX C does not support #if defined(foo). Uses of this construct
322: were removed, but some may have crept back in. They must be rewritten.
323:
324: There is a bug in the C compiler which fails to sign extend characters
325: in conditional expressions. The bug is:
326: char c = -1, d = 1;
327: int i;
328:
329: i = d ? c : d;
330: The result is i == 255; the fix is to typecast the char in the
331: conditional expression as an (int). Known occurrences of such
332: constructs in Emacs have been fixed.
333:
334: * rmail gets error getting new mail
335:
336: rmail gets new mail from /usr/spool/mail/$USER using a program
337: called `movemail'. This program interlocks with /bin/mail using
338: the protocol defined by /bin/mail.
339:
340: There are two different protocols in general use. One of them uses
341: the `flock' system call. The other involves creating a lock file;
342: `movemail' must be able to write in /usr/spool/mail in order to do
343: this. You control which one is used by defining, or not defining,
344: the macro MAIL_USE_FLOCK in config.h or the m- or s- file it includes.
345: IF YOU DON'T USE THE FORM OF INTERLOCKING THAT IS NORMAL ON YOUR
346: SYSTEM, YOU CAN LOSE MAIL!
347:
348: If your system uses the lock file protocol, and fascist restrictions
349: prevent ordinary users from writing the lock files in /usr/spool/mail,
350: you may need to make `movemail' setgid to a suitable group such as
351: `mail'. You can use these commands (as root):
352:
353: chgrp mail movemail
354: chmod 2755 movemail
355:
356: * Emacs won't work with X-windows if the value of DISPLAY is HOSTNAME:0.
357: * GNUs can't make contact with the specified host for nntp.
358:
359: Some people have found that Emacs was unable to connect to the local
360: host by name, as in DISPLAY=prep:0 if you are running on prep, but
361: could handle DISPLAY=unix:0. Here is what [email protected] said:
362:
363: Seems as
364: though gethostbyname was bombing somewhere along the way. Well, we
365: had just upgrade from SunOS 3.5 (which X11 was built under) to SunOS
366: 4.0.1. Any new X applications which tried to be built with the pre
367: OS-upgrade libraries had the same problems which Emacs was having.
368: Missing /etc/resolv.conf for a little while (when one of the libraries
369: was built?) also might have had a hand in it.
370:
371: The result of all of this (with some speculation) was that we rebuilt
372: X and then rebuilt Emacs with the new libraries. Works as it should
373: now. Hoorah.
374:
375: If you have already installed the name resolver in the file libresolv.a,
376: then you need to compile Emacs to use that library. The easiest way to
377: do this is to add to config.h a definition of LIBS_SYSTEM, LIBS_MACHINE
378: or LIB_STANDARD which uses -lresolv. Watch out! If you redefine a macro
379: that is already in use in your configuration to supply some other libraries,
380: be careful not to lose the others.
381:
382: Thus, you could start by adding this to config.h:
383:
384: #define LIBS_SYSTEM -lresolv
385:
386: Then if this gives you an error for redefining a macro, and you see that
387: the s- file defines LIBS_SYSTEM as -lfoo -lbar, you could change config.h
388: again to say this:
389:
390: #define LIBS_SYSTEM -lresolv -lfoo -lbar
391:
392: * Emacs spontaneously displays "I-search: " at the bottom of the screen.
393:
394: This means that Control-S/Control-Q "flow control" is being used.
395: C-s/C-q flow control is bad for Emacs editors because it takes away
396: C-s and C-q as user commands. Since editors do not output long streams
397: of text without user commands, there is no need for a user-issuable
398: "stop output" command in an editor; therefore, a properly designed
399: flow control mechanism would transmit all possible input characters
400: without interference. Designing such a mechanism is easy, for a person
401: with at least half a brain.
402:
403: There are three possible reasons why flow control could be taking place:
404:
405: 1) Terminal has not been told to disable flow control
406: 2) Insufficient padding for the terminal in use
407: 3) Some sort of terminal concentrator or line switch is responsible
408:
409: First of all, many terminals have a set-up mode which controls
410: whether they generate flow control characters. This must be
411: set to "no flow control" in order for Emacs to work. Sometimes
412: there is an escape sequence that the computer can send to turn
413: flow control off and on. If so, perhaps the termcap `ti' string
414: should turn flow control off, and the `te' string should turn it on.
415:
416: Once the terminal has been told "no flow control", you may find it
417: needs more padding. The amount of padding Emacs sends is controlled
418: by the termcap entry for the terminal in use, and by the output baud
419: rate as known by the kernel. The shell command `stty' will print
420: your output baud rate; `stty' with suitable arguments will set it if
421: it is wrong. Setting to a higher speed causes increased padding. If
422: the results are wrong for the correct speed, there is probably a
423: problem in the termcap entry. You must speak to a local Unix wizard
424: to fix this. Perhaps you are just using the wrong terminal type.
425:
426: For terminals that lack a "no flow control" mode, sometimes just
427: giving lots of padding will prevent actual generation of flow control
428: codes. You might as well try it.
429:
430: If you are really unlucky, your terminal is connected to the computer
431: through a concentrator which sends flow control to the computer, or it
432: insists on sending flow control itself no matter how much padding you
433: give it. You are screwed! You should replace the terminal or
434: concentrator with a properly designed one. In the mean time,
435: some drastic measures can make Emacs semi-work.
436:
437: One drastic measure to ignore C-s and C-q, while sending enough
438: padding that the terminal will not really lose any output.
439: Ignoring C-s and C-q can be done by using keyboard-translate-table
440: to map them into an undefined character such as C-^ or C-\. Sending
441: lots of padding is done by changing the termcap entry. Here is how
442: to make such a keyboard-translate-table:
443:
444: (let ((the-table (make-string 128 0)))
445: ;; Default is to translate each character into itself.
446: (let ((i 0))
447: (while (< i 128)
448: (aset the-table i i)
449: (setq i (1+ i))))
450: ;; Swap C-s with C-\
451: (aset the-table ?\C-\\ ?\C-s)
452: (aset the-table ?\C-s ?\C-\\)
453: ;; Swap C-q with C-^
454: (aset the-table ?\C-^ ?\C-q)
455: (aset the-table ?\C-q ?\C-^)
456: (setq keyboard-translate-table the-table))
457:
458: An even more drastic measure is to make Emacs use flow control.
459: To do this, evaluate the Lisp expression (set-input-mode nil t).
460: Emacs will then interpret C-s and C-q as flow control commands. (More
461: precisely, it will allow the kernel to do so as it usually does.) You
462: will lose the ability to use them for Emacs commands. Also, as a
463: consequence of using CBREAK mode, the terminal's Meta-key, if any,
464: will not work, and C-g will be liable to cause a loss of output which
465: will produce garbage on the screen. (These problems apply to 4.2BSD;
466: they may not happen in 4.3 or VMS, and I don't know what would happen
467: in sysV.) You can use keyboard-translate-table, as shown above,
468: to map two other input characters (such as C-^ and C-\) into C-s and
469: C-q, so that you can still search and quote.
470:
471: I have no intention of ever redisigning the Emacs command set for
472: the assumption that terminals use C-s/C-q flow control. This
473: flow control technique is a bad design, and terminals that need
474: it are bad merchandise and should not be purchased. If you can
475: get some use out of GNU Emacs on inferior terminals, I am glad,
476: but I will not make Emacs worse for properly designed systems
477: for the sake of inferior systems.
478:
479: * Control-S and Control-Q commands are ignored completely.
480:
481: For some reason, your system is using brain-damaged C-s/C-q flow
482: control despite Emacs's attempts to turn it off. Perhaps your
483: terminal is connected to the computer through a concentrator
484: that wants to use flow control.
485:
486: You should first try to tell the concentrator not to use flow control.
487: If you succeed in this, try making the terminal work without
488: flow control, as described in the preceding section.
489:
490: If that line of approach is not successful, map some other characters
491: into C-s and C-q using keyboard-translate-table. The example above
492: shows how to do this with C-^ and C-\.
493:
494: * Control-S and Control-Q commands are ignored completely on a net connection.
495:
496: Some versions of rlogin (and possibly telnet) do not pass flow
497: control characters to the remote system to which they connect.
498: On such systems, emacs on the remote system cannot disable flow
499: control on the local system.
500:
501: One way to cure this is to disable flow control on the local host
502: (the one running rlogin, not the one running rlogind) using the
503: stty command, before starting the rlogin process. On many systems,
504: "stty start u stop u" will do this.
505:
506: Some versions of tcsh will prevent even this from working. One way
507: around this is to start another shell before starting rlogin, and
508: issue the stty command to disable flow control from that shell.
509:
510: * Screen is updated wrong, but only on one kind of terminal.
511:
512: This could mean that the termcap entry you are using for that
513: terminal is wrong, or it could mean that Emacs has a bug handing
514: the combination of features specified for that terminal.
515:
516: The first step in tracking this down is to record what characters
517: Emacs is sending to the terminal. Execute the Lisp expression
518: (open-termscript "./emacs-script") to make Emacs write all
519: terminal output into the file ~/emacs-script as well; then do
520: what makes the screen update wrong, and look at the file
521: and decode the characters using the manual for the terminal.
522: There are several possibilities:
523:
524: 1) The characters sent are correct, according to the terminal manual.
525:
526: In this case, there is no obvious bug in Emacs, and most likely you
527: need more padding, or possibly the terminal manual is wrong.
528:
529: 2) The characters sent are incorrect, due to an obscure aspect
530: of the terminal behavior not described in an obvious way
531: by termcap.
532:
533: This case is hard. It will be necessary to think of a way for
534: Emacs to distinguish between terminals with this kind of behavior
535: and other terminals that behave subtly differently but are
536: classified the same by termcap; or else find an algorithm for
537: Emacs to use that avoids the difference. Such changes must be
538: tested on many kinds of terminals.
539:
540: 3) The termcap entry is wrong.
541:
542: See the file etc/TERMS for information on changes
543: that are known to be needed in commonly used termcap entries
544: for certain terminals.
545:
546: 4) The characters sent are incorrect, and clearly cannot be
547: right for any terminal with the termcap entry you were using.
548:
549: This is unambiguously an Emacs bug, and can probably be fixed
550: in termcap.c, tparam.c, term.c, scroll.c, cm.c or dispnew.c.
551:
552: * Output from Control-V is slow.
553:
554: On many bit-map terminals, scrolling operations are fairly slow.
555: Often the termcap entry for the type of terminal in use fails
556: to inform Emacs of this. The two lines at the bottom of the screen
557: before a Control-V command are supposed to appear at the top after
558: the Control-V command. If Emacs thinks scrolling the lines is fast,
559: it will scroll them to the top of the screen.
560:
561: If scrolling is slow but Emacs thinks it is fast, the usual reason is
562: that the termcap entry for the terminal you are using does not
563: specify any padding time for the `al' and `dl' strings. Emacs
564: concludes that these operations take only as much time as it takes to
565: send the commands at whatever line speed you are using. You must
566: fix the termcap entry to specify, for the `al' and `dl', as much
567: time as the operations really take.
568:
569: Currently Emacs thinks in terms of serial lines which send characters
570: at a fixed rate, so that any operation which takes time for the
571: terminal to execute must also be padded. With bit-map terminals
572: operated across networks, often the network provides some sort of
573: flow control so that padding is never needed no matter how slow
574: an operation is. You must still specify a padding time if you want
575: Emacs to realize that the operation takes a long time. This will
576: cause padding characters to be sent unnecessarily, but they do
577: not really cost much. They will be transmitted while the scrolling
578: is happening and then discarded quickly by the terminal.
579:
580: Most bit-map terminals provide commands for inserting or deleting
581: multiple lines at once. Define the `AL' and `DL' strings in the
582: termcap entry to say how to do these things, and you will have
583: fast output without wasted padding characters. These strings should
584: each contain a single %-spec saying how to send the number of lines
585: to be scrolled. These %-specs are like those in the termcap
586: `cm' string.
587:
588: You should also define the `IC' and `DC' strings if your terminal
589: has a command to insert or delete multiple characters. These
590: take the number of positions to insert or delete as an argument.
591:
592: A `cs' string to set the scrolling region will reduce the amount
593: of motion you see on the screen when part of the screen is scrolled.
594:
595: * Your Delete key sends a Backspace to the terminal, using an AIXterm.
596:
597: The solution is to include in your .Xdefaults the lines:
598:
599: *aixterm.Translations: #override <Key>BackSpace: string(0x7f)
600: aixterm*ttyModes: erase ^?
601:
602: This makes your Backspace key send DEL (ASCII 127).
603:
604: * You type Control-H (Backspace) expecting to delete characters.
605:
606: Put `stty dec' in your .login file and your problems will disappear
607: after a day or two.
608:
609: The choice of Backspace for erasure was based on confusion, caused by
610: the fact that backspacing causes erasure (later, when you type another
611: character) on most display terminals. But it is a mistake. Deletion
612: of text is not the same thing as backspacing followed by failure to
613: overprint. I do not wish to propagate this confusion by conforming
614: to it.
615:
616: For this reason, I believe `stty dec' is the right mode to use,
617: and I have designed Emacs to go with that. If there were a thousand
618: other control characters, I would define Control-h to delete as well;
619: but there are not very many other control characters, and I think
620: that providing the most mnemonic possible Help character is more
621: important than adapting to people who don't use `stty dec'.
622:
623: If you are obstinate about confusing buggy overprinting with deletion,
624: you can redefine Backspace in your .emacs file:
625: (global-set-key "\b" 'delete-backward-char)
626: You may then wish to put the function help-command on some
627: other key. I leave to you the task of deciding which key.
628:
629: * Editing files through RFS gives spurious "file has changed" warnings.
630: It is possible that a change in Emacs 18.37 gets around this problem,
631: but in case not, here is a description of how to fix the RFS bug that
632: causes it.
633:
634: There was a serious pair of bugs in the handling of the fsync() system
635: call in the RFS server.
636:
637: The first is that the fsync() call is handled as another name for the
638: close() system call (!!). It appears that fsync() is not used by very
639: many programs; Emacs version 18 does an fsync() before closing files
640: to make sure that the bits are on the disk.
641:
642: This is fixed by the enclosed patch to the RFS server.
643:
644: The second, more serious problem, is that fsync() is treated as a
645: non-blocking system call (i.e., it's implemented as a message that
646: gets sent to the remote system without waiting for a reply). Fsync is
647: a useful tool for building atomic file transactions. Implementing it
648: as a non-blocking RPC call (when the local call blocks until the sync
649: is done) is a bad idea; unfortunately, changing it will break the RFS
650: protocol. No fix was supplied for this problem.
651:
652: (as always, your line numbers may vary)
653:
654: % rcsdiff -c -r1.2 serversyscall.c
655: RCS file: RCS/serversyscall.c,v
656: retrieving revision 1.2
657: diff -c -r1.2 serversyscall.c
658: *** /tmp/,RCSt1003677 Wed Jan 28 15:15:02 1987
659: --- serversyscall.c Wed Jan 28 15:14:48 1987
660: ***************
661: *** 163,169 ****
662: /*
663: * No return sent for close or fsync!
664: */
665: ! if (syscall == RSYS_close || syscall == RSYS_fsync)
666: proc->p_returnval = deallocate_fd(proc, msg->m_args[0]);
667: else
668: {
669: --- 166,172 ----
670: /*
671: * No return sent for close or fsync!
672: */
673: ! if (syscall == RSYS_close)
674: proc->p_returnval = deallocate_fd(proc, msg->m_args[0]);
675: else
676: {
677:
678: * ld complains because `alloca' is not defined on your system.
679:
680: Alloca is a library function in 4.2bsd, which is used very heavily by
681: GNU Emacs. Use of malloc instead is very difficult, as you would have
682: to arrange for the storage to be freed, and do so even in the case of
683: a longjmp happening inside a subroutine. Many subroutines in Emacs
684: can do longjmp.
685:
686: If your system does not support alloca, try defining the symbol
687: C_ALLOCA in the m-...h file for that machine. This will enable the use
688: in Emacs of a portable simulation for alloca. But you will find that
689: Emacs's performance and memory use improve if you write a true
690: alloca in assembler language.
691:
692: alloca (N) should return the address of an N-byte block of memory
693: added dynamically to the current stack frame.
694:
695: * Vax C compiler bugs affecting Emacs.
696:
697: You may get one of these problems compiling Emacs:
698:
699: foo.c line nnn: compiler error: no table entry for op STASG
700: foo.c: fatal error in /lib/ccom
701:
702: These are due to bugs in the C compiler; the code is valid C.
703: Unfortunately, the bugs are unpredictable: the same construct
704: may compile properly or trigger one of these bugs, depending
705: on what else is in the source file being compiled. Even changes
706: in header files that should not affect the file being compiled
707: can affect whether the bug happens. In addition, sometimes files
708: that compile correctly on one machine get this bug on another machine.
709:
710: As a result, it is hard for me to make sure this bug will not affect
711: you. I have attempted to find and alter these constructs, but more
712: can always appear. However, I can tell you how to deal with it if it
713: should happen. The bug comes from having an indexed reference to an
714: array of Lisp_Objects, as an argument in a function call:
715: Lisp_Object *args;
716: ...
717: ... foo (5, args[i], ...)...
718: putting the argument into a temporary variable first, as in
719: Lisp_Object *args;
720: Lisp_Object tem;
721: ...
722: tem = args[i];
723: ... foo (r, tem, ...)...
724: causes the problem to go away.
725: The `contents' field of a Lisp vector is an array of Lisp_Objects,
726: so you may see the problem happening with indexed references to that.
727:
728: * 68000 C compiler problems
729:
730: Various 68000 compilers have different problems.
731: These are some that have been observed.
732:
733: ** Using value of assignment expression on union type loses.
734: This means that x = y = z; or foo (x = z); does not work
735: if x is of type Lisp_Object.
736:
737: ** "cannot reclaim" error.
738:
739: This means that an expression is too complicated. You get the correct
740: line number in the error message. The code must be rewritten with
741: simpler expressions.
742:
743: ** XCONS, XSTRING, etc macros produce incorrect code.
744:
745: If temacs fails to run at all, this may be the cause.
746: Compile this test program and look at the assembler code:
747:
748: struct foo { char x; unsigned int y : 24; };
749:
750: lose (arg)
751: struct foo arg;
752: {
753: test ((int *) arg.y);
754: }
755:
756: If the code is incorrect, your compiler has this problem.
757: In the XCONS, etc., macros in lisp.h you must replace (a).u.val with
758: ((a).u.val + coercedummy) where coercedummy is declared as int.
759:
760: This problem will not happen if the m-...h file for your type
761: of machine defines NO_UNION_TYPE. That is the recommended setting now.
762:
763: * C compilers lose on returning unions
764:
765: I hear that some C compilers cannot handle returning
766: a union type. Most of the functions in GNU Emacs return
767: type Lisp_Object, which is currently defined as a union.
768:
769: This problem will not happen if the m-...h file for your type
770: of machine defines NO_UNION_TYPE. That is the recommended setting now.
771:
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