1 GNU M4 NEWS - User visible changes.
2 Copyright (C) 1992, 1993, 1994, 2004, 2005, 2006, 2007, 2008 Free Software
5 * Noteworthy changes in Version 1.4.12 (2008-10-10) [stable]
6 Released by Eric Blake, based on git version 1.4.11.*
8 ** Fix regression introduced in 1.4.4b where using `traceon' could delete
9 a macro. This was most noticeable with `traceon(`traceon')', but
10 would also happen in cases such as `foo(traceon(`foo'))'.
12 ** Fix regression introduced in 1.4.7 where `m4 -N9' died with an assertion
15 ** Fix regression introduced in 1.4.11 where `defn' died with an assertion
16 failure on a traced but undefined macro.
18 ** New `-g'/`--gnu' command-line option overrides `-G'/`--traditional'.
19 For now, the environment variable POSIXLY_CORRECT has no effect on M4
20 behavior; but a future release of M4 will behave as though --traditional
21 is implied if POSIXLY_CORRECT is set (this future change is necessary,
22 because in the current release, there is no way to disable GNU
23 extensions that conflict with POSIX without the use of a non-POSIX
24 command-line argument). Clients of M4 that want to use GNU extensions,
25 even when POSIXLY_CORRECT is set, should start using the -g command-line
26 argument, even though it is currently a no-op if -G did not appear
27 earlier in the command line, so that the client will not break in the
28 face of an upgraded m4 and a POSIXLY_CORRECT execution environment.
30 ** The `-L'/`--nesting-limit' command-line option now defaults to 0 for
31 unlimited on platforms that can detect and deal with stack overflow. On
32 systems that lack alternate stack support, such as Cygwin, and on
33 systems that do not obey the POSIX semantics for distinguishing stack
34 overflow from other exceptions, such as Linux, you can optionally
35 install the libsigsegv library (version 2.6 or newer recommended) to
36 enhance m4's ability to accurately report stack overflow:
37 http://www.gnu.org/software/libsigsegv/
39 ** A number of portability improvements inherited from gnulib.
41 * Noteworthy changes in Version 1.4.11 (2008-04-02) [stable]
42 Released by Eric Blake, based on git version 1.4.10a
44 ** Security fixes for the -F option, for bugs present since -F was
45 introduced in 1.3: Avoid core dump with 'm4 -F file -t undefined', and
46 avoid arbitrary code execution with certain file names.
48 ** Fix regression introduced in 1.4.9b in the `divert' builtin when more
49 than 512 kibibytes are saved in diversions on platforms like NetBSD
50 or darwin where fopen(name,"a+") seeks to the end of the file.
52 ** The output of the `maketemp' and `mkstemp' builtins is now quoted if a
53 file was created. This is a minor security fix, because it was possible
54 (although rather unlikely) that an unquoted string could match an
55 existing macro name, such that use of the `mkstemp' output would trigger
56 inadvertent macro expansion and operate on the wrong file name.
58 ** Enhance the `defn' builtin to support concatenation of multiple text
59 arguments, as required by POSIX. However, at this time, it is not
60 possible to concatenate a builtin macro with anything else; a warning is
61 now issued if this is attempted, although a future version of M4 may
62 lift this restriction to match other implementations.
64 ** Enhance the `format' builtin to parse all C99 floating point numbers,
65 even on platforms where strtod(3) is buggy, although the replacement
66 function does have the known issue of rounding errors when parsing
67 some decimal floating point values. This fixes testsuite failures
70 ** Enhance the `index' builtin to guarantee linear behavior, in spite of
71 the surprisingly large number of systems with a brain-dead quadratic
74 ** A number of portability improvements inherited from gnulib.
76 * Noteworthy changes in Version 1.4.10 (2007-07-09) [stable]
77 Released by Eric Blake, based on CVS version 1.4.9c
79 ** Upgrade from GPL version 2 to GPL version 3 or later.
81 ** A number of portability improvements inherited from gnulib.
83 ** Avoid undefined behavior introduced in 1.4.9b in the `format' builtin
84 when handling %c. However, this area of code has never been documented,
85 and currently does not match the POSIX behavior of printf(1), so it may
86 have further changes in the next version.
88 * Noteworthy changes in Version 1.4.9b (2007-05-29) [beta]
89 Released by Eric Blake, based on CVS version 1.4.9a
91 ** Fix regression introduced in 1.4.9 in the `eval' builtin when performing
94 ** Fix regression introduced in 1.4.8 in the `-F' option that made it
95 impossible to freeze more than 512 kibibytes of diverted text.
97 ** The synclines option `-s' no longer generates sync lines in the middle of
98 multiline comments or quoted strings.
100 ** Work around a number of corner-case POSIX compliance bugs in various
101 broken stdio libraries. In particular, the `syscmd' builtin behaves
102 more predictably when stdin is seekable.
104 ** The `format' builtin now understands formats such as %a, %A, and %'hhd,
105 and works around a number of platform printf bugs. Furthermore, the
106 sequence format(%*.*d,-1,-1,1) no longer outputs random data. However,
107 some non-compliant platforms such as mingw still have known bugs in
108 strtod that may cause testsuite failures.
110 ** The testsuite is improved to also run gnulib portability tests for the
111 features that M4 imports from gnulib.
113 * Noteworthy changes in Version 1.4.9 (2007-03-23) [stable]
114 Released by Eric Blake, based on CVS version 1.4.8c
116 ** Minor documentation and portability cleanups.
118 * Noteworthy changes in Version 1.4.8b (2007-02-24) [beta]
119 Released by Eric Blake, based on CVS version 1.4.8a
121 ** Fix a regression introduced in 1.4.8 that made m4 unable to process
122 files larger than 2GiB on some platforms.
124 ** Fix a regression introduced in 1.4.8 that made m4 dump core when
125 invoked as 'm4 -- file'.
127 ** The `eval' builtin now follows C precedence rules. Additionally, the
128 short-circuit operators correctly short-circuit division by zero. The
129 previously undocumented alias of '=' meaning '==' in eval now triggers a
130 deprecation warning, so that a future version of M4 can implement a form
131 of variable assignment as an extension.
133 ** The `include' builtin now affects exit status on failure, as required by
134 POSIX. Use `sinclude' if you need a successful exit status.
136 ** The `-E'/`--fatal-warnings' command-line option now has two levels. When
137 specified only once, warnings affect exit status, but execution
138 continues, so that you can see all warnings instead of fixing them one
139 at a time. To achieve 1.4.8 behavior, where the first warning
140 immediately exits, specify -E twice on the command line.
142 ** A new `--warn-macro-sequence' command-line option allows detection of
143 sequences in `define' and `pushdef' definitions that match an optional
144 regular expression. The default regular expression is
145 `\$\({[^}]*}\|[0-9][0-9]+\)', corresponding to the sequences that might
146 not behave correctly when upgrading to the eventual M4 2.0. By default,
147 M4 2.0 will follow the POSIX requirement that a macro definition
148 containing `$11' must expand to the first argument concatenated with 1,
149 rather than the eleventh argument; and will take advantage of the POSIX
150 wording that allows implementations to treat `${11}' as the eleventh
151 argument instead of literal text. Be aware that Autoconf 2.61 will not
152 work with this option enabled with the default regular expression; but
153 Autoconf 2.62 will be compatible with this option.
155 ** Improved portability to platforms such as BSD/OS and AIX.
157 * Noteworthy changes in Version 1.4.8 (2006-11-20) [stable]
158 Released by Eric Blake, based on CVS version 1.4.7a
160 ** The `divert' macro and `-H'/`--hashsize' command line option no longer
161 cause a core dump when handed extra large values. Also, `divert' now
162 uses memory proportional to the number of diversions in use, rather than
163 to the maximum diversion number encountered, so that large diversion
164 numbers are less likely to exhaust system memory; and is no longer
165 limited by the maximum number of file descriptors.
167 ** The `--help' and `--version' command line options now consistently
168 override all earlier options. For example, `m4 --debugfile=trace
169 --help' now no longer accidentally creates an empty file `trace'.
171 ** The `-L'/`--nesting-limit' command line option can now be set to 0
172 to remove the default limit of 1024. However, it is still possible that
173 heavily nested input can cause abrupt program termination due to stack
176 ** Problems encountered when writing to standard error, such as with the
177 `errprint' macro, now always cause a non-zero exit status.
179 ** Warnings and errors issued during macro expansion are now consistently
180 reported at the line where the macro name was detected, rather than
181 where the close parenthesis resides. Text wrapped by `m4wrap' now
182 remembers the location that was in effect when m4wrap was invoked,
183 rather than changing to line 0 and the empty string for a file. The
184 macros `__line__' and `__file__' now work correctly even as the last
185 token in an included file.
187 ** The `builtin' and `indir' macros now transparently handle builtin
188 tokens generated by `defn'.
190 ** When diversions created by the `divert' macro collect enough text that
191 M4 must use temporary files, the environment variable $TMPDIR is now
192 consulted, and a better effort is made to clean up those files in the
193 event of a fatal signal.
195 ** The `mkstemp' builtin is added with the same GNU semantics as `maketemp',
196 based on the recommendation of POSIX to deprecate the POSIX semantics of
197 `maketemp' as inherently insecure. In GNU mode (no -G supplied on the
198 command line), `maketemp' silently retains the secure GNU semantics, but
199 a future release of M4 will change this to emit a warning. In
200 traditional mode (m4 -G), `maketemp' now uses the POSIX-mandated
201 insecure semantics, and issues a warning that you should convert your
202 script to use `mkstemp' instead. Additionally, `mkstemp' and `maketemp'
203 are now well-defined even if the template argument does not end in six
206 ** The manual has been improved, including a new section on a composite
209 ** The `changecom' and `changequote' macros now treat an empty second
210 argument the same as if it were missing, rather than using the empty
211 string and making it impossible to end a comment or quote.
213 ** The `translit' macro now operates in linear instead of quadratic time,
214 and is now eight-bit clean.
216 ** The `-D', `-U', `-s', and `-t' command line options now take effect
217 after any files encountered earlier on the command line, rather than up
218 front, as is done in traditional implementations and required by POSIX.
220 * Noteworthy changes in Version 1.4.7 (2006-09-25) [stable]
221 Released by Eric Blake, based on CVS version 1.4.6a
223 ** Fix regression from 1.4.5 in handling a file that ends in a macro
224 expansion without arguments instead of a newline.
226 ** The define and pushdef macros now warn when the first argument is not
227 a string, rather than silently doing nothing.
229 ** Standard input can now be read more than once, as in 'm4 - file -', and
230 is not closed until all wrapped text is handled. This makes a
231 difference when stdin is not a regular file, and also fixes bugs when
232 using the syscmd or esyscmd macros from wrapped text.
234 ** When standard input is a seekable file, the m4exit, syscmd, and esyscmd
235 macros now restore the current position to the next unread byte rather
236 than discarding an arbitrary amount of buffered data.
238 ** SysV command-line compatibility is no longer a goal of GNU M4; the
239 focus will be instead on POSIX compatibility. This release continues to
240 support previous usage, but adds warnings in areas which will allow a
241 future version of GNU M4 to use its own extensions without being tied to
242 the SysV command line interface.
244 ** The no-op compatibility command line options -B, -N, -S, -T, and
245 --diversions may be withdrawn or assigned new meanings in future
246 releases, so they now issue a warning if used.
248 ** A new command line option -i replaces the compatibility -e as the
249 short spelling of --interactive, for consistency with other GNU tools; a
250 warning is issued if the old spelling is used, and it may be assigned
251 new meaning in future releases.
253 ** A new command line option --debugfile replaces the options -o and
254 --error-output as the preferred spelling. The old options were
255 misleading in their names and inconsistent with other GNU tools; they
256 are still silently accepted, but no longer documented in --help, and may
257 be assigned new meanings in future releases.
259 * Noteworthy changes in Version 1.4.6 (2006-08-25) [stable]
260 Released by Eric Blake, based on CVS version 1.4.5a
262 ** Fix buffer overruns in regexp and patsubst macros when handed a trailing
263 backslash in the replacement text, or when handling \n substitutions
264 beyond the number of \(\) groups.
266 ** Fix memory leak in regexp, patsubst, and changeword macros.
268 ** The format macro now understands %F, %g, and %G.
270 ** When loading frozen files, m4 now exits with status 63 if version
271 mismatch is detected.
273 ** Fix bugs that occurred when invoked with stdout or stderr closed,
274 and detect write failures to stdout or to the target of the debugfile
275 macro. In particular, the syscmd and esyscmd macros can no longer
276 interfere with the debug stream or diversions.
278 ** The m4exit macro now converts values outside the range 0-255 to 1.
280 ** It is now an error if a command-line input file ends in the middle of a
281 comment, matching the behavior of mid-string and mid-argument
284 ** The dnl macro now warns if end of file is encountered instead of a
287 ** The error message when end of file is encountered now uses the file and
288 line where the dangling construct started, rather than `NONE:0:'.
290 ** The debugmode and __file__ macros, and the -s/--synclines option, now
291 show what directory a file was found in when the -I/--include option or
292 M4PATH variable had an effect.
294 ** The changequote and changecom macros now work with 8-bit characters, and
295 quotes and comments that begin with `(' are properly recognized
298 ** The new macro __program__ is added, which allows the input file to issue
299 an error message that resembles messages from m4. Warning and error
300 messages have been reformatted to comply with GNU Coding Standards.
302 ** The errprint, m4wrap, and shift macros are now recognized only with
305 ** The index, substr, translit, regexp, and patsubst macros now produce
306 output when given only one argument, but still warn about a missing
309 ** The patsubst macro now reliably finds zero-length matches at the end
312 * Noteworthy changes in Version 1.4.5 (2006-07-15) [stable]
313 Released by Eric Blake, based on CVS version 1.4.4c
315 ** Fix sysval on BeOS, OS/2, and other systems that store exit status
316 in the low-order byte. Additionally, on Unix platforms, if syscmd was
317 terminated by a signal, sysval now displays the signal number shifted
318 left by eight bits, to match traditional m4 implementations.
320 ** The maketemp macro is no longer subject to platform limitations (such as
321 26 or 32 max files from a given template).
323 ** Frozen files now require that the first directive be V (version), to
324 better diagnose version mismatch. Additionally, if the F directive
325 (builtin function) names an unknown builtin that existed in the m4 that
326 froze the file but not in the current m4 (for example, changeword), the
327 warning is deferred until an attempt is made to actually use the
328 builtin. This allows downgrading from beta m4-1.4o to stable m4-1.4.5
329 without breaking autoconf.
331 ** The format and indir macros are now recognized only with arguments.
333 ** The eval macro no longer crashes on x86 architectures when dividing the
334 minimum integer by -1.
336 ** On systems with ecvt and fcvt, format no longer truncates trailing
337 zeroes on integers printed with %.0f. On systems without these
338 functions, format is no longer subject to a buffer overflow that
339 permitted arbitrary code execution.
341 ** On native Windows builds, the macro __windows__ is provided instead of
342 __unix__. Likewise, on OS/2 builds, the macro __os2__ is provided.
343 This allows input files to determine when syscmd might behave
346 ** Fix bug in 1.4.3 patch to use \n line-endings that did not work for
349 ** When given the empty string or 0, undivert is now documented as a no-op
350 rather than closing stdout, warning about a non-existent file, or trying
351 to read a directory as a file.
353 ** Many documentation improvements. Also, the manual is now distributed
354 under FDL 1.2, rather than a stricter verbatim-only license.
356 ** Raise the -L (--nesting-limit) command line option limit from 250 to
359 ** The decr, incr, divert, m4exit, and substr macros treat an empty number
360 as 0, issue a warning, and expand as normal; rather than issuing an
361 error and expanding to the empty string.
363 ** The eval macro now treats an empty radix argument as 10, handles radix 1,
364 and treats the width argument as number of digits excluding the sign,
365 for compatibility with other m4 implementations.
367 ** The ifdef, divert, m4exit, substr, and translit macros now correctly
368 ignore extra arguments.
370 ** The popdef and undefine macros now correctly accept multiple arguments.
372 ** Although changeword is on its last leg, if enabled, it now reverts to the
373 default (faster) regexp when passed the empty string.
375 ** The regexp and substr macros now warn and ignore a trailing backslash in
376 the replacement, and warn on \n for n larger than the number of
377 sub-expressions in the regexp.
379 * Noteworthy changes in Version 1.4.4b (2006-06-17) [beta]
380 Released by Eric Blake, based on CVS version 1.4.4a
382 ** Fix a recursive push_string crashing bug, which affected changequote of
383 three or more characters on some compilers.
385 ** Use automake to fix build portability issues.
387 ** Fix a recursive m4wrap crashing bug.
389 ** Fix a 1 in 2**32 hash crashing bug.
391 ** Tracing a macro by name is now persistent, even if the macro is
392 subsequently undefined or redefined. The traceon and traceoff macros no
393 longer warn about undefined symbols. This solves a crash when using
394 indir on an undefined macro traced with the -t option, as well as an
395 incorrect result of ifdef. Furthermore, tracing is no longer
396 transferred with builtins, solving the bug of "m4 -tm4_eval" failing to
397 give trace output on the input
398 "define(`m4_eval',defn(`eval'))m4_eval(1)".
400 ** Fix a crash when a macro is undefined while collecting its arguments, by
401 always using the definition that was in effect before argument
402 collection. This behavior matches the C pre-processor, and means that
403 the sequence "define(`f',`1')f(define(`f',`2'))f" is now documented to
404 result in "12", rather than the previously undocumented "22".
406 ** Update the regex engine to fix several bugs.
408 ** Fix a potential crash on machines where char is signed.
410 * Noteworthy changes in Version 1.4.4 (Oct 2005) [stable]
411 Released by Gary V. Vaughan
413 ** ./configure --infodir=/usr/share/info now works correctly.
415 ** When any file named on the command line is missing exit with status 1.
417 * Noteworthy changes in Version 1.4.3 (Mar 2005) [stable]
418 Released by Gary V. Vaughan
420 ** DESTDIR installs now work correctly.
422 ** Don't segfault with uncompilable regexps to changeword().
424 ** Always use \n line-endings for frozen files (fixes a Windows bug).
426 ** Portability fix for systems lacking mkstemp(3).
428 ** Approximately 20% speed up in the common case of usage with autoconf.
430 ** Supported on QNX 6.3.
432 * Noteworthy changes in Version 1.4.2 (Aug 2004) [stable]
433 Released by Paul Eggert
435 ** No user visible changes; portability bug fixes only.
437 * Noteworthy changes in Version 1.4.1 (Jun 2004) [stable]
438 Released by Paul Eggert
440 ** maketemp now creates an empty file with the given name, instead of merely
441 returning the name of a nonexistent file. This closes a security hole.
443 * Noteworthy changes in Version 1.4 (Oct 1994) [stable]
444 Released by Franc,ois Pinard
446 ** (No user visible changes)
449 Version 1.3 - September 1994, by Franc,ois Pinard
451 * Diversions are created as needed. Option `-N' is still accepted, but
452 otherwise ignored. Users should use only negative diversion numbers,
453 instead of high positive numbers, for diverting to nowhere.
455 * Diversions should also work faster. No temporary files will be needed
456 at all if all diversions taken altogether do not use more than 512K.
458 * Frozen state files may be produced with the `--freeze-state' (-F)
459 option and later brought back through the `--reload-state' (-R) option.
461 Version 1.2 - July 1994, by Franc,ois Pinard
463 * In patsubst(STRING, REGEXP, REPLACEMENT), \& in REPLACEMENT has been
464 changed to represent this part of STRING matched by the whole REGEXP,
465 instead of the whole STRING as before. \0 does the same, but emits a
466 diagnostic saying it will disappear in some subsequent release.
468 * eval(EXPR) emits a diagnostic if EXPR has suffixed crumb. The same for
469 other numeric conversions in incr(), decr(), divert(), etc.
471 * `--fatal-warnings' (-E) stops execution at first warning.
473 * `--nesting-limit=LEVEL' (-L LEVEL) sets a limit to macro nesting.
474 It is initially fixed at 250.
476 * `--word-regexp=REGEXP' (-W REGEXP) modifies macro name syntax, like
477 does the new `changeword(REGEXP)' macro. This feature is experimental,
478 tell me your opinions about it. You do need --enable-changeword at
479 configure time to get these things. Do *not* depend on them yet.
481 * Trace output format is scannable by GNU Emacs' next-error function.
483 * Stack overflow is detected and diagnosed on some capable systems.
485 * Various bugs have been corrected, m4 should be more portable. See the
486 ChangeLog for details.
488 Version 1.1 - November 1993, by Franc,ois Pinard
490 Changes which might affect existing GNU m4 scripts:
492 * Option `-V' has been removed, use `--version' instead. `--version'
493 writes on standard output instead of standard error, and inhibits any
496 * `--no-gnu-extensions' has been renamed `--traditional'.
498 * In `eval', `^' used to indicate exponentiation, use `**' instead.
500 * The automatic undiversion which takes place at end of all input is
501 forced into the main output stream.
503 Changes which are unlikely to affect existing scripts:
505 * `--help' prints an usage summary on standard output. Script execution
508 * `--prefix-builtins' (-P) prefixes all builtin macros by `m4_'.
510 * Most builtin macros for which arguments are mandatory, called without
511 any arguments, are no more recognized as builtin macros: they are
512 consequently copied verbatim to the output stream.
514 * `define' and `pushdef' are usable with only one argument, they give
515 this argument an empty definition.
517 * `eval' new operators for binary representation handling: `^' for
518 exclusive-or, `~' for the bitwise negation, `<<' and `>>' for shifts.
520 * `eval' recognizes the notation 0bDIGITS for binary numbers and the
521 notation 0rRADIX:DIGITS for numbers in any radix from 1 to 36.
523 Version 1.0.3 - December 1992, by Franc,ois Pinard
525 Changes for the user:
527 * `dnl' outputs a diagnostic if immediately followed by `('. Usually,
528 `dnl' is followed by newline or whitespace.
530 * `ifelse' accepts without complaining the common idiom of having only
531 one argument. This is useful for introducing long comments.
533 * `eval' always expresses values as signed, whatever the radix.
535 * M4OPTS environment variable is no longer obeyed.
537 * `--no-warnings' option is renamed `--silent'.
539 * Debug lines use a new format more compatible with GNU standards.
541 * Various bugs have been corrected. See the ChangeLog for details.
543 Changes for the installer:
545 * GNU m4 now uses an Autoconf-generated configure script, and should be
546 more easily portable in many ways. (Cray is not supported yet).
548 * `make check' has been made more portable, expect no errors.
550 Changes for the programmer:
552 * Sources have been fully reindented to comply with GNU standards, and
553 cleaned up in many ways.
555 * Sources have been protoized. Non-ANSI compilers are automatically
556 detected, then sources are unprotoized on the fly before compilation.
558 * GNU m4 uses newer versions of obstack, regex, getopt, etc.
560 Version 1.0 - October 1991, by Rene' Seindal
562 * Uses GNU configure, taken from the gdb distribution.
564 * Uses GNU getopt(), with long option names.
566 * The -Q/+quiet option is added, which suppresses warnings about missing
567 or superflous arguments to built-in macros.
569 * Added default options via the M4OPTS environment variable.
571 * Several minor bugs have been fixed.
573 Version 0.99 - July 1991, by Rene' Seindal
575 * The builtins `incr' and `decr' are now implemented without use of
578 * The builtin `indir' is added, to allow for indirect macro calls
579 (allows use of "illegal" macro names).
581 * The debugging and tracing facilities has been enhanced considerably.
582 See the manual for details.
584 * The -tMACRO option is added, marks MACRO for tracing as soon as it
587 * Builtins are traced after renaming iff they were before.
589 * Named files can now be undiverted.
591 * The -Nnum option can be used to increase the number of divertions
594 * Calling changecom without arguments now disables all comment handling.
596 * A bug in `dnl' is fixed.
598 * A bug in the multi-character quoting code is fixed.
600 * Several typos in the manual has been corrected. More probably persist.
602 Version 0.75 - November 1990, by Rene' Seindal
604 * Implemented search path for include files (-I option and M4PATH
605 environment variable).
607 * Implemented builtin `format' for printf-like formatting.
609 * Implemented builtin `regexp' for searching for regular expressions.
611 * Implemented builtin `patsubst' for substitution with regular
614 * Implemented builtin `esyscmd', which expands to a shell commands output.
616 * Implemented `__file__' and `__line__' for use in error messages.
618 * Implemented character ranges in `translit'.
620 * Implemented control over debugging output.
622 * Implemented multi-character quotes.
624 * Implemented multi-character comment delimiters.
626 * Changed predefined macro `gnu' to `__gnu__'.
628 * Changed predefined macro `unix' to `__unix__', when the -G option is
629 not used. With -G, `unix' is still defined.
631 * Added program name to error messages.
633 * Fixed two missing null bytes bugs.
635 Version 0.50 - January 1990, by Rene' Seindal
637 * Initial beta release.