xref: /freebsd/contrib/ncurses/ANNOUNCE (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1                            Announcing ncurses 6.2
2
3Overview
4
5   The  ncurses  (new  curses)  library  is  a free software emulation of
6   curses  in  System  V  Release  4.0 (SVr4), and more. It uses terminfo
7   format,  supports  pads  and  color  and multiple highlights and forms
8   characters and function-key mapping, and has all the other SVr4-curses
9   enhancements  over  BSD curses. SVr4 curses became the basis of X/Open
10   Curses.
11
12   In  mid-June  1995,  the  maintainer of 4.4BSD curses declared that he
13   considered  4.4BSD curses obsolete, and encouraged the keepers of unix
14   releases such as BSD/OS, FreeBSD and NetBSD to switch over to ncurses.
15
16   Since 1995, ncurses has been ported to many systems:
17     * It is used in almost every system based on the Linux kernel (aside
18       from some embedded applications).
19     * It  is  used  as the system curses library on OpenBSD, FreeBSD and
20       MacOS.
21     * It  is used in environments such as Cygwin and MinGW. The first of
22       these was EMX on OS/2 Warp.
23     * It is used (though usually not as the system curses) on all of the
24       vendor  unix  systems,  e.g.,  AIX,  HP-UX,  IRIX64, SCO, Solaris,
25       Tru64.
26     * It should work readily on any ANSI/POSIX-conforming unix.
27
28   The distribution includes the library and support utilities, including
29     * captoinfo, a termcap conversion tool
30     * clear, utility for clearing the screen
31     * infocmp, the terminfo decompiler
32     * tabs, set tabs on a terminal
33     * tic, the terminfo compiler
34     * toe, list (table of) terminfo entries
35     * tput,  utility  for  retrieving  terminal  capabilities  in  shell
36       scripts
37     * tset, to initialize the terminal
38
39   Full manual pages are provided for the library and tools.
40
41   The ncurses distribution is available at ncurses' homepage:
42
43     ftp://ftp.invisible-island.net/ncurses/ or
44     https://invisible-mirror.net/archives/ncurses/ .
45
46   It is also available via anonymous FTP at the GNU distribution site
47
48     ftp://ftp.gnu.org/gnu/ncurses/ .
49
50Release Notes
51
52   These notes are for ncurses 6.2, released February 12, 2020.
53
54   This  release  is  designed  to  be source-compatible with ncurses 5.0
55   through  6.1; providing extensions to the application binary interface
56   (ABI).  Although  the  source  can  still be configured to support the
57   ncurses  5  ABI, the reason for the release is to reflect improvements
58   to the ncurses 6 ABI and the supporting utility programs.
59
60   There  are,  of  course,  numerous  other improvements, listed in this
61   announcement.
62
63   The  most  important  bug-fixes/improvements  dealt  with user-defined
64   capabilities  in terminal descriptions. The release notes also mention
65   some other bug-fixes, but are focused on new features and improvements
66   to existing features since ncurses 6.1 release.
67
68  Library improvements
69
70    New features
71
72   There are several new features:
73     * O_EDGE_INSERT_STAY  tells  the  form  library  to optionally delay
74       cursor movement on a field edge/boundary
75     * O_INPUT_FIELD  extension to form library allows a dynamic field to
76       shrink if the new limit is smaller than the current field size.
77     * added  exit_curses  and  exit_terminfo to replace internal symbols
78       for leak-checking.
79     * added curses_trace, to replace trace().
80
81   Additionally,  to  improve  performance other changes (and extensions)
82   are provided in this release:
83     * mouse  decoding  now handles shift/control/alt logic when decoding
84       xterm's 1006 mode
85     * ncurses  now  defines a limit for wgetnstr, wgetn_wstr when length
86       is negative or "too large".
87     * reordered  loop-limit checks in winsnstr in case the string has no
88       terminating null and only the number of characters is used.
89     * there  is  now  no  buffer-size  limit  when  reading the $TERMCAP
90       variable.
91     * the  $TERMCAP  variable  may  be  interpreted  as  a fallback to a
92       terminfo entry
93     * mvcur  now decides whether to use hard-tabs, using xt, tbc and hts
94       as clues.
95     * extended  colors  are  improved  by  modifying an internal call to
96       vid_puts  to pass extended color pairs e.g., from tty_update.c and
97       lib_mvcur.c
98     * the  initialization  functions  now  avoid relying upon persistent
99       data for the result from getenv
100     * scrolling is improved:
101          + a limit check in newline_forces_scroll handles the case where
102            the row is inside scroll-margins, but not at the end.
103          + improved loop limits in _nc_scroll_window handle a case where
104            the scrolled data is a pad which is taller than the window.
105
106    Other improvements
107
108   These are revised features:
109     * used  "const"  in  some prototypes rather than NCURSES_CONST where
110       X/Open  Curses  was updated to do this, e.g., wscanw, newterm, the
111       terminfo  interface.  Also  use  "const"  for  consistency  in the
112       termcap interface, which was withdrawn by X/Open Curses in Issue 5
113       (2007).  As  of  Issue  7,  X/Open  Curses still lacks "const" for
114       certain return values, e.g., keyname.
115     * modified  wbkgd  and  wbkgrnd  to  improve compatibility with SVr4
116       curses,  changing the way the window rendition is updated when the
117       background character is modified
118     * improved  terminfo  write/read by modifying the fourth item of the
119       extended  header  to  denote  the  number  of valid strings in the
120       extended string table (see term(5)).
121     * modified   the   initialization  checks  for  mouse  so  that  the
122       xterm+sm+1006  block  will  work  with  terminal  descriptions not
123       mentioning xterm.
124
125   These were done to limit or ultimately deprecate features:
126     * deprecated  safe-sprintf, since the vsnprintf function, which does
127       what was needed, was standardized long ago.
128     * marked   vwprintw  and  vwscanw  as  deprecated;  recommend  using
129       vw_printw and vw_scanw, respectively.
130     * added  deprecation warnings for internal functions called by older
131       versions of tack.
132     * removed unused _nc_import_termtype2 function.
133
134   These are improvements to existing features:
135     * check parameter of set_escdelay, return ERR if negative.
136     * check  parameter  of  set_tabsize,  return ERR if not greater than
137       zero
138     * correct  a status-check in _nc_read_tic_entry() so that if reading
139       a hex/b64 $TERMINFO, and the $TERM does not match, fall-through to
140       the compiled-in search list.
141     * amend check for repeat_char to handle a case where setlocale() was
142       called after initscr
143     * move macro for is_linetouched inside NCURSES_NOMACROS ifndef.
144     * use _nc_copy_termtype2 rather than direct assignment in setupterm,
145       in   case   it   is  called  repeatedly  using  fallback  terminfo
146       descriptions
147     * improve   workaround   for  Solaris  wcwidth  versus  line-drawing
148       characters
149     * add  checks  in repair_subwindows to keep the current position and
150       scroll-margins inside the resized subwindow.
151     * correct  a  buffer-limit  in  write_entry.c  for  systems that use
152       caseless filenames.
153     * improved build-time utility report_offsets:
154          + add categories, e.g., "w" for wide-character, "t" for threads
155            to  make the report more readable. Reorganized the structures
156            reported to make the categories more apparent.
157          + add  NCURSES_GLOBALS  and NCURSES_PRESCREEN to report to show
158            how similar the different libtinfo configurations are.
159     * modified  some header files to ensure that those include necessary
160       files except for the previously-documented cases
161     * added  some  traces  in  initialization to show whether a fallback
162       entry is used.
163     * made minor optimization to reduce calls to _nc_reserve_pairs
164
165   These are corrections to existing features:
166     * fix  a  special  case  in  PutAttrChar  where  a cell is marked as
167       alternate-character  set,  but  the  terminal  does  not  actually
168       support the given graphic character. This would happen in an older
169       terminal such as vt52, which lacks most line-drawing capability.
170     * corrected  flag  for "seq" method of db 1.8.5 interface, needed by
171       toe on some of the BSDs.
172     * modify  comparison  in  make_hash.c  to  correct a special case in
173       collision handling for Caps-hpux11
174     * add    extended_slk_color{,_sp}   symbols   to   the   appropriate
175       package/*.{map,sym} files
176     * modify  lib_setup  to  avoid  calling pthread_self() without first
177       verifying that the address is valid, i.e., for weak symbols
178     * add  a  couple  of  broken-linker symbols to the list of versioned
179       symbols to help with link-time optimization versus weak symbols.
180
181  Program improvements
182
183   Several improvements were made to the utility programs:
184
185   clear
186
187          + improved  logic  for  clearing with the E3 extension, in case
188            the  terminal  scrolls  content  onto  its saved-lines before
189            actually  clearing  the  display, by clearing the saved-lines
190            after clearing the display
191
192   infocmp
193
194          + omit  filtering  of  "OTxx" names which are used for obsolete
195            capabilities,  when  the output is sorted by long-names. This
196            change helps when making a table of the short/long capability
197            names.
198
199   tic
200
201          + added   check   for   consistent   alternate   character  set
202            capabilities.
203          + added check for paired indn/rin.
204          + added check for terminals with parm_dch vs parm_ich.
205          + added  check  for  the  case  where setf/setb are given using
206            different   strings,   but   provide   identical  results  to
207            setaf/setab.
208          + corrected check for ich1.
209          + changed  a  too-large  terminal entry from a fatal error to a
210            warning.
211
212   toe
213
214          + ignores  any  hex/b64 $TERMINFO value in the list of terminfo
215            databases.
216
217   tset
218
219          + replace  check  in reset command for obsolete "pt" capability
220            using tbc and hts capabilities as clues
221          + modify reset to allow for tabstops at intervals other than 8.
222          + change   reset's   behavior   for  margins  to  simply  clear
223            soft-margins  if  possible,  rather  than  clearing  and then
224            setting them according to the terminal's width.
225
226   tput
227
228          + add "x" to getopt string so that "tput -x clear" works.
229
230   Several  changes were made to the generated ncurses*config scripts and
231   the   analogous   ".pc"   files  to  reduce  differences  between  the
232   configurations they report:
233     * modified the ncurse*-config and pc-files to more closely match for
234       the -I and -l options.
235     * filtered out linker-specs from the --libs report.
236     * amended  the ncurses*-config and pc-files to take into account the
237       rpath hack which differed between those files.
238     * modified  generated  ncurses*config  and  ncurses.pc, ncursesw.pc,
239       etc., to list helper libraries such as gpm for static linking.
240
241    Examples
242
243   Along  with  the  library and utilities, improvements were made to the
244   ncurses-examples.  Most  of  this  activity  aimed  at  improving  the
245   test-packages.  A few changes are more generally useful, e.g., for the
246   main   ncurses  test-program,  and  for  analyzing  traces  using  the
247   tracemunch script:
248     * improve  recovery  from  error  when  reading command-character in
249       test/ncurses.c, showing the relevant error message and not exiting
250       on EINTR.
251     * improve  tracemunch,  by keeping track of TERMINAL* values, and if
252       tracing  was first turned on after initialization, attempt to show
253       distinct screen, window and terminal names anyway.
254     * modify tracemunch to accept filename parameters in addition to use
255       as a pipe/filter.
256     * update  tracemunch  to  work  with  perl 5.26.2, which changed the
257       rules for escaping regular expressions.
258     * add some checks in tracemunch for undefined variables.
259     * modify TurnOn/TurnOff macros (in lib_vidattr.c and lib_vid_attr.c)
260       to avoid expansion of "CUR" in trace.
261
262   There are other new demo/test programs and reusable examples:
263
264   color_content
265          Demonstrate   the   color_content   and  extended_color_content
266          functions.
267
268   demo_tabs
269          A simple demo of tabs in curses.
270
271   dump_window
272          A  portable  curses screen-dump, used to compare ncurses screen
273          contents with Solaris.
274
275   pair_content
276          Demonstrate    the   pair_content   and   extended_pair_content
277          functions.
278
279   report_hashing
280          Check hash-tables used for terminfo and termcap names.
281
282   parse_rgb
283          Sample   implementation  of  the  ncurses  RGB  extension  from
284          user_caps.5, used in picsmap and savescreen programs.
285
286   A  variety  of  improvements  were made to existing programs, both new
287   features  as  well  as  options added to make the set of programs more
288   consistent.
289     * add  "-l"  option to test/background, to dump screen contents in a
290       form that lets different curses implementations be compared.
291     * add  "@"  command  to  test/ncurses F-test, to allow rapid jump to
292       different character pages.
293     * added enum, regex examples to test/demo_forms
294     * amend  Scaled256() macro in test/picsmap.c to cover the full range
295       0..1000
296     * corrected  pathname used in Ada95 sample programs for explain.txt,
297       to  work  with  test-packages, and used an awk script to split the
298       resulting pathname when it would be too long for a single line.
299     * ignore  interrupted  system-call  in  test/ncurses's command-line,
300       e.g., if the terminal were resized.
301     * improved  ifdef's  for  TABSIZE  variable,  to  help with AIX/HPUX
302       ports.
303
304  Terminal database
305
306   There are several new terminal descriptions:
307
308     alacritty,  domterm,  kitty,  mintty,  mintty-direct,  ms-terminal,
309     n7900,   nsterm-build309,  nsterm-direct,  screen5,  ti703,  ti707,
310     ti703-w, ti707-w vscode, vscode-direct, xterm-mono, xterm.js
311
312   There  are  many  changes to existing terminal descriptions. Some were
313   updates to several descriptions:
314     * use ansi+rep in a dozen places
315     * add rs1 to konsole, mlterm
316     * improve several flash capabilities with trailing mandatory delays
317     * drop   ich1   from   rxvt-basic,   Eterm  and  mlterm  to  improve
318       compatibility with old non-curses programs
319     * add/use xterm+keypad in xterm-new
320     * use xterm+sl-twm for consistency, nine places
321     * improve xm example in xterm+x11mouse and xterm+sm_1006.
322
323   while  others  affected specific descriptions. These were retested, to
324   take into account changes by their developers:
325
326     terminator, st
327
328   while  these are specific fixes based on reviewing documentation, user
329   reports, or warnings from tic:
330
331   adds200:
332
333          + fix typo
334
335   gnome-256color
336
337          + base entry on "gnome", not "vte", for consistency
338
339   interix
340
341          + trim unnecessary setf/setb
342
343   linux-16color
344
345          + accommodate  Linux  console driver incompatibility introduced
346            in early 2018
347
348   nsterm-256color:
349
350          + add nsterm-build309 to replace nsterm-256color, assigning the
351            latter  as  an  alias  of  nsterm,  to  make  mouse work with
352            nsterm-256color
353
354   regent40:
355
356          + renumber function-keys to match manual
357
358   regent60:
359
360          + add cd (clr_eos)
361          + corrected acsc
362          + add shifted function-keys
363
364   tvi950:
365
366          + added  function-key  definitions  to agree with Televideo 950
367            manual
368          + corrected acsc
369          + remove bogus kf0
370          + add bel
371
372   tvi955:
373
374          + fix typo
375
376   vi200:
377
378          + add acsc string, including right/down-arrow
379
380   wy50:
381
382          + corrected acsc
383
384   wy50 and wy60:
385
386          + add shifted function-keys as kF1 to kF16
387
388   xterm+x11hilite:
389
390          + eliminate unused p5 parameter.
391
392   A few entries use extensions (user-defined terminal capabilities):
393     * use  xterm+sm+1006  (aka  "SGR  1006  mouse") for konsole-base and
394       putty
395     * add Smol/Rmol user-defined capability to tmux and vte-2018
396     * add Smulx user-defined capability to tmux, vte-2018
397
398  Documentation
399
400   As usual, this release
401     * improves documentation by describing new features,
402     * attempts  to  improve the description of features which users have
403       found confusing
404     * fills  in overlooked descriptions of features which were described
405       in the NEWS file but treated sketchily in manual pages.
406
407   In  addition  to  providing  background  information  to explain these
408   features   and   show   how   they  evolved,  there  are  corrections,
409   clarifications, etc.:
410     * Corrections:
411          + correct  error-returns  listed in manual pages for a few form
412            functions
413          + corrected  prototypes  in  several  manpages  using script to
414            extract those in compilable form.
415          + fix typo in term.5, improve explanation of format
416     * Clarify in manual pages that vwprintw and vwscanw are obsolete.
417       They have not been part of X/Open Curses since 2007.
418     * New/improved history and portability sections:
419          + curs_addch.3x gives some background for ACS symbols.
420          + curs_getcchar.3x  explains  a  difference between ncurses and
421            X/Open Curses.
422          + curs_getstr.3x  gives  historical/portability  background for
423            the length parameter of wgetnstr.
424          + curs_slk.3x  lists  a few differences between SVr4 curses and
425            X/Open Curses for soft-keys.
426          + curs_terminfo.3x  explains that the initial implementation of
427            terminfo  in  SVr2 was mostly replaced by other developers in
428            SVr3.
429          + infocmp.1  explains  that the initial version of terminfo had
430            no  tool  for decompiling descriptions. That came later, with
431            SVr3, with a different developer.
432          + tabs.1 tells more than you wanted to know about the tool.
433          + tic.1  explains  that  the  initial version of terminfo had a
434            rudimentary  tool  (based  on termcap) for compiling entries.
435            The tool used with Unix was developed by others for SVr3.
436          + toe.1 explains the origin of this tool.
437     * Improvements for user_caps.5:
438          + mention meml, memu and box1
439          + expanded description of XM
440          + add a clarification regarding the RGB capability.
441          + mention user_caps.5 in the tic and infocmp manual pages.
442     * Other improvements:
443          + curs_add_wch.3x  adds  note about Unicode terminology for the
444            line-drawing characters.
445          + curs_color.3x   improves  discussion  of  error  returns  and
446            extensions.
447          + curs_mouse.3x  explains how the kmous and XM capabilities are
448            used for xterm-mouse input.
449          + curs_refresh.3x  improves documentation regarding the virtual
450            and physical screens.
451          + curs_util.3x  mentions  a  difference between SVr4 and X/Open
452            Curses for unctrl.h
453          + curs_variables.3x   improves  description  of  the  init_tabs
454            capability and TABSIZE variable.
455          + ncurses.3x   improves  documentation  regarding  feature-test
456            macros in curses.h
457          + resizeterm.3x   about   top-level  windows  which  touch  the
458            screen's borders.
459          + tput.1 clarifies how tput determines the terminal size.
460
461   There  are  no new manual pages (all of the manual page updates are to
462   existing pages).
463
464   Some  of  the  improvements  are  more subtle, relating to the way the
465   information  is presented. For instance, the generated terminfo.5 file
466   uses  a  different  table  layout,  allowing  it  to use space on wide
467   terminals more effectively.
468
469  Interesting bug-fixes
470
471   While  there  were  many bugs fixed during development of ncurses 6.2,
472   only  a  few  (the  reason  for  this release) were both important and
473   interesting. Most of the bug-fixes were for local issues which did not
474   affect  compatibility across releases. Since those are detailed in the
475   NEWS file no elaboration is needed here.
476
477   The  interesting  bugs  were in tic/infocmp's handling of user-defined
478   capabilities.  These  were  not recent bugs. Initially it was a simple
479   problem:
480     * The  user-defined capabilities can be any type (boolean, number or
481       string),  but  once given a type all uses of the name must conform
482       to  that  type--unless  some  special  support  for  a  particular
483       multi-typed name is built into ncurses.
484     * One of simpleterm's contributors copied some definitions for using
485       tmux's user-defined capabilities in late in 2016.
486
487diff --git a/st.info b/st.info
488@@ -185,7 +185,10 @@ st| simpleterm,
489  tsl=\E]0;,
490  xenl,
491  vpa=\E[%i%p1%dd,
492-
493+# Tmux unofficial extensions, see TERMINFO EXTENSIONS in tmux(1)
494+ Se,
495+ Ss,
496+ Tc,
497
498 st-256color| simpleterm with 256 colors,
499  use=st,
500
501     * Later,  in (referring to a version from mid-2017), a user asked to
502       have it updated in ncurses.
503     * However,  it  had  an  error  from  the  change  in late 2016. The
504       terminal description made what tmux expected to be string actually
505       a boolean.
506       Over  the  years,  there  were  problems with each of simpleterm's
507       terminal  descriptions.  I  repaired those, and usually dealt with
508       the problem.
509     * The  difference  in this case was that when compiling the terminal
510       database, tic may have in memory the definitions for more than one
511       terminal  description  (so  that  it  can resolve "use=" clauses).
512       Seeing   two  different  types  for  the  same  name,  in  certain
513       situations  it  would  incorrectly merge the symbol tables for the
514       two terminal descriptions.
515     * On  simpleterm's  side,  their bug was finally fixed in late 2019,
516       three years after the bug was created.
517
518   For  ncurses,  the  elapsed  time  to fix this bug was less than three
519   years.  Someone reported a problem with the terminal description a few
520   weeks  after  releasing  ncurses 6.1 (in tmux #1264), and the terminal
521   description was updated that week (ncurses patch 20180224):
522
52320180224
524        + modify _nc_resolve_uses2() to detect incompatible types when merging
525          a "use=" clause of extended capabilities.  The problem was seen in a
526          defective terminfo integrated from simpleterm sources in 20171111,
527          compounded by repair in 20180121.
528        + correct Ss/Ms interchange in st-0.7 entry (tmux #1264) -TD
529
530   The larger part of that change added a check to prevent a simple merge
531   of  terminal  descriptions  where  the same user-defined name was used
532   with different types. But it raised some questions:
533     * Was  there  a  reliable  way to manage terminal descriptions which
534       used the same extended name in different ways?
535     * Should  ncurses  provide  a registry of well-known extended names,
536       with their types?
537
538   Since  the  correction to terminfo.src could have been readily adopted
539   by  packagers,  there  was  nothing  more  to  be  done  from ncurses'
540   standpoint  on that part. But improving ncurses to prevent issues like
541   that is the reason for making a release.
542
543   Nothing  more  (constructive) was mentioned with regard to simpleterm.
544   But  a  few  problems  were  found  in  the  handling  of user-defined
545   capabilities:
546     * Forward-references to user-defined capabilities in a "use=" clause
547       did  not  allocate  new  data  for  each  use.  In tic, successive
548       compilation   of   terminal   entries   could   add   user-defined
549       capabilities to the wrong terminal entry.
550       This  was  not noticed before, since xterm's terminal descriptions
551       were  the main users of the feature, and almost all of the uses of
552       the building-blocks which contained user-defined capabilities were
553       backward-references.
554     * There  is  one  (documented)  case  where  ncurses  6.1 supports a
555       user-defined  capability that could be any type (i.e., "RGB"). The
556       check  added  in February 2018 to guard against mismatches did not
557       handle all of the combinations needed.
558
559   Both  of  these  issues  dated  from  the  original  implementation of
560   user-defined  capabilities.  Fixing  them does not change the terminal
561   database, but a older tic without the fixes will not be able to handle
562   terminfo  sources  which rely upon those fixes. Starting in June 2019,
563   the  download  link  for  the  terminfo source file was capped at that
564   date. The development sources have an up-to-date copy of the file, for
565   people with a legitimate need for it.
566
567   The  "-c"  (check) option of tic is not very useful if it cannot offer
568   advice on parameters needed for user-defined capabilities. The various
569   Caps  files  were  reorganized to reduce redundancy, and in the common
570   portion  (Caps-ncurses),  a  registry  of user-defined capabilities is
571   provided for use by tic. While users can still define their own custom
572   capabilities,  tic  will not offer any advice when their parameters do
573   not match.
574
575   In  ncurses  6.2, tic makes a special check to allow any type for RGB,
576   but  its  being  able to do this relies upon fixes made in the ncurses
577   library in mid-2019.
578
579  Configuration changes
580
581    Major changes
582
583   There  are  no  major  changes. Several new options were added to ease
584   integration  of packages with systems using different versions of GNAT
585   and ncurses. Also, improvements were made to configure checks.
586
587    Configuration options
588
589   There are a few new/modified configure options:
590
591   --with-config-suffix
592          helps  work  around  a  filename  conflict with Debian packages
593          versus test-packages.
594
595   --with-ada-libname
596          allows  one  to  rename  the  "AdaCurses" library (at least one
597          packager prefers a lowercase name).
598
599   --with-fallbacks
600          now ensures there is a value, and adds the fallback information
601          to top-level Makefile summary.
602
603   --with-pcre2
604          check for pcre-posix library to help with MinGW port.
605
606   --with-tic-path and
607
608   --with-infocmp-path
609          help  work  around  problems  building  fallback  source  using
610          pre-6.0 tic/infocmp.
611
612   --with-versioned-syms
613          option value can now be a relative pathname.
614
615  Portability
616
617   Many  of  the  portability  changes  are implemented via the configure
618   script:
619     * ignore $TERMINFO as a default value in configure script if it came
620       from the infocmp -Q option.
621     * distinguish  gcc  from  icc  and  clang when the --enable-warnings
622       option   is   not   used,  to  avoid  unnecessary  warnings  about
623       unrecognized inline options
624     * consistently  prepend  new  libraries  as  they  are  found during
625       configuration,  rather  than  relying  upon  the linker to resolve
626       order dependencies of libraries.
627     * modified  configure  scripts  to  reduce  relinking/ranlib  during
628       library install :
629          + use  "install -p" when available, to avoid need for ranlib of
630            static libraries.
631          + scripts which use "--disable-relink;" add a 1-second sleep to
632            work around tools which use whole-second timestamps, e.g., in
633            utime rather than the actual file system resolution.
634     * add configure check for getenv to work around implementation shown
635       in  Emscripten  which overwrites the previous return value on each
636       call.
637       Use  that  to optionally suppress START_TRACE macro, whose call to
638       getenv may not work properly
639     * change  target configure level for _XOPEN_SOURCE to 600 to address
640       use of vsscanf and setenv.
641     * reduce  use of _GNU_SOURCE for current glibc where _DEFAULT_SOURCE
642       combines with _XOPEN_SOURCE
643       Allow  for  Cygwin's  newlib when checking for the _DEFAULT_SOURCE
644       symbol.
645       MidnightBSD   is   now   checked   for  the  _XOPEN_SOURCE-related
646       definitions.
647     * If the check for va_copy or __va_copy fails,
648          + configure  now  tries copying the pointers for va_list, or as
649            an array.
650          + alternatively, it checks for __builtin_va_copy(), which could
651            be used with AIX xlc in c89 mode.
652     * several changes to support a port to Ultrix 3.1:
653          + check if "b" binary feature of fopen works
654          + check for missing feature of locale.h
655          + add fallback for strstr() in test-programs
656          + add fallback for STDOUT_FILENO in test-programs
657     * The test/configure script (used for ncurses-examples) is improved:
658          + work around non-ncurses termcap.h file, e.g., in Slackware.
659          + check for TABSIZE variable.
660          + checks  for  the  X11/Intrinsic.h  header, accommodate recent
661            MacOS changes which largely emptied /usr/include.
662
663   Here are some of the other portability fixes:
664     * added  dummy  "check"  rule  in  top-level  and  test-Makefile  to
665       simplify building test-packages for ArchLinux.
666     * dropped   library-dependency   on  psapi  for  MinGW  port,  since
667       win_driver.c   defines   PSAPI_VERSION   to   2,   making  it  use
668       GetProcessImageFileName from kernel32.dll
669     * made  build-fixes  for  configuration  using --program-suffix with
670       Ada95,  noticed  with  MacOS  but  applicable  to  other platforms
671       without libpanelw, etc.
672     * modified  ncurses/Makefile.in  to  fix a case where Debian/testing
673       changes to the ld --as-needed configuration broke ncurses-examples
674       test packages.
675     * used   _WIN32/_WIN64   in  preference  to  __MINGW32__/__MINGW64__
676       symbols  to simplify building with Microsoft Visual C++, since the
677       former are defined in both compiler configurations.
678     _________________________________________________________________
679
680Features of ncurses
681
682   The  ncurses  package  is  fully upward-compatible with SVr4 (System V
683   Release 4) curses:
684     * All of the SVr4 calls have been implemented (and are documented).
685     * ncurses  supports  all  of  the for SVr4 curses features including
686       keyboard  mapping,  color,  forms-drawing with ACS characters, and
687       automatic recognition of keypad and function keys.
688     * ncurses  provides  these SVr4 add-on libraries (not part of X/Open
689       Curses):
690          + the  panels  library,  supporting  a  stack  of  windows with
691            backing store.
692          + the   menus   library,  supporting  a  uniform  but  flexible
693            interface for menu programming.
694          + the   form   library,   supporting  data  collection  through
695            on-screen forms.
696     * ncurses's  terminal database is fully compatible with that used by
697       SVr4 curses.
698          + ncurses  supports user-defined capabilities which it can see,
699            but  which are hidden from SVr4 curses applications using the
700            same terminal database.
701          + It  can  be optionally configured to match the format used in
702            related systems such as AIX and Tru64.
703          + Alternatively,  ncurses  can  be  configured  to  use  hashed
704            databases  rather  than  the  directory of files used by SVr4
705            curses.
706     * The ncurses utilities have options to allow you to filter terminfo
707       entries for use with less capable curses/terminfo versions such as
708       the HP/UX and AIX ports.
709
710   The ncurses package also has many useful extensions over SVr4:
711     * The  API  is 8-bit clean and base-level conformant with the X/OPEN
712       curses  specification, XSI curses (that is, it implements all BASE
713       level  features,  and  most  EXTENDED  features). It includes many
714       function calls not supported under SVr4 curses (but portability of
715       all calls is documented so you can use the SVr4 subset only).
716     * Unlike  SVr3 curses, ncurses can write to the rightmost-bottommost
717       corner  of  the  screen  if  your terminal has an insert-character
718       capability.
719     * Ada95 and C++ bindings.
720     * Support  for mouse event reporting with X Window xterm and FreeBSD
721       and OS/2 console windows.
722     * Extended mouse support via Alessandro Rubini's gpm package.
723     * The  function  wresize  allows  you  to resize windows, preserving
724       their data.
725     * The  function  use_default_colors allows you to use the terminal's
726       default colors for the default color pair, achieving the effect of
727       transparent colors.
728     * The functions keyok and define_key allow you to better control the
729       use of function keys, e.g., disabling the ncurses KEY_MOUSE, or by
730       defining  more  than  one  control  sequence to map to a given key
731       code.
732     * Support for 256-color terminals, such as modern xterm.
733     * Support for 16-color terminals, such as aixterm and modern xterm.
734     * Better  cursor-movement  optimization.  The package now features a
735       cursor-local-movement computation more efficient than either BSD's
736       or System V's.
737     * Super   hardware   scrolling   support.   The  screen-update  code
738       incorporates  a novel, simple, and cheap algorithm that enables it
739       to  make  optimal  use  of hardware scrolling, line-insertion, and
740       line-deletion  for  screen-line  movements. This algorithm is more
741       powerful than the 4.4BSD curses quickch routine.
742     * Real  support  for  terminals  with  the  magic-cookie glitch. The
743       screen-update  code  will  refrain from drawing a highlight if the
744       magic-   cookie  unattributed  spaces  required  just  before  the
745       beginning  and  after the end would step on a non-space character.
746       It  will  automatically  shift  highlight boundaries when doing so
747       would  make it possible to draw the highlight without changing the
748       visual appearance of the screen.
749     * It  is  possible to generate the library with a list of pre-loaded
750       fallback  entries linked to it so that it can serve those terminal
751       types  even  when  no  terminfo tree or termcap file is accessible
752       (this  may  be useful for support of screen-oriented programs that
753       must run in single-user mode).
754     * The tic/captoinfo utility provided with ncurses has the ability to
755       translate  many  termcaps  from  the XENIX, IBM and AT&T extension
756       sets.
757     * A BSD-like tset utility is provided.
758     * The ncurses library and utilities will automatically read terminfo
759       entries  from  $HOME/.terminfo  if  it exists, and compile to that
760       directory  if  it  exists  and the user has no write access to the
761       system  directory.  This feature makes it easier for users to have
762       personal  terminfo  entries without giving up access to the system
763       terminfo directory.
764     * You  may  specify  a  path  of  directories to search for compiled
765       descriptions  with  the  environment  variable TERMINFO_DIRS (this
766       generalizes  the  feature  provided by TERMINFO under stock System
767       V.)
768     * In  terminfo  source files, use capabilities may refer not just to
769       other entries in the same source file (as in System V) but also to
770       compiled  entries  in  either the system terminfo directory or the
771       user's $HOME/.terminfo directory.
772     * The  table-of-entries  utility  toe makes it easy for users to see
773       exactly what terminal types are available on the system.
774     * The library meets the XSI requirement that every macro entry point
775       have  a  corresponding  function  which may be linked (and will be
776       prototype-checked)  if  the  macro  definition  is  disabled  with
777       #undef.
778     * Extensive  documentation  is  provided (see the Additional Reading
779       section of the ncurses FAQ for online documentation).
780
781Applications using ncurses
782
783   The  ncurses  distribution  includes  a  selection  of  test  programs
784   (including   a   few   games).   These  are  available  separately  as
785   ncurses-examples
786
787   The   ncurses   library  has  been  tested  with  a  wide  variety  of
788   applications including:
789
790   aptitude
791          FrontEnd to Apt, the debian package manager
792
793          https://wiki.debian.org/Aptitude
794
795   cdk
796          Curses Development Kit
797
798          https://invisible-island.net/cdk/
799
800   ded
801          directory-editor
802
803          https://invisible-island.net/ded/
804
805   dialog
806          the  underlying  application used in Slackware's setup, and the
807          basis   for  similar  install/configure  applications  on  many
808          systems.
809
810          https://invisible-island.net/dialog/
811
812   lynx
813          the text WWW browser
814
815          https://lynx.invisible-island.net/
816
817   mutt
818          mail utility
819
820          http://www.mutt.org/
821
822   ncftp
823          file-transfer utility
824
825          https://www.ncftp.com/
826
827   nvi
828          New vi uses ncurses.
829
830          https://sites.google.com/a/bostic.com/keithbostic/vi
831
832   ranger
833          A console file manager with VI key bindings in Python.
834
835          https://ranger.github.io/
836
837   tin
838          newsreader, supporting color, MIME
839
840          http://www.tin.org/
841
842   vifm
843          File manager with vi like keybindings
844
845          https://vifm.info/
846
847   as well as some that use ncurses for the terminfo support alone:
848
849   minicom
850          terminal emulator for serial modem connections
851
852          https://alioth.debian.org/projects/minicom/
853
854   mosh
855          a replacement for ssh.
856
857          https://mosh.mit.edu/
858
859   tack
860          terminfo action checker
861
862          https://invisible-island.net/ncurses/tack.html
863
864   tmux
865          terminal multiplexor
866
867          https://github.com/tmux/tmux/wiki
868
869   vile
870          vi-like-emacs  may  be  built  to  use the terminfo, termcap or
871          curses interfaces.
872
873          https://invisible-island.net/vile/
874
875   and finally, those which use only the termcap interface:
876
877   emacs
878          text editor
879
880          https://www.gnu.org/software/emacs/
881
882   less
883          The  most  commonly  used  pager  (a program that displays text
884          files).
885
886          http://www.greenwoodsoftware.com/less/
887
888   screen
889          terminal multiplexor
890
891          https://www.gnu.org/software/screen/
892
893   vim
894          text editor
895
896          https://www.vim.org/
897
898Development activities
899
900   Zeyd  Ben-Halim  started  ncurses  from  a  previous  package pcurses,
901   written  by  Pavel  Curtis.  Eric  S.  Raymond  continued development.
902   Juergen Pfeifer wrote most of the form and menu libraries.
903
904   Ongoing development work is done by Thomas E. Dickey. Thomas E. Dickey
905   has  acted  as  the maintainer for the Free Software Foundation, which
906   holds  a  copyright on ncurses for releases 4.2 through 6.1. Following
907   the release of ncurses 6.1, effective as of release 6.2, copyright for
908   ncurses  reverted  to  Thomas  E.  Dickey  (see  the  ncurses  FAQ for
909   additional information).
910
911   Contact the current maintainers at
912
913     bug-ncurses@gnu.org
914
915   To join the ncurses mailing list, please write email to
916
917     bug-ncurses-request@gnu.org
918
919   containing the line:
920
921     subscribe <name>@<host.domain>
922
923   This list is open to anyone interested in helping with the development
924   and testing of this package.
925
926   Beta versions of ncurses are made available at
927
928     ftp://ftp.invisible-island.net/ncurses/current/ and
929     https://invisible-mirror.net/archives/ncurses/current/ .
930
931   Patches to the current release are made available at
932
933     ftp://ftp.invisible-island.net/ncurses/6.1/ and
934     https://invisible-mirror.net/archives/ncurses/6.1/ .
935
936   There is an archive of the mailing list here:
937
938     http://lists.gnu.org/archive/html/bug-ncurses (also https)
939
940Related resources
941
942   The  release notes make scattered references to these pages, which may
943   be interesting by themselves:
944     * ncurses licensing
945     * Symbol versioning in ncurses
946     * Comments on ncurses versus slang (S-Lang)
947     * tack - terminfo action checker
948     * tctest - termcap library checker
949     * Terminal Database
950
951Other resources
952
953   The  distribution  provides  a  newer  version  of the terminfo-format
954   terminal description file once maintained by Eric Raymond . Unlike the
955   older  version, the termcap and terminfo data are provided in the same
956   file, which also provides several user-definable extensions beyond the
957   X/Open specification.
958
959   You  can  find  lots  of  information  on  terminal-related topics not
960   covered  in  the  terminfo  file  at  Richard  Shuford's archive . The
961   collection of computer manuals at bitsavers.org has also been useful.
962
963     * Overview
964     * Release Notes
965          + Library improvements
966               o New features
967               o Other improvements
968          + Program improvements
969               o Utilities
970               o Examples
971          + Terminal database
972          + Documentation
973          + Interesting bug-fixes
974          + Configuration changes
975               o Major changes
976               o Configuration options
977          + Portability
978     * Features of ncurses
979     * Applications using ncurses
980     * Development activities
981     * Related resources
982     * Other resources
983