1curs_terminfo(3X) curs_terminfo(3X)
2
6 del_curterm, mvcur, putp, restartterm, set_curterm, setupterm,
7 tigetflag, tigetnum, tigetstr, tiparm, tparm, tputs, vid_attr,
8 vid_puts, vidattr, vidputs - curses interfaces to terminfo database
9
11 #include <curses.h>
12 #include <term.h>
13 TERMINAL *cur_term;
15 const char * const boolnames[];
17 const char * const boolcodes[];
18 const char * const boolfnames[];
19 const char * const numnames[];
20 const char * const numcodes[];
21 const char * const numfnames[];
22 const char * const strnames[];
23 const char * const strcodes[];
24 const char * const strfnames[];
25 int setupterm(const char *term, int filedes, int *errret);
27 TERMINAL *set_curterm(TERMINAL *nterm);
28 int del_curterm(TERMINAL *oterm);
29 int restartterm(const char *term, int filedes, int *errret);
30 char *tparm(const char *str, ...);
32 int tputs(const char *str, int affcnt, int (*putc)(int));
33 int putp(const char *str);
34 int vidputs(chtype attrs, int (*putc)(int));
36 int vidattr(chtype attrs);
37 int vid_puts(attr_t attrs, short pair, void *opts, int (*putc)(int));
38 int vid_attr(attr_t attrs, short pair, void *opts);
39 int mvcur(int oldrow, int oldcol, int newrow, int newcol);
41 int tigetflag(const char *capname);
43 int tigetnum(const char *capname);
44 char *tigetstr(const char *capname);
45 char *tiparm(const char *str, ...);
47
49 These low-level routines must be called by programs that have to deal
50 directly with the terminfo database to handle certain terminal capabil‐
51 ities, such as programming function keys. For all other functionality,
52 curses routines are more suitable and their use is recommended.
53 None of these functions use (or are aware of) multibyte character
55 strings such as UTF-8:
56 • capability names use the POSIX portable character set
58 • capability string values have no associated encoding; they are
60 strings of 8-bit characters.
61 Initialization
63 Initially, setupterm should be called. The high-level curses functions
64 initscr and newterm call setupterm to initialize the low-level set of
65 terminal-dependent variables [listed in terminfo(5)].
66 Applications can use the terminal capabilities either directly (via
68 header definitions), or by special functions. The header files curs‐
69 es.h and term.h should be included (in this order) to get the defini‐
70 tions for these strings, numbers, and flags.
71 The terminfo variables lines and columns are initialized by setupterm
73 as follows:
74 • If use_env(FALSE) has been called, values for lines and columns
76 specified in terminfo are used.
77 • Otherwise, if the environment variables LINES and COLUMNS exist,
79 their values are used. If these environment variables do not exist
80 and the program is running in a window, the current window size is
81 used. Otherwise, if the environment variables do not exist, the
82 values for lines and columns specified in the terminfo database are
83 used.
84 Parameterized strings should be passed through tparm to instantiate
86 them. All terminfo strings (including the output of tparm) should be
87 printed with tputs or putp. Call reset_shell_mode to restore the tty
88 modes before exiting [see curs_kernel(3X)].
89 Programs which use cursor addressing should
91 • output enter_ca_mode upon startup and
93 • output exit_ca_mode before exiting.
95 Programs which execute shell subprocesses should
97 • call reset_shell_mode and output exit_ca_mode before the shell is
99 called and
100 • output enter_ca_mode and call reset_prog_mode after returning from
102 the shell.
103 The setupterm routine reads in the terminfo database, initializing the
105 terminfo structures, but does not set up the output virtualization
106 structures used by curses. These are its parameters:
107 term is the terminal type, a character string. If term is null, the
109 environment variable TERM is used.
110 filedes
112 is the file descriptor used for all output.
113 errret
115 points to an optional location where an error status can be re‐
116 turned to the caller. If errret is not null, then setupterm
117 returns OK or ERR and stores a status value in the integer
118 pointed to by errret. A return value of OK combined with sta‐
119 tus of 1 in errret is normal.
120 If ERR is returned, examine errret:
122 1 means that the terminal is hardcopy, cannot be used for
124 curses applications.
125 setupterm determines if the entry is a hardcopy type by
127 checking the hc (hardcopy) capability.
128 0 means that the terminal could not be found, or that it is
130 a generic type, having too little information for curses
131 applications to run.
132 setupterm determines if the entry is a generic type by
134 checking the gn (generic) capability.
135 -1 means that the terminfo database could not be found.
137 If errret is null, setupterm prints an error message upon find‐
139 ing an error and exits. Thus, the simplest call is:
140 setupterm((char *)0, 1, (int *)0);,
142 which uses all the defaults and sends the output to stdout.
144 The Terminal State
146 The setupterm routine stores its information about the terminal in a
147 TERMINAL structure pointed to by the global variable cur_term. If it
148 detects an error, or decides that the terminal is unsuitable (hardcopy
149 or generic), it discards this information, making it not available to
150 applications.
151 If setupterm is called repeatedly for the same terminal type, it will
153 reuse the information. It maintains only one copy of a given termi‐
154 nal's capabilities in memory. If it is called for different terminal
155 types, setupterm allocates new storage for each set of terminal capa‐
156 bilities.
157 The set_curterm routine sets cur_term to nterm, and makes all of the
159 terminfo boolean, numeric, and string variables use the values from
160 nterm. It returns the old value of cur_term.
161 The del_curterm routine frees the space pointed to by oterm and makes
163 it available for further use. If oterm is the same as cur_term, refer‐
164 ences to any of the terminfo boolean, numeric, and string variables
165 thereafter may refer to invalid memory locations until another se‐
166 tupterm has been called.
167 The restartterm routine is similar to setupterm and initscr, except
169 that it is called after restoring memory to a previous state (for exam‐
170 ple, when reloading a game saved as a core image dump). restartterm
171 assumes that the windows and the input and output options are the same
172 as when memory was saved, but the terminal type and baud rate may be
173 different. Accordingly, restartterm saves various tty state bits,
174 calls setupterm, and then restores the bits.
175 Formatting Output
177 The tparm routine instantiates the string str with parameters pi. A
178 pointer is returned to the result of str with the parameters applied.
179 Application developers should keep in mind these quirks of the inter‐
180 face:
181 • Although tparm's actual parameters may be integers or strings, the
183 prototype expects long (integer) values.
184 • Aside from the set_attributes (sgr) capability, most terminal capa‐
186 bilities require no more than one or two parameters.
187 • Padding information is ignored by tparm; it is interpreted by
189 tputs.
190 • The capability string is null-terminated. Use “\200” where an
192 ASCII NUL is needed in the output.
193 tiparm is a newer form of tparm which uses <stdarg.h> rather than a
195 fixed-parameter list. Its numeric parameters are integers (int) rather
196 than longs.
197 Output Functions
199 The tputs routine applies padding information (i.e., by interpreting
200 marker embedded in the terminfo capability such as “$<5>” as 5 mil‐
201 liseconds) to the string str and outputs it:
202 • The str parameter must be a terminfo string variable or the return
204 value from tparm, tiparm, tgetstr, or tgoto.
205 The tgetstr and tgoto functions are part of the termcap interface,
207 which happens to share this function name with the terminfo inter‐
208 face.
209 • affcnt is the number of lines affected, or 1 if not applicable.
211 • putc is a putchar-like routine to which the characters are passed,
213 one at a time.
214 The putp routine calls tputs(str, 1, putchar). The output of putp al‐
216 ways goes to stdout, rather than the filedes specified in setupterm.
217 The vidputs routine displays the string on the terminal in the video
219 attribute mode attrs, which is any combination of the attributes listed
220 in curses(3X). The characters are passed to the putchar-like routine
221 putc.
222 The vidattr routine is like the vidputs routine, except that it outputs
224 through putchar.
225 The vid_attr and vid_puts routines correspond to vidattr and vidputs,
227 respectively. They use a set of arguments for representing the video
228 attributes plus color, i.e.,
229 • attrs of type attr_t for the attributes and
231 • pair of type short for the color-pair number.
233 The vid_attr and vid_puts routines are designed to use the attribute
235 constants with the WA_ prefix.
236 X/Open Curses reserves the opts argument for future use, saying that
238 applications must provide a null pointer for that argument. As an ex‐
239 tension, this implementation allows opts to be used as a pointer to
240 int, which overrides the pair (short) argument.
241 The mvcur routine provides low-level cursor motion. It takes effect
243 immediately (rather than at the next refresh).
244 While putp and mvcur are low-level functions which do not use the high-
246 level curses state, they are declared in <curses.h> because SystemV did
247 this (see HISTORY).
248 Terminal Capability Functions
250 The tigetflag, tigetnum and tigetstr routines return the value of the
251 capability corresponding to the terminfo capname passed to them, such
252 as xenl. The capname for each capability is given in the table column
253 entitled capname code in the capabilities section of terminfo(5).
254 These routines return special values to denote errors.
256 The tigetflag routine returns
258 -1 if capname is not a boolean capability, or
260 0 if it is canceled or absent from the terminal description.
262 The tigetnum routine returns
264 -2 if capname is not a numeric capability, or
266 -1 if it is canceled or absent from the terminal description.
268 The tigetstr routine returns
270 (char *)-1
272 if capname is not a string capability, or
273 0 if it is canceled or absent from the terminal description.
275 Terminal Capability Names
277 These null-terminated arrays contain
278 • the short terminfo names (“codes”),
280 • the termcap names (“names”), and
282 • the long terminfo names (“fnames”)
284 for each of the predefined terminfo variables:
286 const char *boolnames[], *boolcodes[], *boolfnames[]
288 const char *numnames[], *numcodes[], *numfnames[]
289 const char *strnames[], *strcodes[], *strfnames[]
290 Releasing Memory
292 Each successful call to setupterm allocates memory to hold the terminal
293 description. As a side-effect, it sets cur_term to point to this memo‐
294 ry. If an application calls
295 del_curterm(cur_term);
297 the memory will be freed.
299 The formatting functions tparm and tiparm extend the storage allocated
301 by setupterm:
302 • the “static” terminfo variables [a-z]. Before ncurses 6.3, those
304 were shared by all screens. With ncurses 6.3, those are allocated
305 per screen. See terminfo(5) for details.
306 • to improve performance, ncurses 6.3 caches the result of analyzing
308 terminfo strings for their parameter types. That is stored as a
309 binary tree referenced from the TERMINAL structure.
310 The higher-level initscr and newterm functions use setupterm. Normally
312 they do not free this memory, but it is possible to do that using the
313 delscreen(3X) function.
314
316 Routines that return an integer return ERR upon failure and OK (SVr4
317 only specifies “an integer value other than ERR”) upon successful com‐
318 pletion, unless otherwise noted in the preceding routine descriptions.
319 Routines that return pointers always return NULL on error.
321 X/Open defines no error conditions. In this implementation
323 del_curterm
325 returns an error if its terminal parameter is null.
326 putp calls tputs, returning the same error-codes.
328 restartterm
330 returns an error if the associated call to setupterm returns an
331 error.
332 setupterm
334 returns an error if it cannot allocate enough memory, or create
335 the initial windows (stdscr, curscr, newscr). Other error con‐
336 ditions are documented above.
337 tputs
339 returns an error if the string parameter is null. It does not
340 detect I/O errors: X/Open states that tputs ignores the return
341 value of the output function putc.
342 Compatibility macros
344 This implementation provides a few macros for compatibility with sys‐
345 tems before SVr4 (see HISTORY). Those include crmode, fixterm,
346 gettmode, nocrmode, resetterm, saveterm, and setterm.
347 In SVr4, those are found in <curses.h>, but except for setterm, are
349 likewise macros. The one function, setterm, is mentioned in the manual
350 page. The manual page notes that the setterm routine was replaced by
351 setupterm, stating that the call:
352 setupterm(term, 1, (int *)0)
354 provides the same functionality as setterm(term), and is not recommend‐
356 ed for new programs. This implementation provides each of those sym‐
357 bols as macros for BSD compatibility,
358
360 SVr2 introduced the terminfo feature. Its programming manual mentioned
361 these low-level functions:
362 Function Description
364 ────────────────────────────────────────────────────────────
365 fixterm restore tty to “in curses” state
366 gettmode establish current tty modes
367 mvcur low level cursor motion
368 putp utility function that uses tputs to send char‐
369 acters via putchar.
370 resetterm set tty modes to “out of curses” state
371 resetty reset tty flags to stored value
372 saveterm save current modes as “in curses” state
373 savetty store current tty flags
374 setterm establish terminal with given type
375 setupterm establish terminal with given type
376 tparm instantiate a string expression with parameters
377 tputs apply padding information to a string
378 vidattr like vidputs, but outputs through putchar
379 vidputs output a string to put terminal in a specified
380 video attribute mode
381 The programming manual also mentioned functions provided for termcap
383 compatibility (commenting that they “may go away at a later date”):
384 Function Description
386 ────────────────────────────────────────────────
387 tgetent look up termcap entry for given name
388 tgetflag get boolean entry for given id
389 tgetnum get numeric entry for given id
390 tgetstr get string entry for given id
391 tgoto apply parameters to given capability
392 tputs apply padding to capability, calling
393 a function to put characters
394 Early terminfo programs obtained capability values from the TERMINAL
396 structure initialized by setupterm.
397 SVr3 extended terminfo by adding functions to retrieve capability val‐
399 ues (like the termcap interface), and reusing tgoto and tputs:
400 Function Description
402 ───────────────────────────────────────────
403 tigetflag get boolean entry for given id
404 tigetnum get numeric entry for given id
406 tigetstr get string entry for given id
407 SVr3 also replaced several of the SVr2 terminfo functions which had no
409 counterpart in the termcap interface, documenting them as obsolete:
410 Function Replaced by
412 ─────────────────────────────
413 crmode cbreak
414 fixterm reset_prog_mode
415 gettmode N/A
416 nocrmode nocbreak
417 resetterm reset_shell_mode
418 saveterm def_prog_mode
419 setterm setupterm
420 SVr3 kept the mvcur, vidattr and vidputs functions, along with putp,
422 tparm and tputs. The latter were needed to support padding, and han‐
423 dling functions such as vidattr (which used more than the two parame‐
424 ters supported by tgoto).
425 SVr3 introduced the functions for switching between terminal descrip‐
427 tions, e.g., set_curterm. Some of that was incremental improvements to
428 the SVr2 library:
429 • The TERMINAL type definition was introduced in SVr3.01, for the
431 term structure provided in SVr2.
432 • The various global variables such as boolnames were mentioned in
434 the programming manual at this point, though the variables were
435 provided in SVr2.
436 SVr4 added the vid_attr and vid_puts functions.
438 There are other low-level functions declared in the curses header files
440 on Unix systems, but none were documented. The functions marked “obso‐
441 lete” remained in use by the Unix vi(1) editor.
442
444 Legacy functions
445 X/Open notes that vidattr and vidputs may be macros.
446 The function setterm is not described by X/Open and must be considered
448 non-portable. All other functions are as described by X/Open.
449 Legacy data
451 setupterm copies the terminal name to the array ttytype. This is not
452 part of X/Open Curses, but is assumed by some applications.
453 Other implementions may not declare the capability name arrays. Some
455 provide them without declaring them. X/Open does not specify them.
456 Extended terminal capability names, e.g., as defined by tic -x, are not
458 stored in the arrays described here.
459 Output buffering
461 Older versions of ncurses assumed that the file descriptor passed to
462 setupterm from initscr or newterm uses buffered I/O, and would write to
463 the corresponding stream. In addition to the limitation that the ter‐
464 minal was left in block-buffered mode on exit (like System V curses),
465 it was problematic because ncurses did not allow a reliable way to
466 cleanup on receiving SIGTSTP.
467 The current version (ncurses6) uses output buffers managed directly by
469 ncurses. Some of the low-level functions described in this manual page
470 write to the standard output. They are not signal-safe. The high-lev‐
471 el functions in ncurses use alternate versions of these functions using
472 the more reliable buffering scheme.
473 Function prototypes
475 The X/Open Curses prototypes are based on the SVr4 curses header decla‐
476 rations, which were defined at the same time the C language was first
477 standardized in the late 1980s.
478 • X/Open Curses uses const less effectively than a later design
480 might, in some cases applying it needlessly to values are already
481 constant, and in most cases overlooking parameters which normally
482 would use const. Using constant parameters for functions which do
483 not use const may prevent the program from compiling. On the other
484 hand, writable strings are an obsolescent feature.
485 As an extension, this implementation can be configured to change
487 the function prototypes to use the const keyword. The ncurses ABI
488 6 enables this feature by default.
489 • X/Open Curses prototypes tparm with a fixed number of parameters,
491 rather than a variable argument list.
492 This implementation uses a variable argument list, but can be con‐
494 figured to use the fixed-parameter list. Portable applications
495 should provide 9 parameters after the format; zeroes are fine for
496 this purpose.
497 In response to review comments by Thomas E. Dickey, X/Open Curses
499 Issue 7 proposed the tiparm function in mid-2009.
500 Special TERM treatment
502 If configured to use the terminal-driver, e.g., for the MinGW port,
503 • setupterm interprets a missing/empty TERM variable as the special
505 value “unknown”.
506 • setupterm allows explicit use of the the windows console driver by
508 checking if $TERM is set to “#win32con” or an abbreviation of that
509 string.
510 Other portability issues
512 In System V Release 4, set_curterm has an int return type and returns
513 OK or ERR. We have chosen to implement the X/Open Curses semantics.
514 In System V Release 4, the third argument of tputs has the type int
516 (*putc)(char).
517 At least one implementation of X/Open Curses (Solaris) returns a value
519 other than OK/ERR from tputs. That returns the length of the string,
520 and does no error-checking.
521 X/Open notes that after calling mvcur, the curses state may not match
523 the actual terminal state, and that an application should touch and re‐
524 fresh the window before resuming normal curses calls. Both ncurses and
525 System V Release 4 curses implement mvcur using the SCREEN data allo‐
526 cated in either initscr or newterm. So though it is documented as a
527 terminfo function, mvcur is really a curses function which is not well
528 specified.
529 X/Open states that the old location must be given for mvcur. This im‐
531 plementation allows the caller to use -1's for the old ordinates. In
532 that case, the old location is unknown.
533
535 curses(3X), curs_initscr(3X), curs_kernel(3X), curs_memleaks(3X),
536 curs_termcap(3X), curs_variables(3X), term_variables(3X), putc(3), ter‐
537 minfo(5)
538 curs_terminfo(3X)