$OpenBSD: terminfo.3,v 1.11 2023/10/17 09:52:08 nicm Exp $
***************************************************************************
Copyright 2018-2022,2023 Thomas E. Dickey *
Copyright 1998-2016,2017 Free Software Foundation, Inc. *
*
Permission is hereby granted, free of charge, to any person obtaining a *
copy of this software and associated documentation files (the *
"Software"), to deal in the Software without restriction, including *
without limitation the rights to use, copy, modify, merge, publish, *
distribute, distribute with modifications, sublicense, and/or sell *
copies of the Software, and to permit persons to whom the Software is *
furnished to do so, subject to the following conditions: *
*
The above copyright notice and this permission notice shall be included *
in all copies or substantial portions of the Software. *
*
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
*
Except as contained in this notice, the name(s) of the above copyright *
holders shall not be used in advertising or otherwise to promote the *
sale, use or other dealings in this Software without prior written *
authorization. *
***************************************************************************
$Id: terminfo.3,v 1.11 2023/10/17 09:52:08 nicm Exp $
#include <curses.h> #include <term.h> TERMINAL *cur_term; const char * const boolnames[]; const char * const boolcodes[]; const char * const boolfnames[]; const char * const numnames[]; const char * const numcodes[]; const char * const numfnames[]; const char * const strnames[]; const char * const strcodes[]; const char * const strfnames[]; int setupterm(const char *term, int filedes, int *errret);TERMINAL *set_curterm(TERMINAL *nterm);
int del_curterm(TERMINAL *oterm);
int restartterm(const char *term, int filedes, int *errret); char *tparm(const char *str, ...);
or
char *tparm(const char *str, long p1 ... long p9); int tputs(const char *str, int affcnt, int (*putc)(int));
int putp(const char *str); int vidputs(chtype attrs, int (*putc)(int));
int vidattr(chtype attrs);
int vid_puts(attr_t attrs, short pair, void *opts, int (*putc)(int));
int vid_attr(attr_t attrs, short pair, void *opts); int mvcur(int oldrow, int oldcol, int newrow, int newcol); int tigetflag(const char *capname);
int tigetnum(const char *capname);
char *tigetstr(const char *capname); char *tiparm(const char *str, ...); /* extensions */
char *tiparm_s(int expected, int mask, const char *str, ...);
int tiscan_s(int *expected, int *mask, const char *str);
None of these functions use (or are aware of) multibyte character strings such as UTF-8: .bP capability names use the POSIX portable character set .bP capability string values have no associated encoding; they are strings of 8-bit characters.
Applications can use the terminal capabilities either directly (via header definitions), or by special functions. The header files curses.h and term.h should be included (in this order) to get the definitions for these strings, numbers, and flags.
The terminfo variables lines and columns are initialized by setupterm as follows: .bP If use_env(FALSE) has been called, values for lines and columns specified in terminfo are used. .bP Otherwise, if the environment variables LINES and COLUMNS exist, their values are used. If these environment variables do not exist and the program is running in a window, the current window size is used. Otherwise, if the environment variables do not exist, the values for lines and columns specified in the terminfo database are used.
Parameterized strings should be passed through tparm to instantiate them. All terminfo strings (including the output of tparm) should be printed with tputs or putp. Call reset_shell_mode to restore the tty modes before exiting [see curs_kernel(3)].
Programs which use cursor addressing should .bP output enter_ca_mode upon startup and .bP output exit_ca_mode before exiting.
Programs which execute shell subprocesses should .bP call reset_shell_mode and output exit_ca_mode before the shell is called and .bP output enter_ca_mode and call reset_prog_mode after returning from the shell.
The setupterm routine reads in the terminfo database, initializing the terminfo structures, but does not set up the output virtualization structures used by curses. These are its parameters:
5 term is the terminal type, a character string. If term is null, the environment variable TERM is used.
5 filedes is the file descriptor used for getting and setting terminal I/O modes.
Higher-level applications use newterm(3) for initializing the terminal, passing an output stream rather than a descriptor. In curses, the two are the same because newterm calls setupterm, passing the file descriptor derived from its output stream parameter.5 errret points to an optional location where an error status can be returned to the caller. If errret is not null, then setupterm returns OK or ERR and stores a status value in the integer pointed to by errret. A return value of OK combined with status of 1 in errret is normal.
If ERR is returned, examine errret:
5 1 means that the terminal is hardcopy, cannot be used for curses applications.
setupterm determines if the entry is a hardcopy type by checking the hc (hardcopy) capability.5 0 means that the terminal could not be found, or that it is a generic type, having too little information for curses applications to run.
setupterm determines if the entry is a generic type by checking the gn (generic_type) capability.5 -1 means that the terminfo database could not be found.
If setupterm is called repeatedly for the same terminal type, it will reuse the information. It maintains only one copy of a given terminal's capabilities in memory. If it is called for different terminal types, setupterm allocates new storage for each set of terminal capabilities.
The set_curterm routine sets cur_term to nterm, and makes all of the terminfo boolean, numeric, and string variables use the values from nterm. It returns the old value of cur_term.
The del_curterm routine frees the space pointed to by oterm and makes it available for further use. If oterm is the same as cur_term, references to any of the terminfo boolean, numeric, and string variables thereafter may refer to invalid memory locations until another setupterm has been called.
The restartterm routine is similar to setupterm and initscr,
except that it is called after restoring memory to a previous state (for
example, when reloading a game saved as a core image dump).
restartterm assumes that the windows and the input and output options
are the same as when memory was saved,
but the terminal type and baud rate may be different.
Accordingly, restartterm saves various tty state bits,
calls setupterm, and then restores the bits.
***************************************************************************
tiparm is a newer form of tparm which uses <stdarg.h> rather than a fixed-parameter list. Its numeric parameters are integers (int) rather than longs.
Both tparm and tiparm assume that the application passes parameters consistent with the terminal description. Two extensions are provided as alternatives to deal with untrusted data: .bP tiparm_s is an extension which is a safer formatting function than tparm or tiparm, because it allows the developer to tell the curses library how many parameters to expect in the parameter list, and which may be string parameters.
The mask parameter has one bit set for each of the parameters (up to 9) which will be passed as char* rather than numbers. .bP The extension tiscan_s allows the application to inspect a formatting capability to see what the curses library would assume. ***************************************************************************The putp routine calls tputs(str, 1, putchar). The output of putp always goes to stdout, rather than the filedes specified in setupterm.
The vidputs routine displays the string on the terminal in the video attribute mode attrs, which is any combination of the attributes listed in curses(3). The characters are passed to the putchar-like routine putc.
The vidattr routine is like the vidputs routine, except that it outputs through putchar.
The vid_attr and vid_puts routines correspond to vidattr and vidputs, respectively. They use a set of arguments for representing the video attributes plus color, i.e., .bP attrs of type attr_t for the attributes and .bP pair of type short for the color-pair number.
The vid_attr and vid_puts routines are designed to use the attribute constants with the WA_ prefix.
X/Open Curses reserves the opts argument for future use, saying that applications must provide a null pointer for that argument. As an extension, this implementation allows opts to be used as a pointer to int, which overrides the pair (short) argument.
The mvcur routine provides low-level cursor motion. It takes effect immediately (rather than at the next refresh). Unlike the other low-level output functions, which either write to the standard output or pass an output function parameter, mvcur uses an output file descriptor derived from the output stream parameter of newterm(3).
While putp and mvcur are low-level functions which
do not use the high-level curses state,
they are declared in <curses.h> because SystemV did this
(see HISTORY).
***************************************************************************
These routines return special values to denote errors.
The tigetflag routine returns
-1 if capname is not a boolean capability, or
0 if it is canceled or absent from the terminal description.
The tigetnum routine returns
-2 if capname is not a numeric capability, or
-1 if it is canceled or absent from the terminal description.
The tigetstr routine returns
(char *)-1 if capname is not a string capability, or
0
if it is canceled or absent from the terminal description.
***************************************************************************
for each of the predefined terminfo variables:
const char *boolnames[], *boolcodes[], *boolfnames[]
const char *numnames[], *numcodes[], *numfnames[]
const char *strnames[], *strcodes[], *strfnames[]
The formatting functions tparm and tiparm extend the storage allocated by setupterm: .bP the \*(``static\*('' terminfo variables [a-z]. Before ncurses 6.3, those were shared by all screens. With ncurses 6.3, those are allocated per screen. See terminfo(\*n) for details. .bP to improve performance, ncurses 6.3 caches the result of analyzing terminfo strings for their parameter types. That is stored as a binary tree referenced from the TERMINAL structure.
The higher-level initscr and newterm functions use setupterm.
Normally they do not free this memory, but it is possible to do that using
the delscreen(3) function.
***************************************************************************
Routines that return pointers always return NULL on error.
X/Open defines no error conditions. In this implementation
5 del_curterm returns an error if its terminal parameter is null.
5 putp calls tputs, returning the same error-codes.
5 restartterm returns an error if the associated call to setupterm returns an error.
5 setupterm returns an error if it cannot allocate enough memory, or create the initial windows (stdscr, curscr, newscr). Other error conditions are documented above.
5 tparm returns a null if the capability would require unexpected parameters, e.g., too many, too few, or incorrect types (strings where integers are expected, or vice versa).
5 tputs returns an error if the string parameter is null. It does not detect I/O errors: X/Open states that tputs ignores the return value of the output function putc.
In SVr4, those are found in <curses.h>,
but except for setterm, are likewise macros.
The one function, setterm, is mentioned in the manual page.
The manual page notes that the setterm routine
was replaced by setupterm, stating that the call:
setupterm(term, 1, (int *)0)
provides the same functionality as setterm(term),
and is not recommended for new programs.
This implementation provides each of those symbols
as macros for BSD compatibility,
***************************************************************************
Function Description |
fixterm restore tty to \*(``in curses\*('' state |
gettmode establish current tty modes |
mvcur low level cursor motion |
putp |
utility function that uses tputs to send characters via putchar. |
resetterm set tty modes to \*(``out of curses\*('' state |
resetty reset tty flags to stored value |
saveterm save current modes as \*(``in curses\*('' state |
savetty store current tty flags |
setterm establish terminal with given type |
setupterm establish terminal with given type |
tparm instantiate a string expression with parameters |
tputs apply padding information to a string |
vidattr like vidputs, but outputs through putchar |
vidputs |
output a string to put terminal in a specified video attribute mode |
The programming manual also mentioned functions provided for termcap compatibility (commenting that they \*(``may go away at a later date\*(''):
Function Description |
tgetent look up termcap entry for given name |
tgetflag get boolean entry for given id |
tgetnum get numeric entry for given id |
tgetstr get string entry for given id |
tgoto apply parameters to given capability |
tputs |
apply padding to capability, calling a function to put characters |
Early terminfo programs obtained capability values from the TERMINAL structure initialized by setupterm.
SVr3 extended terminfo by adding functions to retrieve capability values (like the termcap interface), and reusing tgoto and tputs:
Function Description |
tigetflag get boolean entry for given id |
tigetnum get numeric entry for given id |
tigetstr get string entry for given id |
SVr3 also replaced several of the SVr2 terminfo functions which had no counterpart in the termcap interface, documenting them as obsolete:
Function Replaced by |
crmode cbreak |
fixterm reset_prog_mode |
gettmode N/A |
nocrmode nocbreak |
resetterm reset_shell_mode |
saveterm def_prog_mode |
setterm setupterm |
SVr3 kept the mvcur, vidattr and vidputs functions, along with putp, tparm and tputs. The latter were needed to support padding, and handling functions such as vidattr (which used more than the two parameters supported by tgoto).
SVr3 introduced the functions for switching between terminal descriptions, e.g., set_curterm. Some of that was incremental improvements to the SVr2 library: .bP The TERMINAL type definition was introduced in SVr3.01, for the term structure provided in SVr2. .bP The various global variables such as boolnames were mentioned in the programming manual at this point, though the variables were provided in SVr2.
SVr4 added the vid_attr and vid_puts functions.
There are other low-level functions declared in the curses header files on Unix systems, but none were documented. The functions marked \*(``obsolete\*('' remained in use by the Unix vi(1) editor.
The function setterm is not described by X/Open and must be considered non-portable. All other functions are as described by X/Open.
Other implementions may not declare the capability name arrays. Some provide them without declaring them. X/Open does not specify them.
Extended terminal capability names, e.g., as defined by tic -x, are not stored in the arrays described here.
The current version (ncurses6) uses output buffers managed directly by ncurses. Some of the low-level functions described in this manual page write to the standard output. They are not signal-safe. The high-level functions in ncurses use alternate versions of these functions using the more reliable buffering scheme.
Both forms of tparm have drawbacks: .bP Most of the calls to tparm use only one or two parameters. Passing nine on each call is awkward.
Using long for the numeric parameter type is a workaround to make the parameter use the same amount of stack as a pointer. That approach dates back to the mid-1980s, before C was standardized. Since then, there is a standard (and pointers are not required to fit in a long). .bP Providing the right number of parameters for a variadic function such as tiparm can be a problem, in particular for string parameters. However, only a few terminfo capabilities use string parameters (e.g., the ones used for programmable function keys). The ncurses library checks usage of these capabilities, and returns an error if the capability mishandles string parameters. But it cannot check if a calling program provides strings in the right places for the tparm calls. The tput(1) program checks its use of these capabilities with a table, so that it calls tparm correctly.In System V Release 4, the third argument of tputs has the type int (*putc)(char).
At least one implementation of X/Open Curses (Solaris) returns a value other than OK/ERR from tputs. That returns the length of the string, and does no error-checking.
X/Open notes that after calling mvcur, the curses state may not match the actual terminal state, and that an application should touch and refresh the window before resuming normal curses calls. Both ncurses and System V Release 4 curses implement mvcur using the SCREEN data allocated in either initscr or newterm. So though it is documented as a terminfo function, mvcur is really a curses function which is not well specified.
X/Open states that the old location must be given for mvcur. This implementation allows the caller to use -1's for the old ordinates. In that case, the old location is unknown.