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#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 *cap-code); int tigetnum(const char *cap-code); char *tigetstr(const char *cap-code);
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);
/* deprecated */ int setterm(const char *term);
None of these functions use (or are aware of) multibyte character strings such as UTF-8.
| &#187; | Capability names and codes use the POSIX portable character set. |
| &#187; | 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 that order) to get the definitions for these strings, numbers, and flags.
The term info variables lines and columns are initialized by setupterm as follows.
| &#187; | If use_env(FALSE) has been called, values for lines and columns specified in term info are used. |
| &#187; | 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 term info database are used. |
Programs that use cursor addressing should
| &#187; | output enter_ca_mode upon startup and |
| &#187; | output exit_ca_mode before exiting. |
| &#187; | call reset_shell_mode and output exit_ca_mode before the shell is called and |
| &#187; | output enter_ca_mode and call reset_prog_mode after returning from the shell. |
term is the terminal type, a character string. If term is null, the environment variable TERM is read. filedes is the file descriptor used for getting and setting terminal I/O modes. Higher-level applications use newterm(3X) to initialize 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. 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:
1 means that the terminal is hardcopy, and cannot be used for curses applications. setupterm determines if the entry is a hardcopy type by checking the hardcopy (hc) capability. 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 generic_type (gn) capability. -1 means that the term info database could not be found. If errret is null, setupterm reports an error message upon finding an error and exits. Thus, the simplest call is:
setupterm((char *)0, 1, (int *)0); which uses all the defaults and sends the output to stdout.
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.
set_curterm sets cur_term to nterm, and makes all of the term info Boolean, numeric, and string variables use the values from nterm. It returns the old value of cur_term.
del_curterm 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 term info Boolean, numeric, and string variables thereafter may refer to invalid memory locations until another setupterm has been called.
restartterm 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 terminal state bits, calls setupterm, and then restores the bits.
| &#187; | Although tparm's actual parameters may be integers or strings, the prototype expects long (integer) values. |
| &#187; | Aside from the set_attributes (sgr) capability, most terminal capabilities require no more than one or two parameters. |
| &#187; | Padding information is ignored by tparm; it is interpreted by tputs. |
| &#187; | The capability string is null-terminated. Use \200 where an ASCII NUL is needed in the output. |
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.
| &#187; | 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) passed as char pointers rather than numbers. | |
| &#187; | The extension tiscan_s allows the application to inspect a formatting capability to see what the curses library would assume. |
tputs interprets time-delay information in the string str and outputs it, executing the delays:
| &#187; | The str parameter must be a term info string variable or the return value of tparm, tiparm, tgetstr, or tgoto. |
| The tgetstr and tgoto functions are part of the termcap interface, which happens to share these function names with the term info API. | |
| &#187; | affcnt is the number of lines affected, or 1 if not applicable. |
| &#187; | putc is a putchar-like function to which the characters are passed, one at a time. |
| If tputs processes a time-delay, it uses the delay_output(3X) function, routing any resulting padding characters through this function. | |
vidputs displays the string on the terminal in the video attribute mode attrs, which is any combination of the attributes listed in curses(3X). The characters are passed to the putchar-like function putc.
vidattr is like vidputs, except that it outputs through putchar(3).
vid_attr and vid_puts correspond to vidattr and vidputs, respectively. They use multiple parameters to represent the character attributes and color; namely,
| &#187; | attrs, of type attr_t, for the attributes and |
| &#187; | pair, of type short, for the color pair number. |
X/Open Curses reserves the opts argument for future use, saying that applications must provide a null pointer for that argument; but see section EXTENSIONS below.
mvcur 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(3X).
While putp and mvcur are low-level functions that do not use high-level curses state, ncurses declares them in curses.h because System V did this (see section HISTORY below).
These functions return special values to denote errors.
tigetflag returns
| -1 | if cap-code is not a Boolean capability, or |
| 0 | if it is canceled or absent from the terminal description. |
| tigetnum returns | |
| -2 | if cap-code is not a numeric capability, or |
| -1 | if it is canceled or absent from the terminal description. |
| tigetstr returns | |
| (char *)-1 | |
| if cap-code is not a string capability, or | |
| 0 | if it is canceled or absent from the terminal description. |
| &#187; | the short term info names (codes), |
| &#187; | the termcap names (names), and |
| &#187; | the long term info names (fnames) |
const char *boolnames[], *boolcodes[], *boolfnames[] const char *numnames[], *numcodes[], *numfnames[] const char *strnames[], *strcodes[], *strfnames[]
| del_curterm(cur_term); | |
The formatting functions tparm and tiparm extend the storage allocated by setupterm as follows.
| &#187; | They add the static term info variables [a-z]. Before ncurses 6.3, those were shared by all screens. With ncurses 6.3, those are allocated per screen. See terminfo(5). |
| &#187; | To improve performance, ncurses 6.3 caches the result of analyzing term info strings for their parameter types. That is stored as a binary tree referenced from the TERMINAL structure. |
| del_curtem | |
| fails if its terminal parameter is null. | |
| putp | calls tputs, returning the same error codes. |
| restartterm | |
| fails if the associated call to setupterm returns an error. | |
| setupterm | |
| fails if it cannot allocate enough memory, or create the initial windows ( stdscr, curscr, and newscr) Other error conditions are documented above. | |
| tparm | returns a null pointer if the capability would require unexpected parameters; that is, too many, too few, or incorrect types (strings where integers are expected, or vice versa). |
| tputs | fails if the string parameter is null. It does not detect I/O errors: X/Open Curses states that tputs ignores the return value of the output function putc. |
ncurses allows opts to be a pointer to int, which overrides the pair (short) argument.
In SVr4, these are found in curses.h, but except for setterm, are likewise macros. The one function, setterm, is mentioned in the manual page. It further notes that setterm was replaced by setupterm, stating that the call
setupterm(term, 1, (int *)0)provides the same functionality as setterm(term), discouraging the latter for new programs. ncurses implements each of these symbols as macros for BSD curses compatibility.
Other implementions may not declare the capability name arrays. Some provide them without declaring them. X/Open Curses does not specify them.
Extended terminal capability names, 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 employ alternate versions of these functions using the more reliable buffering scheme.
| &#187; | X/Open Curses uses const less effectively than a later design might, sometimes applying it needlessly to values that are already constant, and in most cases overlooking parameters that normally would use const. Passing const-qualified parameters to functions that do not declare them const may prevent the program from compiling. On the other hand, writable strings are an obsolescent feature. |
| As an extension, this implementation can be configured to change the function prototypes to use the const keyword. The ncurses ABI 6 enables this feature by default. | |
| &#187; | X/Open Curses prototypes tparm with a fixed number of parameters, rather than a variable argument list. |
| This implementation uses a variable argument list, but can be configured to use the fixed-parameter list. Portable applications should provide nine parameters after the format; zeroes are fine for this purpose. | |
| In response to review comments by Thomas E. Dickey, X/Open Curses Issue 7 proposed the tiparm function in mid-2009. | |
| While tiparm is always provided in ncurses, the older form is only available as a build-time configuration option. If not specially configured, tparm is the same as tiparm. | |
| &#187; | 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). | |
| &#187; | 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 term info capabilities use string parameters (for instance, 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. | |
| &#187; | setupterm interprets a missing/empty TERM variable as the special value unknown. |
| SVr4 curses uses the special value dumb. | |
| The difference between the two is that the former uses the generic_type (gn) term info capability, while the latter does not. A generic terminal is unsuitable for full-screen applications. | |
| &#187; | setupterm allows explicit use of the the windows console driver by checking if $TERM is set to #win32con or an abbreviation of that string. |
In SVr4, 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 or ERR from tputs. It instead returns the length of the string, and does no error checking.
X/Open Curses 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 SVr4 curses implement mvcur using the SCREEN data allocated in either initscr or newterm. So though it is documented as a term info function, mvcur is really a curses function that is not well specified.
X/Open Curses states that the old location must be given for mvcur to accommodate terminals that lack absolute cursor positioning. ncurses allows the caller to use -1 for either or both old coordinates. The -1 tells ncurses that the old location is unknown, and that it must use only absolute motion, as with the cursor_address (cup) capability, rather than the least costly combination of absolute and relative motion.
Function Description fixterm restore terminal to in curses state gettmode establish current terminal modes mvcur low level cursor motion putp use tputs to send characters via putchar resetterm set terminal modes to out of curses state resetty reset terminal flags to stored value saveterm save current modes as in curses state savetty store current terminal flags setterm establish terminal with given type setupterm establish terminal with given type tparm interpolate parameters into string capability tputs apply padding information to a string vidattr like vidputs, but output through putchar vidputs write string to terminal, applying specified attributes
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 write characters via a function parameter, applying padding
Early term info programs obtained capability values from the TERMINAL structure initialized by setupterm.
SVr3 (1987) extended term info 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 term info functions that 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 to handle capabilities accessed by functions such as vidattr (which used more than the two parameters supported by tgoto).
SVr3 introduced the functions for switching between terminal descriptions; for example, set_curterm. Some changes reflected incremental improvements to the SVr2 library.
| &#187; | The TERMINAL type definition was introduced in SVr3.01, for the term structure provided in SVr2. |
| &#187; | Various global variables such as boolnames were mentioned in the programming manual at this point, though the variables had been provided in SVr2. |
Other low-level functions are declared in the curses header files of Unix systems, but none are documented. Those noted as obsolete by SVr3 remained in use by System V's vi(1) editor.
| 2024-04-13 | curs_terminfo (3X) | ncurses 6.5 |
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