- These low-level routines must be called by programs that
- have to deal directly with the terminfo database to handle
- certain terminal capabilities, such as programming func-
- tion keys. For all other functionality, curses routines
- are more suitable and their use is recommended.
+ inttigetflag(constchar*cap-code);
+ inttigetnum(constchar*cap-code);
+ char*tigetstr(constchar*cap-code);
+ char*tiparm(constchar*str, ...);
-
- Initially, setupterm should be called. Note that se-
- tupterm is automatically called by initscr and newterm.
- This defines the set of terminal-dependent variables
- [listed in terminfo(5)].
-
- Each initialization routine provides applications with the
- terminal capabilities either directly (via header defini-
- tions), or by special functions. The header files curs-
- es.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:
-
- o If use_env(FALSE) has been called, values for lines
- and columns specified in terminfo are used.
-
- o Otherwise, if the environment variables LINES and COL-
- UMNS exist, their values are used. If these environ-
- ment variables do not exist and the program is running
- in a window, the current window size is used. Other-
- wise, 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 ex-
- iting [see curs_kernel(3x)].
-
- Programs which use cursor addressing should
+ /*extensions*/
+ char*tiparm_s(intexpected,intmask,constchar*str,...);
+ inttiscan_s(int*expected,int*mask,constchar*str);
+
+ /*deprecated*/
+ intsetterm(constchar*term);
+
+
+
+ These low-level functions must be called by programs that deal directly
+ with the terminfo database to handle certain terminal capabilities,
+ such as programming function keys. For all other functionality, curses
+ functions are more suitable and their use is recommended.
+
+ None of these functions use (or are aware of) multibyte character
+ strings such as UTF-8.
+
+ o Capability names and codes use the POSIX portable character set.
+
+ o Capability string values have no associated encoding; they are
+ strings of 8-bit characters.
+
+
+
+ Initially, setupterm should be called. The high-level curses functions
+ initscr and newterm call setupterm to initialize the low-level set of
+ terminal-dependent variables listed in term_variables(3x).
+
+ 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 terminfo variables lines and columns are initialized by setupterm
+ as follows.
+
+ o If use_env(FALSE) has been called, values for lines and columns
+ specified in terminfo are used.
+
+ o 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
+ sent to the terminal device with tputs or putp. Call reset_shell_mode
+ to restore the terminal modes before exiting; see curs_kernel(3x).
+
+ Programs that use cursor addressing should
o output enter_ca_mode upon startup and
o output exit_ca_mode before exiting.
- Programs which execute shell subprocesses should
+ Programs that execute shell subprocesses should
- o call reset_shell_mode and output exit_ca_mode before
- the shell is called and
+ o call reset_shell_mode and output exit_ca_mode before the shell is
+ called and
- o output enter_ca_mode and call reset_prog_mode after
- returning from the shell.
+ o output enter_ca_mode and call reset_prog_mode after returning from
+ the shell.
- The setupterm routine reads in the terminfo database, ini-
- tializing the terminfo structures, but does not set up the
- output virtualization structures used by curses. The ter-
- minal type is the character string term; if term is null,
- the environment variable TERM is used. All output is to
- file descriptor fildes which is initialized for output.
- If errret is not null, then setupterm returns OK or ERR
- and stores a status value in the integer pointed to by er-
- rret. A return value of OK combined with status of 1 in
- errret is normal. If ERR is returned, examine errret:
+ setupterm reads in the terminfo database, initializing the terminfo
+ structures, but does not set up the output virtualization structures
+ used by curses. Its parameters follow.
- 1 means that the terminal is hardcopy, cannot be used
- for curses applications.
+ term is the terminal type, a character string. If term is null, the
+ environment variable TERM is read.
- setupterm determines if the entry is a hardcopy type
- by checking the hc (hardcopy) capability.
+ filedes
+ is the file descriptor used for getting and setting terminal
+ I/O modes.
- 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.
+ 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.
- setupterm determines if the entry is a generic type
- by checking the gn (generic) capability.
+ 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.
- -1 means that the terminfo database could not be found.
+ If ERR is returned, examine errret:
- If errret is null, setupterm prints an error message upon
- finding an error and exits. Thus, the simplest call is:
+ 1 means that the terminal is hardcopy, and cannot be used
+ for curses applications.
- setupterm((char*)0,1,(int*)0);,
+ setupterm determines if the entry is a hardcopy type by
+ checking the hardcopy (hc) capability.
- which uses all the defaults and sends the output to std-
- out.
+ 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.
- The setterm routine was replaced by setupterm. The call:
+ setupterm determines if the entry is a generic type by
+ checking the generic_type (gn) capability.
- setupterm(term,1,(int*)0)
+ -1 means that the terminfo database could not be found.
- provides the same functionality as setterm(term). The
- setterm routine is provided for BSD compatibility, and is
- not recommended for new programs.
+ 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);
-
- The setupterm routine stores its information about the
- terminal in a TERMINAL structure pointed to by the global
- variable cur_term. If it detects an error, or decides
- that the terminal is unsuitable (hardcopy or generic), it
- discards this information, making it not available to ap-
- plications.
-
- 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 allo-
- cates 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 re-
- fer 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.
+ which uses all the defaults and sends the output to stdout.
-
+ setupterm stores its information about the terminal in a TERMINAL
+ structure pointed to by the global variable cur_term. If it detects an
+ error, or decides that the terminal is unsuitable (hardcopy or
+ generic), it discards this information, making it not available to
+ applications.
- tiparm is a newer form of tparm which uses <stdarg.h>
- rather than a fixed-parameter list. Its numeric parame-
- ters are integers (int) rather than longs.
+ 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 terminfo
+ Boolean, numeric, and string variables use the values from nterm. It
+ returns the old value of cur_term.
-
- The tputs routine applies padding information to the
- string str and outputs it. The str must be a terminfo
- string variable or the return value from tparm, tgetstr,
- or tgoto. affcnt is the number of lines affected, or 1 if
- not applicable. putc is a putchar-like routine to which
- the characters are passed, one at a time.
-
- The putp routine calls tputs(str,1,putchar). Note that
- the output of putp always goes to stdout, not to the
- fildes 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(3x). 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.,
- one of type attr_t for the attributes and one of short for
- the color_pair number. The vid_attr and vid_puts routines
- are designed to use the attribute constants with the WA_
- prefix. The opts argument is reserved for future use.
- Currently, applications must provide a null pointer for
- that argument.
-
- The mvcur routine provides low-level cursor motion. It
- takes effect immediately (rather than at the next re-
- fresh).
+ 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 terminfo 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.
-
- The tigetflag, tigetnum and tigetstr routines return the
- value of the capability corresponding to the terminfocap-
- name passed to them, such as xenl. The capname for each
- capability is given in the table column entitled capname
- code in the capabilities section of terminfo(5).
- These routines return special values to denote errors.
+
+ tparm instantiates the string str with parameters pi. A pointer is
+ returned to the result of str with the parameters applied. Application
+ developers should keep in mind these quirks of the interface:
+
+ o Although tparm's actual parameters may be integers or strings, the
+ prototype expects long (integer) values.
+
+ o Aside from the set_attributes (sgr) capability, most terminal
+ capabilities require no more than one or two parameters.
+
+ o Padding information is ignored by tparm; it is interpreted by
+ tputs.
+
+ o The capability string is null-terminated. Use "\200" where an
+ ASCII NUL is needed in the output.
+
+ tiparm is a newer form of tparm which uses stdarg.h rather than a
+ fixed-parameter list. Its numeric parameters are ints 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.
+
+ otiparm_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.
+
+ o The extension tiscan_s allows the application to inspect a
+ formatting capability to see what the curses library would assume.
+
+
+
+ String capabilities can contain padding information, a time delay
+ (accommodating performance limitations of hardware terminals) expressed
+ as $<n>, where n is a nonnegative integral count of milliseconds. If n
+ exceeds 30,000 (thirty seconds), it is capped at that value.
+
+ tputs interprets time-delay information in the string str and outputs
+ it, executing the delays:
+
+ o The str parameter must be a terminfo 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 terminfo API.
+
+ oaffcnt is the number of lines affected, or 1 if not applicable.
+
+ oputc 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.
- The tigetflag routine returns
+ putp calls "tputs(str,1,putchar)". The output of putp always goes to
+ stdout, rather than the filedes specified in setupterm.
- -1 if capname is not a boolean capability, or
+ 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.
- 0 if it is canceled or absent from the terminal de-
- scription.
+ vidattr is like vidputs, except that it outputs through putchar(3).
- The tigetnum routine returns
+ vid_attr and vid_puts correspond to vidattr and vidputs, respectively.
+ They use multiple parameters to represent the character attributes and
+ color; namely,
- -2 if capname is not a numeric capability, or
+ oattrs, of type attr_t, for the attributes and
- -1 if it is canceled or absent from the terminal de-
- scription.
+ opair, of type short, for the color pair number.
- The tigetstr routine returns
+ Use the attribute constants prefixed with "WA_" with vid_attr and
+ vid_puts.
+
+ 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).
+
+
+
+ tigetflag, tigetnum, and tigetstr return the value of the capability
+ corresponding to the terminfocap-code, such as xenl, passed to them.
+ The cap-code for each capability is given in the table column entitled
+ cap-code code in the capabilities section of terminfo(5).
+
+ 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 capname is not a string capability, or
+ if cap-code is not a string capability, or
- 0 if it is canceled or absent from the terminal de-
- scription.
+ 0 if it is canceled or absent from the terminal description.
-
- These null-terminated arrays contain the short terminfo
- names ("codes"), the termcap names, and the long terminfo
- names ("fnames") for each of the predefined terminfo vari-
- ables:
- char*boolnames[], *boolcodes[], *boolfnames[]
+
+ These null-terminated arrays contain
- char*numnames[], *numcodes[], *numfnames[]
+ o the short terminfo names ("codes"),
- char*strnames[], *strcodes[], *strfnames[]
+ o the termcap names ("names"), and
+ o the long terminfo names ("fnames")
-
- Routines that return an integer return ERR upon failure
- and OK (SVr4 only specifies "an integer value other than
- ERR") upon successful completion, unless otherwise noted
- in the preceding routine descriptions.
+ for each of the predefined terminfo variables:
- Routines that return pointers always return NULL on error.
+ constchar*boolnames[], *boolcodes[], *boolfnames[]
+ constchar*numnames[], *numcodes[], *numfnames[]
+ constchar*strnames[], *strcodes[], *strfnames[]
- X/Open defines no error conditions. In this implementa-
- tion
- del_curterm
- returns an error if its terminal parameter is
- null.
+
+ Each successful call to setupterm allocates memory to hold the terminal
+ description. As a side effect, it sets cur_term to point to this
+ memory. If an application calls
- putp calls tputs, returning the same error-codes.
+ del_curterm(cur_term);
- restartterm
- returns an error if the associated call to se-
- tupterm returns an error.
+ the memory will be freed.
- setupterm
- returns an error if it cannot allocate enough
- memory, or create the initial windows (stdscr,
- curscr, newscr). Other error conditions are
- documented above.
+ The formatting functions tparm and tiparm extend the storage allocated
+ by setupterm as follows.
- 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.
+ o They add 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(5).
+ o 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.
-
- X/Open notes that vidattr and vidputs may be macros.
+ 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(3x) function.
- The function setterm is not described by X/Open and must
- be considered non-portable. All other functions are as
- described by X/Open.
- setupterm copies the terminal name to the array ttytype.
- This is not part of X/Open Curses, but is assumed by some
- applications.
+
+ X/Open Curses defines no failure conditions. In ncurses,
- If configured to use the terminal-driver, e.g., for the
- MinGW port,
-
- osetupterm interprets a missing/empty TERM variable as
- the special value "unknown".
-
- osetupterm allows explicit use of the the windows con-
- sole driver by checking if $TERM is set to "#win32con"
- or an abbreviation of that string.
-
- Older versions of ncurses assumed that the file descriptor
- passed to setupterm from initscr or newterm uses buffered
- I/O, and would write to the corresponding stream. In ad-
- dition to the limitation that the terminal was left in
- block-buffered mode on exit (like SystemV curses), it was
- problematic because ncurses did not allow a reliable way
- to cleanup on receiving SIGTSTP. The current version 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.
-
- In System V Release 4, set_curterm has an int return type
- and returns OK or ERR. We have chosen to implement the
- X/Open Curses semantics.
-
- 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) re-
- turns a value other than OK/ERR from tputs. That returns
- the length of the string, and does no error-checking.
-
- X/Open Curses prototypes tparm with a fixed number of pa-
- rameters, rather than a variable argument list. This im-
- plementation uses a variable argument list, but can be
- configured to use the fixed-parameter list. Portable ap-
- plications should provide 9 parameters after the format;
- zeroes are fine for this purpose.
-
- In response to comments by Thomas E. Dickey, X/Open Curses
- Issue 7 proposed the tiparm function in mid-2009.
-
- X/Open notes that after calling mvcur, the curses state
- may not match the actual terminal state, and that an ap-
- plication should touch and refresh the window before re-
- suming normal curses calls. Both ncurses and System V Re-
- lease 4 curses implement mvcur using the SCREEN data allo-
- cated in either initscr or newterm. So though it is docu-
- mented 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.
-
- 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.
+ del_curtem
+ fails if its terminal parameter is null.
+ putp calls tputs, returning the same error codes.
-
- curses(3x), curs_initscr(3x), curs_kernel(3x), curs_term-
- cap(3x), curs_variables(3x), term_variables(3x), putc(3),
+ 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.
+
+
+
+ The vid_attr function in ncurses is a special case. It was originally
+ implemented based on a draft of X/Open Curses, as a macro, before other
+ parts of the ncurses wide-character API were developed, and unlike the
+ other wide-character functions, is also provided in the non-wide-
+ character configuration.
+
+
+
+ The functions marked as extensions were designed for ncurses, and are
+ not found in SVr4 curses, 4.4BSD curses, or any other previous curses
+ implementation.
+
+ ncurses allows opts to be a pointer to int, which overrides the pair
+ (short) argument.
+
+
+
+ This implementation provides a few macros for compatibility with
+ systems before SVr4 (see section "HISTORY" below). They include
+ Bcrmode, Bfixterm, Bgettmode, Bnocrmode, Bresetterm, Bsaveterm, and
+ Bsetterm.
+
+ 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.
+
+
+
+ setupterm copies the terminal name to the array ttytype. This is not
+ part of X/Open Curses, but is assumed by some applications.
+
+ 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.
+
+
+
+ Older versions of ncurses assumed that the file descriptor passed to
+ setupterm from initscr or newterm uses buffered I/O, and would write to
+ the corresponding stream. In addition to the limitation that the
+ terminal was left in block-buffered mode on exit (like System V
+ curses), it was problematic because ncurses did not allow a reliable
+ way to clean up on receiving SIGTSTP.
+
+ 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.
+
+
+
+ The X/Open Curses prototypes are based on the SVr4 curses header
+ declarations, which were defined at the same time the C language was
+ first standardized in the late 1980s.
+
+ o 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.
+
+ o 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.
+
+ Both forms of tparm have drawbacks:
+
+ o 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).
+
+ o 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 (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.
+
+ SpecialTERMtreatment
+ If configured to use the terminal driver, as with the MinGW port,
+
+ osetupterm 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) terminfo capability, while the latter does not.
+ A generic terminal is unsuitable for full-screen applications.
+
+ osetupterm 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, set_curterm returns an int, OK or ERR. We have chosen to
+ implement the X/Open Curses semantics.
+
+ 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 terminfo
+ 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.
+
+
+
+ SVr2 (1984) introduced the terminfo feature. Its programming manual
+ mentioned the following low-level functions.
+
+ FunctionDescription
+ ------------------------------------------------------------------------
+ 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").
+
+ FunctionDescription
+ ------------------------------------------------------------------------
+ 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 terminfo programs obtained capability values from the TERMINAL
+ structure initialized by setupterm.
+
+ SVr3 (1987) extended terminfo by adding functions to retrieve
+ capability values (like the termcap interface), and reusing tgoto and
+ tputs.
+
+ FunctionDescription
+ ------------------------------------------------------------------------
+ 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 that had no
+ counterpart in the termcap interface, documenting them as obsolete.
+
+ FunctionReplacedby
+ ------------------------------------------------------------------------
+ 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.
+
+ o The TERMINAL type definition was introduced in SVr3.01, for the
+ term structure provided in SVr2.
+
+ o Various global variables such as boolnames were mentioned in the
+ programming manual at this point, though the variables had been
+ provided in SVr2.
+
+ SVr4 (1989) added the vid_attr and vid_puts functions.
+
+ 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.
+
+
+