These low-level routines must be called by programs that have to deal
@@ -117,39 +123,39 @@
recommended.
None of these functions use (or are aware of) multibyte character
- strings such as UTF-8:
+ strings such as UTF-8.
- o capability names use the POSIX portable character set
+ o Capability names and codes use the POSIX portable character set.
- o capability string values have no associated encoding; they are
+ 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
+ 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 terminfo(5)].
+ 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 this order) to get the
+ 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
+ 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.
+ specified in terminfo are used.
- o Otherwise, if the environment variables LINES and COLUMNS exist,
+ 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
+ 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
+ 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(3x)].
@@ -167,12 +173,12 @@
o 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:
+ 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:
term is the terminal type, a character string. If term is null, the
- environment variable TERM is used.
+ environment variable TERM is used.
filedes
is the file descriptor used for getting and setting terminal
@@ -211,14 +217,14 @@
If errret is null, setupterm prints an error message upon
finding an error and exits. Thus, the simplest call is:
- setupterm((char*)0,1,(int*)0);,
+ setupterm((char*)0,1,(int*)0);
- which uses all the defaults and sends the output to stdout.
+ which uses all the defaults and sends the output to stdout.
The setupterm routine stores its information about the terminal in a
- TERMINAL structure pointed to by the global variable cur_term. If it
+ 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.
@@ -229,13 +235,13 @@
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.
+ 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 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
+ 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.
@@ -266,9 +272,9 @@
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 integers (int) rather
- than longs.
+ 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
@@ -304,7 +310,7 @@
oaffcnt is the number of lines affected, or 1 if not applicable.
- oputc is a putchar-like routine to which the characters are passed,
+ 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)
@@ -316,50 +322,49 @@
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
+ in curses(3x). The characters are passed to the putchar-like function
putc.
The vidattr routine is like the vidputs routine, except that it outputs
- through putchar.
+ 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.,
+ vid_attr and vid_puts correspond to vidattr and vidputs, respectively.
+ They use multiple parameters to represent the character attributes and
+ color; namely,
- oattrs of type attr_t for the attributes and
+ oattrs, of type attr_t, for the attributes and
- opair of type short for the color-pair number.
+ opair, 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.
+ 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. As an
- extension, this implementation allows opts to be used as a pointer to
- int, which overrides the pair (short) argument.
+ applications must provide a null pointer for that argument; but see
+ section "EXTENSIONS" below.
- 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
+ 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(3x).
While putp and mvcur are low-level functions which do not use the high-
- level curses state, they are declared in <curses.h> because System V
- did this (see HISTORY).
+ level curses state, they are declared in curses.h because System V did
+ this (see HISTORY).
- The tigetflag, tigetnum and tigetstr routines return the value of the
- capability corresponding to the terminfocapname passed to them, such
- as xenl. The capname for each capability is given in the table column
+ The tigetflag, tigetnum and tigetstr routines return the value of the
+ capability corresponding to the terminfocapname 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.
The tigetflag routine returns
- -1 if capname is not a boolean capability, or
+ -1 if capname is not a Boolean capability, or
0 if it is canceled or absent from the terminal description.
@@ -395,220 +400,135 @@
Each successful call to setupterm allocates memory to hold the terminal
- description. As a side-effect, it sets cur_term to point to this
+ description. As a side-effect, it sets cur_term to point to this
memory. If an application calls
del_curterm(cur_term);
the memory will be freed.
- The formatting functions tparm and tiparm extend the storage allocated
+ The formatting functions tparm and tiparm extend the storage allocated
by setupterm:
- o the "static" terminfo variables [a-z]. Before ncurses 6.3, those
- were shared by all screens. With ncurses 6.3, those are allocated
+ o 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) for details.
- 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.
+ 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.
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
+ they do not free this memory, but it is possible to do that using the
delscreen(3x) function.
- 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.
-
- Routines that return pointers always return NULL on error.
+ X/Open defines no failure conditions. In ncurses,
- X/Open defines no error conditions. In this implementation
+ del_curterm
+ returns an error if its terminal parameter is null.
- del_curterm
- returns an error if its terminal parameter is null.
+ putp calls tputs, returning the same error-codes.
- putp calls tputs, returning the same error-codes.
+ restartterm
+ returns an error if the associated call to setupterm returns an
+ error.
- restartterm
- returns an error if the associated call to setupterm returns an
- error.
+ setupterm
+ returns an error if it cannot allocate enough memory, or create
+ the initial windows (stdscr, curscr, and newscr) Other error
+ conditions are documented above.
- setupterm
- returns an error if it cannot allocate enough memory, or create
- the initial windows (stdscr, curscr, newscr). Other error
- conditions are documented above.
+ 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).
- 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).
-
- 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.
-
-
-
- This implementation provides a few macros for compatibility with
- systems before SVr4 (see HISTORY). Those include crmode, fixterm,
- gettmode, nocrmode, resetterm, saveterm, and setterm.
+ tputs
+ returns an error 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.
- 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)
+
+ 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.
- 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,
+
+ 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.
-
- SVr2 introduced the terminfo feature. Its programming manual mentioned
- the following low-level functions.
-
- FunctionDescription
- ------------------------------------------------------------------------
- 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").
-
- 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 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:
-
- 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 which 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
- 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:
-
- o The TERMINAL type definition was introduced in SVr3.01, for the
- term structure provided in SVr2.
-
- o 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.
+ ncurses allows opts to be a pointer to int, which overrides the pair
+ (short) argument.
- The functions marked as extensions were designed for ncurses(3x), and
- are not found in SVr4 curses, 4.4BSD curses, or any other previous
- version of curses.
+ setterm is not described by X/Open and must be considered non-portable.
+ All other functions are as described by X/Open.
-
+ 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.
- The function setterm is not described by X/Open and must be considered
- non-portable. All other functions are as described by X/Open.
+ 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 does not specify them.
- Extended terminal capability names, e.g., as defined by tic-x, are not
+ 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 cleanup on receiving SIGTSTP.
+ 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 cleanup 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
+ 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
+ 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
+ o X/Open Curses uses const less effectively than a later design
might, in some cases applying it needlessly to values are already
constant, and in most cases overlooking parameters which normally
- would use const. Using constant parameters for functions which do
- not use const may prevent the program from compiling. On the other
- hand, writablestrings are an obsolescent feature.
+ would use const. Using constant parameters for functions which do
+ not use 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
+ 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,
@@ -622,7 +542,7 @@
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
+ 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.
@@ -631,7 +551,7 @@
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
+ 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
@@ -642,7 +562,7 @@
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
+ 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.
@@ -650,56 +570,146 @@
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, e.g., for the MinGW port,
- osetupterm interprets a missing/empty TERM variable as the special
+ 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 gn
- (generic_type) terminfo capability, while the latter does not. A
+ The difference between the two is that the former uses the gn (-
+ generic_type) 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
+ 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 System V Release 4, the third argument of tputs has the type int
- (*putc)(char).
+ 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/ERR from tputs. That returns the length of the string,
- and does no error-checking.
+ 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 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
+ 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.
+ 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 (such as cursor_address) 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 tty to "in curses" state
+ gettmode establish current tty modes
+ mvcur low level cursor motion
+ putp use 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 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.