'\" t .\"*************************************************************************** .\" Copyright 2018-2023,2024 Thomas E. Dickey * .\" Copyright 1998-2015,2017 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: ncurses.3x,v 1.207 2024/04/14 00:34:00 tom Exp $ .TH ncurses 3X 2024-04-13 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls" .ie \n(.g \{\ .ds `` \(lq .ds '' \(rq .\} .el \{\ .ie t .ds `` `` .el .ds `` "" .ie t .ds '' '' .el .ds '' "" .\} . .de bP .ie n .IP \(bu 4 .el .IP \(bu 2 .. . .ds d @TERMINFO@ .SH NAME \fB\%ncurses\fP \- character-cell terminal interface with optimized output .SH SYNOPSIS .nf \fB#include .fi .SH DESCRIPTION The \*(``new curses\*('' library offers the programmer a terminal-independent means of reading keyboard and mouse input and updating character-cell terminals with output optimized to minimize screen updates. .I \%ncurses replaces the .I curses libraries from System V Release 4 Unix (\*(``SVr4\*('') and 4.4BSD Unix, the development of which ceased in the 1990s. This describes \fI\%ncurses\fP version @NCURSES_MAJOR@.@NCURSES_MINOR@ (patch @NCURSES_PATCH@). .PP .I \%ncurses permits control of the terminal screen's contents; abstraction and subdivision thereof with .I windows and .IR pads ; the reading of terminal input; control of terminal input and output options; environment query routines; color manipulation; the definition and use of .I "soft label" keys; .I \%term\%info capability access; a .I termcap compatibility interface; and an abstraction of the system's API for manipulating the terminal (such as \fI\%termios\fP(3)). .PP .I \%ncurses implements the standard interface described by X/Open Curses Issue\ 7. In many behavioral details not standardized by X/Open, .I \%ncurses emulates the .I curses library of SVr4 and provides numerous useful extensions. .PP .I \%ncurses man pages employ several sections to clarify matters of usage and interoperability with other .I curses implementations. .bP \*(``NOTES\*('' describes issues and caveats of which any user of the .I \%ncurses API should be aware, such as limitations on the size of an underlying integral type or the availability of a preprocessor macro exclusive of a function definition (which prevents its address from being taken). This section also describes implementation details that will be significant to the programmer but which are not standardized. .bP \*(``EXTENSIONS\*('' presents .I \%ncurses innovations beyond the X/Open Curses standard and/or the SVr4 .I curses implementation. They are termed .I extensions to indicate that they cannot be implemented solely by using the library API, but require access to the library's internal state. .bP \*(``PORTABILITY\*('' discusses matters (beyond the exercise of extensions) that should be considered when writing to a .I curses standard, or for multiple implementations. .bP \*(``HISTORY\*('' examines points of detail in .I \%ncurses and other .I curses implementations over the decades of their development, particularly where precedent or inertia have frustrated better design (and, in a few cases, where such inertia has been overcome). .PP A .I curses application must be linked with the library; use the .B \-lncurses option to your compiler or linker. A debugging version of the library may be available; if so, link with it using .BR \-lncurses_g . (Your system integrator may have installed these libraries such that you can use the options .B \-lcurses and .BR \-lcurses_g , respectively.) The .I \%ncurses_g library generates trace logs (in a file called .I \%trace in the current directory) that describe .I \%ncurses actions. See section \*(``ALTERNATE CONFIGURATIONS\*('' below. .SS "Application Structure" A .I curses application uses information from the system locale; \fI\%setlocale\fP(3) prepares it for .I curses library calls. .PP .RS 4 .EX setlocale(LC_ALL, ""); .EE .RE .PP If the locale is not thus initialized, the library assumes that characters are printable as in ISO\ 8859-1, to work with certain legacy programs. You should initialize the locale; do not expect consistent behavior from the library when the locale has not been set up. .PP \fB\%initscr\fP(3X) or \fB\%newterm\fP(3X) must be called to initialize .I curses before use of any functions that deal with windows and screens. .PP To get character-at-a-time input without echoing\(emmost interactive, screen-oriented programs want this\(emuse the following sequence. .PP .RS 4 .EX initscr(); cbreak(); noecho(); .EE .RE .PP Most applications perform further setup as follows. .PP .RS 4 .EX intrflush(stdscr, FALSE); keypad(stdscr, TRUE); .EE .RE .PP A .I curses program then often enters an event loop of some sort. Call \fB\%endwin\fP(3X) before exiting. .SS Overview A .I curses library abstracts the terminal screen by representing all or part of it as a .I \%WINDOW data structure. A .I window is a rectangular grid of character cells, addressed by row and column coordinates .RI ( y , .IR x ), with the upper left corner as (0, 0). A window called .BR \%stdscr , the same size as the terminal screen, is always available. Create others with \fB\%newwin\fP(3X). .PP A .I curses library does not manage overlapping windows (but see below). You can either use .B \%stdscr to manage one screen-filling window, or tile the screen into non-overlapping windows and not use .B \%stdscr at all. Mixing the two approaches will result in unpredictable and undesired effects. .PP Functions permit manipulation of a window and the .I cursor identifying the cell within it at which the next output operation will occur. Among those, the most basic are \fB\%move\fP(3X) and \fB\%addch\fP(3X): these place the cursor and write a character to .BR \%stdscr , respectively. .PP Frequent changes to the terminal screen can cause unpleasant flicker or inefficient use of the communication channel to the device, so the library does not generally update it automatically. Therefore, after using .I curses functions to accumulate a set of desired updates that make sense to present together, call \fB\%refresh\fP(3X) to tell the library to make the user's screen look like \fBstdscr\fP. The library .\" X/Open Curses Issue 7 assumes some optimization will be done, but .\" does not mandate it in any way. .I optimizes its output by computing a minimal number of operations to mutate the screen from its state at the previous refresh to the new one. Effective optimization demands accurate information about the terminal device: the management of such information is the province of the \fB\%terminfo\fP(3X) API, a feature of every standard .I curses implementation. .PP Special windows called .I pads may also be manipulated. These are windows that are not constrained to the size of the terminal screen and whose contents need not be completely displayed. See \fB\%curs_pad\fP(3X). .PP In addition to drawing characters on the screen, rendering attributes and colors may be supported, causing the characters to show up in such modes as underlined, in reverse video, or in color on terminals that support such display enhancements. See \fB\%curs_attr\fP(3X). .PP .I curses predefines constants for a small set of forms-drawing graphics corresponding to the DEC Alternate Character Set (ACS), a feature of VT100 and other terminals. See \fB\%waddch\fP(3X). .PP .I curses is implemented using the operating system's terminal driver; keystroke events are received not as scan codes but as byte sequences. Graphical keycaps (alphanumeric and punctuation keys, and the space) appear as-is. Everything else, including the tab, enter/return, keypad, arrow, and function keys, appears as a control character or a multibyte .I "escape sequence." .I curses translates these into unique .I "key codes." See \fB\%getch\fP(3X). .PP .I \%ncurses provides reimplementations of the SVr4 \fBpanel\fP(3X), \fBform\fP(3X), and \fBmenu\fP(3X) libraries to ease construction of user interfaces with .IR curses . .SS "Initialization" The selection of an appropriate value of .I TERM in the process environment is essential to correct .I curses and .I \%term\%info library operation. A well-configured system selects a correct .I TERM value automatically; \fB\%tset\fP(1) may assist with troubleshooting exotic situations. .PP If you change the terminal type, export the .I TERM environment variable in the shell, then run \fB\%tset\fP(1) or the .RB \*(`` "@TPUT@ init" \*('' command. See subsection \*(``Tabs and Initialization\*('' of \fB\%terminfo\fP(5). .PP If the environment variables .I \%LINES and .I \%COLUMNS are set, or if the .I curses program is executing in a graphical windowing environment, the information obtained thence overrides that obtained by .IR \%term\%info . An .I \%ncurses extension supports resizable terminals; see \fB\%wresize\fP(3X). .PP If the environment variable .I \%TERMINFO is defined, a .I curses program checks first for a terminal type description in the location it identifies. .I \%TERMINFO is useful for developing experimental type descriptions or when write permission to .I \%\*d is not available. .PP See section \*(``ENVIRONMENT\*('' below. .SS "Naming Conventions" .I curses offers many functions in variant forms using a regular set of alternatives to the name of an elemental one. Those prefixed with \*(``w\*('' require a .I \%WINDOW pointer argument; those with a \*(``mv\*('' prefix first perform cursor movement using \fB\%wmove\fP(3X); a \*(``mvw\*('' prefix indicates both. The \*(``w\*('' function is typically the elemental one; the removal of this prefix usually indicates operation on .BR \%stdscr . .PP Four functions prefixed with \*(``p\*('' require a pad argument. .PP In function synopses, .I \%ncurses man pages apply the following names to parameters. .PP .TS center; Li L. bf \fIbool\fP (\fBTRUE\fP or \fBFALSE\fP) win pointer to a \fIWINDOW\fP pad pointer to a \fIWINDOW\fP that is a pad .TE .SS "Wide and Non-wide Character Configurations" This manual page describes functions that appear in any configuration of the library. There are two common configurations; see section \*(``ALTERNATE CONFIGURATIONS\*('' below. .TP 10 \" "ncursesw" + 2n .I \%ncurses is the library in its \*(``non-wide\*('' configuration, handling only eight-bit characters. It stores a character combined with attributes in a .I \%chtype datum, which is often an alias of .IR int . .IP Attributes alone (with no corresponding character) can be stored in variables of .I \%chtype or .I \%attr_t type. In either case, they are represented as an integral bit mask. .IP Each cell of a .I \%WINDOW is stored as a .IR \%chtype . .TP 10 .I \%ncursesw is the library in its \*(``wide\*('' configuration, which handles character encodings requiring a larger data type than .I \%char (a byte-sized type) can represent. It adds about one third more calls using additional data types that can store such .I multibyte characters. .RS 10 \" same as foregoing tag width .TP 9 \" "cchar_t" + 2n .I \%cchar_t corresponds to the non-wide configuration's .IR \%chtype . It always a structure type, because it stores more data than fit into a standard scalar type. A character code may not be representable as a .IR \%char , and moreover more than one character may occupy a cell (as with accent marks and other diacritics). Each character is of type .IR \%wchar_t ; a complex character contains one spacing character and zero or more non-spacing characters (see below). Attributes and color data are stored in separate fields of the structure, not combined as in .IR \%chtype . .PP Each cell of a .I \%WINDOW is stored as a .IR \%cchar_t . .PP \fB\%setcchar\fP(3X) and \fB\%getcchar\fP(3X) store and retrieve .I \%cchar_t data. The wide library API of .I \%ncurses depends on two data types standardized by ISO C95. .TP 9 .I \%wchar_t stores a wide character. Like .IR \%chtype , it may be an alias of .IR int . Depending on the character encoding, a wide character may be .IR spacing , meaning that it occupies a character cell by itself and typically accompanies cursor advancement, or .IR non-spacing , meaning that it occupies the same cell as a spacing character, is often regarded as a \*(``modifier\*('' of the base glyph with which it combines, and typically does not advance the cursor. .TP 9 .I \%wint_t can store a .I \%wchar_t or the constant .BR \%WEOF , analogously to the .IR int -sized character manipulation functions of ISO C and its constant .BR \%EOF . .RE .IP The wide library provides additional functions that complement those in the non-wide library where the size of the underlying character type is significant. A somewhat regular naming convention relates many of the wide variants to their non-wide counterparts; where a non-wide function name contains \*(``ch\*('' or \*(``str\*('', prefix it with \*(``_w\*('' to obtain the wide counterpart. For example, \fB\%waddch\fP becomes \fB\%wadd_wch\fP. (Exceptions that add only \*(``w\*('' comprise .BR \%addwstr , .BR \%inwstr , and their variants.) .IP This convention is inapplicable to some non-wide function names, so other transformations are used for the wide configuration: the window background management function \*(``bkgd\*('' becomes \*(``bkgrnd\*(''; the window border-drawing and -clearing functions are suffixed with \*(``_set\*(''; and character attribute manipulation functions like \*(``attron\*('' become \*(``attr_on\*(''. .\" .SS "Function Name Index" The following table lists the .I curses functions provided in the non-wide and wide APIs and the corresponding man pages that describe them. Those flagged with \*(``*\*('' are .IR \%ncurses "-specific," neither described by X/Open Curses nor present in SVr4. .PP .TS center tab(/); l l . \f(BIcurses\fP Function Name/Man Page _ COLOR_PAIR/\fBcurs_color\fP(3X) PAIR_NUMBER/\fBcurs_color\fP(3X) add_wch/\fBcurs_add_wch\fP(3X) add_wchnstr/\fBcurs_add_wchstr\fP(3X) add_wchstr/\fBcurs_add_wchstr\fP(3X) addch/\fBcurs_addch\fP(3X) addchnstr/\fBcurs_addchstr\fP(3X) addchstr/\fBcurs_addchstr\fP(3X) addnstr/\fBcurs_addstr\fP(3X) addnwstr/\fBcurs_addwstr\fP(3X) addstr/\fBcurs_addstr\fP(3X) addwstr/\fBcurs_addwstr\fP(3X) alloc_pair/\fBnew_pair\fP(3X)* assume_default_colors/\fBdefault_colors\fP(3X)* attr_get/\fBcurs_attr\fP(3X) attr_off/\fBcurs_attr\fP(3X) attr_on/\fBcurs_attr\fP(3X) attr_set/\fBcurs_attr\fP(3X) attroff/\fBcurs_attr\fP(3X) attron/\fBcurs_attr\fP(3X) attrset/\fBcurs_attr\fP(3X) baudrate/\fBcurs_termattrs\fP(3X) beep/\fBcurs_beep\fP(3X) bkgd/\fBcurs_bkgd\fP(3X) bkgdset/\fBcurs_bkgd\fP(3X) bkgrnd/\fBcurs_bkgrnd\fP(3X) bkgrndset/\fBcurs_bkgrnd\fP(3X) border/\fBcurs_border\fP(3X) border_set/\fBcurs_border_set\fP(3X) box/\fBcurs_border\fP(3X) box_set/\fBcurs_border_set\fP(3X) can_change_color/\fBcurs_color\fP(3X) cbreak/\fBcurs_inopts\fP(3X) chgat/\fBcurs_attr\fP(3X) clear/\fBcurs_clear\fP(3X) clearok/\fBcurs_outopts\fP(3X) clrtobot/\fBcurs_clear\fP(3X) clrtoeol/\fBcurs_clear\fP(3X) color_content/\fBcurs_color\fP(3X) color_set/\fBcurs_attr\fP(3X) copywin/\fBcurs_overlay\fP(3X) curs_set/\fBcurs_kernel\fP(3X) curses_trace/\fBcurs_trace\fP(3X)* curses_version/\fBcurs_extend\fP(3X)* def_prog_mode/\fBcurs_kernel\fP(3X) def_shell_mode/\fBcurs_kernel\fP(3X) define_key/\fBdefine_key\fP(3X)* del_curterm/\fBcurs_terminfo\fP(3X) delay_output/\fBcurs_util\fP(3X) delch/\fBcurs_delch\fP(3X) deleteln/\fBcurs_deleteln\fP(3X) delscreen/\fBcurs_initscr\fP(3X) delwin/\fBcurs_window\fP(3X) derwin/\fBcurs_window\fP(3X) doupdate/\fBcurs_refresh\fP(3X) dupwin/\fBcurs_window\fP(3X) echo/\fBcurs_inopts\fP(3X) echo_wchar/\fBcurs_add_wch\fP(3X) echochar/\fBcurs_addch\fP(3X) endwin/\fBcurs_initscr\fP(3X) erase/\fBcurs_clear\fP(3X) erasechar/\fBcurs_termattrs\fP(3X) erasewchar/\fBcurs_termattrs\fP(3X) exit_curses/\fBcurs_memleaks\fP(3X)* exit_terminfo/\fBcurs_memleaks\fP(3X)* extended_color_content/\fBcurs_color\fP(3X)* extended_pair_content/\fBcurs_color\fP(3X)* extended_slk_color/\fBcurs_slk\fP(3X)* filter/\fBcurs_util\fP(3X) find_pair/\fBnew_pair\fP(3X)* flash/\fBcurs_beep\fP(3X) flushinp/\fBcurs_util\fP(3X) free_pair/\fBnew_pair\fP(3X)* get_escdelay/\fBcurs_threads\fP(3X)* get_wch/\fBcurs_get_wch\fP(3X) get_wstr/\fBcurs_get_wstr\fP(3X) getattrs/\fBcurs_attr\fP(3X) getbegx/\fBcurs_legacy\fP(3X)* getbegy/\fBcurs_legacy\fP(3X)* getbegyx/\fBcurs_getyx\fP(3X) getbkgd/\fBcurs_bkgd\fP(3X) getbkgrnd/\fBcurs_bkgrnd\fP(3X) getcchar/\fBcurs_getcchar\fP(3X) getch/\fBcurs_getch\fP(3X) getcurx/\fBcurs_legacy\fP(3X)* getcury/\fBcurs_legacy\fP(3X)* getmaxx/\fBcurs_legacy\fP(3X)* getmaxy/\fBcurs_legacy\fP(3X)* getmaxyx/\fBcurs_getyx\fP(3X) getmouse/\fBcurs_mouse\fP(3X)* getn_wstr/\fBcurs_get_wstr\fP(3X) getnstr/\fBcurs_getstr\fP(3X) getparx/\fBcurs_legacy\fP(3X)* getpary/\fBcurs_legacy\fP(3X)* getparyx/\fBcurs_getyx\fP(3X) getstr/\fBcurs_getstr\fP(3X) getsyx/\fBcurs_kernel\fP(3X) getwin/\fBcurs_util\fP(3X) getyx/\fBcurs_getyx\fP(3X) halfdelay/\fBcurs_inopts\fP(3X) has_colors/\fBcurs_color\fP(3X) has_ic/\fBcurs_termattrs\fP(3X) has_il/\fBcurs_termattrs\fP(3X) has_key/\fBcurs_getch\fP(3X)* has_mouse/\fBcurs_mouse\fP(3X)* hline/\fBcurs_border\fP(3X) hline_set/\fBcurs_border_set\fP(3X) idcok/\fBcurs_outopts\fP(3X) idlok/\fBcurs_outopts\fP(3X) immedok/\fBcurs_outopts\fP(3X) in_wch/\fBcurs_in_wch\fP(3X) in_wchnstr/\fBcurs_in_wchstr\fP(3X) in_wchstr/\fBcurs_in_wchstr\fP(3X) inch/\fBcurs_inch\fP(3X) inchnstr/\fBcurs_inchstr\fP(3X) inchstr/\fBcurs_inchstr\fP(3X) init_color/\fBcurs_color\fP(3X) init_extended_color/\fBcurs_color\fP(3X)* init_extended_pair/\fBcurs_color\fP(3X)* init_pair/\fBcurs_color\fP(3X) initscr/\fBcurs_initscr\fP(3X) innstr/\fBcurs_instr\fP(3X) innwstr/\fBcurs_inwstr\fP(3X) ins_nwstr/\fBcurs_ins_wstr\fP(3X) ins_wch/\fBcurs_ins_wch\fP(3X) ins_wstr/\fBcurs_ins_wstr\fP(3X) insch/\fBcurs_insch\fP(3X) insdelln/\fBcurs_deleteln\fP(3X) insertln/\fBcurs_deleteln\fP(3X) insnstr/\fBcurs_insstr\fP(3X) insstr/\fBcurs_insstr\fP(3X) instr/\fBcurs_instr\fP(3X) intrflush/\fBcurs_inopts\fP(3X) inwstr/\fBcurs_inwstr\fP(3X) is_cbreak/\fBcurs_inopts\fP(3X)* is_cleared/\fBcurs_opaque\fP(3X)* is_echo/\fBcurs_inopts\fP(3X)* is_idcok/\fBcurs_opaque\fP(3X)* is_idlok/\fBcurs_opaque\fP(3X)* is_immedok/\fBcurs_opaque\fP(3X)* is_keypad/\fBcurs_opaque\fP(3X)* is_leaveok/\fBcurs_opaque\fP(3X)* is_linetouched/\fBcurs_touch\fP(3X) is_nl/\fBcurs_inopts\fP(3X)* is_nodelay/\fBcurs_opaque\fP(3X)* is_notimeout/\fBcurs_opaque\fP(3X)* is_pad/\fBcurs_opaque\fP(3X)* is_raw/\fBcurs_inopts\fP(3X)* is_scrollok/\fBcurs_opaque\fP(3X)* is_subwin/\fBcurs_opaque\fP(3X)* is_syncok/\fBcurs_opaque\fP(3X)* is_term_resized/\fBresizeterm\fP(3X)* is_wintouched/\fBcurs_touch\fP(3X) isendwin/\fBcurs_initscr\fP(3X) key_defined/\fBkey_defined\fP(3X)* key_name/\fBcurs_util\fP(3X) keybound/\fBkeybound\fP(3X)* keyname/\fBcurs_util\fP(3X) keyok/\fBkeyok\fP(3X)* keypad/\fBcurs_inopts\fP(3X) killchar/\fBcurs_termattrs\fP(3X) killwchar/\fBcurs_termattrs\fP(3X) leaveok/\fBcurs_outopts\fP(3X) longname/\fBcurs_termattrs\fP(3X) mcprint/\fBcurs_print\fP(3X)* meta/\fBcurs_inopts\fP(3X) mouse_trafo/\fBcurs_mouse\fP(3X)* mouseinterval/\fBcurs_mouse\fP(3X)* mousemask/\fBcurs_mouse\fP(3X)* move/\fBcurs_move\fP(3X) mvadd_wch/\fBcurs_add_wch\fP(3X) mvadd_wchnstr/\fBcurs_add_wchstr\fP(3X) mvadd_wchstr/\fBcurs_add_wchstr\fP(3X) mvaddch/\fBcurs_addch\fP(3X) mvaddchnstr/\fBcurs_addchstr\fP(3X) mvaddchstr/\fBcurs_addchstr\fP(3X) mvaddnstr/\fBcurs_addstr\fP(3X) mvaddnwstr/\fBcurs_addwstr\fP(3X) mvaddstr/\fBcurs_addstr\fP(3X) mvaddwstr/\fBcurs_addwstr\fP(3X) mvchgat/\fBcurs_attr\fP(3X) mvcur/\fBcurs_terminfo\fP(3X) mvdelch/\fBcurs_delch\fP(3X) mvderwin/\fBcurs_window\fP(3X) mvget_wch/\fBcurs_get_wch\fP(3X) mvget_wstr/\fBcurs_get_wstr\fP(3X) mvgetch/\fBcurs_getch\fP(3X) mvgetn_wstr/\fBcurs_get_wstr\fP(3X) mvgetnstr/\fBcurs_getstr\fP(3X) mvgetstr/\fBcurs_getstr\fP(3X) mvhline/\fBcurs_border\fP(3X) mvhline_set/\fBcurs_border_set\fP(3X) mvin_wch/\fBcurs_in_wch\fP(3X) mvin_wchnstr/\fBcurs_in_wchstr\fP(3X) mvin_wchstr/\fBcurs_in_wchstr\fP(3X) mvinch/\fBcurs_inch\fP(3X) mvinchnstr/\fBcurs_inchstr\fP(3X) mvinchstr/\fBcurs_inchstr\fP(3X) mvinnstr/\fBcurs_instr\fP(3X) mvinnwstr/\fBcurs_inwstr\fP(3X) mvins_nwstr/\fBcurs_ins_wstr\fP(3X) mvins_wch/\fBcurs_ins_wch\fP(3X) mvins_wstr/\fBcurs_ins_wstr\fP(3X) mvinsch/\fBcurs_insch\fP(3X) mvinsnstr/\fBcurs_insstr\fP(3X) mvinsstr/\fBcurs_insstr\fP(3X) mvinstr/\fBcurs_instr\fP(3X) mvinwstr/\fBcurs_inwstr\fP(3X) mvprintw/\fBcurs_printw\fP(3X) mvscanw/\fBcurs_scanw\fP(3X) mvvline/\fBcurs_border\fP(3X) mvvline_set/\fBcurs_border_set\fP(3X) mvwadd_wch/\fBcurs_add_wch\fP(3X) mvwadd_wchnstr/\fBcurs_add_wchstr\fP(3X) mvwadd_wchstr/\fBcurs_add_wchstr\fP(3X) mvwaddch/\fBcurs_addch\fP(3X) mvwaddchnstr/\fBcurs_addchstr\fP(3X) mvwaddchstr/\fBcurs_addchstr\fP(3X) mvwaddnstr/\fBcurs_addstr\fP(3X) mvwaddnwstr/\fBcurs_addwstr\fP(3X) mvwaddstr/\fBcurs_addstr\fP(3X) mvwaddwstr/\fBcurs_addwstr\fP(3X) mvwchgat/\fBcurs_attr\fP(3X) mvwdelch/\fBcurs_delch\fP(3X) mvwget_wch/\fBcurs_get_wch\fP(3X) mvwget_wstr/\fBcurs_get_wstr\fP(3X) mvwgetch/\fBcurs_getch\fP(3X) mvwgetn_wstr/\fBcurs_get_wstr\fP(3X) mvwgetnstr/\fBcurs_getstr\fP(3X) mvwgetstr/\fBcurs_getstr\fP(3X) mvwhline/\fBcurs_border\fP(3X) mvwhline_set/\fBcurs_border_set\fP(3X) mvwin/\fBcurs_window\fP(3X) mvwin_wch/\fBcurs_in_wch\fP(3X) mvwin_wchnstr/\fBcurs_in_wchstr\fP(3X) mvwin_wchstr/\fBcurs_in_wchstr\fP(3X) mvwinch/\fBcurs_inch\fP(3X) mvwinchnstr/\fBcurs_inchstr\fP(3X) mvwinchstr/\fBcurs_inchstr\fP(3X) mvwinnstr/\fBcurs_instr\fP(3X) mvwinnwstr/\fBcurs_inwstr\fP(3X) mvwins_nwstr/\fBcurs_ins_wstr\fP(3X) mvwins_wch/\fBcurs_ins_wch\fP(3X) mvwins_wstr/\fBcurs_ins_wstr\fP(3X) mvwinsch/\fBcurs_insch\fP(3X) mvwinsnstr/\fBcurs_insstr\fP(3X) mvwinsstr/\fBcurs_insstr\fP(3X) mvwinstr/\fBcurs_instr\fP(3X) mvwinwstr/\fBcurs_inwstr\fP(3X) mvwprintw/\fBcurs_printw\fP(3X) mvwscanw/\fBcurs_scanw\fP(3X) mvwvline/\fBcurs_border\fP(3X) mvwvline_set/\fBcurs_border_set\fP(3X) napms/\fBcurs_kernel\fP(3X) newpad/\fBcurs_pad\fP(3X) newterm/\fBcurs_initscr\fP(3X) newwin/\fBcurs_window\fP(3X) nl/\fBcurs_inopts\fP(3X) nocbreak/\fBcurs_inopts\fP(3X) nodelay/\fBcurs_inopts\fP(3X) noecho/\fBcurs_inopts\fP(3X) nofilter/\fBcurs_util\fP(3X)* nonl/\fBcurs_inopts\fP(3X) noqiflush/\fBcurs_inopts\fP(3X) noraw/\fBcurs_inopts\fP(3X) notimeout/\fBcurs_inopts\fP(3X) overlay/\fBcurs_overlay\fP(3X) overwrite/\fBcurs_overlay\fP(3X) pair_content/\fBcurs_color\fP(3X) pecho_wchar/\fBcurs_pad\fP(3X) pechochar/\fBcurs_pad\fP(3X) pnoutrefresh/\fBcurs_pad\fP(3X) prefresh/\fBcurs_pad\fP(3X) printw/\fBcurs_printw\fP(3X) putp/\fBcurs_terminfo\fP(3X) putwin/\fBcurs_util\fP(3X) qiflush/\fBcurs_inopts\fP(3X) raw/\fBcurs_inopts\fP(3X) redrawwin/\fBcurs_refresh\fP(3X) refresh/\fBcurs_refresh\fP(3X) reset_color_pairs/\fBcurs_color\fP(3X)* reset_prog_mode/\fBcurs_kernel\fP(3X) reset_shell_mode/\fBcurs_kernel\fP(3X) resetty/\fBcurs_kernel\fP(3X) resize_term/\fBresizeterm\fP(3X)* resizeterm/\fBresizeterm\fP(3X)* restartterm/\fBcurs_terminfo\fP(3X) ripoffline/\fBcurs_kernel\fP(3X) savetty/\fBcurs_kernel\fP(3X) scanw/\fBcurs_scanw\fP(3X) scr_dump/\fBcurs_scr_dump\fP(3X) scr_init/\fBcurs_scr_dump\fP(3X) scr_restore/\fBcurs_scr_dump\fP(3X) scr_set/\fBcurs_scr_dump\fP(3X) scrl/\fBcurs_scroll\fP(3X) scroll/\fBcurs_scroll\fP(3X) scrollok/\fBcurs_outopts\fP(3X) set_curterm/\fBcurs_terminfo\fP(3X) set_escdelay/\fBcurs_threads\fP(3X)* set_tabsize/\fBcurs_threads\fP(3X)* set_term/\fBcurs_initscr\fP(3X) setcchar/\fBcurs_getcchar\fP(3X) setscrreg/\fBcurs_outopts\fP(3X) setsyx/\fBcurs_kernel\fP(3X) setupterm/\fBcurs_terminfo\fP(3X) slk_attr/\fBcurs_slk\fP(3X)* slk_attr_off/\fBcurs_slk\fP(3X) slk_attr_on/\fBcurs_slk\fP(3X) slk_attr_set/\fBcurs_slk\fP(3X) slk_attroff/\fBcurs_slk\fP(3X) slk_attron/\fBcurs_slk\fP(3X) slk_attrset/\fBcurs_slk\fP(3X) slk_clear/\fBcurs_slk\fP(3X) slk_color/\fBcurs_slk\fP(3X) slk_init/\fBcurs_slk\fP(3X) slk_label/\fBcurs_slk\fP(3X) slk_noutrefresh/\fBcurs_slk\fP(3X) slk_refresh/\fBcurs_slk\fP(3X) slk_restore/\fBcurs_slk\fP(3X) slk_set/\fBcurs_slk\fP(3X) slk_touch/\fBcurs_slk\fP(3X) slk_wset/\fBcurs_slk\fP(3X) standend/\fBcurs_attr\fP(3X) standout/\fBcurs_attr\fP(3X) start_color/\fBcurs_color\fP(3X) subpad/\fBcurs_pad\fP(3X) subwin/\fBcurs_window\fP(3X) syncok/\fBcurs_window\fP(3X) term_attrs/\fBcurs_termattrs\fP(3X) termattrs/\fBcurs_termattrs\fP(3X) termname/\fBcurs_termattrs\fP(3X) tgetent/\fBcurs_termcap\fP(3X) tgetflag/\fBcurs_termcap\fP(3X) tgetnum/\fBcurs_termcap\fP(3X) tgetstr/\fBcurs_termcap\fP(3X) tgoto/\fBcurs_termcap\fP(3X) tigetflag/\fBcurs_terminfo\fP(3X) tigetnum/\fBcurs_terminfo\fP(3X) tigetstr/\fBcurs_terminfo\fP(3X) timeout/\fBcurs_inopts\fP(3X) tiparm/\fBcurs_terminfo\fP(3X) tiparm_s/\fBcurs_terminfo\fP(3X)* tiscan_s/\fBcurs_terminfo\fP(3X)* touchline/\fBcurs_touch\fP(3X) touchwin/\fBcurs_touch\fP(3X) tparm/\fBcurs_terminfo\fP(3X) tputs/\fBcurs_termcap\fP(3X) tputs/\fBcurs_terminfo\fP(3X) trace/\fBcurs_trace\fP(3X)* typeahead/\fBcurs_inopts\fP(3X) unctrl/\fBcurs_util\fP(3X) unget_wch/\fBcurs_get_wch\fP(3X) ungetch/\fBcurs_getch\fP(3X) ungetmouse/\fBcurs_mouse\fP(3X)* untouchwin/\fBcurs_touch\fP(3X) use_default_colors/\fBdefault_colors\fP(3X)* use_env/\fBcurs_util\fP(3X) use_extended_names/\fBcurs_extend\fP(3X)* use_legacy_coding/\fBlegacy_coding\fP(3X)* use_screen/\fBcurs_threads\fP(3X)* use_tioctl/\fBcurs_util\fP(3X)* use_window/\fBcurs_threads\fP(3X)* vid_attr/\fBcurs_terminfo\fP(3X) vid_puts/\fBcurs_terminfo\fP(3X) vidattr/\fBcurs_terminfo\fP(3X) vidputs/\fBcurs_terminfo\fP(3X) vline/\fBcurs_border\fP(3X) vline_set/\fBcurs_border_set\fP(3X) vw_printw/\fBcurs_printw\fP(3X) vw_scanw/\fBcurs_scanw\fP(3X) vwprintw/\fBcurs_printw\fP(3X) vwscanw/\fBcurs_scanw\fP(3X) wadd_wch/\fBcurs_add_wch\fP(3X) wadd_wchnstr/\fBcurs_add_wchstr\fP(3X) wadd_wchstr/\fBcurs_add_wchstr\fP(3X) waddch/\fBcurs_addch\fP(3X) waddchnstr/\fBcurs_addchstr\fP(3X) waddchstr/\fBcurs_addchstr\fP(3X) waddnstr/\fBcurs_addstr\fP(3X) waddnwstr/\fBcurs_addwstr\fP(3X) waddstr/\fBcurs_addstr\fP(3X) waddwstr/\fBcurs_addwstr\fP(3X) wattr_get/\fBcurs_attr\fP(3X) wattr_off/\fBcurs_attr\fP(3X) wattr_on/\fBcurs_attr\fP(3X) wattr_set/\fBcurs_attr\fP(3X) wattroff/\fBcurs_attr\fP(3X) wattron/\fBcurs_attr\fP(3X) wattrset/\fBcurs_attr\fP(3X) wbkgd/\fBcurs_bkgd\fP(3X) wbkgdset/\fBcurs_bkgd\fP(3X) wbkgrnd/\fBcurs_bkgrnd\fP(3X) wbkgrndset/\fBcurs_bkgrnd\fP(3X) wborder/\fBcurs_border\fP(3X) wborder_set/\fBcurs_border_set\fP(3X) wchgat/\fBcurs_attr\fP(3X) wclear/\fBcurs_clear\fP(3X) wclrtobot/\fBcurs_clear\fP(3X) wclrtoeol/\fBcurs_clear\fP(3X) wcolor_set/\fBcurs_attr\fP(3X) wcursyncup/\fBcurs_window\fP(3X) wdelch/\fBcurs_delch\fP(3X) wdeleteln/\fBcurs_deleteln\fP(3X) wecho_wchar/\fBcurs_add_wch\fP(3X) wechochar/\fBcurs_addch\fP(3X) wenclose/\fBcurs_mouse\fP(3X)* werase/\fBcurs_clear\fP(3X) wget_wch/\fBcurs_get_wch\fP(3X) wget_wstr/\fBcurs_get_wstr\fP(3X) wgetbkgrnd/\fBcurs_bkgrnd\fP(3X) wgetch/\fBcurs_getch\fP(3X) wgetdelay/\fBcurs_opaque\fP(3X)* wgetn_wstr/\fBcurs_get_wstr\fP(3X) wgetnstr/\fBcurs_getstr\fP(3X) wgetparent/\fBcurs_opaque\fP(3X)* wgetscrreg/\fBcurs_opaque\fP(3X)* wgetstr/\fBcurs_getstr\fP(3X) whline/\fBcurs_border\fP(3X) whline_set/\fBcurs_border_set\fP(3X) win_wch/\fBcurs_in_wch\fP(3X) win_wchnstr/\fBcurs_in_wchstr\fP(3X) win_wchstr/\fBcurs_in_wchstr\fP(3X) winch/\fBcurs_inch\fP(3X) winchnstr/\fBcurs_inchstr\fP(3X) winchstr/\fBcurs_inchstr\fP(3X) winnstr/\fBcurs_instr\fP(3X) winnwstr/\fBcurs_inwstr\fP(3X) wins_nwstr/\fBcurs_ins_wstr\fP(3X) wins_wch/\fBcurs_ins_wch\fP(3X) wins_wstr/\fBcurs_ins_wstr\fP(3X) winsch/\fBcurs_insch\fP(3X) winsdelln/\fBcurs_deleteln\fP(3X) winsertln/\fBcurs_deleteln\fP(3X) winsnstr/\fBcurs_insstr\fP(3X) winsstr/\fBcurs_insstr\fP(3X) winstr/\fBcurs_instr\fP(3X) winwstr/\fBcurs_inwstr\fP(3X) wmouse_trafo/\fBcurs_mouse\fP(3X)* wmove/\fBcurs_move\fP(3X) wnoutrefresh/\fBcurs_refresh\fP(3X) wprintw/\fBcurs_printw\fP(3X) wredrawln/\fBcurs_refresh\fP(3X) wrefresh/\fBcurs_refresh\fP(3X) wresize/\fBwresize\fP(3X)* wscanw/\fBcurs_scanw\fP(3X) wscrl/\fBcurs_scroll\fP(3X) wsetscrreg/\fBcurs_outopts\fP(3X) wstandend/\fBcurs_attr\fP(3X) wstandout/\fBcurs_attr\fP(3X) wsyncdown/\fBcurs_window\fP(3X) wsyncup/\fBcurs_window\fP(3X) wtimeout/\fBcurs_inopts\fP(3X) wtouchln/\fBcurs_touch\fP(3X) wunctrl/\fBcurs_util\fP(3X) wvline/\fBcurs_border\fP(3X) wvline_set/\fBcurs_border_set\fP(3X) .TE .PP .IR \%ncurses 's .I "screen-pointer extension" adds additional functions corresponding to many of the above, each with an \*(``_sp\*('' suffix; see \fBcurs_sp_funcs\fP(3X). .PP The availability of some extensions is configurable when .I \%ncurses is compiled; see sections \*(``ALTERNATE CONFIGURATIONS\*('' and \*(``EXTENSIONS\*('' below. .SH RETURN VALUE Unless otherwise noted, functions that return an integer return .B OK on success and .B ERR on failure. Functions that return pointers return .B NULL on failure. Typically, .I \%ncurses treats a null pointer passed as a function parameter as a failure. Functions with a \*(``mv\*('' prefix first perform cursor movement using \fB\%wmove\fP(3X) and fail if the position is outside the window. .SH ENVIRONMENT The following symbols from the process environment customize the runtime behavior of .I \%ncurses applications. The library may be configured to disregard the variables .IR \%TERMINFO , .IR \%TERMINFO_DIRS , .IR \%TERMPATH , and .IR HOME , if the user is the superuser (root), or the application uses \fI\%setuid\fP(2) or \fI\%setgid\fP(2). .SS "\fIBAUDRATE\fP" The debugging library checks this variable when the application has redirected output to a file. Its integral value is used for the baud rate. If that value is absent or invalid, .I \%ncurses uses 9600. This feature allows testers to construct repeatable test cases that take into account optimization decisions that depend on baud rate. .SS "\fICC\fP (command character)" When set, the .B \%command_character .RB ( \%cmdch ) capability value of loaded .I \%term\%info entries changes to the value of this variable. Very few .I \%term\%info entries provide this feature. .PP Because this name is also used in development environments to represent the C compiler's name, .I \%ncurses ignores its value if it is not one character in length. .SS "\fICOLUMNS\fP" This variable specifies the width of the screen in characters. Applications running in a windowing environment usually are able to obtain the width of the window in which they are executing. If .I \%COLUMNS is not defined and the terminal's screen size is not available from the terminal driver, .I \%ncurses uses the size specified by the .B \%columns .RB ( \%cols ) capability of the terminal type's entry in the .I \%term\%info database, if any. .PP It is important that your application use the correct screen size. Automatic detection thereof is not always possible because an application may be running on a host that does not honor NAWS (Negotiations About Window Size) or as a different user ID than the owner of the terminal device file. Setting .I \%COLUMNS and/or .I \%LINES overrides the library's use of the screen size obtained from the operating system. .PP The .I \%COLUMNS and .I \%LINES variables may be specified independently. This property is useful to circumvent misfeatures of legacy terminal type descriptions; \fI\%xterm\fP(1) descriptions specifying 65 lines were once notorious. For best results, avoid specifying .B cols and .B lines capability codes in .I \%term\%info descriptions of terminal emulators. .PP \fBuse_env\fP(3X) can disable use of the process environment in determining the screen size. \fBuse_tioctl\fP(3X) can update .I \%COLUMNS and .I \%LINES to match the screen size obtained from system calls or the terminal database. .SS "\fIESCDELAY\fP" For .I curses to distinguish the ESC character resulting from a user's press of the \*(``Escape\*('' key on the input device from one beginning an .I "escape sequence" (as commonly produced by function keys), it waits after receiving the escape character to see if further characters are available on the input stream within a short interval. A global variable .B \%ESCDELAY stores this interval in milliseconds. The default value of 1000 (one second) is adequate for most uses. This environment variable overrides it. .PP The most common instance where you may wish to change this value is to work with a remote host over a slow communication channel. If the host running a .I curses application does not receive the characters of an escape sequence in a timely manner, the library can interpret them as multiple key stroke events. .PP \fI\%xterm\fP(1) mouse events are a form of escape sequence; therefore, if your application makes heavy use of multiple-clicking, you may wish to lengthen the default value because the delay applies to the composite multi-click event as well as the individual clicks. .PP Portable applications should not rely upon the presence of .B \%ESCDELAY in either form, but setting the environment variable rather than the global variable does not create problems when compiling an application. .PP If \fB\%keypad\fP(3X) is disabled for the .I curses window receiving input, a program must disambiguate escape sequences itself. .SS "\fIHOME\fP" .I \%ncurses may read and write auxiliary terminal descriptions in .I \%.termcap and .I \%.terminfo files in the user's home directory. .SS "\fILINES\fP" This counterpart to .I \%COLUMNS specifies the height of the screen in characters. The corresponding .I \%term\%info capability and code is .BR \%lines . See the description of the .I \%COLUMNS variable above. .SS "\fIMOUSE_BUTTONS_123\fP" (OS/2 EMX port only) OS/2 numbers a three-button mouse inconsistently with other platforms, such that 1 is the left button, 2 the right, and 3 the middle. This variable customizes the mouse button numbering. Its value must be three digits 1\-3 in any order. By default, .I \%ncurses assumes a numbering of \*(``132\*(''. .SS "\fINCURSES_ASSUMED_COLORS\fP" If set, this variable overrides the .I \%ncurses library's compiled-in assumption that the terminal's default colors are white on black; see \fB\%default_colors\fP(3X). Set the foreground and background color values with this environment variable by assigning it two integer values separated by a comma, indicating foregound and background color numbers, respectively. .PP For example, to tell .I \%ncurses not to assume anything about the colors, use a value of \*(``\-1,\-1\*(''. To make the default color scheme green on black, use \*(``2,0\*(''. .I \%ncurses accepts integral values from \-1 up to the value of the .I \%term\%info .B \%max_colors .RB ( colors ) capability. .SS "\fINCURSES_CONSOLE2\fP" (MinGW port only) The .I \%Console2 .\" https://www.hanselman.com/blog/console2-a-better-windows-command-prompt program defectively handles the Microsoft Console API call .IR \%Create\%Console\%Screen\%Buffer . Applications that use it will hang. However, it is possible to simulate the action of this call by mapping coordinates, explicitly saving and restoring the original screen contents. Setting the environment variable .I \%NCGDB has the same effect. .SS "\fINCURSES_GPM_TERMS\fP" (Linux only) When .I \%ncurses is configured to use the GPM interface, this variable may list one or more terminal names against which the .I TERM variable (see below) is matched. An empty value disables the GPM interface, using .IR \%ncurses 's built-in support for \fIxterm\fP(1) mouse protocols instead. If the variable is absent, .I \%ncurses attempts to open GPM if .I TERM contains \*(``linux\*(''. .SS "\fINCURSES_NO_HARD_TABS\fP" .I \%ncurses may use tab characters in cursor movement optimization. In some cases, your terminal driver may not handle them properly. Set this environment variable to any value to disable the feature. You can also adjust your \fI\%stty\fP(1) settings to avoid the problem. .SS "\fINCURSES_NO_MAGIC_COOKIE\fP" Many terminals store video attributes as a property of a character cell, as .I curses does. Historically, some recorded changes in video attributes as data that logically .I occupies character cells on the display, switching attributes on or off, similarly to tags in a markup language; these are termed \*(``magic cookies\*('', and must be subsequently overprinted. If the .I \%term\%info entry for your terminal type does not adequately describe its handling of magic cookies, set this variable to any value to instruct .I \%ncurses to disable attributes entirely. .SS "\fINCURSES_NO_PADDING\fP" Most terminal type descriptions in the .I \%term\%info database detail hardware devices. Many people use .IR curses -based applications in terminal emulator programs that run in a windowing environment. These programs can duplicate all of the important features of a hardware terminal, but often lack their limitations. Chief among these absent drawbacks is the problem of data flow management; that is, limiting the speed of communication to what the hardware could handle. Unless a hardware terminal is interfaced into a terminal concentrator (which does flow control), an application must manage flow control itself to prevent overruns and data loss. .PP A solution that comes at no hardware cost is for an application to pause after directing a terminal to execute an operation that it performs slowly, such as clearing the display. Many terminal type descriptions, including that for the VT100, embed delay specifications in capabilities. You may wish to use these temrinal descriptions without paying the performance penalty. Set .I \%NCURSES_NO_PADDING to any value to disable all but mandatory padding. Mandatory padding is used by such terminal capabilities as .B \%flash_screen .RB ( flash ). .SS "\fINCURSES_NO_SETBUF\fP" (Obsolete) Prior to internal changes developed in .I \%ncurses 5.9 (patches 20120825 through 20130126), the library used \fI\%setbuf\fP(3) to enable fully buffered output when initializing the terminal. This was done, as in SVr4 .IR curses , to increase performance. For testing purposes, both of .I \%ncurses and of certain applications, this feature was made optional. Setting this variable disabled output buffering, leaving the output stream in the original (usually line-buffered) mode. .PP Nowadays, .I \%ncurses performs its own buffering and does not require this workaround; it does not modify the buffering of the standard output stream. This approach makes signal handling, as for interrupts, more robust. A drawback is that certain unconventional programs mixed \fI\%stdio\fP(3) calls with .I \%ncurses calls and (usually) got the behavior they expected. This is no longer the case; .I \%ncurses does not write to the standard output file descriptor through a .IR stdio -buffered stream. .PP As a special case, low-level API calls such as \fB\%putp\fP(3X) still use the standard output stream. High-level .I curses calls such as \fB\%printw\fP(3X) do not. .SS "\fINCURSES_NO_UTF8_ACS\fP" At initialization, .I \%ncurses inspects the .I TERM environment variable for special cases where VT100 forms-drawing characters (and the corresponding alternate character set .I \%term\%info capabilities) are known to be unsupported by terminal types that otherwise claim VT100 compatibility. Specifically, when running in a UTF-8 locale, the Linux virtual console device and the GNU \fI\%screen\fP(1) program ignore them. Set this variable to a nonzero value to instruct .I \%ncurses that the terminal's ACS support is broken; the library then outputs Unicode code points that correspond to the forms-drawing characters. Set it to zero (or a non-integer) to disable the special check for terminal type names matching \*(``linux\*('' or \*(``screen\*('', directing .I \%ncurses to assume that the ACS feature works if the terminal type description advertises it. .PP As an alternative to use of this variable, .I \%ncurses checks for an extended .I \%term\%info numeric capability \fBU8\fP that can be compiled using .RB \*(`` "@TIC@ \-x" \*(''. Examples follow. .PP .RS 3 .EX # linux console, if patched to provide working # VT100 shift\-in/shift\-out, with corresponding font. linux\-vt100|linux console with VT100 line\-graphics, U8#0, use=linux, \& # uxterm with vt100Graphics resource set to false xterm\-utf8|xterm relying on UTF\-8 line\-graphics, U8#1, use=xterm, .EE .RE .PP The two-character name \*(``U8\*('' was chosen to permit its use via .IR \%ncurses 's .I termcap interface. .SS "\fINCURSES_TRACE\fP" At initialization, .I \%ncurses (in its debugging configuration) checks for this variable's presence. If defined with an integral value, the library calls \fB\%curses_trace\fP(3X) with that value as the argument. .SS "\fITERM\fP" Denotes your terminal type. Each terminal type is distinct, though many are similar. .PP \fITERM\fP is commonly set by terminal emulators to help applications find a workable terminal description. Some of those choose a popular approximation, e.g., \*(``ansi\*('', \*(``vt100\*('', \*(``xterm\*('' rather than an exact fit. Not infrequently, your application will have problems with that approach, e.g., incorrect function-key definitions. .PP If you set \fITERM\fP in your environment, it has no effect on the operation of the terminal emulator. It only affects the way applications work within the terminal. Likewise, as a general rule (\fBxterm\fP(1) being a rare exception), terminal emulators which allow you to specify \fITERM\fP as a parameter or configuration value do not change their behavior to match that setting. .SS "\fITERMCAP\fP" If the \fI\%ncurses\fP library has been configured with \fItermcap\fP support, \fI\%ncurses\fP will check for a terminal's description in termcap form if it is not available in the terminfo database. .PP The \fI\%TERMCAP\fP environment variable contains either a terminal description (with newlines stripped out), or a file name telling where the information denoted by the \fITERM\fP environment variable exists. In either case, setting it directs \fI\%ncurses\fP to ignore the usual place for this information, e.g., /etc/termcap. .SS "\fITERMINFO\fP" \fI\%ncurses\fP can be configured to read from multiple terminal databases. The \fI\%TERMINFO\fP variable overrides the location for the default terminal database. Terminal descriptions (in terminal format) are stored in terminal databases: .bP Normally these are stored in a directory tree, using subdirectories named by the first letter of the terminal names therein. .IP This is the scheme used in System V, which legacy Unix systems use, and the \fI\%TERMINFO\fP variable is used by \fIcurses\fP applications on those systems to override the default location of the terminal database. .IP \(bu 4 If \fI\%ncurses\fP is built to use hashed databases, then each entry in this list may be the path of a hashed database file, e.g., .RS 4 .PP .RS 4 .EX /usr/share/terminfo.db .EE .RE .PP rather than .PP .RS 4 .EX /usr/share/terminfo/ .EE .RE .PP The hashed database uses less disk-space and is a little faster than the directory tree. However, some applications assume the existence of the directory tree, reading it directly rather than using the terminfo library calls. .RE .bP If \fI\%ncurses\fP is built with a support for reading termcap files directly, then an entry in this list may be the path of a termcap file. .IP \(bu 4 If the \fI\%TERMINFO\fP variable begins with \*(``hex:\*('' or \*(``b64:\*('', \fI\%ncurses\fP uses the remainder of that variable as a compiled terminal description. You might produce the base64 format using \fBinfocmp\fP(1M): .RS 4 .PP .RS 4 .EX TERMINFO="$(infocmp \-0 \-Q2 \-q)" export TERMINFO .EE .RE .PP The compiled description is used if it corresponds to the terminal identified by the \fITERM\fP variable. .RE .PP Setting \fI\%TERMINFO\fP is the simplest, but not the only way to set location of the default terminal database. The complete list of database locations in order follows: .RS 3 .bP the last terminal database to which \fI\%ncurses\fP wrote, if any, is searched first .bP the location specified by the \fI\%TERMINFO\fP environment variable .bP $HOME/.terminfo .bP locations listed in the \fI\%TERMINFO_DIRS\fP environment variable .bP one or more locations whose names are configured and compiled into the \fI\%ncurses\fP library, i.e., .RS 3 .bP @TERMINFO_DIRS@ (corresponding to the \fI\%TERMINFO_DIRS\fP variable) .bP @TERMINFO@ (corresponding to the \fITERMINFO\fP variable) .RE .RE .SS "\fITERMINFO_DIRS\fP" Specifies a list of locations to search for terminal descriptions. Each location in the list is a terminal database as described in the section on the \fI\%TERMINFO\fP variable. The list is separated by colons (i.e., ":") on Unix, semicolons on OS/2 EMX. .PP There is no corresponding feature in System V terminfo; it is an extension developed for \fI\%ncurses\fP. .SS "\fITERMPATH\fP" If \fI\%TERMCAP\fP does not hold a file name then \fI\%ncurses\fP checks the \fI\%TERMPATH\fP environment variable. This is a list of filenames separated by spaces or colons (i.e., ":") on Unix, semicolons on OS/2 EMX. .PP If the \fI\%TERMPATH\fP environment variable is not set, \fI\%ncurses\fP looks in the files .PP .RS 4 .EX /etc/termcap, /usr/share/misc/termcap and $HOME/.termcap, .EE .RE .PP in that order. .SH "ALTERNATE CONFIGURATIONS" Many different .I \%ncurses configurations are possible, determined by the options given to the .I \%configure script when building the library. Run the script with the .B \-\-help option to peruse them all. A few are of particular significance to the application developer employing .IR \%ncurses . .TP 5 \-\-disable\-overwrite The standard include for \fI\%ncurses\fP is as noted in \fBSYNOPSIS\fP: .RS 5 .PP .RS 4 .EX \fB#include \fP .EE .RE .PP This option is used to avoid filename conflicts when \fI\%ncurses\fP is not the main implementation of curses of the computer. If \fI\%ncurses\fP is installed disabling overwrite, it puts its headers in a subdirectory, e.g., .PP .RS 4 .EX \fB#include \fP .EE .RE .PP It also omits a symbolic link which would allow you to use \fB\-lcurses\fP to build executables. .RE .TP 5 \-\-enable\-widec The configure script renames the library and (if the \fB\-\-disable\-overwrite\fP option is used) puts the header files in a different subdirectory. All of the library names have a \*(``w\*('' appended to them, i.e., instead of .RS 5 .PP .RS 4 .EX \fB\-lncurses\fP .EE .RE .PP you link with .PP .RS 4 .EX \fB\-lncursesw\fP .EE .RE .PP You must also enable the wide-character features in the header file when compiling for the wide-character library to use the extended (wide-character) functions. The symbol which enables these features has changed since XSI Curses, Issue 4: .bP Originally, the wide-character feature required the symbol \fB_XOPEN_SOURCE_EXTENDED\fP but that was only valid for XPG4 (1996). .bP Later, that was deemed conflicting with \fB_XOPEN_SOURCE\fP defined to 500. .bP As of mid-2018, none of the features in this implementation require a \fB_XOPEN_SOURCE\fP feature greater than 600. However, X/Open Curses, Issue 7 (2009) recommends defining it to 700. .bP Alternatively, you can enable the feature by defining \fBNCURSES_WIDECHAR\fP with the caveat that some other header file than \fBcurses.h\fP may require a specific value for \fB_XOPEN_SOURCE\fP (or a system-specific symbol). .PP The \fI\%curses.h\fP header file installed for the wide-character library is designed to be compatible with the non-wide library's header. Only the size of the \fI\%WINDOW\fP structure differs; few applications require more than pointers to \fI\%WINDOW\fPs. .PP If the headers are installed allowing overwrite, the wide-character library's headers should be installed last, to allow applications to be built using either library from the same set of headers. .RE .TP 5 \-\-with\-pthread The configure script renames the library. All of the library names have a \*(``t\*('' appended to them (before any \*(``w\*('' added by \fB\-\-enable\-widec\fP). .IP The global variables such as \fBLINES\fP are replaced by macros to allow read-only access. At the same time, setter-functions are provided to set these values. Some applications (very few) may require changes to work with this convention. .TP 5 \-\-with\-shared .TP \-\-with\-normal .TP \-\-with\-debug .TP \-\-with\-profile The shared and normal (static) library names differ by their suffixes, e.g., \fBlibncurses.so\fP and \fBlibncurses.a\fP. The debug and profiling libraries add a \*(``_g\*('' and a \*(``_p\*('' to the root names respectively, e.g., \fBlibncurses_g.a\fP and \fBlibncurses_p.a\fP. .TP 5 \-\-with\-termlib Low-level functions which do not depend upon whether the library supports wide-characters, are provided in the tinfo library. .IP By doing this, it is possible to share the tinfo library between wide/normal configurations as well as reduce the size of the library when only low-level functions are needed. .IP Those functions are described in these pages: .RS .bP \fB\%curs_extend\fP(3X) \- miscellaneous \fIcurses\fP extensions .bP \fB\%curs_inopts\fP(3X) \- \fIcurses\fP input options .bP \fB\%curs_kernel\fP(3X) \- low-level \fIcurses\fP routines .bP \fB\%curs_termattrs\fP(3X) \- \fIcurses\fP environment query routines .bP \fB\%curs_termcap\fP(3X) \- \fIcurses\fP emulation of \fItermcap\fP .bP \fB\%curs_terminfo\fP(3X) \- \fIcurses\fP interface to \fIterminfo\fP database .bP \fB\%curs_util\fP(3X) \- miscellaneous \fIcurses\fP utility routines .RE .TP 5 \-\-with\-trace The \fBtrace\fP function normally resides in the debug library, but it is sometimes useful to configure this in the shared library. Configure scripts should check for the function's existence rather than assuming it is always in the debug library. .SH FILES .TP .I @DATADIR@/tabset tab stop initialization database .TP .I \*d compiled terminal capability database .SH NOTES X/Open Curses permits most functions it specifies to be made available as macros as well. .\" See X/Open Curses Issue 4, Version 2, pp. 227-234. .\" See X/Open Curses Issue 7, pp. 311-318. \fI\%ncurses\fP does so .bP for functions that return values via their parameters, .bP to support obsolete features, .bP to reuse functions (for example, those that move the cursor before another operation), and .bP a few special cases. .PP If the standard output file descriptor of an .I \%ncurses program is redirected to something that is not a terminal device, the library writes screen updates to the standard error file descriptor. This was an undocumented feature of SVr3. .PP See subsection \*(``Header files\*('' below regarding symbols exposed by inclusion of \fI\%curses.h\fP. .SH EXTENSIONS .I \%ncurses enables an application to capture mouse events on certain terminals, including .IR \%xterm ; see \fB\%curs_mouse\fP(3X). .PP .I \%ncurses provides a means of responding to window resizing events, as when running in a GUI terminal emulator application such as .IR \%xterm ; see \fB\%resizeterm\fP(3X) and \fB\%wresize\fP(3X). .PP .I \%ncurses allows an application to query the terminal for the presence of a wide variety of special keys; see \fB\%has_key\fP(3X). .PP .I \%ncurses extends the fixed set of function key capabilities specified by X/Open Curses by allowing the application programmer to define additional key sequences at runtime; see \fB\%define_key\fP(3X), \fB\%key_defined\fP(3X), and \fB\%keyok\fP(3X). .PP .I \%ncurses can exploit the capabilities of terminals implementing ISO\ 6429/ECMA-48 SGR\ 39 and SGR\ 49 sequences, which allow an application to reset the terminal to its original foreground and background colors. From a user's perspective, the application is able to draw colored text on a background whose color is set independently, providing better control over color contrasts. See \fB\%default_colors\fP(3X). .PP An .I \%ncurses application can choose to hide the internal details of .I \%WINDOW structures, instead using accessor functions such as \fB\%is_scrollok\fP(3X). .PP .I \%ncurses enables an application to direct application output to a printer attached to the terminal device; see \fB\%curs_print\fP(3X). .PP .I \%ncurses offers \fB\%slk_attr\fP(3X) as a counterpart of \fB\%attr_get\fP(3X) for soft-label key lines, and \fB\%extended_slk_color\fP(3X) as a form of \fB\%slk_color\fP(3X) that can gather color information from them when many colors are supported. .PP Some extensions are only available if .I \%ncurses is compiled to support them; section \*(``ALTERNATE CONFIGURATIONS\*('' describes how. .bP Rudimentary support for multi-threaded applications may be available; see \fBcurs_threads\fP(3X). .bP Functions that ease the management of multiple screens can be exposed; see \fBcurs_sp_funcs\fP(3X). .bP To aid applications to debug their memory usage, .I ncurses optionally offers functions to more aggressively free memory it dynamically allocates itself; see \fBcurs_memleaks\fP(3X). .bP The library facilitates auditing and troubleshooting of its behavior; see \fBcurs_trace\fP(3X). .bP The compiler option .B \%\-DUSE_GETCAP causes the library to fall back to reading .I \%/etc/termcap if the terminal setup code cannot find a .I \%term\%info entry corresponding to .IR TERM . Use of this feature is not recommended, as it essentially includes an entire .I termcap compiler in the .I \%ncurses startup code, at a cost in memory usage and application launch latency. .PP .I \%PDCurses and NetBSD .I curses incorporate some .I \%ncurses extensions. Individual man pages indicate where this is the case. .SH PORTABILITY X/Open Curses defines two levels of conformance, \*(``base\*('' and \*(``enhanced\*(''. The latter includes several additional features, such as wide-character and color support. .I \%ncurses intends base-level conformance with X/Open Curses, and supports nearly all its enhanced features. .\" XXX: What's missing? GBR counts untic(1), and that's all. .PP Differences between X/Open Curses and .I \%ncurses are documented in the \*(``PORTABILITY\*('' sections of applicable man pages. .SS "Error Checking" In many cases, X/Open Curses is vague about error conditions, omitting some of the SVr4 documentation. .PP Unlike other implementations, this one checks parameters such as pointers to \fI\%WINDOW\fP structures to ensure they are not null. The main reason for providing this behavior is to guard against programmer error. The standard interface does not provide a way for the library to tell an application which of several possible errors were detected. Relying on this (or some other) extension will adversely affect the portability of curses applications. .SS "Padding Differences" In historic curses versions, delays embedded in the capabilities \fBcr\fP, \fBind\fP, \fBcub1\fP, \fBff\fP and \fBtab\fP activated corresponding delay bits in the Unix tty driver. In this implementation, all padding is done by sending NUL bytes. This method is slightly more expensive, but narrows the interface to the Unix kernel significantly and increases the package's portability correspondingly. .SS "Header Files" The header file \fI\%curses.h\fP itself includes the header files \fI\%stdio.h\fP and \fI\%unctrl.h\fP. .PP X/Open Curses has more to say, but does not finish the story: .RS 4 .PP The inclusion of may make visible all symbols from the headers , , , and . .RE .PP Here is a more complete story: .bP Starting with BSD curses, all implementations have included . .IP BSD curses included and from an internal header file .I \%curses.ext (\*(``ext\*('' abbreviated \*(``externs\*(''). .IP BSD curses used internally (for \fBprintw\fP and \fBscanw\fP), but nothing in itself relied upon . .bP SVr2 curses added \fBnewterm\fP(3X), which relies upon . That is, the function prototype uses \fBFILE\fP. .IP SVr4 curses added \fBputwin\fP and \fBgetwin\fP, which also use . .IP X/Open Curses documents all three of these functions. .IP SVr4 curses and X/Open Curses do not require the developer to include before including . Both document curses showing as the only required header. .IP As a result, standard will always include . .bP X/Open Curses is inconsistent with respect to SVr4 regarding . .IP As noted in \fBcurs_util\fP(3X), \fI\%ncurses\fP includes from (like SVr4). .bP X/Open's comments about and may refer to HP-UX and AIX: .IP HP-UX curses includes from to declare \fBsetupterm\fP in curses.h, but \fI\%ncurses\fP (and Solaris curses) do not. .IP AIX curses includes and . Again, \fI\%ncurses\fP (and Solaris curses) do not. .bP X/Open says that \fImay\fP include , but there is no requirement that it do that. .IP Some programs use functions declared in both and , and must include both headers in the same module. Very old versions of AIX curses required including before including . .IP Because \fI\%ncurses\fP header files include the headers needed to define datatypes used in the headers, \fI\%ncurses\fP header files can be included in any order. But for portability, you should include before . .bP X/Open Curses says \fI"may make visible"\fP because including a header file does not necessarily make all symbols in it visible (there are ifdef's to consider). .IP For instance, in \fI\%ncurses\fP \fImay\fP be included if the proper symbol is defined, and if \fI\%ncurses\fP is configured for wide-character support. If the header is included, its symbols may be made visible. That depends on the value used for \fB_XOPEN_SOURCE\fP feature test macro. .bP X/Open Curses documents one required header, in a special case: before to prototype the \fBvw_printw\fP and \fBvw_scanw\fP functions (as well as the obsolete the \fBvwprintw\fP and \fBvwscanw\fP functions). Each of those uses a \fBva_list\fP parameter. .IP The two obsolete functions were introduced in SVr3. The other functions were introduced in X/Open Curses. In between, SVr4 curses provided for the possibility that an application might include either or . Initially, that was done by using \fBvoid*\fP for the \fBva_list\fP parameter. Later, a special type (defined in ) was introduced, to allow for compiler type-checking. That special type is always available, because is always included by . .IP None of the X/Open Curses implementations require an application to include before because they either have allowed for a special type, or (like \fI\%ncurses\fP) include directly to provide a portable interface. .SH AUTHORS Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey. Based on \fIpcurses\fP by Pavel Curtis. .SH SEE ALSO \fB\%curs_variables\fP(3X), \fB\%terminfo\fP(5), \fB\%user_caps\fP(5)