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NAME |SYNOPSIS |DESCRIPTION |NOTES |PORTABILITY |SEE ALSO |COLOPHON | |
curs_variables(3X)curs_variables(3X)COLORS,COLOR_PAIRS,COLS,ESCDELAY,LINES,TABSIZE,curscr,newscr,stdscr-cursesglobal variables
#include <curses.h>int COLOR_PAIRS;int COLORS;int COLS;int ESCDELAY;int LINES;int TABSIZE;WINDOW * curscr;WINDOW * newscr;WINDOW * stdscr;
This page summarizes variables provided by thecurseslibrary. A more complete description is given in thecurses(3X) manual page. Depending on the configuration, these may be actual variables, or macros (seecurs_threads(3X) andcurs_opaque(3X)) which provide read-only access tocurses's state. In either case, applications should treat them as read-only to avoid confusing the library.COLOR_PAIRS After initializing curses, this variable contains the number of color pairs which the terminal can support. Usually the number of color pairs will be the productCOLORS*COLORS, however this is not always true: • a few terminals use HLS colors, which do not follow this rule • terminals supporting a large number of colors are limited by the number of color pairs that can be represented in asignedshort value.COLORS After initializing curses, this variable contains the number of colors which the terminal can support.COLS After initializing curses, this variable contains the width of the screen, i.e., the number of columns.ESCDELAY This variable holds the number of milliseconds to wait after read‐ ing an escape character, to distinguish between an individual es‐ cape character entered on the keyboard from escape sequences sent by cursor- and function-keys (see curses(3X)).LINES After initializing curses, this variable contains the height of the screen, i.e., the number of lines.TABSIZE This variable holds the number of columns used by thecurses li‐ brary when converting a tab character to spaces as it adds the tab to a window (seecurs_addch(3X).The Current Screen This implementation of curses uses a special windowcurscrto record its updates to the terminal screen. This is referred to as the “physical screen” in thecurs_re‐fresh(3X) andcurs_outopts(3X) manual pages.The New Screen This implementation of curses uses a special windownewscrto hold updates to the terminal screen before applying them tocurscr. This is referred to as the “virtual screen” in thecurs_ker‐nel(3X),curs_refresh(3X) andcurs_outopts(3X) manual pages.The Standard Screen Upon initializing curses, a default window calledstdscr, which is the size of the terminal screen, is created. Many curses func‐ tions use this window.
The curses library is initialized using eitherinitscr(3X), ornewterm(3X). Ifcursesis configured to use separate curses/terminfo libraries, most of these variables reside in the curses library.
TABSIZEis a feature of SVr4 curses which is not documented by X/Open curses. • In SVr4 curses,TABSIZEis initially set from the terminal de‐ scription'sinit_tabscapability. After that, it can be al‐ tered by the applications using SVr4 curses. SVr4 curses uses the current value ofTABSIZEto compute the position of tabstops for updating both the virtual screen withaddch(3X) as well as the physical screen withmvcur(3X). • This implementation uses the current value ofTABSIZEonly for updating the virtual screen. It uses the terminal descrip‐ tion'sit(init_tabs) capability for computing hardware tabs (i.e., tab stops on the physical screen). • Other implementations differ. For instance, NetBSD curses al‐ lowsTABSIZEto be set through an environment variable. This implementation does not. NetBSD curses does not support hardware tabs; it uses theinit_tabscapability and theTABSIZEvariable only for updat‐ ing the virtual screen.ESCDELAYis an extension in AIX curses: • In AIX, the units forESCDELAYarefifths of a millisecond. • The default value for AIX'sESCDELAYis 0.1 seconds. • AIX also enforces a limit of 10,000 seconds forESCDELAY; this implementation currently has no upper limit. This implementation has long usedESCDELAYwith units of millisec‐ onds, making it impossible to be completely compatible with AIX. Likewise, most users have either decided to override the value, or rely upon its default value.
curses(3X),curs_opaque(3X),curs_terminfo(3X),curs_threads(3X),term_variables(3X),terminfo(5).
This page is part of thencurses (new curses) project. Informa‐ tion about the project can be found at ⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a bug report for this manual page, send it to bug-ncurses-request@gnu.org. This page was obtained from the project's upstream Git mirror of the CVS repository ⟨https://github.com/mirror/ncurses.git⟩ on 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2023-03-12.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgcurs_variables(3X)HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |