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curs_refresh(3x) — Linux manual page

curs_refresh(3X)curs_refresh(3X)

NAME        top

doupdate,redrawwin,refresh,wnoutrefresh,wredrawln,wrefresh-       refreshcurseswindows and lines

SYNOPSIS        top

#include <curses.h>int refresh(void);int wrefresh(WINDOW *win);int wnoutrefresh(WINDOW *win);int doupdate(void);int redrawwin(WINDOW *win);int wredrawln(WINDOW *win, intbeg_line, intnum_lines);

DESCRIPTION        top

refresh/wrefresh       Therefreshandwrefreshroutines (orwnoutrefreshanddoupdate)       must be called to get actual output to the terminal, as other rou‐       tines merely manipulate data  structures.   The  routinewrefresh       copies  the  named  window to thephysical screen, taking into ac‐       count what is already there to do optimizations.  Therefreshrou‐       tine is the same, usingstdscras  the  default  window.   Unlessleaveok(3X)  has been enabled, the physical cursor of the terminal       is left at the location of the cursor for that window.wnoutrefresh/doupdate       Thewnoutrefreshanddoupdateroutines allow multiple updates with       more efficiency thanwrefreshalone.  In addition to all the  win‐       dow  structures,curseskeeps two data structures representing the       terminal screen:       •   aphysical screen, describing what is actually on the screen,           and       •   avirtual screen, describing what the programmer wants to have           on the screen.       The routinewrefreshworks by       •   first callingwnoutrefresh, which copies the named window to           thevirtual screen, and       •   then callingdoupdate, which compares thevirtual screen to           thephysical screen and does the actual update.       If the programmer wishes to output several windows at once, a se‐       ries of calls towrefreshresults in alternating calls townoutre‐freshanddoupdate, causing several bursts of output to the       screen.  By first callingwnoutrefreshfor each window, it is then       possible to calldoupdateonce, resulting in only one burst of       output, with fewer total characters transmitted and less CPU time       used.       If thewin argument towrefreshis thephysical screen (i.e., the       global variablecurscr), the screen is immediately cleared and re‐       painted from scratch.       The phrase “copies the named window to the virtual screen” above       is ambiguous.  What actually happens is that alltouched (changed)       lines in the window are copied to the virtual screen.  This af‐       fects programs that use overlapping windows; it means that if two       windows overlap, you can refresh them in either order and the       overlap region will be modified only when it is explicitly       changed.  (But see the section onPORTABILITYbelow for a warning       about exploiting this behavior.)wredrawln/redrawwin       Thewredrawlnroutine indicates tocursesthat some screen lines       are corrupted and should be thrown away before anything is written       over them.  It touches the indicated lines (marking them changed).       The routineredrawwintouches the entire window.

RETURN VALUE        top

       Routines that return an integer returnERRupon failure, andOK       (SVr4 only specifies "an integer value other thanERR") upon suc‐       cessful completion.       X/Open does not define any error conditions.  In this implementa‐       tionwnoutrefresh               returns an error if the window pointer is null, or if the               window is really a pad.wredrawln               returns an error if the associated call totouchlnreturns               an error.

NOTES        top

       Note thatrefreshandredrawwinmay be macros.

PORTABILITY        top

       The XSI Curses standard, Issue 4 describes these functions.       Whetherwnoutrefreshcopies to the virtual screen the entire con‐       tents of a window or just its changed portions has never been       well-documented in historic curses versions (including SVr4).  It       might be unwise to rely on either behavior in programs that might       have to be linked with other curses implementations.  Instead, you       can do an explicittouchwinbefore thewnoutrefreshcall to guar‐       antee an entire-contents copy anywhere.

SEE ALSO        top

curses(3X),curs_outopts(3X)curs_variables(3X).

COLOPHON        top

       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_refresh(3X)

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