NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | PORTABILITY | NOTES | SEE ALSO | COLOPHON

curs_touch(3X)                                                curs_touch(3X)

NAME         top

       touchwin, touchline, untouchwin, wtouchln, is_linetouched,
       is_wintouched - curses refresh control routines

SYNOPSIS         top

       #include <curses.h>
       int touchwin(WINDOW *win);
       int touchline(WINDOW *win, int start, int count);
       int untouchwin(WINDOW *win);
       int wtouchln(WINDOW *win, int y, int n, int changed);
       bool is_linetouched(WINDOW *win, int line);
       bool is_wintouched(WINDOW *win);

DESCRIPTION         top

       The touchwin and touchline routines throw away all optimization
       information about which parts of the window have been touched, by
       pretending that the entire window has been drawn on.  This is
       sometimes necessary when using overlapping windows, since a change to
       one window affects the other window, but the records of which lines
       have been changed in the other window do not reflect the change.  The
       routine touchline only pretends that count lines have been changed,
       beginning with line start.

       The untouchwin routine marks all lines in the window as unchanged
       since the last call to wrefresh.

       The wtouchln routine makes n lines in the window, starting at line y,
       look as if they have (changed=1) or have not (changed=0) been changed
       since the last call to wrefresh.

       The is_linetouched and is_wintouched routines return TRUE if the
       specified line/window was modified since the last call to wrefresh;
       otherwise they return FALSE.  In addition, is_linetouched returns ERR
       if line is not valid for the given window.

RETURN VALUE         top

       All routines return the integer ERR upon failure and an integer value
       other than ERR upon successful completion, unless otherwise noted in
       the preceding routine descriptions.

       X/Open does not define any error conditions.  In this implementation

          is_linetouched
               returns an error if the window pointer is null, or if the
               line number is outside the window.

               The constant ERR is distinct from TRUE and FALSE, which are
               the normal return values of this function.  Because the
               function returns a bool, returning ERR (which is neither TRUE
               nor FALSE) may not be supported by the compiler.

               To provide error-checking and also match the X/Open function
               prototype, the ERR is provided by a macro named
               is_linetouched.  The actual function returns FALSE when it
               detects an error.

          wtouchln
               returns an error if the window pointer is null, or if the
               line number is outside the window.

PORTABILITY         top

       These functions were introduced by SVr4.  The Solaris curses header
       file, for instance, defines both an actual function and macro for
       each.  The macros give the same result as the actual functions.  SVr4
       curses does not check the window parameter win to ensure that it is
       not NULL; otherwise this implementation behaves the same as SVr4.

       The XSI Curses standard, Issue 4 describes these functions, but
       defines no error conditions.

NOTES         top

       All of these routines except wtouchln may be macros.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Information
       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
       ⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2018-04-30.  (At that
       time, the date of the most recent commit that was found in the repos‐
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       of the original manual page), send a mail to man-pages@man7.org

                                                              curs_touch(3X)