curs_touch(3x) — Linux manual page

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 touchline(WINDOW *win, int start, int count);

       int touchwin(WINDOW *win);
       int wtouchln(WINDOW *win, int y, int n, int changed);

       int untouchwin(WINDOW *win);

       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 wre‐
       fresh; 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 implementa‐
       tion

          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 nei‐
               ther TRUE nor FALSE) may not be supported by the compiler.

               To provide error-checking and also match the X/Open func‐
               tion 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 head‐
       er file, for instance, defines both an actual function and macro
       for each.  The macros give the same result as the actual func‐
       tions.  SVr4 curses does not check the window parameter win to en‐
       sure 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.  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
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       ⟨https://github.com/mirror/ncurses.git⟩ on 2025-02-02.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to
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                                                           curs_touch(3X)