curs_touch(3x) — Linux manual page
curs_touch(3X) curs_touch(3X)
NAME
touchwin, touchline, untouchwin, wtouchln, is_linetouched,
is_wintouched - curses refresh control routines
SYNOPSIS
#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
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
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 compil‐
er.
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
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 be‐
haves the same as SVr4.
The XSI Curses standard, Issue 4 describes these functions, but
defines no error conditions.
NOTES
All of these routines except wtouchln may be macros.
SEE ALSO
curses(3X), curs_refresh(3X), curs_variables(3X).
COLOPHON
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⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have
a bug report for this manual page, send it to
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