curs_touch(3) Library calls curs_touch(3)
NAME
touchwin, touchline, untouchwin, wtouchln, is_linetouched,
is_wintouched - control terminal output refresh in a curses window
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 wrefresh;
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 Curses does not specify 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 boundaries.
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 boundaries.
NOTES
All of these routines except wtouchln may be macros.
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 behaves the same as SVr4.
X/Open Curses, Issue 4 describes these functions, but defines no error
conditions.
SEE ALSO
curses(3X), curs_refresh(3X), curs_variables(3X)
ncurses 6.5 2024-04-20 curs_touch(3)
ncurses 6.5 - Generated Sat May 4 10:30:07 CDT 2024