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<H1 class="no-header">curs_kernel 3x 2025-08-16 ncurses 6.6 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>def_prog_mode</STRONG>, <STRONG>def_shell_mode</STRONG>, <STRONG>reset_prog_mode</STRONG>, <STRONG>reset_shell_mode</STRONG>,
<STRONG>resetty</STRONG>, <STRONG>savetty</STRONG>, <STRONG>getsyx</STRONG>, <STRONG>setsyx</STRONG>, <STRONG>curs_set</STRONG>, <STRONG>mvcur</STRONG>, <STRONG>napms</STRONG>, <STRONG>ripoffline</STRONG> -
low-level <EM>curses</EM> routines
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>def_prog_mode(void);</STRONG>
<STRONG>int</STRONG> <STRONG>def_shell_mode(void);</STRONG>
<STRONG>int</STRONG> <STRONG>reset_prog_mode(void);</STRONG>
<STRONG>int</STRONG> <STRONG>reset_shell_mode(void);</STRONG>
<STRONG>int</STRONG> <STRONG>resetty(void);</STRONG>
<STRONG>int</STRONG> <STRONG>savetty(void);</STRONG>
<STRONG>void</STRONG> <STRONG>getsyx(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG>
<STRONG>void</STRONG> <STRONG>setsyx(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>curs_set(int</STRONG> <EM>visibility</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>mvcur(int</STRONG> <EM>oldrow</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>oldcol</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>newrow</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>newcol</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>napms(int</STRONG> <EM>ms</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>ripoffline(int</STRONG> <EM>line</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>(*</STRONG><EM>init</EM><STRONG>)(WINDOW</STRONG> <STRONG>*,</STRONG> <STRONG>int));</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
The following routines give low-level access to various <STRONG>curses</STRONG>
capabilities. These routines typically are used inside library
routines.
</PRE><H3><a name="h3-def_prog_mode_def_shell_mode">def_prog_mode, def_shell_mode</a></H3><PRE>
The <STRONG>def_prog_mode</STRONG> and <STRONG>def_shell_mode</STRONG> routines save the current terminal
modes as the "program" (in <STRONG>curses</STRONG>) or "shell" (not in <STRONG>curses</STRONG>) state for
use by the <STRONG>reset_prog_mode</STRONG> and <STRONG>reset_shell_mode</STRONG> routines. This is done
automatically by <STRONG>initscr</STRONG>. There is one such save area for each screen
context allocated by <STRONG>newterm</STRONG>.
</PRE><H3><a name="h3-reset_prog_mode_reset_shell_mode">reset_prog_mode, reset_shell_mode</a></H3><PRE>
The <STRONG>reset_prog_mode</STRONG> and <STRONG>reset_shell_mode</STRONG> routines restore the terminal
to "program" (in <STRONG>curses</STRONG>) or "shell" (out of <STRONG>curses</STRONG>) state. These are
done automatically by <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG> and, after an <STRONG>endwin</STRONG>, by <STRONG>doupdate</STRONG>, so
they normally are not called.
</PRE><H3><a name="h3-resetty_savetty">resetty, savetty</a></H3><PRE>
The <STRONG>resetty</STRONG> and <STRONG>savetty</STRONG> routines save and restore the state of the
terminal modes. <STRONG>savetty</STRONG> saves the current state in a buffer and
<STRONG>resetty</STRONG> restores the state to what it was at the last call to <STRONG>savetty</STRONG>.
</PRE><H3><a name="h3-getsyx">getsyx</a></H3><PRE>
<STRONG>getsyx</STRONG> stores the coordinates of virtual screen (<STRONG>newscr</STRONG>) cursor in <EM>y</EM>
and <EM>x</EM>. If <STRONG>newscr</STRONG>'s <STRONG><A HREF="leaveok.3x.html">leaveok(3x)</A></STRONG> output option is <STRONG>TRUE</STRONG>, <STRONG>getsyx</STRONG> stores <STRONG>-1</STRONG>
in both <EM>y</EM> and <EM>x</EM>. If lines have been removed from the top of the screen
using <STRONG>ripoffline</STRONG>, <EM>y</EM> includes these lines; therefore, <EM>y</EM> and <EM>x</EM> populated
by <STRONG>getsyx</STRONG> should be used only as arguments for <STRONG>setsyx</STRONG>.
Few applications use this feature; most call <STRONG><A HREF="curs_getyx.3x.html">getyx(3x)</A></STRONG> instead.
</PRE><H3><a name="h3-setsyx">setsyx</a></H3><PRE>
<STRONG>setsyx</STRONG> sets the virtual screen (<STRONG>newscr</STRONG>) cursor location to (<EM>y</EM>, <EM>x</EM>).
<STRONG>setsyx(-1,</STRONG> <STRONG>-1)</STRONG> is equivalent to <STRONG>leaveok(newscr,</STRONG> <STRONG>TRUE)</STRONG>.
<STRONG>getsyx</STRONG> and <STRONG>setsyx</STRONG> are designed to be used by a function that
manipulates <EM>curses</EM> windows but seeks to avoid changing the cursor
position. Such a function would first call <STRONG>getsyx</STRONG>, modify its windows'
content, call <STRONG><A HREF="curs_refresh.3x.html">wnoutrefresh(3x)</A></STRONG> on them, call <STRONG>setsyx</STRONG>, then call
<STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG>.
Few applications use this feature; most call <STRONG><A HREF="curs_move.3x.html">wmove(3x)</A></STRONG> instead.
</PRE><H3><a name="h3-curs_set">curs_set</a></H3><PRE>
<STRONG>curs_set</STRONG> adjusts the cursor visibility to "invisible", "visible", "very
visible", as its argument is <STRONG>0</STRONG>, <STRONG>1</STRONG>, or <STRONG>2</STRONG>, respectively. It returns the
previous <EM>visibility</EM> if the requested one is supported, and <STRONG>ERR</STRONG>
otherwise.
</PRE><H3><a name="h3-mvcur">mvcur</a></H3><PRE>
<STRONG>mvcur</STRONG> provides low-level cursor motion. It takes effect immediately,
rather than at the next refresh. Unlike the other low-level output
functions, which either write to the standard output stream or are
passed a function pointer to perform output, <STRONG>mvcur</STRONG> uses a file
descriptor derived from the output stream parameter of <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG>.
One application of <STRONG>mvcur</STRONG> accompanies the temporary use of another
program to write to the terminal screen. For example, first call
<STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG> to ensure that the screen and the library's model of it are
up to date; then call <STRONG>reset_shell_mode</STRONG>; write to the screen with the
external application; call <STRONG>reset_prog_mode</STRONG>; and finally call <STRONG>mvcur(</STRONG>...<STRONG>,</STRONG>
...<STRONG>,</STRONG> <STRONG>-1,</STRONG> <STRONG>-1)</STRONG> to move the terminal cursor to where <EM>curses</EM> thinks it is,
since the library has no knowledge of how the external application
moved it.
</PRE><H3><a name="h3-napms">napms</a></H3><PRE>
<STRONG>napms</STRONG> sleeps for <EM>ms</EM> milliseconds. If <EM>ms</EM> exceeds 30,000 (thirty
seconds), <EM>ncurses</EM> caps it at that value.
</PRE><H3><a name="h3-ripoffline">ripoffline</a></H3><PRE>
<STRONG>ripoffline</STRONG> provides access to the same facility that <STRONG><A HREF="curs_slk.3x.html">slk_init(3x)</A></STRONG> uses
to reduce the size of the screen. The application must call <STRONG>ripoffline</STRONG>
before <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> or <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG> so that the latter functions prepare
a <STRONG>stdscr</STRONG> of the correct size.
<STRONG>o</STRONG> If <EM>line</EM> is positive, <STRONG>ripoffline</STRONG> removes a line from the top of what
will become <STRONG>stdscr</STRONG>.
<STRONG>o</STRONG> If <EM>line</EM> is negative, <STRONG>ripoffline</STRONG> removes a line from the bottom of
what will become <STRONG>stdscr</STRONG>.
When <STRONG>initscr</STRONG> initializes <EM>curses</EM>, it calls the <EM>init</EM> function supplied to
<STRONG>ripoffline</STRONG> by the application with two arguments:
<STRONG>o</STRONG> a pointer to the one-line <EM>WINDOW</EM> that it allocates, and
<STRONG>o</STRONG> an integer with the number of columns in the window.
Inside this <EM>init</EM> function, the values of the integer variables <STRONG>LINES</STRONG>
and <STRONG>COLS</STRONG> (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>) are not guaranteed to be reliable; it
must not call <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG> or <STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG>. A <STRONG><A HREF="curs_refresh.3x.html">wnoutrefresh(3x)</A></STRONG> call is
permissible.
<STRONG>ripoffline</STRONG> can be called up to five times before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
Except for <STRONG>curs_set</STRONG>, these functions return <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on
failure.
<STRONG>curs_set</STRONG> returns the previous cursor visibility, and returns <STRONG>ERR</STRONG> if the
terminal type does not support the requested <EM>visibility</EM>.
<STRONG>napms</STRONG> always succeeds.
<STRONG>mvcur</STRONG> fails if the position (<EM>newrow</EM>, <EM>newcol</EM>) is outside the screen
boundaries.
In <EM>ncurses</EM>,
<STRONG>o</STRONG> <STRONG>def_prog_mode</STRONG>, <STRONG>def_shell_mode</STRONG>, <STRONG>reset_prog_mode</STRONG>, and
<STRONG>reset_shell_mode</STRONG> return <STRONG>ERR</STRONG> if the terminal was not initialized, or
if the operating system's function for obtaining terminal settings
fails.
<STRONG>o</STRONG> <STRONG>ripoffline</STRONG> returns <STRONG>ERR</STRONG> if the accumulated quantity of ripped-off
lines would exceed the maximum (5).
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
<STRONG>getsyx</STRONG> is a macro; use of the <STRONG>&</STRONG> operator before its arguments is
unnecessary.
The <STRONG>endwin</STRONG> function of both <EM>ncurses</EM> and SVr4 <EM>curses</EM> calls <STRONG>curs_set</STRONG> if
the latter has previously been called to set the cursor visibility to a
value other than normal; that is, either invisible or very visible.
There is no way for <EM>ncurses</EM> to determine the initial cursor visibility
to restore it.
<EM>ncurses</EM> imposes a limit of 30 seconds on a delay requested of <STRONG>napms</STRONG>.
While the <EM>init</EM> function called by <STRONG>ripoffline</STRONG> is specified to return an
<EM>int</EM>, <EM>ncurses</EM> pays no attention to its return value.
If <STRONG>ripoffline</STRONG> cannot allocate memory for the required <EM>WINDOW</EM> structure
backing the ripped-off line, it stores a null pointer to the <EM>WINDOW</EM>
pointer argument supplied by the <EM>init</EM> function the application
specifies. The application must check this argument for validity after
calling <STRONG>initscr</STRONG> and prior to performing <EM>curses</EM> operations on that
window.
</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
In <EM>ncurses</EM>, <STRONG>mvcur</STRONG> accepts <STRONG>-1</STRONG> for either or both old coordinates. This
value tells <EM>ncurses</EM> that the old location is unknown, and that it must
use only absolute motion, as with the <STRONG>cursor_address</STRONG> (<STRONG>cup</STRONG>) capability,
rather than the least costly combination of absolute and relative
motion.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
Applications employing <EM>ncurses</EM> extensions should condition their use on
the visibility of the <STRONG>NCURSES_VERSION</STRONG> preprocessor macro.
The <EM>virtual</EM> <EM>screen</EM> functions <EM>setsyx</EM> and <EM>getsyx</EM> are not described in
X/Open Curses Issue 4. SVr4 documents each of them as returning an
<EM>int</EM>. This is misleading, as they are macros with no documented
semantics for returning values.
All other functions are as described in X/Open Curses. It specifies no
error conditions for them, except as described for <EM>curs</EM><STRONG>_</STRONG><EM>set</EM> in section
"RETURN VALUE" above.
The System V Interface Definition, Version 4 (1995), specified all of
these functions except <EM>curs</EM><STRONG>_</STRONG><EM>set</EM> as returning <EM>OK</EM>.
Older SVr4 man pages warn that the return value of <EM>curs</EM><STRONG>_</STRONG><EM>set</EM> "is
currently incorrect". This implementation gets it right, but counting
on its correctness anywhere else may be unwise.
X/Open Curses specifies <EM>ripoffline</EM> as returning <EM>OK</EM> with no possibility
of failure ("[c]alls to <EM>ripoffline</EM> above this limit [five lines] have
no effect but report success").
X/Open Curses notes:
After use of <EM>mvcur</EM>(), the model Curses maintains of the state of
the terminal might not match the actual state of the terminal.
An application should touch and refresh the window before
resuming conventional use of Curses.
Both <EM>ncurses</EM> and SVr4 <EM>curses</EM> implement <EM>mvcur</EM> using the <EM>SCREEN</EM> object
allocated in either <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> or <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG>. X/Open Curses states
that the old location must be given for <EM>mvcur</EM> to accommodate terminals
that lack absolute cursor positioning.
If interrupted by a signal, <EM>ncurses</EM> restarts <EM>napms</EM>. That, and the
limitation to 30 seconds, differ from other implementations.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>,
<STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>
ncurses 6.6 2025-08-16 <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-def_prog_mode_def_shell_mode">def_prog_mode, def_shell_mode</a></li>
<li><a href="#h3-reset_prog_mode_reset_shell_mode">reset_prog_mode, reset_shell_mode</a></li>
<li><a href="#h3-resetty_savetty">resetty, savetty</a></li>
<li><a href="#h3-getsyx">getsyx</a></li>
<li><a href="#h3-setsyx">setsyx</a></li>
<li><a href="#h3-curs_set">curs_set</a></li>
<li><a href="#h3-mvcur">mvcur</a></li>
<li><a href="#h3-napms">napms</a></li>
<li><a href="#h3-ripoffline">ripoffline</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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