ncurses 6.5 - patch 20240525

[ncurses.git] / man / curs_kernel.3x

diff --git a/man/curs_kernel.3x b/man/curs_kernel.3x
index 505ea1eee8e7336cdc8112430f3e23fff6448b99..8c4119de66e915dc9673d28b72f9f33583916c58 100644 (file)
--- a/man/curs_kernel.3x
+++ b/man/curs_kernel.3x
@@ -1,5 +1,6 @@
 .\"***************************************************************************
 .\"***************************************************************************

-.\" Copyright (c) 1998-2016,2017 Free Software Foundation, Inc.              *
+.\" Copyright 2018-2023,2024 Thomas E. Dickey                                *
+.\" Copyright 1998-2016,2017 Free Software Foundation, Inc.                  *

 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *


@@ -26,109 +27,174 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"

-.\" $Id: curs_kernel.3x,v 1.22 2017/01/07 19:25:15 tom Exp $
+.\" $Id: curs_kernel.3x,v 1.63 2024/05/25 21:13:56 tom Exp $
+.TH curs_kernel 3X 2024-05-25 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
+.ie \n(.g \{\
+.ds `` \(lq
+.ds '' \(rq
+.\}
+.el \{\
+.ie t .ds `` ``
+.el   .ds `` ""
+.ie t .ds '' ''
+.el   .ds '' ""
+.\}
+.

 .de bP
 .de bP

-.IP \(bu 4
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2

 ..
 ..

-.TH curs_kernel 3X ""
-.na
-.hy 0

 .SH NAME
 .SH NAME

-\fBdef_prog_mode\fR,
-\fBdef_shell_mode\fR,
-\fBreset_prog_mode\fR,
-\fBreset_shell_mode\fR,
-\fBresetty\fR,
-\fBsavetty\fR,
-\fBgetsyx\fR,
-\fBsetsyx\fR,
-\fBripoffline\fR,
-\fBcurs_set\fR,
-\fBnapms\fR \- low-level \fBcurses\fR routines
-.ad
-.hy
+\fB\%def_prog_mode\fP,
+\fB\%def_shell_mode\fP,
+\fB\%reset_prog_mode\fP,
+\fB\%reset_shell_mode\fP,
+\fB\%resetty\fP,
+\fB\%savetty\fP,
+\fB\%getsyx\fP,
+\fB\%setsyx\fP,
+\fB\%curs_set\fP,
+\fB\%mvcur\fP,
+\fB\%napms\fP,
+\fB\%ripoffline\fP \-
+low-level \fIcurses\fR routines

 .SH SYNOPSIS
 .SH SYNOPSIS

-\fB#include <curses.h>\fR
-.sp
-\fBint def_prog_mode(void);\fR
-.br
-\fBint def_shell_mode(void);\fR
-.br
-\fBint reset_prog_mode(void);\fR
-.br
-\fBint reset_shell_mode(void);\fR
-.br
-\fBint resetty(void);\fR
-.br
-\fBint savetty(void);\fR
-.br
-\fBvoid getsyx(int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
-.br
-\fBvoid setsyx(int \fP\fIy\fP\fB, int \fP\fIx\fP\fB);\fR
-.br
-\fBint ripoffline(int \fP\fIline\fP\fB, int (*\fP\fIinit\fP\fB)(WINDOW *, int));\fR
-.br
-\fBint curs_set(int \fP\fIvisibility\fP\fB);\fR
-.br
-\fBint napms(int \fP\fIms\fP\fB);\fR
-.br
+.nf
+\fB#include <curses.h>
+.PP
+\fBint def_prog_mode(void);
+\fBint def_shell_mode(void);
+.PP
+\fBint reset_prog_mode(void);
+\fBint reset_shell_mode(void);
+.PP
+\fBint resetty(void);
+\fBint savetty(void);
+.PP
+\fBvoid getsyx(int \fIy\fP, int \fIx\fP);
+\fBvoid setsyx(int \fIy\fP, int \fIx\fP);
+.PP
+\fBint curs_set(int \fIvisibility\fP);
+\fBint mvcur(int \fIoldrow\fP, int \fIoldcol\fP, int \fInewrow\fP, int \fInewcol\fP);
+\fBint napms(int \fIms\fP);
+\fBint ripoffline(int \fIline\fP, int (*\fIinit\fP)(WINDOW *, int));
+.fi

 .SH DESCRIPTION
 .SH DESCRIPTION

-The following routines give low-level access to various \fBcurses\fR
-capabilities.  These routines typically are used inside library
-routines.
-.SS def_prog_mode, def_shell_mode
-.PP
-The \fBdef_prog_mode\fR and \fBdef_shell_mode\fR routines save the
-current terminal modes as the "program" (in \fBcurses\fR) or "shell"
-(not in \fBcurses\fR) state for use by the \fBreset_prog_mode\fR and
-\fBreset_shell_mode\fR routines.  This is done automatically by
-\fBinitscr\fR.  There is one such save area for each screen context
-allocated by \fBnewterm\fR.
-.SS reset_prog_mode, reset_shell_mode
-.PP
-The \fBreset_prog_mode\fR and \fBreset_shell_mode\fR routines restore
-the terminal to "program" (in \fBcurses\fR) or "shell" (out of
-\fBcurses\fR) state.  These are done automatically by \fBendwin\fR(3X)
-and, after an \fBendwin\fR, by \fBdoupdate\fR, so they normally are
-not called.
-.SS resetty, savetty
-.PP
-The \fBresetty\fR and \fBsavetty\fR routines save and restore the
-state of the terminal modes.  \fBsavetty\fR saves the current state in
-a buffer and \fBresetty\fR restores the state to what it was at the
-last call to \fBsavetty\fR.
+The following routines give low-level access
+to various \fBcurses\fP capabilities.
+These routines typically are used inside library routines.
+.SS "def_prog_mode, def_shell_mode"
+The \fBdef_prog_mode\fP and \fBdef_shell_mode\fP routines save the
+current terminal modes as the \*(``program\*(''
+(in \fBcurses\fP) or \*(``shell\*(''
+(not in \fBcurses\fP) state for use by the \fBreset_prog_mode\fP and
+\fBreset_shell_mode\fP routines.
+This is done automatically by \fBinitscr\fP.
+There is one such save area for each screen context
+allocated by \fBnewterm\fP.
+.SS "reset_prog_mode, reset_shell_mode"
+The \fBreset_prog_mode\fP and \fBreset_shell_mode\fP routines restore
+the terminal to \*(``program\*('' (in \fBcurses\fP) or \*(``shell\*('' (out of
+\fBcurses\fP) state.
+These are done automatically by \fBendwin\fP(3X) and,
+after an \fBendwin\fP, by \fBdoupdate\fP,
+so they normally are not called.
+.SS "resetty, savetty"
+The \fBresetty\fP and \fBsavetty\fP routines save and restore the
+state of the terminal modes.
+\fBsavetty\fP saves the current state in
+a buffer and \fBresetty\fP restores the state to what it was at the
+last call to \fBsavetty\fP.

 .SS getsyx
 .SS getsyx

+The \fBgetsyx\fP routine returns the current coordinates
+of the \fIvirtual screen\fP cursor in \fIy\fP and \fIx\fP.
+If \fBleaveok\fP is currently \fBTRUE\fP, then
+\fB\-1\fP,\fB\-1\fP is returned.
+If lines have been removed from the top of the
+screen, using \fBripoffline\fP, \fIy\fP and \fIx\fP include these lines;
+therefore, \fIy\fP and \fIx\fP should be used only as arguments for
+\fBsetsyx\fP.

 .PP
 .PP

-The \fBgetsyx\fR routine returns the current coordinates of the virtual screen
-cursor in \fIy\fR and \fIx\fR.  If \fBleaveok\fR is currently \fBTRUE\fR, then
-\fB\-1\fR,\fB\-1\fR is returned.  If lines have been removed from the top of the
-screen, using \fBripoffline\fR, \fIy\fR and \fIx\fR include these lines;
-therefore, \fIy\fR and \fIx\fR should be used only as arguments for
-\fBsetsyx\fR.
+Few applications will use this feature,
+most use \fBgetyx\fP instead.

 .SS setsyx
 .SS setsyx

-.PP
-The \fBsetsyx\fR routine sets the virtual screen cursor to
-\fIy\fR, \fIx\fR.  If \fIy\fR and \fIx\fR are both \fB\-1\fR, then
-\fBleaveok\fR is set.  The two routines \fBgetsyx\fR and \fBsetsyx\fR
+The \fBsetsyx\fP routine sets
+the \fIvirtual screen\fP cursor to \fIy\fP, \fIx\fP.
+If \fIy\fP and \fIx\fP are both \fB\-1\fP, then
+\fBleaveok\fP is set.
+The two routines \fBgetsyx\fP and \fBsetsyx\fP

 are designed to be used by a library routine, which manipulates
 are designed to be used by a library routine, which manipulates

-\fBcurses\fR windows but does not want to change the current position
-of the program's cursor.  The library routine would call \fBgetsyx\fR
+\fBcurses\fP windows but does not want to change the current position
+of the program's cursor.
+The library routine would call \fBgetsyx\fP

 at the beginning, do its manipulation of its own windows, do a
 at the beginning, do its manipulation of its own windows, do a

-\fBwnoutrefresh\fR on its windows, call \fBsetsyx\fR, and then call
-\fBdoupdate\fR.
-.SS ripoffline
+\fBwnoutrefresh\fP on its windows, call \fBsetsyx\fP, and then call
+\fBdoupdate\fP.

 .PP
 .PP

-The \fBripoffline\fR routine provides access to the same facility that
-\fBslk_init\fR [see \fBcurs_slk\fR(3X)] uses to reduce the size of the
-screen.  \fBripoffline\fR must be called before \fBinitscr\fR or
-\fBnewterm\fR is called, to prepare these initial actions:
+Few applications will use this feature,
+most use \fBwmove\fP instead.
+.SS curs_set
+The \fBcurs_set\fP routine sets the cursor state to invisible,
+normal, or very visible for \fBvisibility\fP equal to \fB0\fP,
+\fB1\fP, or \fB2\fP respectively.
+If the terminal supports the \fIvisibility\fP requested,
+the previous \fIcursor\fP state is returned;
+otherwise, \fBERR\fP is returned.
+.SS mvcur
+.B \%mvcur
+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,
+.B \%mvcur
+uses a file descriptor derived from the output stream parameter of
+\fB\%newterm\fP(3X).
+.PP
+One application of
+.B \%mvcur
+accompanies the temporary use of another program to write to the
+terminal screen.
+For example,
+first call \fB\%refresh\fP(3X) to ensure that the screen and the
+library's model of it is up to date;
+then call
+.BR \%reset_shell_mode ";"
+write to the screen with the external application;
+call
+.BR \%reset_prog_mode ";"
+and finally call
+.B \%mvcur
+to set the cursor's location to where
+.I \%curses
+thinks it is,
+since the library has no knowledge of how the external application
+moved it.
+.\" https://lists.gnu.org/archive/html/bug-ncurses/2016-10/msg00002.html
+.SS napms
+.B \%napms
+sleeps for
+.I ms
+milliseconds.
+If
+.I ms
+exceeds 30,000
+(thirty seconds),
+it is capped at that value.
+.SS ripoffline
+.B \%ripoffline
+provides access to the same facility that \fB\%slk_init\fP(3X) uses to
+reduce the size of the screen.
+\fB\%ripoffline\fP must be called before \fBinitscr\fP or
+\fBnewterm\fP is called, to prepare these initial actions:

 .bP
 .bP

-If \fIline\fR is positive, a line is removed from the top of \fBstdscr\fR.
+If \fIline\fP is positive, a line is removed from the top of \fBstdscr\fP.

 .bP
 .bP

-if \fIline\fR is negative, a line is removed from the bottom.
+if \fIline\fP is negative, a line is removed from the bottom.

 .PP
 .PP

-When the resulting initialization is done inside \fBinitscr\fR, the
-routine \fBinit\fR (supplied by the user) is called with two
+When the resulting initialization is done inside \fBinitscr\fP, the
+routine \fBinit\fP (supplied by the user) is called with two

 arguments:
 .bP
 a window pointer to the one-line window that has been
 arguments:
 .bP
 a window pointer to the one-line window that has been


@@ -136,72 +202,109 @@ allocated and
 .bP
 an integer with the number of columns in the window.
 .PP
 .bP
 an integer with the number of columns in the window.
 .PP

-Inside this initialization routine, the integer variables \fBLINES\fR
-and \fBCOLS\fR (defined in \fB<curses.h>\fR) are not guaranteed to be
-accurate and \fBwrefresh\fR or \fBdoupdate\fR must not be called.  It
-is allowable to call \fBwnoutrefresh\fR during the initialization
-routine.
-.PP
-\fBripoffline\fR can be called up to five times before calling \fBinitscr\fR or
-\fBnewterm\fR.
-.SS curs_set
-.PP
-The \fBcurs_set\fR routine sets the cursor state to invisible,
-normal, or very visible for \fBvisibility\fR equal to \fB0\fR,
-\fB1\fR, or \fB2\fR respectively.  If the terminal supports the
-\fIvisibility\fR requested, the previous \fIcursor\fR state is
-returned; otherwise, \fBERR\fR is returned.
-.SS napms
+Inside this initialization routine, the integer variables \fBLINES\fP
+and \fBCOLS\fP (defined in \fB<curses.h>\fP) are not guaranteed to be
+accurate and \fBwrefresh\fP or \fBdoupdate\fP must not be called.
+It is allowable to call \fBwnoutrefresh\fP during the initialization routine.

 .PP
 .PP

-The \fBnapms\fR routine is used to sleep for \fIms\fR milliseconds.
+\fBripoffline\fP can be called up to five times before calling \fBinitscr\fP or
+\fBnewterm\fP.

 .SH RETURN VALUE
 .SH RETURN VALUE

-Except for \fBcurs_set\fR, these routines always return \fBOK\fR.
+Except for \fBcurs_set\fP, these routines always return \fBOK\fP.

 .PP
 .PP

-\fBcurs_set\fR
-returns the previous cursor state, or \fBERR\fR if the
-requested \fIvisibility\fR is not supported.
+\fBcurs_set\fP
+returns the previous cursor state, or \fBERR\fP if the
+requested \fIvisibility\fP is not supported.

 .PP
 X/Open defines no error conditions.
 In this implementation
 .TP 5
 .PP
 X/Open defines no error conditions.
 In this implementation
 .TP 5

-.na
-.hy 0
-\fBdef_prog_mode\fR, \fBdef_shell_mode\fR, \fBreset_prog_mode\fR, \fBreset_shell_mode\fR
-.hy
-.ad
-return an error
+\fBdef_prog_mode\fP, \fBdef_shell_mode\fP, \fBreset_prog_mode\fP, \fBreset_shell_mode\fP
+return
+.B ERR

 if the terminal was not initialized, or
 if the I/O call to obtain the terminal settings fails.
 .TP 5
 \fBripoffline\fP
 if the terminal was not initialized, or
 if the I/O call to obtain the terminal settings fails.
 .TP 5
 \fBripoffline\fP

-returns an error if the maximum number of ripped-off lines
-exceeds the maximum (NRIPS = 5).
+returns
+.B ERR
+if the maximum number of ripped-off lines
+exceeds the maximum (5).

 .SH NOTES
 .SH NOTES

-Note that \fBgetsyx\fR is a macro, so \fB&\fR is not necessary before
-the variables \fIy\fR and \fIx\fR.
+Note that \fBgetsyx\fP is a macro, so \fB&\fP is not necessary before
+the variables \fIy\fP and \fIx\fP.

 .PP
 .PP

-Older SVr4 man pages warn that the return value of \fBcurs_set\fR "is currently
-incorrect".  This implementation gets it right, but it may be unwise to count
+Older SVr4 man pages warn that the return value
+of \fBcurs_set\fP \*(``is currently incorrect\*(''.
+This implementation gets it right, but it may be unwise to count

 on the correctness of the return value anywhere else.
 .PP
 on the correctness of the return value anywhere else.
 .PP

-Both ncurses and SVr4 will call \fBcurs_set\fR in \fBendwin\fR
-if \fBcurs_set\fR
+Both \fI\%ncurses\fP and SVr4 will call \fBcurs_set\fP in \fBendwin\fP
+if \fBcurs_set\fP

 has been called to make the cursor other than normal, i.e., either
 invisible or very visible.
 has been called to make the cursor other than normal, i.e., either
 invisible or very visible.

-There is no way for ncurses to determine the initial cursor state to
-restore that.
+There is no way for \fI\%ncurses\fP to determine the initial cursor
+state to restore that.
+.SH EXTENSIONS
+In
+.IR \%ncurses ","
+.B \%mvcur
+accepts
+.B \-1
+for either or both old coordinates.
+This value tells
+.I \%ncurses
+that the old location is unknown,
+and that it must use only absolute motion,
+as with the
+.B \%cursor_address
+.RB ( cup )
+capability,
+rather than the least costly combination of absolute and relative
+motion.

 .SH PORTABILITY
 .SH PORTABILITY

-The functions \fBsetsyx\fR and \fBgetsyx\fR are not described in the XSI
-Curses standard, Issue 4.  All other functions are as described in XSI Curses.
+The \fIvirtual screen\fP functions \fBsetsyx\fP and \fBgetsyx\fP
+are not described in X/Open Curses, Issue 4.
+All other functions are as described in X/Open Curses.

 .PP
 .PP

-The SVr4 documentation describes \fBsetsyx\fR and \fBgetsyx\fR as having return
-type int. This is misleading, as they are macros with no documented semantics
+The SVr4 documentation describes \fBsetsyx\fP and \fBgetsyx\fP
+as having return type int.
+This is misleading, as they are macros with no documented semantics

 for the return value.
 for the return value.

+.PP
+X/Open Curses notes:
+.RS
+.PP
+\*(``After use of
+.IR \%mvcur "(),"
+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.\*(''
+.RE
+.PP
+Both
+.I \%ncurses
+and SVr4
+.I curses
+implement
+.B \%mvcur
+using the
+.I SCREEN
+data allocated in either \fB\%initscr\fP(3X) or \fB\%newterm\fP(3X).
+X/Open Curses states that the old location must be given for
+.B \%mvcur
+to accommodate terminals that lack absolute cursor positioning.
+.\" X/Open Curses Issue 7, p. 161
+.PP
+If interrupted, \fI\%ncurses\fP restarts \fBnapms\fP.
+That, and the limitation to 30 seconds,
+are different from other implementations.

 .SH SEE ALSO
 .SH SEE ALSO

-\fBcurses\fR(3X),
-\fBcurs_initscr\fR(3X),
-\fBcurs_outopts\fR(3X),
-\fBcurs_refresh\fR(3X),
-\fBcurs_scr_dump\fR(3X),
-\fBcurs_slk\fR(3X),
-\fBcurs_variables\fR(3X).
+\fB\%curses\fP(3X),
+\fB\%curs_initscr\fP(3X),
+\fB\%curs_outopts\fP(3X),
+\fB\%curs_refresh\fP(3X),
+\fB\%curs_scr_dump\fP(3X),
+\fB\%curs_slk\fP(3X),
+\fB\%curs_variables\fP(3X)