ncurses 6.2 - patch 20210213

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

diff --git a/man/curs_clear.3x b/man/curs_clear.3x
index 1a9efb7ce153b825af30fef805d1312ae9c7188e..d86acbde6b000392b698140a1130d2e22d3d6f9d 100644 (file)
--- a/man/curs_clear.3x
+++ b/man/curs_clear.3x
@@ -1,65 +1,134 @@
+.\"***************************************************************************
+.\" Copyright 2018,2020 Thomas E. Dickey                                     *
+.\" Copyright 1998-2010,2016 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            *
+.\" "Software"), to deal in the Software without restriction, including      *
+.\" without limitation the rights to use, copy, modify, merge, publish,      *
+.\" distribute, distribute with modifications, sublicense, and/or sell       *
+.\" copies of the Software, and to permit persons to whom the Software is    *
+.\" furnished to do so, subject to the following conditions:                 *
+.\"                                                                          *
+.\" The above copyright notice and this permission notice shall be included  *
+.\" in all copies or substantial portions of the Software.                   *
+.\"                                                                          *
+.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+.\"                                                                          *
+.\" Except as contained in this notice, the name(s) of the above copyright   *
+.\" holders shall not be used in advertising or otherwise to promote the     *
+.\" sale, use or other dealings in this Software without prior written       *
+.\" authorization.                                                           *
+.\"***************************************************************************
+.\"
+.\" $Id: curs_clear.3x,v 1.20 2020/10/24 09:19:37 tom Exp $

 .TH curs_clear 3X ""
 .TH curs_clear 3X ""

+.na
+.hy 0
+.de bP
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
+..

 .SH NAME
 .SH NAME

-\fBerase\fR, \fBwerase\fR, \fBclear\fR,
-\fBwclear\fR, \fBclrtobot\fR, \fBwclrtobot\fR, \fBclrtoeol\fR,
-\fBwclrtoeol\fR - clear all or part of a \fBcurses\fR window
+\fBerase\fR,
+\fBwerase\fR,
+\fBclear\fR,
+\fBwclear\fR,
+\fBclrtobot\fR,
+\fBwclrtobot\fR,
+\fBclrtoeol\fR,
+\fBwclrtoeol\fR \- clear all or part of a \fBcurses\fR window
+.ad
+.hy

 .SH SYNOPSIS
 .SH SYNOPSIS

-\fB# include <curses.h>\fR
-
+\fB#include <curses.h>\fR
+.sp

 \fBint erase(void);\fR
 .br
 \fBint erase(void);\fR
 .br

-\fBint werase(WINDOW *win);\fR
-.br
+\fBint werase(WINDOW *\fP\fIwin\fP\fB);\fR
+.sp

 \fBint clear(void);\fR
 .br
 \fBint clear(void);\fR
 .br

-\fBint wclear(WINDOW *win);\fR
-.br
+\fBint wclear(WINDOW *\fP\fIwin\fP\fB);\fR
+.sp

 \fBint clrtobot(void);\fR
 .br
 \fBint clrtobot(void);\fR
 .br

-\fBint wclrtobot(WINDOW *win);\fR
-.br
+\fBint wclrtobot(WINDOW *\fP\fIwin\fP\fB);\fR
+.sp

 \fBint clrtoeol(void);\fR
 .br
 \fBint clrtoeol(void);\fR
 .br

-\fBint wclrtoeol(WINDOW *win);\fR
+\fBint wclrtoeol(WINDOW *\fP\fIwin\fP\fB);\fR

 .br
 .SH DESCRIPTION
 The \fBerase\fR and \fBwerase\fR routines copy blanks to every
 position in the window, clearing the screen.
 .br
 .SH DESCRIPTION
 The \fBerase\fR and \fBwerase\fR routines copy blanks to every
 position in the window, clearing the screen.

-
+.PP

 The \fBclear\fR and \fBwclear\fR routines are like \fBerase\fR and
 \fBwerase\fR, but they also call \fBclearok\fR, so that the screen is
 cleared completely on the next call to \fBwrefresh\fR for that window
 and repainted from scratch.
 The \fBclear\fR and \fBwclear\fR routines are like \fBerase\fR and
 \fBwerase\fR, but they also call \fBclearok\fR, so that the screen is
 cleared completely on the next call to \fBwrefresh\fR for that window
 and repainted from scratch.

-
+.PP

 The \fBclrtobot\fR and \fBwclrtobot\fR routines erase from the cursor to the
 The \fBclrtobot\fR and \fBwclrtobot\fR routines erase from the cursor to the

-end of screen.  That is, they erase all lines below the cursor in the window.
+end of screen.
+That is, they erase all lines below the cursor in the window.

 Also, the current line to the right of the cursor, inclusive, is erased.
 Also, the current line to the right of the cursor, inclusive, is erased.

-
+.PP

 The \fBclrtoeol\fR and \fBwclrtoeol\fR routines erase the current line
 to the right of the cursor, inclusive, to the end of the current line.
 The \fBclrtoeol\fR and \fBwclrtoeol\fR routines erase the current line
 to the right of the cursor, inclusive, to the end of the current line.

-
+.PP

 Blanks created by erasure have the current background rendition (as set
 by \fBwbkgdset\fR) merged into them.
 .SH RETURN VALUE
 Blanks created by erasure have the current background rendition (as set
 by \fBwbkgdset\fR) merged into them.
 .SH RETURN VALUE

-All routines return the integer \fBOK\fR.  The SVr4.0 manual says "or a
-non-negative integer if \fBimmedok\fR is set", but this appears to be an error.
+All routines return the integer \fBOK\fR on success and \fBERR\fP on failure.
+.PP
+X/Open defines no error conditions.
+In this implementation,
+.bP
+functions using a window pointer parameter return an error if it is null
+.bP
+\fBwclrtoeol\fP returns an error
+if the cursor position is about to wrap.

 .SH NOTES
 Note that \fBerase\fR, \fBwerase\fR, \fBclear\fR, \fBwclear\fR,
 \fBclrtobot\fR, and \fBclrtoeol\fR may be macros.
 .SH PORTABILITY
 .SH NOTES
 Note that \fBerase\fR, \fBwerase\fR, \fBclear\fR, \fBwclear\fR,
 \fBclrtobot\fR, and \fBclrtoeol\fR may be macros.
 .SH PORTABILITY

-These functions are described in the XSI Curses standard, Issue 4.  The
+These functions are described in the XSI Curses standard, Issue 4.
+The

 standard specifies that they return \fBERR\fR on failure, but specifies no
 error conditions.
 standard specifies that they return \fBERR\fR on failure, but specifies no
 error conditions.

-
+.PP
+The SVr4.0 manual says that these functions could
+return "a non-negative integer if \fBimmedok\fR is set",
+referring to the return-value of \fBwrefresh\fP.
+In that implementation, \fBwrefresh\fP would return a count of
+the number of characters written to the terminal.
+.PP

 Some historic curses implementations had, as an undocumented feature, the
 ability to do the equivalent of \fBclearok(..., 1)\fR by saying
 Some historic curses implementations had, as an undocumented feature, the
 ability to do the equivalent of \fBclearok(..., 1)\fR by saying

-\fBtouchwin(stdscr)\fR or \fBclear(stdscr)\fR.  This will not work under
+\fBtouchwin(stdscr)\fR or \fBclear(stdscr)\fR.
+This will not work under

 ncurses.
 ncurses.

+.PP
+This implementation, and others such as Solaris,
+sets the current position to 0,0 after erasing
+via \fBwerase\fP and \fBwclear\fP.
+That fact is not documented in other implementations,
+and may not be true of implementations
+which were not derived from SVr4 source.
+.PP
+Not obvious from the description,
+most implementations clear the screen after \fBwclear\fP
+even for a subwindow or derived window.
+If you do not want to clear the screen during the next \fBwrefresh\fP,
+use \fBwerase\fP instead.

 .SH SEE ALSO
 .SH SEE ALSO

-\fBcurses\fR(3X), \fBcurs_outopts\fR(3X), \fBcurs_refresh\fR(3X)
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
+\fBcurses\fR(3X),
+\fBcurs_outopts\fR(3X),
+\fBcurs_refresh\fR(3X),
+\fBcurs_variables\fR(3X)