.\"***************************************************************************
-.\" Copyright (c) 1998-2005,2007 Free Software Foundation, Inc. *
+.\" Copyright 2018-2022,2023 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 *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_clear.3x,v 1.11 2007/12/29 15:58:38 tom Exp $
-.TH curs_clear 3X ""
+.\" $Id: curs_clear.3x,v 1.31 2023/07/01 15:43:20 tom Exp $
+.TH curs_clear 3X 2023-07-01 "ncurses 6.4" "Library calls"
.na
.hy 0
+.de bP
+.ie n .IP \(bu 4
+.el .IP \(bu 2
+..
.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\fP,
+\fBwerase\fP,
+\fBclear\fP,
+\fBwclear\fP,
+\fBclrtobot\fP,
+\fBwclrtobot\fP,
+\fBclrtoeol\fP,
+\fBwclrtoeol\fP \- clear all or part of a \fBcurses\fP window
.ad
.hy
.SH SYNOPSIS
-\fB# include <curses.h>\fR
+\fB#include <curses.h>\fP
.sp
-\fBint erase(void);\fR
+\fBint erase(void);\fP
.br
-\fBint werase(WINDOW *win);\fR
-.br
-\fBint clear(void);\fR
-.br
-\fBint wclear(WINDOW *win);\fR
-.br
-\fBint clrtobot(void);\fR
-.br
-\fBint wclrtobot(WINDOW *win);\fR
+\fBint werase(WINDOW *\fIwin\fB);\fR
+.sp
+\fBint clear(void);\fP
.br
-\fBint clrtoeol(void);\fR
+\fBint wclear(WINDOW *\fIwin\fB);\fR
+.sp
+\fBint clrtobot(void);\fP
.br
-\fBint wclrtoeol(WINDOW *win);\fR
+\fBint wclrtobot(WINDOW *\fIwin\fB);\fR
+.sp
+\fBint clrtoeol(void);\fP
.br
+\fBint wclrtoeol(WINDOW *\fIwin\fB);\fR
.SH DESCRIPTION
-The \fBerase\fR and \fBwerase\fR routines copy blanks to every
+.SS erase/werase
+The \fBerase\fP and \fBwerase\fP 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
+Blanks created by erasure have the current background rendition (as set
+by \fBwbkgdset\fP(3X)) merged into them.
+.SS clear/wclear
+The \fBclear\fP and \fBwclear\fP routines are like \fBerase\fP and
+\fBwerase\fP, but they also call \fBclearok\fP(3X), so that the screen is
+cleared completely on the next call to \fBwrefresh\fP for that window
and repainted from scratch.
-.PP
-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.
+.SS clrtobot/wclrtobot
+The \fBclrtobot\fP and \fBwclrtobot\fP routines erase from the cursor to the
+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.
-.PP
-The \fBclrtoeol\fR and \fBwclrtoeol\fR routines erase the current line
+.SS clrtoeol/wclrtoeol
+The \fBclrtoeol\fP and \fBwclrtoeol\fP 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
-All routines return the integer \fBOK\fR on success and \fBERR\fP on failure.
-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\fP on success and \fBERR\fP on failure.
.PP
X/Open defines no error conditions.
In this implementation,
-functions using a window pointer parameter return an error if it is null.
+.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.
+Note that \fBerase\fP, \fBwerase\fP, \fBclear\fP, \fBwclear\fP,
+\fBclrtobot\fP, and \fBclrtoeol\fP may be macros.
.SH PORTABILITY
-These functions are described in the XSI Curses standard, Issue 4. The
-standard specifies that they return \fBERR\fR on failure, but specifies no
+These functions are described in the XSI Curses standard, Issue 4.
+The
+standard specifies that they return \fBERR\fP on failure, but specifies no
error conditions.
.PP
+The SVr4.0 manual says that these functions could
+return "a non-negative integer if \fBimmedok\fP(3X) 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
-\fBtouchwin(stdscr)\fR or \fBclear(stdscr)\fR. This will not work under
+ability to do the equivalent of \fBclearok(..., 1)\fP by saying
+\fBtouchwin(stdscr)\fP or \fBclear(stdscr)\fP.
+This will not work under
ncurses.
.PP
This implementation, and others such as Solaris,
sets the current position to 0,0 after erasing
-via \fBwerase()\fP and \fBwclear()\fP.
+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.
If you do not want to clear the screen during the next \fBwrefresh\fP,
use \fBwerase\fP instead.
.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\fP(3X),
+\fBcurs_outopts\fP(3X),
+\fBcurs_refresh\fP(3X),
+\fBcurs_variables\fP(3X)
projects / ncurses.git / blobdiff