ncurses/man/curs_util.3x - nest-cam/4320010/ncurses - Git at Google

 '\" t
 .\"***************************************************************************
 .\" Copyright (c) 1998-2013,2015 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_util.3x,v 1.43 2015/06/06 23:36:27 tom Exp $
 .TH curs_util 3X ""
 .ie \n(.g .ds `` \(lq
 .el       .ds `` ``
 .ie \n(.g .ds '' \(rq
 .el       .ds '' ''
 .de bP
 .IP \(bu 4
 ..
 .na
 .hy 0
 .SH NAME
 \fBdelay_output\fR,
 \fBfilter\fR,
 \fBflushinp\fR,
 \fBgetwin\fR,
 \fBkey_name\fR,
 \fBkeyname\fR,
 \fBnofilter\fR,
 \fBputwin\fR,
 \fBunctrl\fR,
 \fBuse_env\fR,
 \fBuse_tioctl\fR,
 \fBwunctrl\fR \- miscellaneous \fBcurses\fR utility routines
 .ad
 .hy
 .SH SYNOPSIS
 \fB#include <curses.h>\fR
 .sp
 \fBchar *unctrl(chtype c);\fR
 .br
 \fBwchar_t *wunctrl(cchar_t *c);\fR
 .br
 \fBchar *keyname(int c);\fR
 .br
 \fBchar *key_name(wchar_t w);\fR
 .br
 \fBvoid filter(void);\fR
 .br
 \fBvoid nofilter(void);\fR
 .br
 \fBvoid use_env(bool f);\fR
 .br
 \fBvoid use_tioctl(bool f);\fR
 .br
 \fBint putwin(WINDOW *win, FILE *filep);\fR
 .br
 \fBWINDOW *getwin(FILE *filep);\fR
 .br
 \fBint delay_output(int ms);\fR
 .br
 \fBint flushinp(void);\fR
 .br
 .SH DESCRIPTION
 .SS unctrl
 .PP
 The \fBunctrl\fR routine returns a character string which is a printable
 representation of the character \fIc\fR, ignoring attributes.
 Control characters are displayed in the \fB^\fR\fIX\fR notation.
 Printing characters are displayed as is.
 The corresponding \fBwunctrl\fR returns a printable representation of
 a wide character.
 .SS keyname/key_name
 .PP
 The \fBkeyname\fR routine returns a character string
 corresponding to the key \fIc\fR:
 .bP
 Printable characters are displayed as themselves,
 e.g., a one-character string containing the key.
 .bP
 Control characters are displayed in the \fB^\fR\fIX\fR notation.
 .bP
 DEL (character 127) is displayed as \fB^?\fP.
 .bP
 Values above 128 are either meta characters
 (if the screen has not been initialized,
 or if \fBmeta\fP has been called with a \fBTRUE\fP parameter),
 shown in the \fBM\-\fR\fIX\fR notation,
 or are displayed as themselves.
 In the latter case, the values may not be printable;
 this follows the X/Open specification.
 .bP
 Values above 256 may be the names of the names of function keys.
 .bP
 Otherwise (if there is no corresponding name) the function returns null,
 to denote an error.
 X/Open also lists an "UNKNOWN KEY" return value, which some implementations
 return rather than null.
 .LP
 The corresponding \fBkey_name\fR returns a character string corresponding
 to the wide-character value \fIw\fR.
 The two functions do not return the same set of strings;
 the latter returns null where the former would display a meta character.
 .SS filter/nofilter
 .PP
 The \fBfilter\fR routine, if used, must be called before \fBinitscr\fR or
 \fBnewterm\fR are called.
 The effect is that, during those calls, \fBLINES\fR
 is set to 1; the capabilities \fBclear\fR, \fBcup\fR, \fBcud\fR, \fBcud1\fR,
 \fBcuu1\fR, \fBcuu\fR, \fBvpa\fR are disabled; and the \fBhome\fR string is
 set to the value of \fBcr\fR.
 .PP
 The \fBnofilter\fP routine cancels the effect of a preceding \fBfilter\fP
 call.
 That allows the caller to initialize a screen on a different device,
 using a different value of \fB$TERM\fP.
 The limitation arises because the \fBfilter\fP routine modifies the
 in-memory copy of the terminal information.
 .SS use_env
 .PP
 The \fBuse_env\fR routine, if used,
 should be called before \fBinitscr\fR or
 \fBnewterm\fR are called
 (because those compute the screen size).
 It modifies the way \fBncurses\fP treats environment variables
 when determining the screen size.
 .bP
 Normally ncurses looks first at the terminal database for the screen size.
 .IP
 If \fBuse_env\fP was called with \fBFALSE\fP for parameter,
 it stops here unless
 If \fBuse_tioctl\fP was also called with \fBTRUE\fP for parameter.
 .bP
 Then it asks for the screen size via operating system calls.
 If successful,
 it overrides the values from the terminal database.
 .bP
 Finally (unless \fBuse_env\fP was called with \fBFALSE\fP parameter),
 ncurses examines the \fBLINES\fR or \fBCOLUMNS\fR environment variables,
 using a value in those to override the results
 from the operating system or terminal database.
 .IP
 Ncurses also updates the screen size in response to SIGWINCH,
 unless overridden by the \fBLINES\fR or \fBCOLUMNS\fR environment variables,
 .SS use_tioctl
 .PP
 The \fBuse_tioctl\fR routine, if used,
 should be called before \fBinitscr\fR or \fBnewterm\fR are called
 (because those compute the screen size).
 After \fBuse_tioctl\fR is called with \fBTRUE\fR as an argument,
 ncurses modifies the last step in its computation of screen size as follows:
 .bP
 checks if the \fBLINES\fR and \fBCOLUMNS\fR environment variables
 are set to a number greater than zero.
 .bP
 for each, ncurses updates the corresponding environment variable
 with the value that it has obtained via operating system call
 or from the terminal database.
 .bP
 ncurses re-fetches the value of the environment variables so that
 it is still the environment variables which set the screen size.
 .PP
 The \fBuse_env\fP and \fBuse_tioctl\fP routines combine as
 summarized here:
 .TS
 center tab(/);
 l l l
 _ _ _
 lw7 lw7 lw40.
 \fIuse_env\fR/\fIuse_tioctl\fR/\fISummary\fR
 TRUE/FALSE/T{
 This is the default behavior.
 ncurses uses operating system calls
 unless overridden by $LINES or $COLUMNS environment variables.
 T}
 TRUE/TRUE/T{
 ncurses updates $LINES and $COLUMNS based on operating system calls.
 T}
 FALSE/TRUE/T{
 ncurses ignores $LINES and $COLUMNS, uses operating system calls to obtain size.
 T}
 FALSE/FALSE/T{
 ncurses relies on the terminal database to determine size.
 T}
 .TE
 .SS putwin/getwin
 .PP
 The \fBputwin\fR routine writes all data associated
 with window (or pad) \fIwin\fR into
 the file to which \fIfilep\fR points.
 This information can be later retrieved
 using the \fBgetwin\fR function.
 .PP
 The \fBgetwin\fR routine reads window related data stored in the file by
 \fBputwin\fR.
 The routine then creates and initializes a new window using that
 data.
 It returns a pointer to the new window.
 There are a few caveats:
 .bP
 the data written is a copy of the \fBWINDOW\fP structure,
 and its associated character cells.
 The format differs between the wide-character (ncursesw) and
 non-wide (ncurses) libraries.
 You can transfer data between the two, however.
 .bP
 the retrieved window is always created as a top-level window (or pad),
 rather than a subwindow.
 .bP
 the window's character cells contain the color pair \fIvalue\fP,
 but not the actual color \fInumbers\fP.
 If cells in the retrieved window use color pairs which have not been
 created in the application using \fBinit_pair\fP,
 they will not be colored when the window is refreshed.
 .SS delay_output
 .PP
 The \fBdelay_output\fR routine inserts an \fIms\fR millisecond pause
 in output.
 This routine should not be used extensively because
 padding characters are used rather than a CPU pause.
 If no padding character is specified,
 this uses \fBnapms\fR to perform the delay.
 .SS flushinp
 .PP
 The \fBflushinp\fR routine throws away any typeahead that has been typed by the
 user and has not yet been read by the program.
 .SH RETURN VALUE
 Except for \fBflushinp\fR, routines that return an integer return \fBERR\fR
 upon failure and \fBOK\fR (SVr4 specifies only "an integer value other than
 \fBERR\fR") upon successful completion.
 .PP
 Routines that return pointers return \fBNULL\fR on error.
 .PP
 X/Open does not define any error conditions.
 In this implementation
 .RS 3
 .TP 5
 \fBflushinp\fR
 returns an error if the terminal was not initialized.
 .TP 5
 \fBmeta\fR
 returns an error if the terminal was not initialized.
 .TP 5
 \fBputwin\fP
 returns an error if the associated \fBfwrite\fP calls return an error.
 .RE
 .SH PORTABILITY
 .SS filter
 .PP
 The SVr4 documentation describes the action of \fBfilter\fR only in the vaguest
 terms.
 The description here is adapted from the XSI Curses standard (which
 erroneously fails to describe the disabling of \fBcuu\fR).
 .SS keyname
 .PP
 The \fBkeyname\fP function may return the names of user-defined
 string capabilities which are defined in the terminfo entry via the \fB\-x\fP
 option of \fB@TIC@\fP.
 This implementation automatically assigns at run-time keycodes to
 user-defined strings which begin with "k".
 The keycodes start at KEY_MAX, but are not guaranteed to be
 the same value for different runs because user-defined codes are
 merged from all terminal descriptions which have been loaded.
 The \fBuse_extended_names\fP function controls whether this data is
 loaded when the terminal description is read by the library.
 .SS nofilter/use_tioctl
 .PP
 The \fBnofilter\fP and \fBuse_tioctl\fP routines are specific to ncurses.
 They were not supported on Version 7, BSD or System V implementations.
 It is recommended that any code depending on ncurses extensions
 be conditioned using NCURSES_VERSION.
 .SS putwin/getwin
 .PP
 The \fBputwin\fP and \fBgetwin\fP functions have several issues with
 portability:
 .bP
 The files written and read by these functions
 use an implementation-specific format.
 Although the format is an obvious target for standardization,
 it has been overlooked.
 .IP
 Interestingly enough, according to the copyright dates in Solaris source,
 the functions (along with \fBscr_init\fP, etc.) originated with
 the University of California, Berkeley (in 1982)
 and were later (in 1988) incorporated into SVr4.
 Oddly, there are no such functions in the 4.3BSD curses sources.
 .bP
 Most implementations simply dump the binary \fBWINDOW\fP structure to the file.
 These include SVr4 curses, NetBSD and PDCurses, as well as older ncurses versions.
 This implementation (as well as the X/Open variant of Solaris curses, dated 1995)
 uses textual dumps.
 .IP
 The implementations which use binary dumps use block-I/O
 (the \fBfwrite\fP and \fBfread\fP functions).
 Those that use textual dumps use buffered-I/O.
 A few applications may happen to write extra data in the file using
 these functions.
 Doing that can run into problems mixing block- and buffered-I/O.
 This implementation reduces the problem on writes by flushing the output.
 However, reading from a file written using mixed schemes may not be successful.
 .SS unctrl/wunctrl
 .PP
 The XSI Curses standard, Issue 4 describes these functions.
 It states that \fBunctrl\fR and \fBwunctrl\fR will return a null pointer if
 unsuccessful, but does not define any error conditions.
 This implementation checks for three cases:
 .bP
 the parameter is a 7-bit US\-ASCII code.
 This is the case that X/Open Curses documented.
 .bP
 the parameter is in the range 128\-159, i.e., a C1 control code.
 If \fBuse_legacy_coding\fP has been called with a \fB2\fP parameter,
 \fBunctrl\fP returns the parameter, i.e., a one-character string with
 the parameter as the first character.
 Otherwise, it returns \*(``~@\*('', \*(``~A\*('', etc.,
 analogous to \*(``^@\*('', \*(``^A\*('', C0 controls.
 .IP
 X/Open Curses does not document whether \fBunctrl\fP can be called before
 initializing curses.
 This implementation permits that,
 and returns the \*(``~@\*('', etc., values in that case.
 .bP
 parameter values outside the 0 to 255 range.
 \fBunctrl\fP returns a null pointer.
 .PP
 The strings returned by \fBunctrl\fR in this implementation are determined
 at compile time,
 showing C1 controls from the upper-128 codes with a `~' prefix rather than `^'.
 Other implementations have different conventions.
 For example, they may show both sets of control characters with `^',
 and strip the parameter to 7 bits.
 Or they may ignore C1 controls and treat all of the upper-128 codes as
 printable.
 This implementation uses 8 bits but does not modify the string to reflect
 locale.
 The \fBuse_legacy_coding\fP function allows the caller to
 change the output of \fBunctrl\fP.
 .PP
 Likewise, the \fBmeta\fP function allows the caller to change the
 output of \fBkeyname\fP, i.e.,
 it determines whether to use the `M\-' prefix
 for \*(``meta\*('' keys (codes in the range 128 to 255).
 Both \fBuse_legacy_coding\fP and \fBmeta\fP succeed only after
 curses is initialized.
 X/Open Curses does not document the treatment of codes 128 to 159.
 When treating them as \*(``meta\*('' keys
 (or if \fBkeyname\fP is called before initializing curses),
 this implementation returns strings \*(``M\-^@\*('', \*(``M\-^A\*('', etc.
 .SH SEE ALSO
 \fBlegacy_coding\fR(3X),
 \fBcurses\fR(3X),
 \fBcurs_initscr\fR(3X),
 \fBcurs_kernel\fR(3X),
 \fBcurs_scr_dump\fR(3X),
 \fBcurs_variables\fR(3X),
 \fBlegacy_coding\fR(3X).
	'\" t
	.\"***************************************************************************
	.\" Copyright (c) 1998-2013,2015 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_util.3x,v 1.43 2015/06/06 23:36:27 tom Exp $
	.TH curs_util 3X ""
	.ie \n(.g .ds `` \(lq
	.el .ds `` ``
	.ie \n(.g .ds '' \(rq
	.el .ds '' ''
	.de bP
	.IP \(bu 4
	..
	.na
	.hy 0
	.SH NAME
	\fBdelay_output\fR,
	\fBfilter\fR,
	\fBflushinp\fR,
	\fBgetwin\fR,
	\fBkey_name\fR,
	\fBkeyname\fR,
	\fBnofilter\fR,
	\fBputwin\fR,
	\fBunctrl\fR,
	\fBuse_env\fR,
	\fBuse_tioctl\fR,
	\fBwunctrl\fR \- miscellaneous \fBcurses\fR utility routines
	.ad
	.hy
	.SH SYNOPSIS
	\fB#include <curses.h>\fR
	.sp
	\fBchar *unctrl(chtype c);\fR
	.br
	\fBwchar_t wunctrl(cchar_t c);\fR
	.br
	\fBchar *keyname(int c);\fR
	.br
	\fBchar *key_name(wchar_t w);\fR
	.br
	\fBvoid filter(void);\fR
	.br
	\fBvoid nofilter(void);\fR
	.br
	\fBvoid use_env(bool f);\fR
	.br
	\fBvoid use_tioctl(bool f);\fR
	.br
	\fBint putwin(WINDOW win, FILE filep);\fR
	.br
	\fBWINDOW getwin(FILE filep);\fR
	.br
	\fBint delay_output(int ms);\fR
	.br
	\fBint flushinp(void);\fR
	.br
	.SH DESCRIPTION
	.SS unctrl
	.PP
	The \fBunctrl\fR routine returns a character string which is a printable
	representation of the character \fIc\fR, ignoring attributes.
	Control characters are displayed in the \fB^\fR\fIX\fR notation.
	Printing characters are displayed as is.
	The corresponding \fBwunctrl\fR returns a printable representation of
	a wide character.
	.SS keyname/key_name
	.PP
	The \fBkeyname\fR routine returns a character string
	corresponding to the key \fIc\fR:
	.bP
	Printable characters are displayed as themselves,
	e.g., a one-character string containing the key.
	.bP
	Control characters are displayed in the \fB^\fR\fIX\fR notation.
	.bP
	DEL (character 127) is displayed as \fB^?\fP.
	.bP
	Values above 128 are either meta characters
	(if the screen has not been initialized,
	or if \fBmeta\fP has been called with a \fBTRUE\fP parameter),
	shown in the \fBM\-\fR\fIX\fR notation,
	or are displayed as themselves.
	In the latter case, the values may not be printable;
	this follows the X/Open specification.
	.bP
	Values above 256 may be the names of the names of function keys.
	.bP
	Otherwise (if there is no corresponding name) the function returns null,
	to denote an error.
	X/Open also lists an "UNKNOWN KEY" return value, which some implementations
	return rather than null.
	.LP
	The corresponding \fBkey_name\fR returns a character string corresponding
	to the wide-character value \fIw\fR.
	The two functions do not return the same set of strings;
	the latter returns null where the former would display a meta character.
	.SS filter/nofilter
	.PP
	The \fBfilter\fR routine, if used, must be called before \fBinitscr\fR or
	\fBnewterm\fR are called.
	The effect is that, during those calls, \fBLINES\fR
	is set to 1; the capabilities \fBclear\fR, \fBcup\fR, \fBcud\fR, \fBcud1\fR,
	\fBcuu1\fR, \fBcuu\fR, \fBvpa\fR are disabled; and the \fBhome\fR string is
	set to the value of \fBcr\fR.
	.PP
	The \fBnofilter\fP routine cancels the effect of a preceding \fBfilter\fP
	call.
	That allows the caller to initialize a screen on a different device,
	using a different value of \fB$TERM\fP.
	The limitation arises because the \fBfilter\fP routine modifies the
	in-memory copy of the terminal information.
	.SS use_env
	.PP
	The \fBuse_env\fR routine, if used,
	should be called before \fBinitscr\fR or
	\fBnewterm\fR are called
	(because those compute the screen size).
	It modifies the way \fBncurses\fP treats environment variables
	when determining the screen size.
	.bP
	Normally ncurses looks first at the terminal database for the screen size.
	.IP
	If \fBuse_env\fP was called with \fBFALSE\fP for parameter,
	it stops here unless
	If \fBuse_tioctl\fP was also called with \fBTRUE\fP for parameter.
	.bP
	Then it asks for the screen size via operating system calls.
	If successful,
	it overrides the values from the terminal database.
	.bP
	Finally (unless \fBuse_env\fP was called with \fBFALSE\fP parameter),
	ncurses examines the \fBLINES\fR or \fBCOLUMNS\fR environment variables,
	using a value in those to override the results
	from the operating system or terminal database.
	.IP
	Ncurses also updates the screen size in response to SIGWINCH,
	unless overridden by the \fBLINES\fR or \fBCOLUMNS\fR environment variables,
	.SS use_tioctl
	.PP
	The \fBuse_tioctl\fR routine, if used,
	should be called before \fBinitscr\fR or \fBnewterm\fR are called
	(because those compute the screen size).
	After \fBuse_tioctl\fR is called with \fBTRUE\fR as an argument,
	ncurses modifies the last step in its computation of screen size as follows:
	.bP
	checks if the \fBLINES\fR and \fBCOLUMNS\fR environment variables
	are set to a number greater than zero.
	.bP
	for each, ncurses updates the corresponding environment variable
	with the value that it has obtained via operating system call
	or from the terminal database.
	.bP
	ncurses re-fetches the value of the environment variables so that
	it is still the environment variables which set the screen size.
	.PP
	The \fBuse_env\fP and \fBuse_tioctl\fP routines combine as
	summarized here:
	.TS
	center tab(/);
	l l l
	_ _ _
	lw7 lw7 lw40.
	\fIuse_env\fR/\fIuse_tioctl\fR/\fISummary\fR
	TRUE/FALSE/T{
	This is the default behavior.
	ncurses uses operating system calls
	unless overridden by $LINES or $COLUMNS environment variables.
	T}
	TRUE/TRUE/T{
	ncurses updates $LINES and $COLUMNS based on operating system calls.
	T}
	FALSE/TRUE/T{
	ncurses ignores $LINES and $COLUMNS, uses operating system calls to obtain size.
	T}
	FALSE/FALSE/T{
	ncurses relies on the terminal database to determine size.
	T}
	.TE
	.SS putwin/getwin
	.PP
	The \fBputwin\fR routine writes all data associated
	with window (or pad) \fIwin\fR into
	the file to which \fIfilep\fR points.
	This information can be later retrieved
	using the \fBgetwin\fR function.
	.PP
	The \fBgetwin\fR routine reads window related data stored in the file by
	\fBputwin\fR.
	The routine then creates and initializes a new window using that
	data.
	It returns a pointer to the new window.
	There are a few caveats:
	.bP
	the data written is a copy of the \fBWINDOW\fP structure,
	and its associated character cells.
	The format differs between the wide-character (ncursesw) and
	non-wide (ncurses) libraries.
	You can transfer data between the two, however.
	.bP
	the retrieved window is always created as a top-level window (or pad),
	rather than a subwindow.
	.bP
	the window's character cells contain the color pair \fIvalue\fP,
	but not the actual color \fInumbers\fP.
	If cells in the retrieved window use color pairs which have not been
	created in the application using \fBinit_pair\fP,
	they will not be colored when the window is refreshed.
	.SS delay_output
	.PP
	The \fBdelay_output\fR routine inserts an \fIms\fR millisecond pause
	in output.
	This routine should not be used extensively because
	padding characters are used rather than a CPU pause.
	If no padding character is specified,
	this uses \fBnapms\fR to perform the delay.
	.SS flushinp
	.PP
	The \fBflushinp\fR routine throws away any typeahead that has been typed by the
	user and has not yet been read by the program.
	.SH RETURN VALUE
	Except for \fBflushinp\fR, routines that return an integer return \fBERR\fR
	upon failure and \fBOK\fR (SVr4 specifies only "an integer value other than
	\fBERR\fR") upon successful completion.
	.PP
	Routines that return pointers return \fBNULL\fR on error.
	.PP
	X/Open does not define any error conditions.
	In this implementation
	.RS 3
	.TP 5
	\fBflushinp\fR
	returns an error if the terminal was not initialized.
	.TP 5
	\fBmeta\fR
	returns an error if the terminal was not initialized.
	.TP 5
	\fBputwin\fP
	returns an error if the associated \fBfwrite\fP calls return an error.
	.RE
	.SH PORTABILITY
	.SS filter
	.PP
	The SVr4 documentation describes the action of \fBfilter\fR only in the vaguest
	terms.
	The description here is adapted from the XSI Curses standard (which
	erroneously fails to describe the disabling of \fBcuu\fR).
	.SS keyname
	.PP
	The \fBkeyname\fP function may return the names of user-defined
	string capabilities which are defined in the terminfo entry via the \fB\-x\fP
	option of \fB@TIC@\fP.
	This implementation automatically assigns at run-time keycodes to
	user-defined strings which begin with "k".
	The keycodes start at KEY_MAX, but are not guaranteed to be
	the same value for different runs because user-defined codes are
	merged from all terminal descriptions which have been loaded.
	The \fBuse_extended_names\fP function controls whether this data is
	loaded when the terminal description is read by the library.
	.SS nofilter/use_tioctl
	.PP
	The \fBnofilter\fP and \fBuse_tioctl\fP routines are specific to ncurses.
	They were not supported on Version 7, BSD or System V implementations.
	It is recommended that any code depending on ncurses extensions
	be conditioned using NCURSES_VERSION.
	.SS putwin/getwin
	.PP
	The \fBputwin\fP and \fBgetwin\fP functions have several issues with
	portability:
	.bP
	The files written and read by these functions
	use an implementation-specific format.
	Although the format is an obvious target for standardization,
	it has been overlooked.
	.IP
	Interestingly enough, according to the copyright dates in Solaris source,
	the functions (along with \fBscr_init\fP, etc.) originated with
	the University of California, Berkeley (in 1982)
	and were later (in 1988) incorporated into SVr4.
	Oddly, there are no such functions in the 4.3BSD curses sources.
	.bP
	Most implementations simply dump the binary \fBWINDOW\fP structure to the file.
	These include SVr4 curses, NetBSD and PDCurses, as well as older ncurses versions.
	This implementation (as well as the X/Open variant of Solaris curses, dated 1995)
	uses textual dumps.
	.IP
	The implementations which use binary dumps use block-I/O
	(the \fBfwrite\fP and \fBfread\fP functions).
	Those that use textual dumps use buffered-I/O.
	A few applications may happen to write extra data in the file using
	these functions.
	Doing that can run into problems mixing block- and buffered-I/O.
	This implementation reduces the problem on writes by flushing the output.
	However, reading from a file written using mixed schemes may not be successful.
	.SS unctrl/wunctrl
	.PP
	The XSI Curses standard, Issue 4 describes these functions.
	It states that \fBunctrl\fR and \fBwunctrl\fR will return a null pointer if
	unsuccessful, but does not define any error conditions.
	This implementation checks for three cases:
	.bP
	the parameter is a 7-bit US\-ASCII code.
	This is the case that X/Open Curses documented.
	.bP
	the parameter is in the range 128\-159, i.e., a C1 control code.
	If \fBuse_legacy_coding\fP has been called with a \fB2\fP parameter,
	\fBunctrl\fP returns the parameter, i.e., a one-character string with
	the parameter as the first character.
	Otherwise, it returns \(``~@\('', \(``~A\('', etc.,
	analogous to \(``^@\('', \(``^A\('', C0 controls.
	.IP
	X/Open Curses does not document whether \fBunctrl\fP can be called before
	initializing curses.
	This implementation permits that,
	and returns the \(``~@\('', etc., values in that case.
	.bP
	parameter values outside the 0 to 255 range.
	\fBunctrl\fP returns a null pointer.
	.PP
	The strings returned by \fBunctrl\fR in this implementation are determined
	at compile time,
	showing C1 controls from the upper-128 codes with a `~' prefix rather than `^'.
	Other implementations have different conventions.
	For example, they may show both sets of control characters with `^',
	and strip the parameter to 7 bits.
	Or they may ignore C1 controls and treat all of the upper-128 codes as
	printable.
	This implementation uses 8 bits but does not modify the string to reflect
	locale.
	The \fBuse_legacy_coding\fP function allows the caller to
	change the output of \fBunctrl\fP.
	.PP
	Likewise, the \fBmeta\fP function allows the caller to change the
	output of \fBkeyname\fP, i.e.,
	it determines whether to use the `M\-' prefix
	for \(``meta\('' keys (codes in the range 128 to 255).
	Both \fBuse_legacy_coding\fP and \fBmeta\fP succeed only after
	curses is initialized.
	X/Open Curses does not document the treatment of codes 128 to 159.
	When treating them as \(``meta\('' keys
	(or if \fBkeyname\fP is called before initializing curses),
	this implementation returns strings \(``M\-^@\('', \(``M\-^A\('', etc.
	.SH SEE ALSO
	\fBlegacy_coding\fR(3X),
	\fBcurses\fR(3X),
	\fBcurs_initscr\fR(3X),
	\fBcurs_kernel\fR(3X),
	\fBcurs_scr_dump\fR(3X),
	\fBcurs_variables\fR(3X),
	\fBlegacy_coding\fR(3X).