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<H1 class="no-header">curs_util 3x</H1>
<PRE>
<STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG> <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>delay_output</STRONG>, <STRONG>filter</STRONG>, <STRONG>flushinp</STRONG>, <STRONG>getwin</STRONG>, <STRONG>key_name</STRONG>, <STRONG>keyname</STRONG>, <STRONG>nofilter</STRONG>,
<STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> - miscellaneous <STRONG>curses</STRONG>
utility routines
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <STRONG>c);</STRONG>
<STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*c);</STRONG>
<STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <STRONG>c);</STRONG>
<STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <STRONG>w);</STRONG>
<STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
<STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
<STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <STRONG>f);</STRONG>
<STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <STRONG>f);</STRONG>
<STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>FILE</STRONG> <STRONG>*filep);</STRONG>
<STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*filep);</STRONG>
<STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <STRONG>ms);</STRONG>
<STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
</PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
The <STRONG>unctrl</STRONG> routine returns a character string which is a printable rep-
resentation of the character <EM>c</EM>, ignoring attributes. Control charac-
ters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation. Printing characters are dis-
played as is. The corresponding <STRONG>wunctrl</STRONG> returns a printable represen-
tation of a wide character.
</PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
The <STRONG>keyname</STRONG> routine returns a character string corresponding to the key
<EM>c</EM>:
<STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-char-
acter string containing the key.
<STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
<STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
<STRONG>o</STRONG> Values above 128 are either meta characters (if the screen has not
been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has been called with a <STRONG>TRUE</STRONG> param-
eter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves.
In the latter case, the values may not be printable; this follows
the X/Open specification.
<STRONG>o</STRONG> Values above 256 may be the names of the names of function keys.
<STRONG>o</STRONG> Otherwise (if there is no corresponding name) the function returns
null, to denote an error. X/Open also lists an "UNKNOWN KEY" re-
turn value, which some implementations return rather than null.
The corresponding <STRONG>key_name</STRONG> returns a character string corresponding to
the wide-character value <EM>w</EM>. The two functions do not return the same
set of strings; the latter returns null where the former would display
a meta character.
</PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>
are called. Calling <STRONG>filter</STRONG> causes these changes in initialization:
<STRONG>o</STRONG> <STRONG>LINES</STRONG> is set to 1;
<STRONG>o</STRONG> the capabilities <STRONG>clear</STRONG>, <STRONG>cud1</STRONG>, <STRONG>cud</STRONG>, <STRONG>cup</STRONG>, <STRONG>cuu1</STRONG>, <STRONG>cuu</STRONG>, <STRONG>vpa</STRONG> are dis-
abled;
<STRONG>o</STRONG> the capability <STRONG>ed</STRONG> is disabled if <STRONG>bce</STRONG> is set;
<STRONG>o</STRONG> and the <STRONG>home</STRONG> string is set to the value of <STRONG>cr</STRONG>.
The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding <STRONG>filter</STRONG> call.
That allows the caller to initialize a screen on a different device,
using a different value of <STRONG>$TERM</STRONG>. The limitation arises because the
<STRONG>filter</STRONG> routine modifies the in-memory copy of the terminal information.
</PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
The <STRONG>use_env</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
<STRONG>newterm</STRONG> are called (because those compute the screen size). It modi-
fies the way <STRONG>ncurses</STRONG> treats environment variables when determining the
screen size.
<STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> looks first at the terminal database for the
screen size.
If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it stops here un-
less <STRONG>use_tioctl</STRONG> was also called with <STRONG>TRUE</STRONG> for parameter.
<STRONG>o</STRONG> Then it asks for the screen size via operating system calls. If
successful, it overrides the values from the terminal database.
<STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parameter), <STRONG>ncurses</STRONG>
examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables, using a value
in those to override the results from the operating system or ter-
minal database.
<STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>, un-
less overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables,
</PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
The <STRONG>use_tioctl</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
<STRONG>newterm</STRONG> are called (because those compute the screen size). After
<STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an argument, <STRONG>ncurses</STRONG> modifies the
last step in its computation of screen size as follows:
<STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables are set to a
number greater than zero.
<STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environment variable
with the value that it has obtained via operating system call or
from the terminal database.
<STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment variables so that
it is still the environment variables which set the screen size.
The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized here:
<EM>use</EM><STRONG>_</STRONG><EM>env</EM> <EM>use</EM><STRONG>_</STRONG><EM>tioctl</EM> <EM>Summary</EM>
----------------------------------------------------------------
TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
uses operating system calls unless over-
ridden by $LINES or $COLUMNS environment
variables.
TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
based on operating system calls.
FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
es operating system calls to obtain
size.
FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
to determine size.
</PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
into the file to which <EM>filep</EM> points. This information can be later re-
trieved using the <STRONG>getwin</STRONG> function.
The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
<STRONG>putwin</STRONG>. 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:
<STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its associ-
ated character cells. The format differs between the wide-charac-
ter (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can transfer
data between the two, however.
<STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
pad), rather than a subwindow.
<STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
the actual color <EM>numbers</EM>. If cells in the retrieved window use
color pairs which have not been created in the application using
<STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
</PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> 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 speci-
fied, this uses <STRONG>napms</STRONG> to perform the delay.
</PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
the user and has not yet been read by the program.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
upon successful completion.
Routines that return pointers return <STRONG>NULL</STRONG> on error.
X/Open does not define any error conditions. In this implementation
<STRONG>flushinp</STRONG>
returns an error if the terminal was not initialized.
<STRONG>putwin</STRONG>
returns an error if the associated <STRONG>fwrite</STRONG> calls return an er-
ror.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
</PRE><H3><a name="h3-filter">filter</a></H3><PRE>
The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
vaguest terms. The description here is adapted from the XSI Curses
standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
</PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
The <STRONG>keyname</STRONG> function may return the names of user-defined string capa-
bilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option of
<STRONG>tic</STRONG>. 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 <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
whether this data is loaded when the terminal description is read by
the library.
</PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
were not supported on Version 7, BSD or System V implementations. It
is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be condi-
tioned using NCURSES_VERSION.
</PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
<STRONG>o</STRONG> The files written and read by these functions use an implementa-
tion-specific format. Although the format is an obvious target for
standardization, it has been overlooked.
Interestingly enough, according to the copyright dates in Solaris
source, the functions (along with <STRONG>scr_init</STRONG>, 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.
<STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
file. These include SVr4 curses, NetBSD and PDCurses, as well as
older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
variant of Solaris curses, dated 1995) uses textual dumps.
The implementations which use binary dumps use block-I/O (the
<STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> 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.
</PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
The XSI Curses standard, Issue 4 describes these functions. It states
that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
does not define any error conditions. This implementation checks for
three cases:
<STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
X/Open Curses documented.
<STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
<STRONG>use_legacy_coding</STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> re-
turns the parameter, i.e., a one-character string with the parame-
ter as the first character. Otherwise, it returns "~@", "~A",
etc., analogous to "^@", "^A", C0 controls.
X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
initializing curses. This implementation permits that, and returns
the "~@", etc., values in that case.
<STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
pointer.
The strings returned by <STRONG>unctrl</STRONG> 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 conven-
tions. 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
<STRONG>use_legacy_coding</STRONG> function allows the caller to change the output of
<STRONG>unctrl</STRONG>.
Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
"meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_coding</STRONG>
and <STRONG>meta</STRONG> 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 <STRONG>keyname</STRONG> is called before initializing curses), this
implementation returns strings "M-^@", "M-^A", etc.
X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
behavior of SVr4 curses. Other implementations may not do that.
</PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
If <STRONG>ncurses</STRONG> is configured to provide the sp-functions extension, the
state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
<EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
<STRONG>use_env</STRONG> is not provided by other implementation of curses.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>, <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_inopts.3x.html">curs_inopts(3x)</A></STRONG>,
<STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>, <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>, <STRONG>curs_vari-</STRONG>
<STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>.
<STRONG><A HREF="curs_util.3x.html">curs_util(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-unctrl">unctrl</a></li>
<li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
<li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
<li><a href="#h3-use_env">use_env</a></li>
<li><a href="#h3-use_tioctl">use_tioctl</a></li>
<li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
<li><a href="#h3-delay_output">delay_output</a></li>
<li><a href="#h3-flushinp">flushinp</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a>
<ul>
<li><a href="#h3-filter">filter</a></li>
<li><a href="#h3-keyname">keyname</a></li>
<li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
<li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
<li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
<li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
</ul>
</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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