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43 <H1 class="no-header">curs_util 3x 2023-09-30 ncurses 6.4 Library calls</H1>
45 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>delay_output</STRONG>, <STRONG>filter</STRONG>, <STRONG>flushinp</STRONG>, <STRONG>getwin</STRONG>, <STRONG>key_name</STRONG>, <STRONG>keyname</STRONG>, <STRONG>nofilter</STRONG>,
52 <STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> - miscellaneous <EM>curses</EM>
56 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
57 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
59 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <EM>c</EM><STRONG>);</STRONG>
60 <STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*</STRONG><EM>c</EM><STRONG>);</STRONG>
62 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <EM>c</EM><STRONG>);</STRONG>
63 <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <EM>w</EM><STRONG>);</STRONG>
65 <STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
67 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
69 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
70 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
72 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <EM>ms</EM><STRONG>);</STRONG>
73 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
75 <EM>/*</EM> <EM>extensions</EM> <EM>*/</EM>
76 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
77 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
80 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
82 </PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
83 The <STRONG>unctrl</STRONG> routine returns a character string which is a printable
84 representation of the character <EM>c</EM>:
86 <STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-
87 character string containing the key.
89 <STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
91 <STRONG>o</STRONG> Printing characters are displayed as is.
93 <STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
95 <STRONG>o</STRONG> Values above 128 are either meta characters (if the screen has not
96 been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has been called with a <STRONG>TRUE</STRONG>
97 parameter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as
98 themselves. In the latter case, the values may not be printable;
99 this follows the X/Open specification.
101 The corresponding <STRONG>wunctrl</STRONG> returns a printable representation of a
102 complex character <EM>c</EM>.
104 In both <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> the attributes and color associated with the
105 character parameter are ignored.
108 </PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
109 The <STRONG>keyname</STRONG> routine returns a character string corresponding to the key
110 <EM>c</EM>. Key codes are different from character codes.
112 <STRONG>o</STRONG> Key codes below 256 are characters. They are displayed using
113 <STRONG>unctrl</STRONG>.
115 <STRONG>o</STRONG> Values above 256 may be the codes for function keys. The function
116 key name is displayed.
118 <STRONG>o</STRONG> Otherwise (if there is no corresponding name and the key is not a
119 character) the function returns null, to denote an error. X/Open
120 also lists an "UNKNOWN KEY" return value, which some
121 implementations return rather than null.
123 The corresponding <STRONG>key_name</STRONG> returns a multibyte character string
124 corresponding to the wide-character value <EM>w</EM>. The two functions
125 (<STRONG>keyname</STRONG> and <STRONG>key_name</STRONG>) do not return the same set of strings:
127 <STRONG>o</STRONG> <STRONG>keyname</STRONG> returns null where <STRONG>key_name</STRONG> would display a meta character.
129 <STRONG>o</STRONG> <STRONG>key_name</STRONG> does not return the name of a function key.
132 </PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
133 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>
134 are called. Calling <STRONG>filter</STRONG> causes these changes in initialization:
136 <STRONG>o</STRONG> <STRONG>LINES</STRONG> is set to 1;
138 <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
141 <STRONG>o</STRONG> the capability <STRONG>ed</STRONG> is disabled if <STRONG>bce</STRONG> is set;
143 <STRONG>o</STRONG> and the <STRONG>home</STRONG> string is set to the value of <STRONG>cr</STRONG>.
145 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding <STRONG>filter</STRONG> call.
146 That allows the caller to initialize a screen on a different device,
147 using a different value of <STRONG>$TERM</STRONG>. The limitation arises because the
148 <STRONG>filter</STRONG> routine modifies the in-memory copy of the terminal information.
151 </PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
152 The <STRONG>use_env</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
153 <STRONG>newterm</STRONG> are called (because those compute the screen size). It
154 modifies the way <EM>ncurses</EM> treats environment variables when determining
157 <STRONG>o</STRONG> Normally <EM>ncurses</EM> looks first at the terminal database for the
160 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it stops here
161 unless <STRONG>use_tioctl</STRONG> was also called with <STRONG>TRUE</STRONG> for parameter.
163 <STRONG>o</STRONG> Then it asks for the screen size via operating system calls. If
164 successful, it overrides the values from the terminal database.
166 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parameter), <STRONG>ncurses</STRONG>
167 examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables, using a value
168 in those to override the results from the operating system or
171 <STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>,
172 unless overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables,
175 </PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
176 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
177 <STRONG>newterm</STRONG> are called (because those compute the screen size). After
178 <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an argument, <STRONG>ncurses</STRONG> modifies the
179 last step in its computation of screen size as follows:
181 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables are set to a
182 number greater than zero.
184 <STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environment variable
185 with the value that it has obtained via operating system call or
186 from the terminal database.
188 <STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment variables so that
189 it is still the environment variables which set the screen size.
191 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as follows.
193 <STRONG>use_env</STRONG> <STRONG>use_tioctl</STRONG> <STRONG>Summary</STRONG>
194 -----------------------------------------------------------------
195 <STRONG>TRUE</STRONG> <STRONG>FALSE</STRONG> This is the default behavior. <EM>ncurses</EM>
196 uses operating system calls unless
197 overridden by <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG>
198 environment variables; default.
199 <STRONG>TRUE</STRONG> <STRONG>TRUE</STRONG> <EM>ncurses</EM> updates <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> based
200 on operating system calls.
201 <STRONG>FALSE</STRONG> <STRONG>TRUE</STRONG> <EM>ncurses</EM> ignores <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG>, using
202 operating system calls to obtain size.
205 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
206 The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
207 into the file to which <EM>filep</EM> points. This information can be later
208 retrieved using the <STRONG>getwin</STRONG> function.
210 The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
211 <STRONG>putwin</STRONG>. The routine then creates and initializes a new window using
212 that data. It returns a pointer to the new window. There are a few
215 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its
216 associated character cells. The format differs between the wide-
217 character (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can
218 transfer data between the two, however.
220 <STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
221 pad), rather than a subwindow.
223 <STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
224 the actual color <EM>numbers</EM>. If cells in the retrieved window use
225 color pairs which have not been created in the application using
226 <STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
229 </PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
230 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause in output.
231 This routine should not be used extensively because padding characters
232 are used rather than a CPU pause. If no padding character is
233 specified, this uses <STRONG>napms</STRONG> to perform the delay.
236 </PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
237 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
238 the user and has not yet been read by the program.
241 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
242 Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
243 failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
244 upon successful completion.
246 Routines that return pointers return <STRONG>NULL</STRONG> on error.
248 X/Open does not define any error conditions. In this implementation
250 <STRONG>flushinp</STRONG>
251 returns an error if the terminal was not initialized.
253 <STRONG>putwin</STRONG>
254 returns an error if the associated <STRONG>fwrite</STRONG> calls return an
258 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
260 </PRE><H3><a name="h3-filter">filter</a></H3><PRE>
261 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
262 vaguest terms. The description here is adapted from the XSI Curses
263 standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
266 </PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
267 The <STRONG>keyname</STRONG> function may return the names of user-defined string
268 capabilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option
269 of <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes
270 to user-defined strings which begin with "k". The keycodes start at
271 KEY_MAX, but are not guaranteed to be the same value for different runs
272 because user-defined codes are merged from all terminal descriptions
273 which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
274 whether this data is loaded when the terminal description is read by
278 </PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
279 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
280 were not supported on Version 7, BSD or System V implementations. It
281 is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be
282 conditioned using <STRONG>NCURSES_VERSION</STRONG>.
285 </PRE><H3><a name="h3-putwin_getwin-file-format">putwin/getwin file-format</a></H3><PRE>
286 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
288 <STRONG>o</STRONG> The files written and read by these functions use an
289 implementation-specific format. Although the format is an obvious
290 target for standardization, it has been overlooked.
292 Interestingly enough, according to the copyright dates in Solaris
293 source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
294 the University of California, Berkeley (in 1982) and were later (in
295 1988) incorporated into SVr4. Oddly, there are no such functions
296 in the 4.3BSD curses sources.
298 <STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
299 file. These include SVr4 curses, NetBSD and PDCurses, as well as
300 older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
301 variant of Solaris curses, dated 1995) uses textual dumps.
303 The implementations which use binary dumps use block-I/O (the
304 <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
305 buffered-I/O. A few applications may happen to write extra data in
306 the file using these functions. Doing that can run into problems
307 mixing block- and buffered-I/O. This implementation reduces the
308 problem on writes by flushing the output. However, reading from a
309 file written using mixed schemes may not be successful.
312 </PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
313 The XSI Curses standard, Issue 4 describes these functions. It states
314 that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
315 does not define any error conditions. This implementation checks for
318 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
319 X/Open Curses documented.
321 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
322 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG>
323 returns the parameter, i.e., a one-character string with the
324 parameter as the first character. Otherwise, it returns "~@",
325 "~A", etc., analogous to "^@", "^A", C0 controls.
327 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
328 initializing curses. This implementation permits that, and returns
329 the "~@", etc., values in that case.
331 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
334 The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
335 compile time, showing C1 controls from the upper-128 codes with a "~"
336 prefix rather than "^". Other implementations have different
337 conventions. For example, they may show both sets of control
338 characters with "^", and strip the parameter to 7 bits. Or they may
339 ignore C1 controls and treat all of the upper-128 codes as printable.
340 This implementation uses 8 bits but does not modify the string to
341 reflect locale. The <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> function allows the caller
342 to change the output of <STRONG>unctrl</STRONG>.
344 Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
345 of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
346 "meta" keys (codes in the range 128 to 255). Both
347 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> and <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> succeed only after curses is
348 initialized. X/Open Curses does not document the treatment of codes
349 128 to 159. When treating them as "meta" keys (or if <STRONG>keyname</STRONG> is called
350 before initializing curses), this implementation returns strings
353 X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
354 does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
355 behavior of SVr4 curses. Other implementations may not do that.
358 </PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
359 If <STRONG>ncurses</STRONG> is configured to provide the sp-functions extension, the
360 state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
361 <EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
362 <STRONG>use_env</STRONG> is not provided by other implementations of curses.
365 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
366 <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>,
367 <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><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>,
368 <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>
372 ncurses 6.4 2023-09-30 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
376 <li><a href="#h2-NAME">NAME</a></li>
377 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
378 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
380 <li><a href="#h3-unctrl">unctrl</a></li>
381 <li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
382 <li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
383 <li><a href="#h3-use_env">use_env</a></li>
384 <li><a href="#h3-use_tioctl">use_tioctl</a></li>
385 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
386 <li><a href="#h3-delay_output">delay_output</a></li>
387 <li><a href="#h3-flushinp">flushinp</a></li>
390 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
391 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
393 <li><a href="#h3-filter">filter</a></li>
394 <li><a href="#h3-keyname">keyname</a></li>
395 <li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
396 <li><a href="#h3-putwin_getwin-file-format">putwin/getwin file-format</a></li>
397 <li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
398 <li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
401 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>