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43 <H1 class="no-header">curs_util 3x 2023-08-05 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 <STRONG>curses</STRONG>
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>
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 rep-
84 resentation of the character <EM>c</EM>:
86 <STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-char-
87 acter 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> param-
97 eter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves.
98 In the latter case, the values may not be printable; this follows
99 the X/Open specification.
101 The corresponding <STRONG>wunctrl</STRONG> returns a printable representation of a com-
102 plex 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 <STRONG>unc-</STRONG>
113 <STRONG>trl</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 implementa-
121 tions return rather than null.
123 The corresponding <STRONG>key_name</STRONG> returns a multibyte character string corre-
124 sponding to the wide-character value <EM>w</EM>. The two functions (<STRONG>keyname</STRONG> and
125 <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 dis-
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 modi-
154 fies the way <STRONG>ncurses</STRONG> treats environment variables when determining the
157 <STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> 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 un-
161 less <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 ter-
171 <STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>, un-
172 less 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 summarized here:
193 <STRONG>use_env</STRONG> <STRONG>use_tioctl</STRONG> <STRONG>Summary</STRONG>
194 ----------------------------------------------------------------
195 TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
196 uses operating system calls unless over-
197 ridden by $LINES or $COLUMNS environment
199 TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
200 based on operating system calls.
201 FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
202 es operating system calls to obtain
204 FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
208 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
209 The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
210 into the file to which <EM>filep</EM> points. This information can be later re-
211 trieved using the <STRONG>getwin</STRONG> function.
213 The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
214 <STRONG>putwin</STRONG>. The routine then creates and initializes a new window using
215 that data. It returns a pointer to the new window. There are a few
218 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its associ-
219 ated character cells. The format differs between the wide-charac-
220 ter (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can transfer
221 data between the two, however.
223 <STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
224 pad), rather than a subwindow.
226 <STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
227 the actual color <EM>numbers</EM>. If cells in the retrieved window use
228 color pairs which have not been created in the application using
229 <STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
232 </PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
233 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause in output.
234 This routine should not be used extensively because padding characters
235 are used rather than a CPU pause. If no padding character is speci-
236 fied, this uses <STRONG>napms</STRONG> to perform the delay.
239 </PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
240 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
241 the user and has not yet been read by the program.
244 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
245 Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
246 failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
247 upon successful completion.
249 Routines that return pointers return <STRONG>NULL</STRONG> on error.
251 X/Open does not define any error conditions. In this implementation
253 <STRONG>flushinp</STRONG>
254 returns an error if the terminal was not initialized.
256 <STRONG>putwin</STRONG>
257 returns an error if the associated <STRONG>fwrite</STRONG> calls return an er-
261 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
263 </PRE><H3><a name="h3-filter">filter</a></H3><PRE>
264 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
265 vaguest terms. The description here is adapted from the XSI Curses
266 standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
269 </PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
270 The <STRONG>keyname</STRONG> function may return the names of user-defined string capa-
271 bilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option of
272 <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes to
273 user-defined strings which begin with "k". The keycodes start at
274 KEY_MAX, but are not guaranteed to be the same value for different runs
275 because user-defined codes are merged from all terminal descriptions
276 which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
277 whether this data is loaded when the terminal description is read by
281 </PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
282 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
283 were not supported on Version 7, BSD or System V implementations. It
284 is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be condi-
285 tioned using NCURSES_VERSION.
288 </PRE><H3><a name="h3-putwin_getwin-file-format">putwin/getwin file-format</a></H3><PRE>
289 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
291 <STRONG>o</STRONG> The files written and read by these functions use an implementa-
292 tion-specific format. Although the format is an obvious target for
293 standardization, it has been overlooked.
295 Interestingly enough, according to the copyright dates in Solaris
296 source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
297 the University of California, Berkeley (in 1982) and were later (in
298 1988) incorporated into SVr4. Oddly, there are no such functions
299 in the 4.3BSD curses sources.
301 <STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
302 file. These include SVr4 curses, NetBSD and PDCurses, as well as
303 older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
304 variant of Solaris curses, dated 1995) uses textual dumps.
306 The implementations which use binary dumps use block-I/O (the
307 <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
308 buffered-I/O. A few applications may happen to write extra data in
309 the file using these functions. Doing that can run into problems
310 mixing block- and buffered-I/O. This implementation reduces the
311 problem on writes by flushing the output. However, reading from a
312 file written using mixed schemes may not be successful.
315 </PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
316 The XSI Curses standard, Issue 4 describes these functions. It states
317 that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
318 does not define any error conditions. This implementation checks for
321 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
322 X/Open Curses documented.
324 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
325 <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>
326 returns the parameter, i.e., a one-character string with the param-
327 eter as the first character. Otherwise, it returns "~@", "~A",
328 etc., analogous to "^@", "^A", C0 controls.
330 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
331 initializing curses. This implementation permits that, and returns
332 the "~@", etc., values in that case.
334 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
337 The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
338 compile time, showing C1 controls from the upper-128 codes with a "~"
339 prefix rather than "^". Other implementations have different conven-
340 tions. For example, they may show both sets of control characters with
341 "^", and strip the parameter to 7 bits. Or they may ignore C1 controls
342 and treat all of the upper-128 codes as printable. This implementation
343 uses 8 bits but does not modify the string to reflect locale. The
344 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> function allows the caller to change the output
345 of <STRONG>unctrl</STRONG>.
347 Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
348 of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
349 "meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_cod-</STRONG>
350 <STRONG><A HREF="use_legacy_coding.3x.html">ing(3x)</A></STRONG> and <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> succeed only after curses is initialized. X/Open
351 Curses does not document the treatment of codes 128 to 159. When
352 treating them as "meta" keys (or if <STRONG>keyname</STRONG> is called before initializ-
353 ing curses), this implementation returns strings "M-^@", "M-^A", etc.
355 X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
356 does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
357 behavior of SVr4 curses. Other implementations may not do that.
360 </PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
361 If <STRONG>ncurses</STRONG> is configured to provide the sp-functions extension, the
362 state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
363 <EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
364 <STRONG>use_env</STRONG> is not provided by other implementations of curses.
367 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
368 <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>,
369 <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>, <STRONG>legacy_cod-</STRONG>
370 <STRONG><A HREF="legacy_coding.3x.html">ing(3x)</A></STRONG>.
374 ncurses 6.4 2023-08-05 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
378 <li><a href="#h2-NAME">NAME</a></li>
379 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
380 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
382 <li><a href="#h3-unctrl">unctrl</a></li>
383 <li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
384 <li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
385 <li><a href="#h3-use_env">use_env</a></li>
386 <li><a href="#h3-use_tioctl">use_tioctl</a></li>
387 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
388 <li><a href="#h3-delay_output">delay_output</a></li>
389 <li><a href="#h3-flushinp">flushinp</a></li>
392 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
393 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
395 <li><a href="#h3-filter">filter</a></li>
396 <li><a href="#h3-keyname">keyname</a></li>
397 <li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
398 <li><a href="#h3-putwin_getwin-file-format">putwin/getwin file-format</a></li>
399 <li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
400 <li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
403 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>