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43 <H1 class="no-header">curs_util 3x 2023-07-15 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>
66 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
68 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
69 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <EM>f</EM><STRONG>);</STRONG>
71 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
72 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*</STRONG><EM>filep</EM><STRONG>);</STRONG>
74 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <EM>ms</EM><STRONG>);</STRONG>
75 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
78 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
80 </PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
81 The <STRONG>unctrl</STRONG> routine returns a character string which is a printable rep-
82 resentation of the character <EM>c</EM>:
84 <STRONG>o</STRONG> Printable characters are displayed as themselves, e.g., a one-char-
85 acter string containing the key.
87 <STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
89 <STRONG>o</STRONG> Printing characters are displayed as is.
91 <STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
93 <STRONG>o</STRONG> Values above 128 are either meta characters (if the screen has not
94 been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has been called with a <STRONG>TRUE</STRONG> param-
95 eter), shown in the <STRONG>M-</STRONG><EM>X</EM> notation, or are displayed as themselves.
96 In the latter case, the values may not be printable; this follows
97 the X/Open specification.
99 The corresponding <STRONG>wunctrl</STRONG> returns a printable representation of a com-
100 plex character <EM>c</EM>.
102 In both <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> the attributes and color associated with the
103 character parameter are ignored.
106 </PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
107 The <STRONG>keyname</STRONG> routine returns a character string corresponding to the key
108 <EM>c</EM>. Key codes are different from character codes.
110 <STRONG>o</STRONG> Key codes below 256 are characters. They are displayed using <STRONG>unc-</STRONG>
111 <STRONG>trl</STRONG>.
113 <STRONG>o</STRONG> Values above 256 may be the codes for function keys. The function
114 key name is displayed.
116 <STRONG>o</STRONG> Otherwise (if there is no corresponding name and the key is not a
117 character) the function returns null, to denote an error. X/Open
118 also lists an "UNKNOWN KEY" return value, which some implementa-
119 tions return rather than null.
121 The corresponding <STRONG>key_name</STRONG> returns a multibyte character string corre-
122 sponding to the wide-character value <EM>w</EM>. The two functions (<STRONG>keyname</STRONG> and
123 <STRONG>key_name</STRONG>) do not return the same set of strings:
125 <STRONG>o</STRONG> <STRONG>keyname</STRONG> returns null where <STRONG>key_name</STRONG> would display a meta character.
127 <STRONG>o</STRONG> <STRONG>key_name</STRONG> does not return the name of a function key.
130 </PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
131 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>
132 are called. Calling <STRONG>filter</STRONG> causes these changes in initialization:
134 <STRONG>o</STRONG> <STRONG>LINES</STRONG> is set to 1;
136 <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-
139 <STRONG>o</STRONG> the capability <STRONG>ed</STRONG> is disabled if <STRONG>bce</STRONG> is set;
141 <STRONG>o</STRONG> and the <STRONG>home</STRONG> string is set to the value of <STRONG>cr</STRONG>.
143 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding <STRONG>filter</STRONG> call.
144 That allows the caller to initialize a screen on a different device,
145 using a different value of <STRONG>$TERM</STRONG>. The limitation arises because the
146 <STRONG>filter</STRONG> routine modifies the in-memory copy of the terminal information.
149 </PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
150 The <STRONG>use_env</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
151 <STRONG>newterm</STRONG> are called (because those compute the screen size). It modi-
152 fies the way <STRONG>ncurses</STRONG> treats environment variables when determining the
155 <STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> looks first at the terminal database for the
158 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it stops here un-
159 less <STRONG>use_tioctl</STRONG> was also called with <STRONG>TRUE</STRONG> for parameter.
161 <STRONG>o</STRONG> Then it asks for the screen size via operating system calls. If
162 successful, it overrides the values from the terminal database.
164 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parameter), <STRONG>ncurses</STRONG>
165 examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables, using a value
166 in those to override the results from the operating system or ter-
169 <STRONG>Ncurses</STRONG> also updates the screen size in response to <STRONG>SIGWINCH</STRONG>, un-
170 less overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environment variables,
173 </PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
174 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before <STRONG>initscr</STRONG> or
175 <STRONG>newterm</STRONG> are called (because those compute the screen size). After
176 <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an argument, <STRONG>ncurses</STRONG> modifies the
177 last step in its computation of screen size as follows:
179 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables are set to a
180 number greater than zero.
182 <STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environment variable
183 with the value that it has obtained via operating system call or
184 from the terminal database.
186 <STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment variables so that
187 it is still the environment variables which set the screen size.
189 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized here:
191 <STRONG>use_env</STRONG> <STRONG>use_tioctl</STRONG> <STRONG>Summary</STRONG>
192 ----------------------------------------------------------------
193 TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
194 uses operating system calls unless over-
195 ridden by $LINES or $COLUMNS environment
197 TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
198 based on operating system calls.
199 FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
200 es operating system calls to obtain
202 FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
206 </PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
207 The <STRONG>putwin</STRONG> routine writes all data associated with window (or pad) <EM>win</EM>
208 into the file to which <EM>filep</EM> points. This information can be later re-
209 trieved using the <STRONG>getwin</STRONG> function.
211 The <STRONG>getwin</STRONG> routine reads window related data stored in the file by
212 <STRONG>putwin</STRONG>. The routine then creates and initializes a new window using
213 that data. It returns a pointer to the new window. There are a few
216 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure, and its associ-
217 ated character cells. The format differs between the wide-charac-
218 ter (<STRONG>ncursesw</STRONG>) and non-wide (<STRONG>ncurses</STRONG>) libraries. You can transfer
219 data between the two, however.
221 <STRONG>o</STRONG> the retrieved window is always created as a top-level window (or
222 pad), rather than a subwindow.
224 <STRONG>o</STRONG> the window's character cells contain the color pair <EM>value</EM>, but not
225 the actual color <EM>numbers</EM>. If cells in the retrieved window use
226 color pairs which have not been created in the application using
227 <STRONG>init_pair</STRONG>, they will not be colored when the window is refreshed.
230 </PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
231 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause in output.
232 This routine should not be used extensively because padding characters
233 are used rather than a CPU pause. If no padding character is speci-
234 fied, this uses <STRONG>napms</STRONG> to perform the delay.
237 </PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
238 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has been typed by
239 the user and has not yet been read by the program.
242 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
243 Except for <STRONG>flushinp</STRONG>, routines that return an integer return <STRONG>ERR</STRONG> upon
244 failure and <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>")
245 upon successful completion.
247 Routines that return pointers return <STRONG>NULL</STRONG> on error.
249 X/Open does not define any error conditions. In this implementation
251 <STRONG>flushinp</STRONG>
252 returns an error if the terminal was not initialized.
254 <STRONG>putwin</STRONG>
255 returns an error if the associated <STRONG>fwrite</STRONG> calls return an er-
259 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
261 </PRE><H3><a name="h3-filter">filter</a></H3><PRE>
262 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
263 vaguest terms. The description here is adapted from the XSI Curses
264 standard (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
267 </PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
268 The <STRONG>keyname</STRONG> function may return the names of user-defined string capa-
269 bilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option of
270 <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes to
271 user-defined strings which begin with "k". The keycodes start at
272 KEY_MAX, but are not guaranteed to be the same value for different runs
273 because user-defined codes are merged from all terminal descriptions
274 which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
275 whether this data is loaded when the terminal description is read by
279 </PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
280 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <STRONG>ncurses</STRONG>. They
281 were not supported on Version 7, BSD or System V implementations. It
282 is recommended that any code depending on <STRONG>ncurses</STRONG> extensions be condi-
283 tioned using NCURSES_VERSION.
286 </PRE><H3><a name="h3-putwin_getwin-file-format">putwin/getwin file-format</a></H3><PRE>
287 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
289 <STRONG>o</STRONG> The files written and read by these functions use an implementa-
290 tion-specific format. Although the format is an obvious target for
291 standardization, it has been overlooked.
293 Interestingly enough, according to the copyright dates in Solaris
294 source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
295 the University of California, Berkeley (in 1982) and were later (in
296 1988) incorporated into SVr4. Oddly, there are no such functions
297 in the 4.3BSD curses sources.
299 <STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG> structure to the
300 file. These include SVr4 curses, NetBSD and PDCurses, as well as
301 older <STRONG>ncurses</STRONG> versions. This implementation (as well as the X/Open
302 variant of Solaris curses, dated 1995) uses textual dumps.
304 The implementations which use binary dumps use block-I/O (the
305 <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
306 buffered-I/O. A few applications may happen to write extra data in
307 the file using these functions. Doing that can run into problems
308 mixing block- and buffered-I/O. This implementation reduces the
309 problem on writes by flushing the output. However, reading from a
310 file written using mixed schemes may not be successful.
313 </PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
314 The XSI Curses standard, Issue 4 describes these functions. It states
315 that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
316 does not define any error conditions. This implementation checks for
319 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
320 X/Open Curses documented.
322 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
323 <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>
324 returns the parameter, i.e., a one-character string with the param-
325 eter as the first character. Otherwise, it returns "~@", "~A",
326 etc., analogous to "^@", "^A", C0 controls.
328 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
329 initializing curses. This implementation permits that, and returns
330 the "~@", etc., values in that case.
332 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
335 The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
336 compile time, showing C1 controls from the upper-128 codes with a "~"
337 prefix rather than "^". Other implementations have different conven-
338 tions. For example, they may show both sets of control characters with
339 "^", and strip the parameter to 7 bits. Or they may ignore C1 controls
340 and treat all of the upper-128 codes as printable. This implementation
341 uses 8 bits but does not modify the string to reflect locale. The
342 <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> function allows the caller to change the output
343 of <STRONG>unctrl</STRONG>.
345 Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
346 of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
347 "meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_cod-</STRONG>
348 <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
349 Curses does not document the treatment of codes 128 to 159. When
350 treating them as "meta" keys (or if <STRONG>keyname</STRONG> is called before initializ-
351 ing curses), this implementation returns strings "M-^@", "M-^A", etc.
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 implementation 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>, <STRONG>legacy_cod-</STRONG>
368 <STRONG><A HREF="legacy_coding.3x.html">ing(3x)</A></STRONG>.
372 ncurses 6.4 2023-07-15 <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>