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30 * @Id: curs_util.3x,v 1.42 2015/04/26 14:27:03 Sven.Joachim Exp @
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42 <H1 class="no-header">curs_util 3x</H1>
44 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG> <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
50 <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>,
52 <STRONG>nofilter</STRONG>, <STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> -
53 miscellaneous <STRONG>curses</STRONG> utility routines
57 <H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
58 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
60 <STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <STRONG>c);</STRONG>
61 <STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*c);</STRONG>
62 <STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <STRONG>c);</STRONG>
63 <STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <STRONG>w);</STRONG>
64 <STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
65 <STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
66 <STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <STRONG>f);</STRONG>
67 <STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <STRONG>f);</STRONG>
68 <STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>FILE</STRONG> <STRONG>*filep);</STRONG>
69 <STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*filep);</STRONG>
70 <STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <STRONG>ms);</STRONG>
71 <STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
75 <H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
76 The <STRONG>unctrl</STRONG> routine returns a character string which is a
77 printable representation of the character <EM>c</EM>, ignoring at-
78 tributes. Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> no-
79 tation. Printing characters are displayed as is. The
80 corresponding <STRONG>wunctrl</STRONG> returns a printable representation
83 The <STRONG>keyname</STRONG> routine returns a character string correspond-
84 ing to the key <EM>c</EM>:
86 <STRONG>o</STRONG> Printable characters are displayed as themselves,
87 e.g., a one-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> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
93 <STRONG>o</STRONG> Values above 128 are either meta characters (if the
94 screen has not been initialized, or if <STRONG>meta</STRONG> has been
95 called with a <STRONG>TRUE</STRONG> parameter), shown in the <STRONG>M-</STRONG><EM>X</EM> nota-
96 tion, or are displayed as themselves. In the latter
97 case, the values may not be printable; this follows
98 the X/Open specification.
100 <STRONG>o</STRONG> Values above 256 may be the names of the names of
103 <STRONG>o</STRONG> Otherwise (if there is no corresponding name) the
104 function returns null, to denote an error. X/Open al-
105 so lists an "UNKNOWN KEY" return value, which some im-
106 plementations return rather than null.
108 The corresponding <STRONG>key_name</STRONG> returns a character string cor-
109 responding to the wide-character value <EM>w</EM>. The two func-
110 tions do not return the same set of strings; the latter
111 returns null where the former would display a meta charac-
114 The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG>
115 or <STRONG>newterm</STRONG> are called. The effect is that, during those
116 calls, <STRONG>LINES</STRONG> is set to 1; the capabilities <STRONG>clear</STRONG>, <STRONG>cup</STRONG>,
117 <STRONG>cud</STRONG>, <STRONG>cud1</STRONG>, <STRONG>cuu1</STRONG>, <STRONG>cuu</STRONG>, <STRONG>vpa</STRONG> are disabled; and the <STRONG>home</STRONG>
118 string is set to the value of <STRONG>cr</STRONG>.
120 The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding
121 <STRONG>filter</STRONG> call. That allows the caller to initialize a
122 screen on a different device, using a different value of
123 <STRONG>$TERM</STRONG>. The limitation arises because the <STRONG>filter</STRONG> routine
124 modifies the in-memory copy of the terminal information.
126 The <STRONG>use_env</STRONG> routine, if used, should be called before
127 <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
128 screen size). It modifies the way <STRONG>ncurses</STRONG> treats environ-
129 ment variables when determining the screen size.
131 <STRONG>o</STRONG> Normally ncurses looks first at the terminal database
134 If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it
135 stops here unless If <STRONG>use_tioctl</STRONG> was also called with
136 <STRONG>TRUE</STRONG> for parameter.
138 <STRONG>o</STRONG> Then it asks for the screen size via operating system
139 calls. If successful, it overrides the values from
140 the terminal database.
142 <STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parame-
143 ter), ncurses examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environ-
144 ment variables, using a value in those to override the
145 results from the operating system or terminal data-
148 Ncurses also updates the screen size in response to
149 SIGWINCH, unless overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG>
150 environment variables,
152 The <STRONG>use_tioctl</STRONG> routine, if used, should be called before
153 <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
154 screen size). After <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an
155 argument, ncurses modifies the last step in its computa-
156 tion of screen size as follows:
158 <STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables
159 are set to a number greater than zero.
161 <STRONG>o</STRONG> for each, ncurses updates the corresponding environ-
162 ment variable with the value that it has obtained via
163 operating system call or from the terminal database.
165 <STRONG>o</STRONG> ncurses re-fetches the value of the environment vari-
166 ables so that it is still the environment variables
167 which set the screen size.
169 The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized
172 <EM>use</EM><STRONG>_</STRONG><EM>env</EM> <EM>use</EM><STRONG>_</STRONG><EM>tioctl</EM> <EM>Summary</EM>
173 ----------------------------------------------------------------
174 TRUE FALSE This is the default behavior. ncurses
175 uses operating system calls unless over-
176 ridden by $LINES or $COLUMNS environment
178 TRUE TRUE ncurses updates $LINES and $COLUMNS
179 based on operating system calls.
182 FALSE TRUE ncurses ignores $LINES and $COLUMNS, us-
183 es operating system calls to obtain
185 FALSE FALSE ncurses relies on the terminal database
188 The <STRONG>putwin</STRONG> routine writes all data associated with window
189 (or pad) <EM>win</EM> into the file to which <EM>filep</EM> points. This
190 information can be later retrieved using the <STRONG>getwin</STRONG> func-
193 The <STRONG>getwin</STRONG> routine reads window related data stored in the
194 file by <STRONG>putwin</STRONG>. The routine then creates and initializes
195 a new window using that data. It returns a pointer to the
196 new window. There are a few caveats:
198 <STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure,
199 and its associated character cells. The format dif-
200 fers between the wide-character (ncursesw) and non-
201 wide (ncurses) libraries. You can transfer data be-
202 tween the two, however.
204 <STRONG>o</STRONG> the retrieved window is always created as a top-level
205 window (or pad), rather than a subwindow.
207 <STRONG>o</STRONG> the window's character cells contain the color pair
208 <EM>value</EM>, but not the actual color <EM>numbers</EM>. If cells in
209 the retrieved window use color pairs which have not
210 been created in the application using <STRONG>init_pair</STRONG>, they
211 will not be colored when the window is refreshed.
213 The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause
214 in output. This routine should not be used extensively
215 because padding characters are used rather than a CPU
216 pause. If no padding character is specified, this uses
217 <STRONG>napms</STRONG> to perform the delay.
219 The <STRONG>flushinp</STRONG> routine throws away any typeahead that has
220 been typed by the user and has not yet been read by the
225 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
226 Except for <STRONG>flushinp</STRONG>, routines that return an integer re-
227 turn <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 specifies only "an in-
228 teger value other than <STRONG>ERR</STRONG>") upon successful completion.
230 Routines that return pointers return <STRONG>NULL</STRONG> on error.
232 X/Open does not define any error conditions. In this im-
235 <STRONG>flushinp</STRONG>
236 returns an error if the terminal was not initial-
239 <STRONG>meta</STRONG> returns an error if the terminal was not initial-
242 <STRONG>putwin</STRONG>
243 returns an error if the associated <STRONG>fwrite</STRONG> calls
248 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
251 <H3><a name="h3-filter">filter</a></H3><PRE>
252 The SVr4 documentation describes the action of <STRONG>filter</STRONG> only
253 in the vaguest terms. The description here is adapted
254 from the XSI Curses standard (which erroneously fails to
255 describe the disabling of <STRONG>cuu</STRONG>).
259 <H3><a name="h3-keyname">keyname</a></H3><PRE>
260 The <STRONG>keyname</STRONG> function may return the names of user-defined
261 string capabilities which are defined in the terminfo en-
262 try via the <STRONG>-x</STRONG> option of <STRONG>tic</STRONG>. This implementation auto-
263 matically assigns at run-time keycodes to user-defined
264 strings which begin with "k". The keycodes start at
265 KEY_MAX, but are not guaranteed to be the same value for
266 different runs because user-defined codes are merged from
267 all terminal descriptions which have been loaded. The
268 <STRONG>use_extended_names</STRONG> function controls whether this data is
269 loaded when the terminal description is read by the li-
274 <H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
275 The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to
276 ncurses. They were not supported on Version 7, BSD or
277 System V implementations. It is recommended that any code
278 depending on ncurses extensions be conditioned using
283 <H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
284 The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with
287 <STRONG>o</STRONG> The files written and read by these functions use an
288 implementation-specific format. Although the format
289 is an obvious target for standardization, it has been
292 Interestingly enough, according to the copyright dates
293 in Solaris source, the functions (along with <STRONG>scr_init</STRONG>,
294 etc.) originated with the University of California,
295 Berkeley (in 1982) and were later (in 1988) incorpo-
296 rated 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>
300 structure to the file. These include SVr4 curses,
301 NetBSD and PDCurses, as well as older ncurses ver-
302 sions. This implementation (as well as the X/Open
303 variant of Solaris curses, dated 1995) uses textual
306 The implementations which use binary dumps use block-
307 I/O (the <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use
308 textual dumps use buffered-I/O. A few applications
309 may happen to write extra data in the file using these
310 functions. Doing that can run into problems mixing
311 block- and buffered-I/O. This implementation reduces
312 the problem on writes by flushing the output. Howev-
313 er, reading from a file written using mixed schemes
314 may not be successful.
318 <H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
319 The XSI Curses standard, Issue 4 describes these func-
320 tions. It states that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a
321 null pointer if unsuccessful, but does not define any er-
322 ror conditions. This implementation checks for three cas-
325 <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the
326 case that X/Open Curses documented.
328 <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 con-
329 trol code. If <STRONG>use_legacy_coding</STRONG> has been called with
330 a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> returns the parameter, i.e., a
331 one-character string with the parameter as the first
332 character. Otherwise, it returns "~@", "~A", etc.,
333 analogous to "^@", "^A", C0 controls.
335 X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be
336 called before initializing curses. This implementa-
337 tion permits that, and returns the "~@", etc., values
340 <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG>
341 returns a null pointer.
343 The strings returned by <STRONG>unctrl</STRONG> in this implementation are
344 determined at compile time, showing C1 controls from the
345 upper-128 codes with a `~' prefix rather than `^'. Other
346 implementations have different conventions. For example,
347 they may show both sets of control characters with `^',
348 and strip the parameter to 7 bits. Or they may ignore C1
349 controls and treat all of the upper-128 codes as print-
350 able. This implementation uses 8 bits but does not modify
351 the string to reflect locale. The <STRONG>use_legacy_coding</STRONG> func-
352 tion allows the caller to change the output of <STRONG>unctrl</STRONG>.
354 Likewise, the <STRONG>meta</STRONG> function allows the caller to change
355 the output of <STRONG>keyname</STRONG>, i.e., it determines whether to use
356 the `M-' prefix for "meta" keys (codes in the range 128 to
357 255). Both <STRONG>use_legacy_coding</STRONG> and <STRONG>meta</STRONG> succeed only after
358 curses is initialized. X/Open Curses does not document
359 the treatment of codes 128 to 159. When treating them as
360 "meta" keys (or if <STRONG>keyname</STRONG> is called before initializing
361 curses), this implementation returns strings "M-^@",
366 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
367 <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>curs_ker-</STRONG>
368 <STRONG><A HREF="curs_kernel.3x.html">nel(3x)</A></STRONG>, <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>lega-</STRONG>
369 <STRONG><A HREF="legacy_coding.3x.html">cy_coding(3x)</A></STRONG>.
373 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
377 <li><a href="#h2-NAME">NAME</a></li>
378 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
379 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
380 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
381 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
383 <li><a href="#h3-filter">filter</a></li>
384 <li><a href="#h3-keyname">keyname</a></li>
385 <li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
386 <li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
387 <li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
390 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>