1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
|
<!--
****************************************************************************
* Copyright 2018-2020,2021 Thomas E. Dickey *
* Copyright 1998-2017,2018 Free Software Foundation, Inc. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the *
* "Software"), to deal in the Software without restriction, including *
* without limitation the rights to use, copy, modify, merge, publish, *
* distribute, distribute with modifications, sublicense, and/or sell *
* copies of the Software, and to permit persons to whom the Software is *
* furnished to do so, subject to the following conditions: *
* *
* The above copyright notice and this permission notice shall be included *
* in all copies or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
* IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
* THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
* *
* Except as contained in this notice, the name(s) of the above copyright *
* holders shall not be used in advertising or otherwise to promote the *
* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
* @Id: curs_termcap.3x,v 1.49 2021/04/03 21:17:09 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts">
<TITLE>curs_termcap 3x</TITLE>
<link rel="author" href="mailto:bug-ncurses@gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</HEAD>
<BODY>
<H1 class="no-header">curs_termcap 3x</H1>
<PRE>
<STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG> <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>PC</STRONG>, <STRONG>UP</STRONG>, <STRONG>BC</STRONG>, <STRONG>ospeed</STRONG>, <STRONG>tgetent</STRONG>, <STRONG>tgetflag</STRONG>, <STRONG>tgetnum</STRONG>, <STRONG>tgetstr</STRONG>, <STRONG>tgoto</STRONG>, <STRONG>tputs</STRONG> -
<STRONG>curses</STRONG> emulation of termcap
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>#include</STRONG> <STRONG><term.h></STRONG>
<STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>PC;</STRONG>
<STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>UP;</STRONG>
<STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>BC;</STRONG>
<STRONG>extern</STRONG> <STRONG>short</STRONG> <STRONG>ospeed;</STRONG>
<STRONG>int</STRONG> <STRONG>tgetent(char</STRONG> <STRONG>*</STRONG><EM>bp</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>name</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>tgetflag(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>tgetnum(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>);</STRONG>
<STRONG>char</STRONG> <STRONG>*tgetstr(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>**</STRONG><EM>area</EM><STRONG>);</STRONG>
<STRONG>char</STRONG> <STRONG>*tgoto(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>cap</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>col</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>row</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>tputs(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>affcnt</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>(*</STRONG><EM>putc</EM><STRONG>)(int));</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
These routines are included as a conversion aid for programs that use
the <EM>termcap</EM> library. Their parameters are the same, but the routines
are emulated using the <EM>terminfo</EM> database. Thus, they can only be used
to query the capabilities of entries for which a terminfo entry has
been compiled.
</PRE><H3><a name="h3-INITIALIZATION">INITIALIZATION</a></H3><PRE>
The <STRONG>tgetent</STRONG> routine loads the entry for <EM>name</EM>. It returns:
1 on success,
0 if there is no such entry (or that it is a generic type, having
too little information for curses applications to run), and
-1 if the terminfo database could not be found.
This differs from the <EM>termcap</EM> library in two ways:
<STRONG>o</STRONG> The emulation ignores the buffer pointer <EM>bp</EM>. The <EM>termcap</EM> li-
brary would store a copy of the terminal description in the area
referenced by this pointer. However, ncurses stores its termi-
nal descriptions in compiled binary form, which is not the same
thing.
<STRONG>o</STRONG> There is a difference in return codes. The <EM>termcap</EM> library does
not check if the terminal description is marked with the <EM>generic</EM>
capability, or if the terminal description has cursor-address-
ing.
</PRE><H3><a name="h3-CAPABILITY-VALUES">CAPABILITY VALUES</a></H3><PRE>
The <STRONG>tgetflag</STRONG> routine gets the boolean entry for <EM>id</EM>, or zero if it is
not available.
The <STRONG>tgetnum</STRONG> routine gets the numeric entry for <EM>id</EM>, or -1 if it is not
available.
The <STRONG>tgetstr</STRONG> routine returns the string entry for <EM>id</EM>, or zero if it is
not available. Use <STRONG>tputs</STRONG> to output the returned string. The <EM>area</EM> pa-
rameter is used as follows:
<STRONG>o</STRONG> It is assumed to be the address of a pointer to a buffer managed
by the calling application.
<STRONG>o</STRONG> However, ncurses checks to ensure that <STRONG>area</STRONG> is not NULL, and al-
so that the resulting buffer pointer is not NULL. If either
check fails, the <EM>area</EM> parameter is ignored.
<STRONG>o</STRONG> If the checks succeed, ncurses also copies the return value to
the buffer pointed to by <EM>area</EM>, and the <EM>area</EM> value will be updat-
ed to point past the null ending this value.
<STRONG>o</STRONG> The return value itself is an address in the terminal descrip-
tion which is loaded into memory.
Only the first two characters of the <STRONG>id</STRONG> parameter of <STRONG>tgetflag</STRONG>, <STRONG>tgetnum</STRONG>
and <STRONG>tgetstr</STRONG> are compared in lookups.
</PRE><H3><a name="h3-FORMATTING-CAPABILITIES">FORMATTING CAPABILITIES</a></H3><PRE>
The <STRONG>tgoto</STRONG> routine expands the given capability using the parameters.
<STRONG>o</STRONG> Because the capability may have padding characters, the output of
<STRONG>tgoto</STRONG> should be passed to <STRONG>tputs</STRONG> rather than some other output func-
tion such as <STRONG>printf</STRONG>.
<STRONG>o</STRONG> While <STRONG>tgoto</STRONG> is assumed to be used for the two-parameter cursor po-
sitioning capability, termcap applications also use it for single-
parameter capabilities.
Doing this shows a quirk in <STRONG>tgoto</STRONG>: most hardware terminals use cur-
sor addressing with <EM>row</EM> first, but the original developers of the
termcap interface chose to put the <EM>column</EM> parameter first. The
<STRONG>tgoto</STRONG> function swaps the order of parameters. It does this also
for calls requiring only a single parameter. In that case, the
first parameter is merely a placeholder.
<STRONG>o</STRONG> Normally the ncurses library is compiled with terminfo support. In
that case, <STRONG>tgoto</STRONG> uses <STRONG><A HREF="curs_terminfo.3x.html">tparm(3x)</A></STRONG> (a more capable formatter).
However, <STRONG>tparm</STRONG> is not a <EM>termcap</EM> feature, and portable <EM>termcap</EM> ap-
plications should not rely upon its availability.
The <STRONG>tputs</STRONG> routine is described on the <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG> manual page.
It can retrieve capabilities by either termcap or terminfo name.
</PRE><H3><a name="h3-GLOBAL-VARIABLES">GLOBAL VARIABLES</a></H3><PRE>
The variables <STRONG>PC</STRONG>, <STRONG>UP</STRONG> and <STRONG>BC</STRONG> are set by <STRONG>tgetent</STRONG> to the terminfo entry's
data for <STRONG>pad_char</STRONG>, <STRONG>cursor_up</STRONG> and <STRONG>backspace_if_not_bs</STRONG>, respectively. <STRONG>UP</STRONG>
is not used by ncurses. <STRONG>PC</STRONG> is used in the <STRONG>tdelay_output</STRONG> function. <STRONG>BC</STRONG>
is used in the <STRONG>tgoto</STRONG> emulation. The variable <STRONG>ospeed</STRONG> is set by ncurses
in a system-specific coding to reflect the terminal speed.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
Except where explicitly noted, routines that return an integer return
<STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value other
than <STRONG>ERR</STRONG>") upon successful completion.
Routines that return pointers return <STRONG>NULL</STRONG> on error.
</PRE><H2><a name="h2-BUGS">BUGS</a></H2><PRE>
If you call <STRONG>tgetstr</STRONG> to fetch <STRONG>ca</STRONG> or any other parameterized string, be
aware that it will be returned in terminfo notation, not the older and
not-quite-compatible termcap notation. This will not cause problems if
all you do with it is call <STRONG>tgoto</STRONG> or <STRONG>tparm</STRONG>, which both expand terminfo-
style strings as terminfo. (The <STRONG>tgoto</STRONG> function, if configured to sup-
port termcap, will check if the string is indeed terminfo-style by
looking for "%p" parameters or "$<..>" delays, and invoke a termcap-
style parser if the string does not appear to be terminfo).
Because terminfo conventions for representing padding in string capa-
bilities differ from termcap's, users can be surprised:
<STRONG>o</STRONG> <STRONG>tputs("50")</STRONG> in a terminfo system will put out a literal "50" rather
than busy-waiting for 50 milliseconds.
<STRONG>o</STRONG> However, if ncurses is configured to support termcap, it may also
have been configured to support the BSD-style padding.
In that case, <STRONG>tputs</STRONG> inspects strings passed to it, looking for dig-
its at the beginning of the string.
<STRONG>tputs("50")</STRONG> in a termcap system may wait for 50 milliseconds rather
than put out a literal "50"
Note that termcap has nothing analogous to terminfo's <STRONG>sgr</STRONG> string. One
consequence of this is that termcap applications assume <STRONG>me</STRONG> (terminfo
<STRONG>sgr0</STRONG>) does not reset the alternate character set. This implementation
checks for, and modifies the data shown to the termcap interface to ac-
commodate termcap's limitation in this respect.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
</PRE><H3><a name="h3-Standards">Standards</a></H3><PRE>
These functions are provided for supporting legacy applications, and
should not be used in new programs:
<STRONG>o</STRONG> The XSI Curses standard, Issue 4 describes these functions. Howev-
er, they are marked TO BE WITHDRAWN and may be removed in future
versions.
<STRONG>o</STRONG> X/Open Curses, Issue 5 (December 2007) marked the termcap interface
(along with <STRONG>vwprintw</STRONG> and <STRONG>vwscanw</STRONG>) as withdrawn.
Neither the XSI Curses standard nor the SVr4 man pages documented the
return values of <STRONG>tgetent</STRONG> correctly, though all three were in fact re-
turned ever since SVr1. In particular, an omission in the XSI Curses
documentation has been misinterpreted to mean that <STRONG>tgetent</STRONG> returns <STRONG>OK</STRONG>
or <STRONG>ERR</STRONG>. Because the purpose of these functions is to provide compati-
bility with the <EM>termcap</EM> library, that is a defect in XCurses, Issue 4,
Version 2 rather than in ncurses.
</PRE><H3><a name="h3-Compatibility-with-BSD-Termcap">Compatibility with BSD Termcap</a></H3><PRE>
External variables are provided for support of certain termcap applica-
tions. However, termcap applications' use of those variables is poorly
documented, e.g., not distinguishing between input and output. In par-
ticular, some applications are reported to declare and/or modify <STRONG>os-</STRONG>
<STRONG>peed</STRONG>.
The comment that only the first two characters of the <STRONG>id</STRONG> parameter are
used escapes many application developers. The original BSD 4.2 termcap
library (and historical relics thereof) did not require a trailing null
NUL on the parameter name passed to <STRONG>tgetstr</STRONG>, <STRONG>tgetnum</STRONG> and <STRONG>tgetflag</STRONG>.
Some applications assume that the termcap interface does not require
the trailing NUL for the parameter name. Taking into account these is-
sues:
<STRONG>o</STRONG> As a special case, <STRONG>tgetflag</STRONG> matched against a single-character
identifier provided that was at the end of the terminal descrip-
tion. You should not rely upon this behavior in portable programs.
This implementation disallows matches against single-character ca-
pability names.
<STRONG>o</STRONG> This implementation disallows matches by the termcap interface
against extended capability names which are longer than two charac-
ters.
The BSD termcap function <STRONG>tgetent</STRONG> returns the text of a termcap entry in
the buffer passed as an argument. This library (like other terminfo
implementations) does not store terminal descriptions as text. It sets
the buffer contents to a null-terminated string.
</PRE><H3><a name="h3-Other-Compatibility">Other Compatibility</a></H3><PRE>
This library includes a termcap.h header, for compatibility with other
implementations. But the header is rarely used because the other im-
plementations are not strictly compatible.
The original BSD termcap (through 4.3BSD) had no header file which gave
function prototypes, because that was a feature of ANSI C. BSD termcap
was written several years before C was standardized. However, there
were two different termcap.h header files in the BSD sources:
<STRONG>o</STRONG> One was used internally by the <EM>jove</EM> editor in 2BSD through 4.4BSD.
It defined global symbols for the termcap variables which it used.
<STRONG>o</STRONG> The other appeared in 4.4BSD Lite Release 2 (mid-1993) as part of
<EM>libedit</EM> (also known as the <EM>editline</EM> library). The CSRG source his-
tory shows that this was added in mid-1992. The <EM>libedit</EM> header
file was used internally, as a convenience for compiling the <EM>edit-</EM>
<EM>line</EM> library. It declared function prototypes, but no global vari-
ables.
The header file from <EM>libedit</EM> was added to NetBSD's termcap library in
mid-1994.
Meanwhile, GNU termcap was under development, starting in 1990. The
first release (termcap 1.0) in 1991 included a termcap.h header. The
second release (termcap 1.1) in September 1992 modified the header to
use <STRONG>const</STRONG> for the function prototypes in the header where one would ex-
pect the parameters to be read-only. This was a difference versus the
original BSD termcap. The prototype for <STRONG>tputs</STRONG> also differed, but in
that instance, it was <EM>libedit</EM> which differed from BSD termcap.
A copy of GNU termcap 1.3 was bundled with <EM>bash</EM> in mid-1993, to support
the <EM>readline</EM> library.
A termcap.h file was provided in ncurses 1.8.1 (November 1993). That
reflected influence by <EM>emacs</EM> (rather than <EM>jove</EM>) and GNU termcap:
<STRONG>o</STRONG> it provided declarations for a few global symbols used by <EM>emacs</EM>
<STRONG>o</STRONG> it provided function prototypes (using <STRONG>const</STRONG>).
<STRONG>o</STRONG> a prototype for <STRONG>tparam</STRONG> (a GNU termcap feature) was provided.
Later (in mid-1996) the <STRONG>tparam</STRONG> function was removed from ncurses. As a
result, there are differences between any of the four implementations,
which must be taken into account by programs which can work with all
termcap library interfaces.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>, <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>.
https://invisible-island.net/ncurses/tctest.html
<STRONG><A HREF="curs_termcap.3x.html">curs_termcap(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-INITIALIZATION">INITIALIZATION</a></li>
<li><a href="#h3-CAPABILITY-VALUES">CAPABILITY VALUES</a></li>
<li><a href="#h3-FORMATTING-CAPABILITIES">FORMATTING CAPABILITIES</a></li>
<li><a href="#h3-GLOBAL-VARIABLES">GLOBAL VARIABLES</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-BUGS">BUGS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a>
<ul>
<li><a href="#h3-Standards">Standards</a></li>
<li><a href="#h3-Compatibility-with-BSD-Termcap">Compatibility with BSD Termcap</a></li>
<li><a href="#h3-Other-Compatibility">Other Compatibility</a></li>
</ul>
</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
</BODY>
</HTML>
|
