* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: curs_termcap.3x,v 1.74 2023/12/02 20:49:04 tom Exp @
+ * @Id: curs_termcap.3x,v 1.76 2023/12/18 00:22:30 tom Exp @
+ * See <https://minnie.tuhs.org/cgi-bin/utree.pl?file=2BSD/src/\
+ * termlib/termcap.c>.
+ * See https://www.oreilly.com/openbook/opensources/book/kirkmck.html
+ * for much BSD release history.
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=1BSD/s7/ttycap.c
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=1BSD/man7/ttycap.7
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=2BSD/src/termlib/
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=2BSD/bin/etc/termcap
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=3BSD/usr/src/lib/\
+ * libtermlib/
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=3BSD/usr/man/man3/\
+ * termlib.3
+ * ...except in the source tree...
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=4BSD/usr/src/lib/\
+ * libtermlib/makefile
+ * Observe the `tncktc()`, `tnamatch()`, `tskip()`, and `tdecode()`
+ * entry points disappearing from termcap.c.
+ * 2BSD became a branch retaining support for non-virtual memory
+ * systems (like the PDP-11) whereas most BSD development focused on
+ * the VAX and other VM-enabled systems starting with 3BSD.
+ * This man page previously located a termcap.h in 2BSD, but that may
+ * be confusion arising from its backport to 2.9BSD (and still present
+ * in surviving sources for 2.11BSD, the "end of the line" for that
+ * branch's development).
+ * Observe the copyright notice in
+ * https://minnie.tuhs.org/cgi-bin/utree.pl?file=4.3BSD/usr/contrib/\
+ * jove/Makefile
+ * --much too late for 2BSD (1979).
-->
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-<H1 class="no-header">curs_termcap 3x 2023-12-02 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_termcap 3x 2023-12-17 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
<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>char</STRONG> <STRONG>PC;</STRONG>
+ <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>UP;</STRONG>
+ <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>BC;</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>
</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.
+ <EM>ncurses</EM> provides the foregoing variables and functions as a
+ compatibility layer for programs that use the <EM>termcap</EM> library. The API
+ is the same, but behavior is emulated using the <EM>terminfo</EM> database.
+ Thus, it can be used only to query the capabilities of terminal
+ database entries for which a <EM>terminfo</EM> 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:
+ <STRONG>tgetent</STRONG> loads the terminal database entry for <EM>name</EM>; see <STRONG><A HREF="term.7.html">term(7)</A></STRONG>. This
+ must be done before calling any of the other functions. It returns:
- 1 on success,
+ 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
+ 0 if there is no such entry (or if the matching entry describes a
+ generic terminal, having too little information for <EM>curses</EM>
+ applications to run), and
- -1 if the terminfo database could not be found.
+ -1 if the <EM>terminfo</EM> database could not be found.
- This differs from the <EM>termcap</EM> library in two ways:
+ This implementation differs from those of historical <EM>termcap</EM> libraries.
- <STRONG>o</STRONG> The emulation ignores the buffer pointer <EM>bp</EM>. The <EM>termcap</EM>
- library would store a copy of the terminal description in the
- area referenced by this pointer. However, ncurses stores its
- terminal descriptions in compiled binary form, which is not the
- same thing.
+ <STRONG>o</STRONG> <EM>ncurses</EM> ignores the buffer pointer <EM>bp</EM>, as do other <EM>termcap</EM>
+ implementations conforming to portions of X/Open Curses now
+ withdrawn. The BSD <EM>termcap</EM> library would store a copy of the
+ terminal type description in the area referenced by this
+ pointer. <EM>ncurses</EM> stores terminal type descriptions in compiled
+ 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-
- addressing.
+ <STRONG>o</STRONG> The meanings of the return values differ. The BSD <EM>termcap</EM>
+ library does not check whether the terminal type description is
+ marked with the <STRONG>gn</STRONG> (<STRONG>generic</STRONG>) capability, nor whether the
+ terminal type description supports an addressable cursor, a
+ property essential for any <EM>curses</EM> implementation to operate.
-</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
+</PRE><H3><a name="h3-Retrieving-Capability-Values">Retrieving Capability Values</a></H3><PRE>
+ <STRONG>tgetflag</STRONG> reports the Boolean entry for <EM>id</EM>, or zero 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>
- parameter is used as follows:
+ <STRONG>tgetnum</STRONG> obtains the numeric entry for <EM>id</EM>, or -1 if it is not available.
+
+ <STRONG>tgetstr</STRONG> returns the string entry for <EM>id</EM>, or <STRONG>NULL</STRONG> if it is not
+ available. Use <STRONG>tputs</STRONG> to output the string returned. The <EM>area</EM>
+ parameter 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
- also that the resulting buffer pointer is not NULL. If either
- check fails, the <EM>area</EM> parameter is ignored.
+ <STRONG>o</STRONG> However, <EM>ncurses</EM> checks to ensure that <EM>area</EM> is not <STRONG>NULL</STRONG>, and
+ also that the resulting buffer pointer is not <STRONG>NULL</STRONG>. If either
+ check fails, <EM>area</EM> 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
- updated to point past the null ending this value.
+ <STRONG>o</STRONG> If the checks succeed, <EM>ncurses</EM> also copies the return value to
+ the buffer pointed to by <EM>area</EM>, and the library updates <EM>area</EM> to
+ point past the null character terminating this value.
- <STRONG>o</STRONG> The return value itself is an address in the terminal
- description which is loaded into memory.
+ <STRONG>o</STRONG> The return value itself is an address in the terminal type
+ description 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-Applying-String-Capabilities">Applying String Capabilities</a></H3><PRE>
+ String capabilities can be parameterized; see subsection "Parameterized
+ Strings" in <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>. <STRONG>tgoto</STRONG> applies its second and third arguments
+ to the parametric placeholders in the capability stored in the first
+ argument.
-</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
- function such as <STRONG>printf(3)</STRONG>.
+ <STRONG>o</STRONG> The capability may contain padding specifications; see subsection
+ "Delays and Padding" of <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>. The output of <STRONG>tgoto</STRONG> should
+ thus be passed to <STRONG>tputs</STRONG> rather than some other output function such
+ as <STRONG>printf(3)</STRONG>.
<STRONG>o</STRONG> While <STRONG>tgoto</STRONG> is assumed to be used for the two-parameter cursor
- positioning capability, termcap applications also use it for
+ positioning capability, <EM>termcap</EM> applications also use it for
single-parameter capabilities.
- Doing this shows a quirk in <STRONG>tgoto</STRONG>: most hardware terminals use
+ Doing so reveals a quirk in <STRONG>tgoto</STRONG>: most hardware terminals use
cursor 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.
+ the <EM>termcap</EM> interface chose to put the <EM>col</EM> (column) parameter
+ first. The <STRONG>tgoto</STRONG> function swaps the order of parameters. It does
+ this even 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 an internal version of <STRONG><A HREF="curs_terminfo.3x.html">tparm(3x)</A></STRONG> (a more
- capable formatter).
+ <STRONG>o</STRONG> Normally the <EM>ncurses</EM> library is compiled without full <EM>termcap</EM>
+ support. In that case, <STRONG>tgoto</STRONG> uses an internal version of <STRONG><A HREF="curs_terminfo.3x.html">tparm(3x)</A></STRONG>
+ (a more capable function).
- With terminfo support, <STRONG>tgoto</STRONG> is able to use some of the terminfo
- features, but not all. In particular, it allows only numeric
+ Because it uses <STRONG>tparm</STRONG> internally, <STRONG>tgoto</STRONG> is able to use some <EM>term-</EM>
+ <EM>info</EM> features, but not all. In particular, it allows only numeric
parameters; <STRONG>tparm</STRONG> supports string parameters.
However, <STRONG>tparm</STRONG> is not a <EM>termcap</EM> feature, and portable <EM>termcap</EM>
applications 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.
+ <STRONG>tputs</STRONG> is described in <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>. It can retrieve capabilities
+ by either <EM>termcap</EM> or <EM>terminfo</EM> 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
+ The variables <STRONG>PC</STRONG>, <STRONG>UP</STRONG> and <STRONG>BC</STRONG> are set by <STRONG>tgetent</STRONG> to the <EM>terminfo</EM> 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.
+ is not used by <EM>ncurses</EM>. <STRONG>PC</STRONG> is used by <STRONG><A HREF="curs_util.3x.html">delay_output(3x)</A></STRONG>. <STRONG>BC</STRONG> is used by
+ <STRONG>tgoto</STRONG> emulation. The variable <STRONG>ospeed</STRONG> is set by <EM>ncurses</EM> using a system-
+ specific encoding to indicate the terminal's data rate.
</PRE><H3><a name="h3-Releasing-Memory">Releasing Memory</a></H3><PRE>
- The termcap functions provide no means for freeing memory, because
- legacy termcap implementations used only the buffer areas provided by
- the caller via <STRONG>tgetent</STRONG> and <STRONG>tgetstr</STRONG>. Those buffers are unused in
- terminfo.
+ The <EM>termcap</EM> functions provide no means of freeing memory, because
+ legacy <EM>termcap</EM> implementations used only the buffer areas provided by
+ the caller via <STRONG>tgetent</STRONG> and <STRONG>tgetstr</STRONG>. Those buffers are unused in <EM>term-</EM>
+ <EM>info</EM>.
+
+ By contrast, <EM>terminfo</EM> allocates memory. It uses <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG> to
+ obtain the data used by <STRONG>tgetent</STRONG> and the functions that retrieve
+ capability values. One could use
+ del_curterm(cur_term);
+ to free this memory, but there is an additional complication with
+ <EM>ncurses</EM>. It uses a fixed-size pool of storage locations, one per value
+ of the <EM>TERM</EM> environment variable when <STRONG>tgetent</STRONG> is called. The <STRONG>screen(1)</STRONG>
+ program relies upon this arrangement to improve its performance.
- On the other hand, terminfo allocates memory. It uses <STRONG>setupterm</STRONG> to
- retrieve the data used by <STRONG>tgetent</STRONG> and the functions which return
- capability values such as <STRONG>tgetstr</STRONG>. One could use
+ An application that uses only the <EM>termcap</EM> functions, not the higher
+ level <EM>curses</EM> API, could release the memory using <STRONG><A HREF="curs_terminfo.3x.html">del_curterm(3x)</A></STRONG>,
+ because the pool is freed using other functions; see <STRONG><A HREF="curs_memleaks.3x.html">curs_memleaks(3x)</A></STRONG>.
- <STRONG>del_curterm(cur_term);</STRONG>
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ The return values of <STRONG>tgetent</STRONG>, <STRONG>tgetflag</STRONG>, <STRONG>tgetname</STRONG>, and <STRONG>tgetstr</STRONG> are
+ documented above.
- to free this memory, but there is an additional complication with
- ncurses. It uses a fixed-size <EM>pool</EM> of storage locations, one per
- setting of the <EM>TERM</EM> variable when <STRONG>tgetent</STRONG> is called. The <STRONG>screen(1)</STRONG>
- program relies upon this arrangement, to improve its performance.
+ <STRONG>tgoto</STRONG> returns <STRONG>NULL</STRONG> on error. Error conditions include:
- An application which uses only the low-level termcap functions could
- free the memory using <STRONG>del_curterm</STRONG>, because the pool is freed using
- other functions (see <STRONG><A HREF="curs_memleaks.3x.html">curs_memleaks(3x)</A></STRONG>).
+ <STRONG>o</STRONG> uninitialized state (<STRONG>tgetent</STRONG> was not called successfully),
+ <STRONG>o</STRONG> <EM>cap</EM> being a null pointer,
-</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.
+ <STRONG>o</STRONG> <EM>cap</EM> referring to a canceled capability,
- Routines that return pointers return <STRONG>NULL</STRONG> on error.
+ <STRONG>o</STRONG> <EM>cap</EM> being a capability with string-valued parameters (a <EM>term-</EM>
+ <EM>info</EM>-only feature), and
- A few special cases apply:
+ <STRONG>o</STRONG> <EM>cap</EM> being a capability with more than two parameters.
- <STRONG>o</STRONG> If the terminal database has not been initialized, these return an
- error.
+ See <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG> regarding <STRONG>tputs</STRONG>.
- <STRONG>o</STRONG> The calls with a string parameter (<STRONG>tgoto</STRONG>, <STRONG>tputs</STRONG>) check if the
- string is null, or cancelled. Those return an error.
- <STRONG>o</STRONG> A call to <STRONG>tgoto</STRONG> using a capability with string parameters is an
- error.
-
- <STRONG>o</STRONG> A call to <STRONG>tgoto</STRONG> using a capability with more than two parameters is
- an error.
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ <EM>ncurses</EM> compares only the first two characters of the <EM>id</EM> parameter of
+ <STRONG>tgetflag</STRONG>, <STRONG>tgetnum</STRONG>, and <STRONG>tgetstr</STRONG> to the capability names in the database.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ These functions are no longer standardized (and the variables never
+ were); <EM>ncurses</EM> provides them to support legacy applications. They
+ should not be used in new programs.
-</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.
- However, they are marked TO BE WITHDRAWN and may be removed in
- future versions.
+</PRE><H3><a name="h3-Standards">Standards</a></H3><PRE>
+ <STRONG>o</STRONG> X/Open Curses, Issue 4, Version 2 (1996), describes these
+ functions. However, they are marked "TO BE WITHDRAWN".
- <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.
+ <STRONG>o</STRONG> X/Open Curses, Issue 7 (2009) marked the <EM>termcap</EM> 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
- returned 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>
+ Neither X/Open Curses nor the SVr4 man pages documented the return
+ values of <STRONG>tgetent</STRONG> correctly, though all three were in fact returned
+ ever since SVr1. In particular, an omission in the X/Open Curses
+ specification 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
- compatibility 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
- applications. However, termcap applications' use of those variables is
- poorly documented, e.g., not distinguishing between input and output.
- In particular, some applications are reported to declare and/or modify
- <STRONG>ospeed</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
- issues:
-
- <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
- description. You should not rely upon this behavior in portable
- programs. This implementation disallows matches against single-
- character capability names.
-
- <STRONG>o</STRONG> This implementation disallows matches by the termcap interface
- against extended capability names which are longer than two
- characters.
-
- 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
+ compatibility with the <EM>termcap</EM> library, that is a defect in X/Open
+ Curses, Issue 4, Version 2 rather than in <EM>ncurses</EM>.
+
+ <STRONG>Compatibility</STRONG> <STRONG>with</STRONG> <STRONG>BSD</STRONG> <EM>termcap</EM>
+ Externally visible variables are provided for support of certain
+ <EM>termcap</EM> applications. However, their correct usage is poorly
+ documented; for example, it is unclear when reading and writing them is
+ meaningful. In particular, some applications are reported to declare
+ and/or modify <STRONG>ospeed</STRONG>.
+
+ The constraint that only the first two characters of the <EM>id</EM> parameter
+ are used escapes many application developers. The BSD <EM>termcap</EM> library
+ did not require a trailing null character on the capability identifier
+ passed to <STRONG>tgetstr</STRONG>, <STRONG>tgetnum</STRONG>, and <STRONG>tgetflag</STRONG>. Some applications thus
+ assume that the <EM>termcap</EM> interface does not require the trailing null
+ character for the capability identifier.
+
+ <STRONG>o</STRONG> <EM>ncurses</EM> disallows matches by the <EM>termcap</EM> interface against extended
+ capability names that are longer than two characters; see
+ <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>.
+
+ The BSD <EM>termcap</EM> function <STRONG>tgetent</STRONG> returns the text of a <EM>termcap</EM> entry in
+ the buffer passed as an argument. This library, like other <EM>terminfo</EM>
+ implementations, does not store terminal type descriptions as text. It
+ sets the buffer contents to a null-terminated string.
+
+
+</PRE><H3><a name="h3-Header-File">Header File</a></H3><PRE>
+ This library includes a <EM>termcap.h</EM> header for compatibility with other
+ implementations, but the header is rarely used because the other
implementations 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 <STRONG>jove</STRONG> editor in 2BSD through 4.4BSD.
- It defined global symbols for the termcap variables which it used.
+</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
+ Bill Joy originated a forerunner of <EM>termcap</EM> called "ttycap", dated
+ September 1977, and released in 1BSD (March 1978). It used many of the
+ same function names as the later <EM>termcap</EM>, such as <STRONG>tgetent</STRONG>, <STRONG>tgetflag</STRONG>,
+ <STRONG>tgetnum</STRONG>, and <STRONG>tgetstr</STRONG>.
+
+ A clear descendant, the <EM>termlib</EM> library, followed in 2BSD (May 1979),
+ adding <STRONG>tgoto</STRONG> and <STRONG>tputs</STRONG>. The former applied at that time only to cursor
+ positioning capabilities, thus the overly specific name. Little
+ changed in 3BSD (late 1979) except the addition of test programs and a
+ <EM>termlib</EM> man page, which documented the API shown in section "SYNOPSIS"
+ above.
+
+ 4BSD (November 1980) renamed <EM>termlib</EM> to <EM>termcap</EM> and added another test
+ program. The library remained much the same though 4.3BSD (June 1986).
+ 4.4BSD-Lite (June 1994) refactored it but left the API unchanged.
+
+ Function prototypes were a feature of the forthcoming ANSI C (1989).
+ Thus the library provided no header file declaring them. Nevertheless,
+ the BSD sources included two different <EM>termcap.h</EM> header files over
+ time.
- <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
- history shows that this was added in mid-1992. The <EM>libedit</EM> header
- file was used internally, as a convenience for compiling the
- <EM>editline</EM> library. It declared function prototypes, but no global
- variables.
+ <STRONG>o</STRONG> One was used internally by <STRONG>jove(1)</STRONG> from 4.3BSD onward. It delcared
+ global symbols for the <EM>termcap</EM> variables that it used.
- The header file from <EM>libedit</EM> was added to NetBSD's termcap library in
- mid-1994.
+ <STRONG>o</STRONG> The other appeared in 4.4BSD-Lite Release 2 (June 1995) as part of
+ <EM>libedit</EM> (also known as the <EM>editline</EM> library). CSRG source history
+ shows that this was added in mid-1992. The <EM>libedit</EM> header file was
+ used internally as a convenience for compiling the <EM>editline</EM>
+ library. It declared function prototypes, but no global variables.
+ This header file was added to NetBSD's <EM>termcap</EM> 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
- expect 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.
+ Meanwhile, GNU <EM>termcap</EM> began development in 1990. Its first release
+ (1.0) in 1991 included a <EM>termcap.h</EM> header. Its second (1.1) in
+ September 1992 modified the header to use <EM>const</EM> for the function
+ prototypes in the header where one would expect the parameters to be
+ read-only. BSD <EM>termcap</EM> did not. The prototype for <STRONG>tputs</STRONG> also
+ differed, but in that instance, it was <EM>libedit</EM> that differed from BSD
+ <EM>termcap</EM>.
- A copy of GNU termcap 1.3 was bundled with <EM>bash</EM> in mid-1993, to support
- the <STRONG>readline(3)</STRONG> library.
+ GNU <EM>termcap</EM> 1.3 was bundled with <EM>bash</EM> in mid-1993 to support the
+ <STRONG>readline(3)</STRONG> library.
- A termcap.h file was provided in ncurses 1.8.1 (November 1993). That
- reflected influence by <STRONG>emacs(1)</STRONG> (rather than <STRONG>jove(1)</STRONG>) and GNU termcap:
+ <EM>ncurses</EM> 1.8.1 (November 1993) provided a <EM>termcap.h</EM> file. It reflected
+ influence from GNU <EM>termcap</EM> and <STRONG>emacs(1)</STRONG> (rather than <STRONG>jove(1)</STRONG>),
+ providing the following interface:
- <STRONG>o</STRONG> it provided declarations for a few global symbols used by <STRONG>emacs</STRONG>
+ <STRONG>o</STRONG> global symbols used by <EM>emacs</EM>,
- <STRONG>o</STRONG> it provided function prototypes (using <STRONG>const</STRONG>).
+ <STRONG>o</STRONG> <EM>const</EM>-qualified function prototypes, and
- <STRONG>o</STRONG> a prototype for <STRONG>tparam</STRONG> (a GNU termcap feature) was provided.
+ <STRONG>o</STRONG> a prototype for <STRONG>tparam</STRONG>, a GNU <EM>termcap</EM> feature.
- 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.
+ Later (in mid-1996) the <STRONG>tparam</STRONG> function was removed from <EM>ncurses</EM>. Any
+ two of the four implementations thus differ, and programs that intend
+ to work with all <EM>termcap</EM> library interfaces must account for that fact.
</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
- capability, be aware that it is returned in <EM>terminfo</EM> notation, not the
- older and not-quite-compatible <EM>termcap</EM> notation. This does not cause
- problems if all you do with it is call <STRONG>tgoto</STRONG> or <STRONG>tparm</STRONG>, which both
- expand <EM>terminfo</EM>-style strings as <EM>terminfo</EM> does. (The <STRONG>tgoto</STRONG> function,
- if configured to support <EM>termcap,</EM> checks if the string is indeed
- <EM>terminfo</EM>-style by looking for "<STRONG>%p</STRONG>" parameters or "<STRONG><</STRONG>...<STRONG>></STRONG>" delays, and
- invokes a <EM>termcap</EM>-style parser if the string appears not to use
- <EM>terminfo</EM> syntax.)
-
- Because <EM>terminfo</EM>'s syntax for padding in string capabilities differs
+ If you call <STRONG>tgetstr</STRONG> to fetch <STRONG>ca</STRONG> or any other parameterized string
+ capability, be aware that it is returned in <EM>terminfo</EM> notation, not the
+ older and not-quite-compatible <EM>termcap</EM> notation. This does not cause
+ problems if all you do with it is call <STRONG>tgoto</STRONG> or <STRONG>tparm</STRONG>, which both
+ expand <EM>terminfo</EM>-style strings as <EM>terminfo</EM> does. (If <EM>ncurses</EM> is
+ configured to support <EM>termcap,</EM> <STRONG>tgoto</STRONG> checks whether the string is <EM>term-</EM>
+ <EM>info</EM>-style by looking for "<STRONG>%p</STRONG>" parameters or "<STRONG><</STRONG>...<STRONG>></STRONG>" delays, and
+ invokes a <EM>termcap</EM>-style parser if the string appears not to use <EM>term-</EM>
+ <EM>info</EM> syntax.)
+
+ Because <EM>terminfo</EM>'s syntax for padding in string capabilities differs
from <EM>termcap</EM>'s, users can be surprised.
- <STRONG>o</STRONG> <STRONG>tputs("50")</STRONG> in a <EM>terminfo</EM> system transmits "50" rather than busy-
+ <STRONG>o</STRONG> <STRONG>tputs("50")</STRONG> in a <EM>terminfo</EM> system transmits "50" rather than busy-
waiting for 50 milliseconds.
- <STRONG>o</STRONG> However, if <EM>ncurses</EM> is configured to support <EM>termcap</EM>, it may also
+ <STRONG>o</STRONG> However, if <EM>ncurses</EM> is configured to support <EM>termcap</EM>, it may also
have been configured to support BSD-style padding.
- In that case, <STRONG>tputs</STRONG> inspects strings passed to it, looking for
+ In that case, <STRONG>tputs</STRONG> inspects strings passed to it, looking for
digits at the beginning of the string.
- <STRONG>tputs("50")</STRONG> in a <EM>termcap</EM> system may busy-wait for 50 milliseconds
+ <STRONG>tputs("50")</STRONG> in a <EM>termcap</EM> system may busy-wait for 50 milliseconds
rather than transmitting "50".
- <EM>termcap</EM> has nothing analogous to <EM>terminfo</EM>'s <STRONG>sgr</STRONG> string. One
- consequence is that <EM>termcap</EM> applications assume that <STRONG>me</STRONG> (equivalent to
- <EM>terminfo</EM>'s <STRONG>sgr0</STRONG> capability) does not reset the alternate character set.
- <EM>ncurses</EM> checks for, and modifies the data shared with, the <EM>termcap</EM>
- interface to accommodate the latter's limitation in this respect.
+ <EM>termcap</EM> has nothing analogous to <EM>terminfo</EM>'s <STRONG>sgr</STRONG> string. One
+ consequence is that <EM>termcap</EM> applications assume that "<STRONG>me</STRONG>" (equivalent
+ to <EM>terminfo</EM>'s <STRONG>sgr0</STRONG> capability) does not reset the alternate character
+ set. <EM>ncurses</EM> checks for, and modifies the data shared with, the
+ <EM>termcap</EM> interface to accommodate the latter's limitation in this
+ respect.
</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>
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG>
<A HREF="curs_terminfo.3x.html">curs_terminfo(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
-ncurses 6.4 2023-12-
02 <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
+ncurses 6.4 2023-12-
17 <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<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-Retrieving-Capability-Values">Retrieving Capability Values</a></li>
+<li><a href="#h3-Applying-String-Capabilities">Applying String Capabilities</a></li>
<li><a href="#h3-Global-Variables">Global Variables</a></li>
<li><a href="#h3-Releasing-Memory">Releasing Memory</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
+<li><a href="#h2-NOTES">NOTES</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>
+<li><a href="#h3-Header-File">Header File</a></li>
</ul>
</li>
+<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-BUGS">BUGS</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
projects / ncurses.git / blobdiff