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- * @Id: curs_termcap.3x,v 1.30 2013/01/19 15:58:48 tom Exp @
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-<H1>curs_termcap 3x</H1>
-<HR>
+<H1 class="no-header">curs_termcap 3x 2024-03-16 ncurses 6.4 Library calls</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>
+<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>
-</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> - direct <STRONG>curses</STRONG> interface to the terminfo
- capability database
+</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> -
+ <EM>curses</EM> emulation of <EM>termcap</EM>
-</PRE>
-<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+</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>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>*bp,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*name);</STRONG>
- <STRONG>int</STRONG> <STRONG>tgetflag(char</STRONG> <STRONG>*id);</STRONG>
- <STRONG>int</STRONG> <STRONG>tgetnum(char</STRONG> <STRONG>*id);</STRONG>
- <STRONG>char</STRONG> <STRONG>*tgetstr(char</STRONG> <STRONG>*id,</STRONG> <STRONG>char</STRONG> <STRONG>**area);</STRONG>
- <STRONG>char</STRONG> <STRONG>*tgoto(const</STRONG> <STRONG>char</STRONG> <STRONG>*cap,</STRONG> <STRONG>int</STRONG> <STRONG>col,</STRONG> <STRONG>int</STRONG> <STRONG>row);</STRONG>
- <STRONG>int</STRONG> <STRONG>tputs(const</STRONG> <STRONG>char</STRONG> <STRONG>*str,</STRONG> <STRONG>int</STRONG> <STRONG>affcnt,</STRONG> <STRONG>int</STRONG> <STRONG>(*putc)(int));</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 pro-
- grams that use the <EM>termcap</EM> library. Their parameters are
- the same and the routines are emulated using the <EM>terminfo</EM>
- database. Thus, they can only be used to query the capa-
- bilities of entries for which a terminfo entry has been
- compiled.
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+ <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:
+</PRE><H3><a name="h3-Initialization">Initialization</a></H3><PRE>
+ <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 ap-
- plications 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
+ includes the <STRONG>generic</STRONG> (<STRONG>gn</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 ze-
- ro if it is not available.
+</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>tgetnum</STRONG> routine gets the numeric entry for <EM>id</EM>, or -1
- if it is not available.
+ <STRONG>tgetnum</STRONG> obtains 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 re-
- turned string. The return value will also be copied 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>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.
- Only the first two characters of the <STRONG>id</STRONG> parameter of <STRONG>tget-</STRONG>
- <STRONG>flag</STRONG>, <STRONG>tgetnum</STRONG> and <STRONG>tgetstr</STRONG> are compared in lookups.
+ <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, <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.
-</PRE>
-<H3><a name="h3-FORMATTING-CAPABILITIES">FORMATTING CAPABILITIES</a></H3><PRE>
- The <STRONG>tgoto</STRONG> routine instantiates the parameters into the
- given capability. The output from this routine is to be
- passed to <STRONG>tputs</STRONG>.
+ <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.
- 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 term-
- cap or terminfo name.
+ <STRONG>o</STRONG> The return value itself is an address in the terminal type
+ description loaded into memory.
-</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 ter-
- minfo 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 ter-
- minal speed.
+</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.
+ <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>.
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- Except where explicitly noted, routines that return an in-
- teger return <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 only specifies
- "an integer value other than <STRONG>ERR</STRONG>") upon successful comple-
- tion.
+ <STRONG>o</STRONG> While <STRONG>tgoto</STRONG> is assumed to be used for the two-parameter cursor
+ positioning capability, <EM>termcap</EM> applications also use it for
+ single-parameter capabilities.
- Routines that return pointers return <STRONG>NULL</STRONG> on error.
+ 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 <EM>termcap</EM> interface chose to put the <EM>col</EM> (column) parameter
+ first. The <STRONG>tgoto</STRONG> function swaps the order of its 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 <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).
-</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 no-
- tation, not the older and not-quite-compatible termcap no-
- tation. 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 con-
- figured to support 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 capabilities differ from termcap's, <STRONG>tputs("50");</STRONG>
- will put out a literal "50" rather than busy-waiting for
- 50 milliseconds. Cope with it.
-
- Note that termcap has nothing analogous to terminfo's <STRONG>sgr</STRONG>
- string. One consequence of this is that termcap applica-
- tions assume me (terminfo <STRONG>sgr0</STRONG>) does not reset the alter-
- nate character set. This implementation checks for, and
- modifies the data shown to the termcap interface to accom-
- modate termcap's limitation in this respect.
+ 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.
-</PRE>
-<H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- The XSI Curses standard, Issue 4 describes these func-
- tions. However, they are marked TO BE WITHDRAWN and may
- be removed in future versions.
-
- 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 par-
- ticular, 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
- compatibility with the <EM>termcap</EM> library, that is a defect
- in XCurses, Issue 4, Version 2 rather than in ncurses.
-
- External variables are provided for support of certain
- termcap applications. However, termcap applications' use
- of those variables is poorly documented, e.g., not distin-
- guishing 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. Tak-
- ing 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 implementa-
- tion disallows matches against single-character capa-
- bility names.
-
- <STRONG>o</STRONG> This implementation disallows matches by the termcap
- interface against extended capability names which are
- longer than two characters.
+ <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> code.
-</PRE>
-<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>, <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>.
+</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 <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 <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 <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 terminal name parameter given to <STRONG>tgetent</STRONG>. The <STRONG>screen(1)</STRONG> program
+ relies upon this arrangement to improve its performance.
+
+ 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>.
+
+
+</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.
+
+ <STRONG>tgoto</STRONG> returns <STRONG>NULL</STRONG> on error. Error conditions include:
+
+ <STRONG>o</STRONG> uninitialized state (<STRONG>tgetent</STRONG> was not called successfully),
+
+ <STRONG>o</STRONG> <EM>cap</EM> being a null pointer,
+
+ <STRONG>o</STRONG> <EM>cap</EM> referring to a canceled capability,
+
+ <STRONG>o</STRONG> <EM>cap</EM> being a capability with string-valued parameters (a <EM>term-</EM>
+ <EM>info</EM>-only feature), and
+
+ <STRONG>o</STRONG> <EM>cap</EM> being a capability with more than two parameters.
+
+ See <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG> regarding <STRONG>tputs</STRONG>.
+
+
+</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>
+ <STRONG>o</STRONG> X/Open Curses, Issue 4, Version 2 (1996), describes these
+ functions, marking them as "TO BE WITHDRAWN".
+
+ <STRONG>o</STRONG> X/Open Curses, Issue 7 (2009) marks the <EM>termcap</EM> interface (along
+ with <STRONG>vwprintw</STRONG> and <STRONG>vwscanw</STRONG>) as withdrawn.
+
+ Neither X/Open Curses nor the SVr4 man pages documented the return
+ values of <STRONG>tgetent</STRONG> correctly, though all three shown here 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
+ X/Open Curses, Issue 4, Version 2 rather than in <EM>ncurses</EM>.
- http://invisible-island.net/ncurses/tctest.html
+ <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>.
- <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</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.
+
+
+</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, leaving the API unchanged.
+
+ Function prototypes were a feature of ANSI C (1989). The library long
+ antedated the standard and thus provided no header file declaring them.
+ Nevertheless, the BSD sources included two different <EM>termcap.h</EM> header
+ files over time.
+
+ <STRONG>o</STRONG> One was used internally by <STRONG>jove(1)</STRONG> from 4.3BSD onward. It declared
+ global symbols for the <EM>termcap</EM> variables that it used.
+
+ <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 <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>.
+
+ GNU <EM>termcap</EM> 1.3 was bundled with <STRONG>bash(1)</STRONG> in mid-1993 to support the
+ <STRONG>readline(3)</STRONG> library.
+
+ <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> global symbols used by <EM>emacs</EM>,
+
+ <STRONG>o</STRONG> <EM>const</EM>-qualified function prototypes, and
+
+ <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 <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>column_address</STRONG> (<STRONG>ch</STRONG>) or any other
+ parameterized string capability, be aware that it is returned in <EM>term-</EM>
+ <EM>info</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>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
+ 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-
+ waiting for 50 milliseconds.
+
+ <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
+ digits at the beginning of the string.
+
+ <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>set_attributes</STRONG> (<STRONG>sgr</STRONG>)
+ capability. One consequence is that <EM>termcap</EM> applications assume that
+ "<STRONG>me</STRONG>" (equivalent to <EM>terminfo</EM>'s <STRONG>exit_attribute_mode</STRONG> (<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><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 2024-03-16 <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<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>
+<li><a href="#h3-Initialization">Initialization</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-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-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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