* sale, use or other dealings in this Software without prior written *
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****************************************************************************
- * @Id: tabs.1,v 1.30 2021/10/09 23:48:50 tom Exp @
+ * @Id: tabs.1,v 1.32 2021/10/16 13:37:43 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
The PWB/Unix <STRONG>tabs</STRONG> utility, which was included in System III (1980),
used built-in tables rather than the terminal database, to support a
- half-dozen terminal types. It also had built-in logic to support the
- left-margin, as well as a feature for copying the tab settings from a
- file.
+ half-dozen hardcopy terminal (printer) types. It also had built-in
+ logic to support the left-margin, as well as a feature for copying the
+ tab settings from a file.
Later versions of Unix, e.g., SVr4, added support for the terminal
- database, but kept the tables, as a fallback. In an earlier
+ database, but kept the tables to support the printers. In an earlier
development effort, the tab-stop initialization provided by <STRONG>tset</STRONG> (1982)
and incorporated into <STRONG>tput</STRONG> uses the terminal database,
- POSIX documents no limits on the number of tab stops. Documentation
+ The <STRONG>+m</STRONG> option was documented in the Base Specifications Issue 5
+ (Unix98, 1997), and omitted in Issue 6 (Unix03, 2004) without
+ documenting the rationale, though an introductory comment <EM>"and</EM>
+ <EM>optionally</EM> <EM>adjusts</EM> <EM>the</EM> <EM>margin"</EM> remains, overlooked in the removal. The
+ documented <STRONG>tabs</STRONG> utility in Issues 6 and later has no mechanism for
+ setting margins. The <STRONG>+m</STRONG> option in this implementation differs from the
+ feature in SVr4 by using terminal capabilities rather than built-in
+ tables.
+
+ POSIX documents no limits on the number of tab stops. Documentation
for other implementations states that there is a limit on the number of
- tab stops (e.g., 20 in PWB/Unix's <STRONG>tabs</STRONG> utility). While some terminals
- may not accept an arbitrary number of tab stops, this implementation
- will attempt to set tab stops up to the right margin of the screen, if
+ tab stops (e.g., 20 in PWB/Unix's <STRONG>tabs</STRONG> utility). While some terminals
+ may not accept an arbitrary number of tab stops, this implementation
+ will attempt to set tab stops up to the right margin of the screen, if
the given list happens to be that long.
- The <EM>Rationale</EM> section of the POSIX documentation goes into some detail
- about the ways the committee considered redesigning the <STRONG>tabs</STRONG> and <STRONG>tput</STRONG>
+ The <EM>Rationale</EM> section of the POSIX documentation goes into some detail
+ about the ways the committee considered redesigning the <STRONG>tabs</STRONG> and <STRONG>tput</STRONG>
utilities, without proposing an improved solution. It comments that
- no known historical version of tabs supports the capability of
+ no known historical version of tabs supports the capability of
setting arbitrary tab stops.
However, the <EM>Explicit</EM> <EM>Lists</EM> described in this manual page were
- implemented in PWB/Unix. Those provide the capability of setting
+ implemented in PWB/Unix. Those provide the capability of setting
abitrary tab stops.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="infocmp.1m.html">infocmp(1m)</A></STRONG>, <STRONG><A HREF="tset.1.html">tset(1)</A></STRONG>, <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>.
- This describes <STRONG>ncurses</STRONG> version 6.2 (patch 20211009).
+ This describes <STRONG>ncurses</STRONG> version 6.2 (patch 20211016).
projects / ncurses.git / blobdiff