X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Ftabs.1.html;h=63e453ee34e199d3f9f7ca48c00adc0a54d9715c;hb=42259b594b5dabd37fe2bc294051d2db82e873a2;hp=eef270d8ce7246fe42a2a26ed1c91427ba81f6ce;hpb=02c4e383be9337e73a0e75844dfd1047745adb28;p=ncurses.git diff --git a/doc/html/man/tabs.1.html b/doc/html/man/tabs.1.html index eef270d8..63e453ee 100644 --- a/doc/html/man/tabs.1.html +++ b/doc/html/man/tabs.1.html @@ -1,6 +1,7 @@ @@ -34,7 +35,7 @@
@@ -141,30 +154,59 @@
- IEEE Std 1003.1/The Open Group Base Specifications Issue 7 + IEEE Std 1003.1/The Open Group Base Specifications Issue 7 (POSIX.1-2008) describes a tabs utility. However o This standard describes a +m option, to set a terminal's left-mar- - gin. Very few of the entries in the terminal database provide this - capability. + gin. Very few of the entries in the terminal database provide the + smgl (set_left_margin) or smglp (set_left_margin_parm) capability + needed to support the feature. - o There is no counterpart in X/Open Curses Issue 7 for this utility, + o There is no counterpart in X/Open Curses Issue 7 for this utility, unlike tput(1). - The -d (debug) and -n (no-op) options are extensions not provided by + The -d (debug) and -n (no-op) options are extensions not provided by other implementations. - Documentation for other implementations states that there is a limit on - the number of tab stops. While some terminals may not accept an arbi- - trary 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. + A tabs utility appeared in PWB/Unix 1.0 (1977). There was a reduced + version of the tabs utility in Unix 7th edition and in 3BSD (1979). + The latter supported a single "-n" option (to cause the first tab stop + to be set on the left margin). That option is not documented by POSIX. + + The PWB/Unix tabs 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. + + Later versions of Unix, e.g., SVr4, added support for the terminal + database, but kept the tables, as a fallback. In an earlier develop- + ment effort, the tab-stop initialization provided by tset (1982) and + incorporated into tput uses the terminal database, + + 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 tabs 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 Rationale section of the POSIX documentation goes into some detail + about the ways the committee considered redesigning the tabs and tput + utilities, without proposing an improved solution. It comments that + + no known historical version of tabs supports the capability of + setting arbitrary tab stops. + + However, the Explicit Lists described in this manual page were imple- + mented in PWB/Unix. Those provide the capability of setting abitrary + tab stops.
tset(1), infocmp(1m), curses(3x), terminfo(5). - This describes ncurses version 6.1 (patch 20180407). + This describes ncurses version 6.2 (patch 20201205).