X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Ftabs.1.html;h=b921bf8570da9e2aabe4da1b60b83da7bc99b99b;hp=073235edc3abc5c791b3bb30ce1ae1b176707d67;hb=51a395aaa20e4aa687310bb8cb1616ccf8e8fd0d;hpb=cd142df6d9934f1bda19f5b968cc666291be5072 diff --git a/doc/html/man/tabs.1.html b/doc/html/man/tabs.1.html index 073235ed..b921bf85 100644 --- a/doc/html/man/tabs.1.html +++ b/doc/html/man/tabs.1.html @@ -1,6 +1,6 @@ - + tabs 1 - +

tabs 1

-tabs(1)                                                                tabs(1)
+tabs(1)                     General Commands Manual                    tabs(1)
 
 
 
@@ -59,13 +59,25 @@
        absent,  tabs is unable to clear/set tab-stops.  The terminal should be
        configured to use hard tabs, e.g.,
 
-         stty tab0
+           stty tab0
 
        Like clear(1), tabs writes to the standard output.   You  can  redirect
        the standard output to a file (which prevents tabs from actually chang-
        ing the tabstops), and later cat the file to the screen,  setting  tab-
        stops at that point.
 
+       These  are  hardware  tabs, which cannot be queried rapidly by applica-
+       tions running in the terminal, if at all.  Curses and other full-screen
+       applications  may  use  hardware tabs in optimizing their output to the
+       terminal.  If the hardware tabstops differ from the information in  the
+       terminal  database, the result is unpredictable.  Before running curses
+       programs, you should either reset tab-stops to the standard interval
+
+           tabs -8
+
+       or use the reset program, since the normal initialization sequences  do
+       not ensure that tab-stops are reset.
+

OPTIONS

 
@@ -107,13 +119,13 @@
        greater than zero.  They are separated by a comma or a blank, for exam-
        ple,
 
-         tabs 1,6,11,16,21
-         tabs 1 6 11 16 21
+           tabs 1,6,11,16,21
+           tabs 1 6 11 16 21
 
        Use  a  "+"  to treat a number as an increment relative to the previous
        value, e.g.,
 
-         tabs 1,+5,+5,+5,+5
+           tabs 1,+5,+5,+5,+5
 
        which is equivalent to the 1,6,11,16,21 example.
 
@@ -141,30 +153,55 @@

PORTABILITY

-       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), and thereafter in  3BSD
+       (1979).  It 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.
+       Initially, tabs 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 set-
+       tings 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.  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.

SEE ALSO

        tset(1), infocmp(1m), curses(3x), terminfo(5).
 
-       This describes ncurses version 6.0 (patch 20171007).
+       This describes ncurses version 6.1 (patch 20190615).