ncurses 6.0 - patch 20161029

[ncurses.git] / man / curs_termcap.3x

diff --git a/man/curs_termcap.3x b/man/curs_termcap.3x
index f8977bebca9c9c49abf6d346392de98acbff11b2..9b21505603b968b74af2ea357cd98d4129a06a9e 100644 (file)
--- a/man/curs_termcap.3x
+++ b/man/curs_termcap.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
 .\"***************************************************************************

-.\" Copyright (c) 1998-2012,2013 Free Software Foundation, Inc.              *
+.\" Copyright (c) 1998-2015,2016 Free Software Foundation, Inc.              *

 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *


@@ -26,7 +26,7 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"

-.\" $Id: curs_termcap.3x,v 1.30 2013/01/19 15:58:48 tom Exp $
+.\" $Id: curs_termcap.3x,v 1.32 2016/03/19 22:52:25 tom Exp $

 .TH curs_termcap 3X ""
 .de bP
 .IP \(bu 4
 .TH curs_termcap 3X ""
 .de bP
 .IP \(bu 4


@@ -121,9 +121,24 @@ or \-1 if it is not available.
 The \fBtgetstr\fR routine returns the string entry for \fIid\fR,
 or zero if it is not available.
 Use \fBtputs\fR to output the returned string.
 The \fBtgetstr\fR routine returns the string entry for \fIid\fR,
 or zero if it is not available.
 Use \fBtputs\fR to output the returned string.

-The return value will also be copied to the buffer pointed to by \fIarea\fR,
+The \fIarea\fP parameter is used as follows:
+.RS 3
+.bP
+It is assumed to be the address of a pointer to a buffer managed by the
+calling application.
+.bP
+However, ncurses checks to ensure that \fBarea\fP is not NULL,
+and also that the resulting buffer pointer is not NULL.
+If either check fails, the \fIarea\fP parameter is ignored.
+.bP
+If the checks succeed, ncurses also copies the return value to
+the buffer pointed to by \fIarea\fR,

 and the \fIarea\fR value will be updated to point past the null ending
 this value.
 and the \fIarea\fR value will be updated to point past the null ending
 this value.

+.bP
+The return value itself is an address in the terminal description which
+is loaded into memory.
+.RE

 .PP
 Only the first two characters of the \fBid\fR parameter of
 \fBtgetflag\fR,
 .PP
 Only the first two characters of the \fBid\fR parameter of
 \fBtgetflag\fR,


@@ -131,8 +146,26 @@ Only the first two characters of the \fBid\fR parameter of
 \fBtgetstr\fR are compared in lookups.
 .SS FORMATTING CAPABILITIES
 .PP
 \fBtgetstr\fR are compared in lookups.
 .SS FORMATTING CAPABILITIES
 .PP

-The \fBtgoto\fR routine instantiates the parameters into the given capability.
-The output from this routine is to be passed to \fBtputs\fR.
+The \fBtgoto\fR routine expands the given capability using the parameters.
+.bP
+Because the capability may have padding characters,
+the output of \fBtgoto\fP should be passed to \fBtputs\fR
+rather than some other output function such as \fBprintf\fP.
+.bP
+While \fBtgoto\fP is assumed to be used for the two-parameter
+cursor positioning capability,
+termcap applications also use it for single-parameter capabilities.
+.IP
+Doing this shows a quirk in \fBtgoto\fP: most hardware
+terminals use cursor addressing with \fIrow\fP first,
+but the original developers of the termcap interface chose to
+put the \fIcolumn\fP parameter first.
+The \fBtgoto\fP 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.
+.bP
+Normally the ncurses library is compiled with terminfo support.
+In that case, \fBtgoto\fP uses \fBtparm\fP (a more capable formatter).

 .PP
 The \fBtputs\fR routine is described on the \fBcurs_terminfo\fR(3X) manual
 page.  It can retrieve capabilities by either termcap or terminfo name.
 .PP
 The \fBtputs\fR routine is described on the \fBcurs_terminfo\fR(3X) manual
 page.  It can retrieve capabilities by either termcap or terminfo name.