X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=man%2Fcurs_termcap.3x;h=2f0eea875838882c71d616d0c0bc67d0e93ec5a7;hp=a3b8bd8c3e041eea621940a73d3a3a3669fd503f;hb=445bfe6a0fb691e3433d586a188be2ebe062384b;hpb=5ae2721913c0d2adde0d65063e37a723bf8a0987

diff --git a/man/curs_termcap.3x b/man/curs_termcap.3x
index a3b8bd8c..2f0eea87 100644
--- a/man/curs_termcap.3x
+++ b/man/curs_termcap.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
-.\" Copyright (c) 1998-2011,2012 Free Software Foundation, Inc.              *
+.\" Copyright (c) 1998-2013,2015 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            *
@@ -26,7 +26,7 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_termcap.3x,v 1.28 2012/11/03 21:56:15 tom Exp $
+.\" $Id: curs_termcap.3x,v 1.31 2015/04/26 00:49:10 tom Exp $
 .TH curs_termcap 3X ""
 .de bP
 .IP \(bu 4
@@ -78,6 +78,7 @@ the \fItermcap\fR library.  Their parameters are the same and the
 routines are emulated using the \fIterminfo\fR database.  Thus, they
 can only be used to query the capabilities of entries for which a
 terminfo entry has been compiled.
+.SS INITIALIZATION
 .PP
 The \fBtgetent\fR routine loads the entry for \fIname\fR.
 It returns:
@@ -109,6 +110,7 @@ The \fItermcap\fP library does not check if the terminal
 description is marked with the \fIgeneric\fP capability,
 or if the terminal description has cursor-addressing.
 .RE
+.SS CAPABILITY VALUES
 .PP
 The \fBtgetflag\fR routine gets the boolean entry for \fIid\fR,
 or zero if it is not available.
@@ -119,20 +121,37 @@ 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 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.
+.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,
 \fBtgetnum\fR and
 \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.
 .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.
+.SS GLOBAL VARIABLES
 .PP
 The variables
 \fBPC\fR,
@@ -194,8 +213,28 @@ However, termcap applications' use of those variables is poorly documented,
 e.g., not distinguishing between input and output.
 In particular, some applications are reported to declare and/or
 modify \fBospeed\fR.
+.PP
+The comment that only the first two characters of the \fBid\fR 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 \fBtgetstr\fP, \fBtgetnum\fP and \fBtgetflag\fP.
+Some applications assume that the termcap interface does not require
+the trailing NUL for the parameter name.
+Taking into account these issues:
+.bP
+As a special case,
+\fBtgetflag\fP 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 implementation disallows matches against single-character capability names.
+.bP
+This implementation disallows matches by the termcap interface against
+extended capability names which are longer than two characters.
 .SH SEE ALSO
 \fBcurses\fR(3X),
 \fBterminfo\fR(\*n),
 \fBterm_variables\fR(3X),
 \fBputc\fR(3).
+.sp
+http://invisible-island.net/ncurses/tctest.html