termcap.3x

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)termcap.3x	8.1	9/11/90
.TH termcap 3x
.SH Name
tgetent, tgetnum, tgetflag, tgetstr, tgoto, tputs \- terminal independent operation routines
.SH Syntax
.nf
.B char PC;
.B char *BC;
.B char *UP;
.B short ospeed;
.PP
.B tgetent(bp, name)
.B char *bp, *name;
.PP
.B tgetnum(id)
.B char *id;
.PP
.B tgetflag(id)
.B char *id;
.PP
.B char *
.B tgetstr(id, area)
.B char *id, **area;
.PP
.B char *
.B tgoto(cm, destcol, destline)
.B char *cm;
.PP
.B tputs(cp, affcnt, outc)
.B register char *cp;
.B int affcnt;
.B int (*outc)();
.fi
.SH Description
.NXR "termcap keyword"
.NXA "tgetent subroutine" "termcap file"
.NXA "tgetent subroutine" "curses package"
.NXR "tgetent subroutine"
.NXR "tgetnum subroutine"
.NXR "tgetflag subroutine"
.NXR "tgetstr subroutine"
.NXR "tgoto subroutine"
.NXR "tputs subroutine"
.NXR "terminal" "independent operation routines"
These functions extract and use capabilities 
from the terminal capability data
base 
.MS termcap 5 .
These are low level routines;
see 
.MS curses 3x
for a higher level package.
.PP
The
.PN tgetent
function extracts the entry for terminal
.I name
into the buffer at
.I bp.
The
.I bp
should be a character buffer of size
1024 and must be retained through all subsequent calls
to
.PN tgetnum ,
.PN tgetflag ,
and
.PN tgetstr .
The
.PN tgetent
function returns \-1 if it cannot open the
.PN termcap
file, 0 if the terminal name given does not have an entry,
and 1 if all goes well.
It will look in the environment for a TERMCAP variable.
If found, and the value does not begin with a slash,
and the terminal type
.B name
is the same as the environment string TERM,
the TERMCAP string is used instead of reading the termcap file.
If it does begin with a slash,
the string is used as a pathname rather than 
.PN /etc/termcap .
This can speed up entry into programs that call
.PN tgetent ,
as well as to help debug new terminal descriptions
or to make one for your terminal if you cannot write the file
.PN /etc/termcap .
.PP
The
.PN tgetnum
function gets the numeric value of capability
.I id,
returning \-1 if is not given for the terminal.
The
.PN tgetflag
returns 1 if the specified capability is present in
the terminal's entry, 0 if it is not.
The
.PN tgetstr
function gets the string value of capability
.I id,
placing it in the buffer at
.I area,
advancing the
.I area
pointer.
It decodes the abbreviations for this field described in
.MS termcap 5 ,
except for cursor addressing and padding information.
.PP
The
.PN tgoto
function returns a cursor addressing string decoded from
.I cm
to go to column
.I destcol
in line
.I destline.
It uses the external variables UP
(from the \fBup\fR capability)
and BC (if \fBbc\fR is given rather than \fBbs\fR)
if necessary to avoid placing \fB\en\fR, \fB^D\fR or \fB^@\fR in
the returned string.
Programs that call 
.PN tgoto 
should be sure to turn off the XTABS bit(s),
because 
.PN tgoto
may now output a tab.
Note that programs using termcap should in general turn off XTABS
anyway, because some terminals use control I for other functions,
such as nondestructive space.
If a \fB%\fR sequence is given that is not understood, then
.PN tgoto
returns \*(lqOOPS\*(rq.
.PP
The
.PN tputs
function decodes the leading padding information of the string
.IR cp ;
.I affcnt
gives the number of lines affected by the operation, or 1 if this is
not applicable,
.I outc
is a routine that is called with each character in turn.
The external variable
.I ospeed
should contain the output speed of the terminal as encoded by
.MS stty 3 .
The external variable PC
should contain a pad character to be used (from the \fBpc\fR capability)
if a null (\fB^@\fR) is inappropriate.
.SH Files
.ta \w'/usr/lib/libtermcap.a  'u
/usr/lib/libtermcap.a	\-ltermcap library
.br
/etc/termcap	data base
.DT
.SH See Also
ex(1), curses(3x), termcap(5)