path: root/lib/libterm/termcap.3

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.\"     @(#)termcap.3	8.2 (Berkeley) 12/11/93
.\"
.Dd December 11, 1993
.Dt TERMCAP 3
.Os BSD 4
.Sh NAME
.Nm tgetent ,
.Nm tgetnum ,
.Nm tgetflag ,
.Nm tgetstr ,
.Nm tgoto ,
.Nm tputs
.Nd terminal independent operation routines
.Sh SYNOPSIS
.Fd #include <term.h>
.Vt char PC;
.Vt char *BC;
.Vt char *UP;
.Vt short ospeed;
.Fn tgetent "char *bp" "char *name"
.Fn tgetnum "char *id"
.Fn tgetflag "char *id"
.Ft char *
.Fn tgetstr "char *id" "char **area"
.Ft char *
.Fn tgoto "char *cm" destcol destline
.Ft void
.Fn tputs "register char *cp" "int affcnt" "int (*outc)()"
.Sh DESCRIPTION
These functions extract and use capabilities from a terminal capability data
base, usually
.Pa /usr/share/misc/termcap ,
the format of which is described in
.Xr termcap 5 .
These are low level routines;
see
.Xr curses 3
for a higher level package.
.Pp
The
.Fn tgetent
function
extracts the entry for terminal
.Fa name
into the buffer at
.Fa bp .
The
.Fa bp
argument
should be a character buffer of size
1024 and must be retained through all subsequent calls to
.Fn tgetnum ,
.Fn tgetflag ,
and
.Fn tgetstr .
As an extension
.Fn tgetent
can be passed NULL
for the
.Fa bp
argument, in which case an internal buffer will be used.
If repeated calls to
.Fn tgetent
is made with a NULL
.Fa bp
argument, some memory will be leaked on each call subsequent
to the first.
The
.Fn tgetent
function
returns \-1 if none of the
.Nm termcap
data base files could be opened,
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
.Ev TERMCAP
variable.
If found, and the value does not begin with a slash,
and the terminal type
.Fa name
is the same as the environment string
.Ev TERM ,
the
.Ev TERMCAP
string is used instead of reading a
.Nm termcap
file.
If it does begin with a slash, the string is used as a path name
of the
.Nm termcap
file to search.
If
.Ev TERMCAP
does not begin with a slash and
.Fa name
is different from
.Ev TERM ,
.Fn tgetent
searches the files
.Pa $HOME/.termcap
and
.Pa /usr/share/misc/termcap ,
in that order, unless the environment variable
.Ev TERMPATH
exists,
in which case it specifies a list of file pathnames
(separated by spaces or colons) to be searched instead.
Whenever multiple files are searched and a
.Sy tc
field occurs in the requested entry, the entry it names must be found
in the same file or one of the succeeding files.
This can speed up entry into programs that call
.Fn tgetent ,
as well as help debug new terminal descriptions
or make one for your terminal if you can't write the file
.Pa /usr/share/misc/termcap .
.Pp
The
.Fn tgetnum
function
gets the numeric value of capability
.Fa id ,
returning \-1 if it is not given for the terminal.
The
.Fn tgetflag
function
returns 1 if the specified capability is present in
the terminal's entry, 0 if it is not.
The
.Fn tgetstr
function
returns the string value of the capability
.Fa id ,
places it in the buffer at
.Fa area ,
and advances the
.Fa area
pointer.
It decodes the abbreviations for this field described in
.Xr termcap 5 ,
except for cursor addressing and padding information.
The
.Fn tgetstr
function
returns
.Dv NULL
if the capability was not found.
.Pp
The
.Fn tgoto
function
returns a cursor addressing string decoded from
.Fa cm
to go to column
.Fa destcol
in line
.Fa destline .
It uses the external variables
.Va UP
(from the
.Sy up
capability)
and
.Va BC
(if
.Sy bc
is given rather than
.Sy bs )
if necessary to avoid placing
.Sy \en ,
.Sy ^D
or
.Sy ^@
in
the returned string.
(Programs which call
.Fn tgoto
should be sure to turn off the
.Dv XTABS
bit(s),
since
.Fn tgoto
may now output a tab.
Note that programs using termcap should in general turn off
.Dv XTABS
anyway since some terminals use control-I for other functions,
such as nondestructive space.)
If a
.Sy %
sequence is given which is not understood, then
.Fn tgoto
returns
.Pq Dv OOPS .
.Pp
The
.Fn tputs
function
decodes the leading padding information of the string
.Fa cp ;
.Fa affcnt
gives the number of lines affected by the operation, or 1 if this is
not applicable,
.Fa outc
is a routine which is called with each character in turn.
The external variable
.Va ospeed
should contain the output speed of the terminal as encoded by
.Xr stty 3 .
The external variable
.Va PC
should contain a pad character to be used (from the
.SY pc
capability)
if a null
.Pq Sy ^@
is inappropriate.
.Sh FILES
.Bl -tag -width /usr/share/misc/termcap -compact
.It Pa /usr/lib/libtermcap.a
.Fl l Ar ltermcap
library (also known as
.Fl l Ar ltermlib )
.It Pa /usr/share/misc/termcap
standard terminal capability data base
.It Pa $HOME/.termcap
user's terminal capability data base
.El
.Sh SEE ALSO
.Xr ex 1 ,
.Xr curses 3 ,
.Xr termcap 5
.Sh HISTORY
The
.Nm
functions appeared in 
.Bx 4.0 .