PC, UP, BC, ospeed, tgetent, tgetflag, tgetnum, tgetstr,
tgoto, tputs - direct curses interface to the terminfo
extern char PC;
extern char * UP;
extern char * BC;
extern short ospeed;
int tgetent(char *bp, const char *name);
int tgetflag(char *id);
int tgetnum(char *id);
char *tgetstr(char *id, char **area);
char *tgoto(const char *cap, int col, int row);
int tputs(const char *str, int affcnt, int (*putc)(int));
These routines are included as a conversion aid for pro-
grams that use the termcap library. Their parameters are
the same and the routines are emulated using the terminfo
database. Thus, they can only be used to query the capa-
bilities of entries for which a terminfo entry has been
The tgetent routine loads the entry for name. It returns:
1 on success,
0 if there is no such entry (or that it is a generic
type, having too little information for curses ap-
plications to run), and
-1 if the terminfo database could not be found.
This differs from the termcap library in two ways:
o The emulation ignores the buffer pointer bp. The
termcap library would store a copy of the terminal
description in the area referenced by this pointer.
However, ncurses stores its terminal descriptions
in compiled binary form, which is not the same
o There is a difference in return codes. The termcap
library does not check if the terminal description
is marked with the generic capability, or if the
terminal description has cursor-addressing.
The tgetflag routine gets the boolean entry for id, or ze-
ro if it is not available.
The tgetnum routine gets the numeric entry for id, or -1
if it is not available.
The tgetstr routine returns the string entry for id, or
zero if it is not available. Use tputs to output the re-
turned string. The return value will also be copied to
the buffer pointed to by area, and the area value will be
updated to point past the null ending this value.
Only the first two characters of the id parameter of tget-
flag, tgetnum and tgetstr are compared in lookups.
The tgoto routine instantiates the parameters into the
given capability. The output from this routine is to be
passed to tputs.
The tputs routine is described on the curs_terminfo(3x)
manual page. It can retrieve capabilities by either term-
cap or terminfo name.
The variables PC, UP and BC are set by tgetent to the ter-
minfo entry's data for pad_char, cursor_up and
backspace_if_not_bs, respectively. UP is not used by
ncurses. PC is used in the tdelay_output function. BC is
used in the tgoto emulation. The variable ospeed is set
by ncurses in a system-specific coding to reflect the ter-
Except where explicitly noted, routines that return an in-
teger return ERR upon failure and OK (SVr4 only specifies
"an integer value other than ERR") upon successful comple-
Routines that return pointers return NULL on error.
If you call tgetstr to fetch ca or any other parameterized
string, be aware that it will be returned in terminfo no-
tation, not the older and not-quite-compatible termcap no-
tation. This will not cause problems if all you do with
it is call tgoto or tparm, which both expand terminfo-
style strings as terminfo. (The tgoto function, if con-
figured to support termcap, will check if the string is
indeed terminfo-style by looking for "%p" parameters or
"$<..>" delays, and invoke a termcap-style parser if the
string does not appear to be terminfo).
Because terminfo conventions for representing padding in
string capabilities differ from termcap's, tputs("50");
will put out a literal "50" rather than busy-waiting for
50 milliseconds. Cope with it.
Note that termcap has nothing analogous to terminfo's sgr
string. One consequence of this is that termcap applica-
tions assume me (terminfo sgr0) does not reset the alter-
nate character set. This implementation checks for, and
modifies the data shown to the termcap interface to accom-
modate termcap's limitation in this respect.
The XSI Curses standard, Issue 4 describes these func-
tions. However, they are marked TO BE WITHDRAWN and may
be removed in future versions.
Neither the XSI Curses standard nor the SVr4 man pages
documented the return values of tgetent correctly, though
all three were in fact returned ever since SVr1. In par-
ticular, an omission in the XSI Curses documentation has
been misinterpreted to mean that tgetent returns OK or
ERR. Because the purpose of these functions is to provide
compatibility with the termcap library, that is a defect
in XCurses, Issue 4, Version 2 rather than in ncurses.
External variables are provided for support of certain
termcap applications. However, termcap applications' use
of those variables is poorly documented, e.g., not distin-
guishing between input and output. In particular, some
applications are reported to declare and/or modify ospeed.
The comment that only the first two characters of the id
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 tgetstr, tgetnum and tgetflag.
Some applications assume that the termcap interface does
not require the trailing NUL for the parameter name. Tak-
ing into account these issues:
o As a special case, tgetflag 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 implementa-
tion disallows matches against single-character capa-
o This implementation disallows matches by the termcap
interface against extended capability names which are
longer than two characters.
curses(3x), terminfo(5), term_variables(3x), putc(3).
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