termcap(3)termcap(3)NAME
tgetent, tgetflag, tgetnum, tgetstr, tgoto, tputs - direct curses
interface to the terminfo capability database
SYNOPSIS
#include <curses.h>
#include <term.h>
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));
DESCRIPTION
These routines are included as a conversion aid for programs 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 capabilities of entries for which a terminfo entry has
been compiled.
The tgetent routine loads the entry for name. It returns 1 on success,
0 if there is no such entry, and -1 if the terminfo database could not
be found. The emulation ignores the buffer pointer bp.
The tgetflag routine gets the boolean entry for id, or zero 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 returned 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 tgetflag, 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 terminfo(3) manual page. It can
retrieve capabilities by either termcap or terminfo name.
The variables PC, UP and BC are set by tgetent to the terminfo 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 terminal speed.
RETURN VALUE
Except where explicitly noted, routines that return an integer return
ERR upon failure and OK (SVr4 only specifies "an integer value other
than ERR") upon successful completion.
Routines that return pointers return NULL on error.
BUGS
If you call tgetstr to fetch ca or any other parameterized string, be
aware that it will be returned in terminfo notation, not the older and
not-quite-compatible termcap notation. 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 configured
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 applications assume me (terminfo
sgr0) does not reset the alternate character set. This implementation
checks for, and modifies the data shown to the termcap interface to
accommodate termcap's limitation in this respect.
PORTABILITY
The XSI Curses standard, Issue 4 describes these functions. 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 particular, 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 distinguishing between input and output.
In particular, some applications are reported to declare and/or modify
ospeed.
SEE ALSOcurses(3), terminfo(5), putc(3).
March 1, 2011
