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
@@ -79,47 +80,78 @@
bilities 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 ig-
- nores the buffer pointer bp.
+
+ 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
+ thing.
+
+ 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
+ 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
+ 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
+
+
+ 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)
+ 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
+ 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
+ used in the tgoto emulation. The variable ospeed is set
by ncurses in a system-specific coding to reflect the ter-
minal speed.
Except where explicitly noted, routines that return an in-
- teger return ERR upon failure and OK (SVr4 only specifies
+ teger return ERR upon failure and OK (SVr4 only specifies
"an integer value other than ERR") upon successful comple-
tion.
@@ -127,65 +159,100 @@
If you call tgetstr to fetch ca or any other parameterized
- string, be aware that it will be returned in terminfo no-
+ 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
- "$<..>" delays, and invoke a termcap-style parser if the
+ tation. This will not cause problems if all you do with
+ it is call tgoto or tparm, which both expand terminfo-
+ style strings as terminfo. (The tgoto function, if con-
+ figured to support termcap, will check if the string is
+ indeed terminfo-style by looking for "%p" parameters or
+ "$<..>" 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
+ 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
+ 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.
-
PORTABILITY
- The XSI Curses standard, Issue 4 describes these func-
- tions. However, they are marked TO BE WITHDRAWN and may
+
+ 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
+ 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
+ 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
+ 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
+ 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-
+ bility names.
+
+ o This implementation disallows matches by the termcap
+ interface against extended capability names which are
+ longer than two characters.
+