PC, UP, BC, ospeed, tgetent, tgetflag, tgetnum, tgetstr, tgoto, tputs − direct curses interface to the terminfo capability database


#include <ncurses/curses.h>
#include <term.h>

extern char PC;
extern char * UP;
extern char * BC;
extern speed_t 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 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:


on success,


if there is no such entry (or that it is a generic type, having too little information for curses applications to run), and


if the terminfo database could not be found.

This differs from the termcap library in two ways:

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.

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 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(3NCURSES) 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.


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.


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.


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.

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. Taking into account these issues:

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 implementation disallows matches against single-character capability names.

This implementation disallows matches by the termcap interface against extended capability names which are longer than two characters.


ncurses(3NCURSES), terminfo(5), terminfo_variables(3NCURSES), putc(3).



Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.