Beginning Linux Programming, 4th Edition

Chapter 6

Managing Text-Based Screens with curses

In Chapter 5, you learned how to obtain much finer control over the input of characters and how to provide character output in a terminal-independent way. The problem with using the general terminal interface (GTI, or termios) and manipulating escape sequences with tparm and its related functions is that it requires a lot of lower-level code. For many programs, a higher-level interface is more desirable. We would like to be able to simply draw on the screen and use a library of functions to take care of terminal dependencies automatically.

In this chapter, you’ll learn about just such a library, the curses library. The curses standard is important as a halfway house between simple “line-based” programs and the fully graphical (and generally harder to program) X Window System programs, such as GTK+/GNOME and Qt/KDE. Linux does have the svgalib (Super VGA Library, a low-level graphics library), but that is not a UNIX standard library, so is not generally available in other UNIX-like operating systems. The curses library is used in many full-screen applications as a reasonably easy and terminal-independent way to write full-screen, albeit character-based, programs. It’s almost always easier to write such programs with curses than to use escape sequences directly. curses can also manage the keyboard, providing an easy-to-use, nonblocking character input mode.

You may find that a few of the examples in this chapter don’t always display ...