<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
<HTML>
<HEAD>
<TITLE>8.3 Ncurses - Introduction</TITLE>
<META NAME="description" CONTENT="8.3 Ncurses - Introduction">
<META NAME="keywords" CONTENT="lpg">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<LINK REL=STYLESHEET HREF="lpg.css">
</HEAD>
<BODY LANG="EN">
<A NAME="tex2html1597" HREF="node98.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="/icons//next_motif.gif"></A> <A NAME="tex2html1595" HREF="node85.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="/icons//up_motif.gif"></A> <A NAME="tex2html1589" HREF="node96.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="/icons//previous_motif.gif"></A> <A NAME="tex2html1599" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="/icons//contents_motif.gif"></A> <BR>
<B> Next:</B> <A NAME="tex2html1598" HREF="node98.html">8.4 Initializing</A>
<B>Up:</B> <A NAME="tex2html1596" HREF="node85.html">8 Character Cell Graphics</A>
<B> Previous:</B> <A NAME="tex2html1590" HREF="node96.html">String Capabilities</A>
<BR> <P>
<H1><A NAME="SECTION00930000000000000000">8.3 Ncurses - Introduction</A></H1>
<P>
The following terminology will be used in this chapter:
<P>
<UL><LI> window - is an internal representation containing an image
of a part of the screen. WINDOW is defined in
.h.<LI> screen - is a window with the size of the entire screen (from the
upper left to the lower right). and
are screens.<LI> terminal - is a special screen with information about what the screen
currently looks like.<LI> variables - the following variables and constants defined in
.h
<UL><LI> WINDOW *curscr - current screen<LI> WINDOW *stdscr - standard screen<LI> int LINES - lines on the terminal<LI> int COLS - columns on the terminal<LI> bool TRUE - true flag, 1<LI> bool FALSE - false flag, 0<LI> int ERR - error flag, -1<LI> int OK - ok flag, 0
</UL><LI> functions - in the function description the arguments are of the
following type:
<UL><LI> win - WINDOW*<LI> bf - bool<LI> ch - chtype<LI> str - char*<LI> chstr - chtype*<LI> fmt - char*<LI> otherwise int
</UL></UL>
<P>
Usually a program using the ncurses library looks like this:
<P>
<P><P>
<P>
Including .h will define variables and types for ncurses, such
as WINDOW and function prototypes. It automatically includes .h,
.h, .h and .h.
<P>
<B>initscr()</B> is used to initialize the ncurses data structures and to
read the proper terminfo file. Memory for
and will be allocated. If an error occurs,
initscr will return ERR, otherwise a pointer to will be
returned. Additionally, the
screen will be erased and and will be initialized.
<P>
<B>endwin()</B> will clean up all allocated resources from ncurses and
restore the tty modes to the status they had before calling
<B>initscr()</B>. It must be called before any other function from the
ncurses library and <B>endwin()</B> must be called before your program
exits. When you want to do output to more than one terminal, you can use
<B>newterm(...)</B> instead of <B>initscr()</B>.
<P>
Compile the program with:
<P>
<P><P>
<P>
In flags you can include anything you like (gcc(1)). Since the
path for ncurses.h has changed you have to include the following line:
<P>
<P><P>
<P>
Otherwise, ncurses.h, nterm.h, termcap.h and unctrl.h will not be found.
Possible other flags for Linux are:
<P>
<P><P>
<P>
2 tells gcc to do some optimization, <I>-ansi</I> is for ansi
conformant c-code, <I>-Wall</I> will print out all warnings,
<I>-m486</I> will use optimized code for an Intel 486 (the binary can be
used on an Intel 386, too).
<P>
The ncurses library can be found in /usr/lib/. There are three versions
of the ncurses library:
<UL><LI> <B>libncurses.a</B> the normal ncurses library.<LI> <B>libdcurses.a</B> ncurses for debugging.<LI> <B>libpcurses.a</B> ncurses for profiling (since 1.8.6
libpcurses.a exists no longer ?).<LI> <B>libcurses.a</B> No fourth version, but the original BSD curses
(in my slackware 2.1.0 it is the bsd package).
</UL>
<P>
The data structures for the screen are called <I>windows</I> as defined in
.h. A window is something like a character
array in memory which the programmer can manipulate without
output to the terminal. The default window is with the size of
the terminal. You can create other windows with <B>newwin(...)</B>.
<P>
To update the physical terminal optimally, ncurses has another window
declared, . This is an image of how the terminal
actually looks and is an image of how the terminal should look.
The output will be done when you call <B>refresh()</B>. Ncurses will then
update and the physical terminal with the information in
.
The library functions will use internal optimization for the update process so
you can
change different windows and then update the screen at once in the most
optimal way.
<P>
With the ncurses functions you can manipulate the data structure
<I>window</I>. Functions beginning with <I>w</I> allow you to
specify a <I>window</I>, while
others will usually affect . Functions beginning with <I>mv</I>
will move the cursor to the position <I>y,x</I> first.
<P>
A character has the type <I>chtype</I> which is <I>long unsigned int</I> to
store additional information about it (attributes etc.).
<P>
Ncurses use the database. Normally the database is
located in /lib/terminfo/ and ncurses will look there for
local terminal definitions. If you want to test some other
definitions for a terminal without changing the original terminfo, set the
environment variable . Ncurses will check this variable
and use the definitions stored there instead of /usr/lib/terminfo/.
<P>
Current ncurses version is 1.8.6 ().
<P>
At the end of this chapter you can find a table with an overview for
the BSD-Curses, ncurses and the curses from Sun-OS 5.4. Refer to it
when you want to look for a specific function and where it is implemented.
<P>
<HR><A NAME="tex2html1597" HREF="node98.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="/icons//next_motif.gif"></A> <A NAME="tex2html1595" HREF="node85.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="/icons//up_motif.gif"></A> <A NAME="tex2html1589" HREF="node96.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="/icons//previous_motif.gif"></A> <A NAME="tex2html1599" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="/icons//contents_motif.gif"></A> <BR>
<B> Next:</B> <A NAME="tex2html1598" HREF="node98.html">8.4 Initializing</A>
<B>Up:</B> <A NAME="tex2html1596" HREF="node85.html">8 Character Cell Graphics</A>
<B> Previous:</B> <A NAME="tex2html1590" HREF="node96.html">String Capabilities</A>
<P><ADDRESS>
<I>Converted on: <BR>
Fri Mar 29 14:43:04 EST 1996</I>
</ADDRESS>
</BODY>
</HTML>
