1. Ncurses Programming
2. Lib Ncurses
3. C Ncurses Library
4. Ncurses C Tutorial
5. Ncurses Example
6. Ncurses Download

This program implements the good old 'Hello, world!'application using ncurses. It clears the screen, displays the phrasein the centre, waits for a few seconds, then exits.

Programming Issues

All programs using ncurses must call initscr()before using any of the library functions. This function canfail, so we always check the return value.

1. Look, C is a compiled langauge, and Clang is a compiler unlike Python or Ruby which are interpreted language. When you type the command clang simple.c, clang takes the source code and compiles it into machine code into a.out (a.out is default output name) and to run the program you must execute the binary like this $./a.out.
2. The ncurses library will probably do this. I don’t know it well enough to provide an answer, but here are links to docs and a related question. This comment is based on Wil Shipley’s answer from 2009, which may be deleted. – Tom Zych Jan 17 '16 at 14:54.

We output the 'Hello, world!' phrase usingmvaddstr, or 'move to the specifiedposition and add a string there'. Note that thecoordinates are specified in the order of row,column, or y, x,and not the other way around.

Dev c is very very outdated, but forgoing that. If you want to write something using ncurses you should look up the documentation for that library. I'm looking for c api example for ncurses programming and needless to say that it is not available except 7 part snake game development video on youtube which is a bit difficult for a noob like me to.

Note that the above function (along with most other libraryfunctions) do not actually directly modify the display; they justmodify data structures held in memory. To actually reflect ourchanges on the screen, we must call one of the refresh()functions.

We call the sleep() function to sleep for a fewseconds, to show the full screen display for a moment before ourcommand prompt returns. Note that sleep() here is aUNIX function and defined in <unistd.h>; if youare using a version of ncurses ported to a non-UNIX platform, yourcompiler may not have this header file or this function, though itwill almost certainly have something similar.

Finally, we must clean up after ourselves, as we want theterminal to be in a useable state after our program exits. First,we must delete all of our windows using delwin(),including the one returned by initscr(). Then, we callendwin() and finally refresh() again, beforewe exit safely.

Note that when you are learning ncurses development, you will almostcertainly foul up your terminal with alarming regularity. On UNIX, youcan type stty sane at the command prompt to return theterminal to a useable state without needing to log out.

Usage

Ncurses Programming

You will need to link to the ncurses library in order to use thefunctions in it. On UNIX, this is typically done using the -lcompiler switch, e.g.:

[paul@localhost src]$ cc -o curhello curhello.c -lncurses

On other systems, consult your compiler's documentation, or the ncursesdocumentation for more information.

Also note that in most of these ncurses examples, we assume a terminal with80 columns and 25 rows. If your terminal has different dimensions, you mayneed to adapt the examples to suit.

Source and Downloads

• Download the tarred, gzipped source
• Download the zipped source

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by X. Li

If you have some beginning experience in Unix programming, you may have felt the need of some text user interface operations, such as moving the cursor on the screen, editing user input, using colors, .. Such terminal IO related operations are not portable and not defined in C language. You need to either use the low-level termcap library or the curses library. Using curses/ncurses library is much easier and more portable.

Contents

Using the library

Installations, header inclusions and link options.

Before and after using ncurses function

Thing you need to do before calling curses functions

Creating windows

Creating windows

Moving the cursor

Move the cursor around the window

Input

Read user input from keyboard

Output

Write text to the window

Using colors and other text attributes

Text colors, highlighting, blinking, ..

Using curses in Xterm

How to cope window resizing by user

An example of complete programs

A typing speed test program by me

Using ncurses library

To compile your C/C++ programs using ncurses/curses library you need to include the curses header file <curses.h>. For ncurses, you may include either <curses.h> or <ncurses.h>. In some systems, you must include <ncurses.h>.

#include <curses.h>

To link the programs you need to use the -lcurses or -lncurses option, like

gcc -lncurses prog.c

This way the program is dynamically linked to the ncurses library. To run it in another computer, the system must have the ncurses library installed. If you want to avoid the trouble, you may have it statically linked. To do that, find the file libncurses.a in /usr/lib and do

gcc prog.c libncurses.a

Most Unix systems have curses or ncurses installed as a default option. To find out if it's installed, you can try man ncurses man curses or go to /usr/lib and /usr/include to list the files.

If you're installing Linux or FreeBSD on your own machine, be sure to install the ncurses-development package in order to do ncurses programming.

Initialization

The very first thing to do: Before you use any other curses routines, the initscr() routine must be called first.

initscr();

If your program is going to write to several terminals, you should call newterm instead, which is another story.

One-character-a-time. To disable the buffering of typed characters by the TTY driver and get a character-at-a-time input, you need to call

cbreak();

No echo. To suppress the automatic echoing of typed characters, you need to call

noecho();

Special keys. In order to capture special keystrokes like Backspace, Delete and the four arrow keys by getch(), you need to call

keypad(stdscr, TRUE);

Before exiting. Before the program is terminated, endwin() must be called to restore the terminal settings.

Windows

A window is a 2-dimensional array of characters representing all or part of a CRT screen. Character input and output should pertain to a specific window.

The default window. A default window called stdscr, which is the size of the terminal screen, is supplied. To use the stdscr window, you don't need to do any initializations. You can also divide the screen to several parts and create a window to represent each part.

Create a new window. The data structure of window is WINDOW, defined in ncurses.h. To declare and create a new window, do

WINDOW * win = newwin(nlines, ncols, y0, x0);

All the 4 parameters are

Lib Ncurses

ints. Here nline is the height of the window -- number of lines, ncols is the width -- number of columns of the window. y0 and x0 are the coordinates of the upper left corner of win on the screen -- line y0 and columns x0. You should make sure that the area of the new window is inside the screen.

Height and width of the window. The size of the whole screen can be determined by the two global variables COLUMNS and LINES. y0 and x0 should satisfy

In X window system, the actual xterm size might be changed leaving these two variables obslete. In this case you should use the macro void getmaxyx(WINDOW *, int y, int x) to get the size of the screen.

No overlapping. Windows cannot overlap with each other. Therefore you have two options: only use stdscr and no other windows, or create several non-overlapping windows but do not use stdscr.

Refresh. If you make some change to a window, such as printing something or moving the cursor, the effect is not shown on the screen until you call the wrefresh() function

Clear window. To erase everything written in the window win, call wrefresh(win). refresh() is equivalent to wrefresh(stdscr).

Delete window. If a window win is no longer needed, and you're going to create new windows to overlap it, you should call delwin(win) to delete the window (release the memory it is using).

Moving the cursor

The position of the cursor on the screen is important because it is default beginning place for most output functions. The cursor also shows the user where the input is expected.

To move the cursor to a new position on a window, use the function int wmove(WINDOW *win, int y, int x)

wmove(win, y, x);

where (x, y) are the coordinates of the new position in the window. If the window has nlines lines and ncolumns columns, then

Refresh. The actual cursor motion is not shown on the screen untill you do a wrefresh(win).

move(y, x) is equivalent to the wmove(stdscr, y, x).

Input

To read a character from stdscr, use the function int getch(void)

C Ncurses Library

. No echoing. If you have called noecho(), the character ch will not be printed on the screen, otherwise it will. Disabling automatic echoing gives you more control over the user interface.

No buffering. If you have called cbreak(void) each key the user hits is returned immediately by getch(). Otherwise the keys hit by the user are queued until a newline is read. Then calls to getch() take characters from the queue in FIFO manner until the queue is empty and the next whole line is read.

No delaying. Usually a call to getch() waits until a key is hit. If you have called nodelay(stdscr, TRUE), then getch() will work in a non-blocking manner -- it will return ERR if the key input is not ready. This is usually useful for writing game-like programs, where the promptness of user response matters. For example

Special keys. If you have called keypad(stdstr, TRUE), then if the user hits a special key such as the Delete key, the arrow keys, Ctrl combined keys and function keys, a single int value will be returned. Here is the definition of several special keys For a complete list read the man page of getch().

Catch special keys. To use these keys, you need to check the return value of getch(). For example Read character from a window. The function int wgetch(WINDOW *win). reads a key from a window. The user input of course comes from the keyboard and not the screen window. But the different windows on the screen might have different delay modes and other properties, therefore affect the behavior of wgetch().

Moving the cursor and read a character. There are also functions which combine cursor moving and character reading together

Output

The function int waddch(WINDOW * win, chtype ch) adds a character on the window at the current cursor position, and the cursor position is advanced then.

Wrap. If the new position of the cursor is out of the window, it wraps to the beginning of the next line.

Scroll. If the next line is out of the window, and you have called scrollok(win, TRUE) when the window was created, the stuff in the window is scrolled up one line.

Character attribute. The parameter ch is of type chtype(), which is the ASCII value of the character combined with some video attributes such as colors. The combination is through the logical OR of the character value and the attribute, which I will talk about in the section.

Refresh. After a call to waddch, the screen is not updated until you call wrefresh(win).

Ohter output functions

mvwaddch(win, y, x, ch); is equivalent to wmove(win, y, x); waddch(win, ch);

addch(ch); is equivalent to waddch(stdscr, ch);.

Ncurses C Tutorial

wechochar(win, ch); function and echochar(ch) are equivalent to waddch(win, ch); wrefresh(win); and addch(ch); refresh(); respectively. But echochar and wechochar may be more efficient.

int waddstr(WINDOW *win, const char *str) and int addstr(const char *str) prints a null-terminated string at the cursor position of the window, and advance the cursor position accordingly.

The functions int wprintw(WINDOW *win, char *fmt ..) and int printw(char *fmt ..) do formatted output in the same fashion as the analogous standard library function printf.

Attribute

When characters are drawn on the screen some special video effects, like foreground and background color, highlight, underline, blinking, .., can be shown. Such video effects are represented by integers called text attributes. Each significant bit of the attribute corresponds to one video effect.

Using attribute

There are two ways to use attribute. One is by passing waddch(win, ch)

Ncurses Example

a character value combined with attribute. The other is setting the global window attribute.

Character type. When calling waddch(win, ch) or addch(ch), logical OR the character value with the attribute. For example, A_UNDERLINE is the predefined attribute for underlining. To print the character 'X' with underlining, do Using several attributes is of course possible. For example, to To print the character 'X' with highlight in color pair 3

Setting window attribute.int wattron(WINDOW *win, int attr) function to turn on an attribute attr. Then anything printed by subsequent calls to waddch, addstr and waddstr will have the attribute attr, For example, to print a highlighted message on the screen Predefined attributes. Here is some attributes defined in ncurses.h

Using colors

The combination of foreground and background color is an attribute. Unlike other attributes, before using colors, you must call start_color().

When start_color() is called, a set of colors and color pairs are created which you can use. The number of available colors and the number of the color pairs are stored in two global variables COLORS and COLOR_PAIRS. To use an predefined color pair as an attribute, you need to cal the macro COLOR_PAIR(n), where n must satisfy Example. To give a window the color attribute defined by color pair #2, so that each subsequent character printed in this window has the foreground and background color defined by color pair #2 The meaning of a color pair can be redefined. For example redefine the color pair #1 with foreground color #2 and background color #0. In the function int init_pair(short n, short f, short b) the parameters must satisfy

When start_color() is called, 8 basic colors are initialized You can use these names in init_pair() for specifying foreground and background color.

To find out what foreground color and background color is used by a color pair, use the function int pair_content(short pair, short *f, short *b). To find out the definition of a color use the function int color_content(short color, short *r, short *g, short *b)

Color can also be redefined by int init_color(short n, short r, short g, short b), where n is the index of color, must be less than COLORS. r, g, and b represent the intensity of red, green and blue. Each value of r, g and b must be less than 1000. /nitro-pro-9-with-serial-key-free-download.html.

Line graphics

Line graphics. Here are some special characters which can be used in addch and addstr routines as the chtype. Usually on terminals using these symbols can draw pretty windows and shapes. One place to use this is the wborder function, which draws borders for a window. See the man page for details about the parameters, but usually do it the following way will make a good looking window.

Ncurses Download

To draw a horizontal line across the window, do

X window

If an xterm is resized the contents on your text windows might be messed up. To handle this gracefully you should redraw all the stuff based on the new height and width of the screen. When resizing happens, your program is sent a SIGWINCH signal. You should catch this signal and do redrawing accordingly. Here is some hint.