Copyright (c) 1980 Regents of the University of California.
All rights reserved. The Berkeley software License Agreement
specifies the terms and conditions for redistribution.
@(#)intro.3 6.1 (Berkeley) 04/23/86
.sh 1 Usage .pp This is a description of how to actually use the screen package. In it, we assume all updating, reading, etc. is applied to .Vn stdscr . All instructions will work on any window, with changing the function name and parameters as mentioned above. .sh 2 "Starting up" .pp In order to use the screen package, the routines must know about terminal characteristics, and the space for .Vn curscr and .Vn stdscr must be allocated. These functions are performed by .Fn initscr . Since it must allocate space for the windows, it can overflow core when attempting to do so. On this rather rare occasion, .Fn initscr returns ERR. .Fn initscr must .bi always be called before any of the routines which affect windows are used. If it is not, the program will core dump as soon as either .Vn curscr or .Vn stdscr are referenced. However, it is usually best to wait to call it until after you are sure you will need it, like after checking for startup errors. Terminal status changing routines like .Fn nl and .Fn cbreak should be called after .Fn initscr . .pp Now that the screen windows have been allocated, you can set them up for the run. If you want to, say, allow the window to scroll, use .Fn scrollok . If you want the cursor to be left after the last change, use .Fn leaveok . If this isn't done, .Fn refresh will move the cursor to the window's current \*y after updating it. New windows of your own can be created, too, by using the functions .Fn newwin and .Fn subwin . .Fn delwin will allow you to get rid of old windows. If you wish to change the official size of the terminal by hand, just set the variables .Vn LINES and .Vn COLS to be what you want, and then call .Fn initscr . This is best done before, but can be done either before or after, the first call to .Fn initscr , as it will always delete any existing .Vn stdscr and/or .Vn curscr before creating new ones. .pp .sh 2 "The Nitty-Gritty" .sh 3 Output .pp Now that we have set things up, we will want to actually update the terminal. The basic functions used to change what will go on a window are .Fn addch and .Fn move . .Fn addch adds a character at the current \*y, returning ERR if it would cause the window to illegally scroll, .i i.e. , printing a character in the lower right-hand corner of a terminal which automatically scrolls if scrolling is not allowed. .Fn move changes the current \*y to whatever you want them to be. It returns ERR if you try to move off the window when scrolling is not allowed. As mentioned above, you can combine the two into .Fn mvaddch to do both things in one fell swoop. .pp The other output functions, such as .Fn addstr and .Fn printw , all call .Fn addch to add characters to the window. .pp After you have put on the window what you want there, when you want the portion of the terminal covered by the window to be made to look like it, you must call .Fn refresh . In order to optimize finding changes, .Fn refresh assumes that any part of the window not changed since the last .Fn refresh of that window has not been changed on the terminal, .i i.e. , that you have not refreshed a portion of the terminal with an overlapping window. If this is not the case, the routines .Fn touchwin , .Fn touchline , and .Fn touchoverlap are provided to make it look like a desired part of window has been changed, thus forcing .Fn refresh check that whole subsection of the terminal for changes. .pp If you call .Fn wrefresh with .Vn curscr , it will make the screen look like .Vn curscr thinks it looks like. This is useful for implementing a command which would redraw the screen in case it get messed up. .sh 3 Input .pp Input is essentially a mirror image of output. The complementary function to .Fn addch is .Fn getch which, if echo is set, will call .Fn addch to echo the character. Since the screen package needs to know what is on the terminal at all times, if characters are to be echoed, the tty must be in raw or cbreak mode. If it is not, .Fn getch sets it to be cbreak, and then reads in the character. .sh 3 Miscellaneous .pp All sorts of fun functions exists for maintaining and changing information about the windows. For the most part, the descriptions in section 5.4. should suffice. .sh 2 "Finishing up" .pp In order to do certain optimizations, and, on some terminals, to work at all, some things must be done before the screen routines start up. These functions are performed in .Fn getttmode and .Fn setterm , which are called by .Fn initscr . In order to clean up after the routines, the routine .Fn endwin is provided. It restores tty modes to what they were when .Fn initscr was first called. Thus, anytime after the call to initscr, .Fn endwin should be called before exiting.
All rights reserved. The Berkeley software License Agreement
specifies the terms and conditions for redistribution.
@(#)intro.3 6.1 (Berkeley) 04/23/86
.sh 1 Usage .pp This is a description of how to actually use the screen package. In it, we assume all updating, reading, etc. is applied to .Vn stdscr . All instructions will work on any window, with changing the function name and parameters as mentioned above. .sh 2 "Starting up" .pp In order to use the screen package, the routines must know about terminal characteristics, and the space for .Vn curscr and .Vn stdscr must be allocated. These functions are performed by .Fn initscr . Since it must allocate space for the windows, it can overflow core when attempting to do so. On this rather rare occasion, .Fn initscr returns ERR. .Fn initscr must .bi always be called before any of the routines which affect windows are used. If it is not, the program will core dump as soon as either .Vn curscr or .Vn stdscr are referenced. However, it is usually best to wait to call it until after you are sure you will need it, like after checking for startup errors. Terminal status changing routines like .Fn nl and .Fn cbreak should be called after .Fn initscr . .pp Now that the screen windows have been allocated, you can set them up for the run. If you want to, say, allow the window to scroll, use .Fn scrollok . If you want the cursor to be left after the last change, use .Fn leaveok . If this isn't done, .Fn refresh will move the cursor to the window's current \*y after updating it. New windows of your own can be created, too, by using the functions .Fn newwin and .Fn subwin . .Fn delwin will allow you to get rid of old windows. If you wish to change the official size of the terminal by hand, just set the variables .Vn LINES and .Vn COLS to be what you want, and then call .Fn initscr . This is best done before, but can be done either before or after, the first call to .Fn initscr , as it will always delete any existing .Vn stdscr and/or .Vn curscr before creating new ones. .pp .sh 2 "The Nitty-Gritty" .sh 3 Output .pp Now that we have set things up, we will want to actually update the terminal. The basic functions used to change what will go on a window are .Fn addch and .Fn move . .Fn addch adds a character at the current \*y, returning ERR if it would cause the window to illegally scroll, .i i.e. , printing a character in the lower right-hand corner of a terminal which automatically scrolls if scrolling is not allowed. .Fn move changes the current \*y to whatever you want them to be. It returns ERR if you try to move off the window when scrolling is not allowed. As mentioned above, you can combine the two into .Fn mvaddch to do both things in one fell swoop. .pp The other output functions, such as .Fn addstr and .Fn printw , all call .Fn addch to add characters to the window. .pp After you have put on the window what you want there, when you want the portion of the terminal covered by the window to be made to look like it, you must call .Fn refresh . In order to optimize finding changes, .Fn refresh assumes that any part of the window not changed since the last .Fn refresh of that window has not been changed on the terminal, .i i.e. , that you have not refreshed a portion of the terminal with an overlapping window. If this is not the case, the routines .Fn touchwin , .Fn touchline , and .Fn touchoverlap are provided to make it look like a desired part of window has been changed, thus forcing .Fn refresh check that whole subsection of the terminal for changes. .pp If you call .Fn wrefresh with .Vn curscr , it will make the screen look like .Vn curscr thinks it looks like. This is useful for implementing a command which would redraw the screen in case it get messed up. .sh 3 Input .pp Input is essentially a mirror image of output. The complementary function to .Fn addch is .Fn getch which, if echo is set, will call .Fn addch to echo the character. Since the screen package needs to know what is on the terminal at all times, if characters are to be echoed, the tty must be in raw or cbreak mode. If it is not, .Fn getch sets it to be cbreak, and then reads in the character. .sh 3 Miscellaneous .pp All sorts of fun functions exists for maintaining and changing information about the windows. For the most part, the descriptions in section 5.4. should suffice. .sh 2 "Finishing up" .pp In order to do certain optimizations, and, on some terminals, to work at all, some things must be done before the screen routines start up. These functions are performed in .Fn getttmode and .Fn setterm , which are called by .Fn initscr . In order to clean up after the routines, the routine .Fn endwin is provided. It restores tty modes to what they were when .Fn initscr was first called. Thus, anytime after the call to initscr, .Fn endwin should be called before exiting.