-by Eric S. Raymond and Zeyd M. Ben-Halim- -
-updates since release 1.9.9e by Thomas Dickey -
curses. It is
-not an exhaustive reference for the curses Application Programming Interface
-(API); that role is filled by the curses manual pages. Rather, it
-is intended to help C programmers ease into using the package.
-
-This document is aimed at C applications programmers not yet specifically
-familiar with ncurses. If you are already an experienced curses
-programmer, you should nevertheless read the sections on
-Mouse Interfacing, Debugging,
-Compatibility with Older Versions,
-and Hints, Tips, and Tricks. These will bring you up
-to speed on the special features and quirks of the ncurses
-implementation. If you are not so experienced, keep reading.
-
-The curses package is a subroutine library for
-terminal-independent screen-painting and input-event handling which
-presents a high level screen model to the programmer, hiding differences
-between terminal types and doing automatic optimization of output to change
-one screen full of text into another. Curses uses terminfo, which
-is a database format that can describe the capabilities of thousands of
-different terminals.
-
-The curses API may seem something of an archaism on UNIX desktops
-increasingly dominated by X, Motif, and Tcl/Tk. Nevertheless, UNIX still
-supports tty lines and X supports xterm(1); the curses
-API has the advantage of (a) back-portability to character-cell terminals,
-and (b) simplicity. For an application that does not require bit-mapped
-graphics and multiple fonts, an interface implementation using curses
-will typically be a great deal simpler and less expensive than one using an
-X toolkit.
-
-
curses was the routines written to
-provide screen-handling for the game rogue; these used the
-already-existing termcap database facility for describing terminal
-capabilities. These routines were abstracted into a documented library and
-first released with the early BSD UNIX versions.
-
-System III UNIX from Bell Labs featured a rewritten and much-improved
-curses library. It introduced the terminfo format. Terminfo is based
-on Berkeley's termcap database, but contains a number of improvements and
-extensions. Parameterized capabilities strings were introduced, making it
-possible to describe multiple video attributes, and colors and to handle far
-more unusual terminals than possible with termcap. In the later AT&T
-System V releases, curses evolved to use more facilities and offer
-more capabilities, going far beyond BSD curses in power and flexibility.
-
-
ncurses, a free implementation of
-the System V curses API with some clearly marked extensions.
-It includes the following System V curses features:
-
-
-The ncurses package can also capture and use event reports from a
-mouse in some environments (notably, xterm under the X window system). This
-document includes tips for using the mouse.
-
-The ncurses package was originated by Pavel Curtis. The original
-maintainer of this package is
-Zeyd Ben-Halim
-<zmbenhal@netcom.com>.
-Eric S. Raymond
-<esr@snark.thyrsus.com>
-wrote many of the new features in versions after 1.8.1
-and wrote most of this introduction.
-Jürgen Pfeifer
-wrote all of the menu and forms code as well as the
-Ada95 binding.
-Ongoing work is being done by
-Thomas Dickey (maintainer).
-Contact the current maintainers at
-bug-ncurses@gnu.org.
-
- -This document also describes the panels extension library, -similarly modeled on the SVr4 panels facility. This library allows you to -associate backing store with each of a stack or deck of overlapping windows, -and provides operations for moving windows around in the stack that change -their visibility in the natural way (handling window overlaps).
- -Finally, this document describes in detail the menus and forms extension libraries, also cloned from System V, -which support easy construction and sequences of menus and fill-in -forms. - - -
stdscr, is automatically provided for the programmer.
-- #include <curses.h> -- -at the top of the program source. The screen package uses the Standard I/O -library, so
<curses.h> includes
-<stdio.h>. <curses.h> also includes
-<termios.h>, <termio.h>, or
-<sgtty.h> depending on your system. It is redundant (but
-harmless) for the programmer to do these includes, too. In linking with
-curses you need to have -lncurses in your LDFLAGS or on the
-command line. There is no need for any other libraries.
-
-curscr, for current screen) is a
-screen image of what the terminal currently looks like. Another screen (called
-stdscr, for standard screen) is provided by default to make changes
-on. - -A window is a purely internal representation. It is used to build and store a -potential image of a portion of the terminal. It doesn't bear any necessary -relation to what is really on the terminal screen; it's more like a -scratchpad or write buffer.
-
-To make the section of physical screen corresponding to a window reflect the
-contents of the window structure, the routine refresh() (or
-wrefresh() if the window is not stdscr) is called.
- -A given physical screen section may be within the scope of any number of -overlapping windows. Also, changes can be made to windows in any order, -without regard to motion efficiency. Then, at will, the programmer can -effectively say ``make it look like this,'' and let the package implementation -determine the most efficient way to repaint the screen. - -
curscr, which knows what the terminal looks like,
-and stdscr, which is what the programmer wants the terminal to look
-like next. The user should never actually access curscr directly.
-Changes should be made to through the API, and then the routine
-refresh() (or wrefresh()) called.
-
-Many functions are defined to use stdscr as a default screen. For
-example, to add a character to stdscr, one calls addch() with
-the desired character as argument. To write to a different window. use the
-routine waddch() (for `w'indow-specific addch()) is provided. This
-convention of prepending function names with a `w' when they are to be
-applied to specific windows is consistent. The only routines which do not
-follow it are those for which a window must always be specified.
-
-In order to move the current (y, x) coordinates from one point to another, the
-routines move() and wmove() are provided. However, it is
-often desirable to first move and then perform some I/O operation. In order to
-avoid clumsiness, most I/O routines can be preceded by the prefix 'mv' and
-the desired (y, x) coordinates prepended to the arguments to the function. For
-example, the calls
-
-
- move(y, x); - addch(ch); -- -can be replaced by - -
- mvaddch(y, x, ch); -- -and - -
- wmove(win, y, x); - waddch(win, ch); -- -can be replaced by - -
- mvwaddch(win, y, x, ch); -- -Note that the window description pointer (win) comes before the added (y, x) -coordinates. If a function requires a window pointer, it is always the first -parameter passed. - -
curses library sets some variables describing the terminal
-capabilities.
-
-+ + + + + + +Writing Programs with NCURSES + + + + + +Writing Programs with NCURSES
+ ++ by Eric S. Raymond and Zeyd M. Ben-Halim+ +
+ updates since release 1.9.9e by Thomas Dickey +Contents
+ +
This document is an introduction to programming with
+ curses. It is not an exhaustive reference for the
+ curses Application Programming Interface (API); that role is
+ filled by the curses manual pages. Rather, it is
+ intended to help C programmers ease into using the package.
This document is aimed at C applications programmers not yet
+ specifically familiar with ncurses. If you are already an
+ experienced curses programmer, you should
+ nevertheless read the sections on Mouse
+ Interfacing, Debugging, Compatibility with Older Versions, and Hints, Tips, and Tricks. These will bring you up to
+ speed on the special features and quirks of the
+ ncurses implementation. If you are not so
+ experienced, keep reading.
The curses package is a subroutine library for
+ terminal-independent screen-painting and input-event handling
+ which presents a high level screen model to the programmer,
+ hiding differences between terminal types and doing automatic
+ optimization of output to change one screen full of text into
+ another. Curses uses terminfo, which is a database
+ format that can describe the capabilities of thousands of
+ different terminals.
The curses API may seem something of an archaism
+ on UNIX desktops increasingly dominated by X, Motif, and Tcl/Tk.
+ Nevertheless, UNIX still supports tty lines and X supports
+ xterm(1); the curses API has the advantage
+ of (a) back-portability to character-cell terminals, and (b)
+ simplicity. For an application that does not require bit-mapped
+ graphics and multiple fonts, an interface implementation using
+ curses will typically be a great deal simpler and
+ less expensive than one using an X toolkit.
Historically, the first ancestor of curses was
+ the routines written to provide screen-handling for the game
+ rogue; these used the already-existing
+ termcap database facility for describing terminal
+ capabilities. These routines were abstracted into a documented
+ library and first released with the early BSD UNIX versions.
System III UNIX from Bell Labs featured a rewritten and
+ much-improved curses library. It introduced the
+ terminfo format. Terminfo is based on Berkeley's termcap
+ database, but contains a number of improvements and extensions.
+ Parameterized capabilities strings were introduced, making it
+ possible to describe multiple video attributes, and colors and to
+ handle far more unusual terminals than possible with termcap. In
+ the later AT&T System V releases, curses evolved
+ to use more facilities and offer more capabilities, going far
+ beyond BSD curses in power and flexibility.
This document describes ncurses, a free
+ implementation of the System V curses API with some
+ clearly marked extensions. It includes the following System V
+ curses features:
Also, this package makes use of the insert and delete line and + character features of terminals so equipped, and determines how + to optimally use these features with no help from the programmer. + It allows arbitrary combinations of video attributes to be + displayed, even on terminals that leave “magic + cookies” on the screen to mark changes in attributes.
+ +The ncurses package can also capture and use
+ event reports from a mouse in some environments (notably, xterm
+ under the X window system). This document includes tips for using
+ the mouse.
The ncurses package was originated by Pavel
+ Curtis. The original maintainer of this package is Zeyd Ben-Halim
+ <zmbenhal@netcom.com>. Eric S. Raymond
+ <esr@snark.thyrsus.com> wrote many of the new features in
+ versions after 1.8.1 and wrote most of this introduction.
+ Jürgen Pfeifer wrote all of the menu and forms code as well
+ as the Ada95 binding.
+ Ongoing work is being done by Thomas Dickey
+ (maintainer). Contact the current maintainers at bug-ncurses@gnu.org.
This document also describes the panels + extension library, similarly modeled on the SVr4 panels facility. + This library allows you to associate backing store with each of a + stack or deck of overlapping windows, and provides operations for + moving windows around in the stack that change their visibility + in the natural way (handling window overlaps).
+ +Finally, this document describes in detail the menus and forms extension + libraries, also cloned from System V, which support easy + construction and sequences of menus and fill-in forms.
+ +In this document, the following terminology is used with + reasonable consistency:
+ +stdscr, is automatically provided for the
+ programmer.In order to use the library, it is necessary to have certain + types and variables defined. Therefore, the programmer must have + a line:
++ #include <curses.h> ++ +
at the top of the program source. The screen package uses the
+ Standard I/O library, so <curses.h> includes
+ <stdio.h>. <curses.h> also
+ includes <termios.h>,
+ <termio.h>, or <sgtty.h>
+ depending on your system. It is redundant (but harmless) for the
+ programmer to do these includes, too. In linking with
+ curses you need to have -lncurses in
+ your LDFLAGS or on the command line. There is no need for any
+ other libraries.
In order to update the screen optimally, it is necessary for
+ the routines to know what the screen currently looks like and
+ what the programmer wants it to look like next. For this purpose,
+ a data type (structure) named WINDOW is defined which describes a
+ window image to the routines, including its starting position on
+ the screen (the (y, x) coordinates of the upper left hand corner)
+ and its size. One of these (called curscr, for
+ current screen) is a screen image of what the terminal currently
+ looks like. Another screen (called stdscr, for
+ standard screen) is provided by default to make changes on.
A window is a purely internal representation. It is used to + build and store a potential image of a portion of the terminal. + It does not bear any necessary relation to what is really on the + terminal screen; it is more like a scratchpad or write + buffer.
+ +To make the section of physical screen corresponding to a
+ window reflect the contents of the window structure, the routine
+ refresh() (or wrefresh() if the window
+ is not stdscr) is called.
A given physical screen section may be within the scope of any + number of overlapping windows. Also, changes can be made to + windows in any order, without regard to motion efficiency. Then, + at will, the programmer can effectively say “make it look + like this,” and let the package implementation determine + the most efficient way to repaint the screen.
+ +As hinted above, the routines can use several windows, but two
+ are automatically given: curscr, which knows what
+ the terminal looks like, and stdscr, which is what
+ the programmer wants the terminal to look like next. The user
+ should never actually access curscr directly.
+ Changes should be made to through the API, and then the routine
+ refresh() (or wrefresh()) called.
Many functions are defined to use stdscr as a
+ default screen. For example, to add a character to
+ stdscr, one calls addch() with the
+ desired character as argument. To write to a different window.
+ use the routine waddch() (for
+ window-specific addch()) is provided. This
+ convention of prepending function names with a “w”
+ when they are to be applied to specific windows is consistent.
+ The only routines which do not follow it are those for which a
+ window must always be specified.
In order to move the current (y, x) coordinates from one point
+ to another, the routines move() and
+ wmove() are provided. However, it is often desirable
+ to first move and then perform some I/O operation. In order to
+ avoid clumsiness, most I/O routines can be preceded by the prefix
+ “mv” and the desired (y, x) coordinates prepended to
+ the arguments to the function. For example, the calls
+ move(y, x); + addch(ch); ++ +
can be replaced by
++ mvaddch(y, x, ch); ++ +
and
++ wmove(win, y, x); + waddch(win, ch); ++ +
can be replaced by
++ mvwaddch(win, y, x, ch); ++ +
Note that the window description pointer (win) comes before + the added (y, x) coordinates. If a function requires a window + pointer, it is always the first parameter passed.
+ +The curses library sets some variables describing
+ the terminal capabilities.
type name description
------------------------------------------------------------------
int LINES number of lines on the terminal
int COLS number of columns on the terminal
-
-
-The curses.h also introduces some #define constants and types
-of general usefulness:
-
-bool
-bool doneit;)
-TRUE
-FALSE
-ERR
-OK
-stdscr. These instructions will
-work on any window, providing you change the function names and parameters as
-mentioned above. - -Here is a sample program to motivate the discussion: - -
++ +
The curses.h also introduces some
+ #define constants and types of general
+ usefulness:
boolbool doneit;)TRUEFALSEERROKNow we describe how to actually use the screen package. In it,
+ we assume all updating, reading, etc. is applied to
+ stdscr. These instructions will work on any window,
+ providing you change the function names and parameters as
+ mentioned above.
Here is a sample program to motivate the discussion:
+
+#include <stdlib.h>
#include <curses.h>
#include <signal.h>
@@ -430,9 +652,9 @@ main(int argc, char *argv[])
/*
* Simple color assignment, often all we need. Color pair 0 cannot
- * be redefined. This example uses the same value for the color
- * pair as for the foreground color, though of course that is not
- * necessary:
+ * be redefined. This example uses the same value for the color
+ * pair as for the foreground color, though of course that is not
+ * necessary:
*/
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
@@ -446,13 +668,13 @@ main(int argc, char *argv[])
for (;;)
{
int c = getch(); /* refresh, accept single keystroke of input */
- attrset(COLOR_PAIR(num % 8));
- num++;
+ attrset(COLOR_PAIR(num % 8));
+ num++;
/* process the command keystroke */
}
- finish(0); /* we're done */
+ finish(0); /* we are done */
}
static void finish(int sig)
@@ -463,1157 +685,1364 @@ static void finish(int sig)
exit(0);
}
-
-
-curscr and stdscr must be
-allocated. These function initscr() does both these things. Since it
-must allocate space for the windows, it can overflow memory when attempting to
-do so. On the rare occasions this happens, initscr() will terminate
-the program with an error message. initscr() must 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 curscr or 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 nl() and cbreak() should be called
-after initscr().
-
-Once the screen windows have been allocated, you can set them up for
-your program. If you want to, say, allow a screen to scroll, use
-scrollok(). If you want the cursor to be left in place after
-the last change, use leaveok(). If this isn't done,
-refresh() will move the cursor to the window's current (y, x)
-coordinates after updating it.
-
-You can create new windows of your own using the functions newwin(),
-derwin(), and subwin(). The routine delwin() will
-allow you to get rid of old windows. All the options described above can be
-applied to any window.
-
-
addch() and move(). addch() adds a character at the
-current (y, x) coordinates. move() changes the current (y, x)
-coordinates to whatever you want them to be. It returns ERR if you
-try to move off the window. As mentioned above, you can combine the two into
-mvaddch() to do both things at once.
-
-The other output functions, such as addstr() and printw(),
-all call addch() to add characters to the window.
-
-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
-refresh(). In order to optimize finding changes, refresh()
-assumes that any part of the window not changed since the last
-refresh() of that window has not been changed on the terminal, i.e.,
-that you have not refreshed a portion of the terminal with an overlapping
-window. If this is not the case, the routine touchwin() is provided
-to make it look like the entire window has been changed, thus making
-refresh() check the whole subsection of the terminal for changes.
-
-If you call wrefresh() with curscr as its argument, it will
-make the screen look like curscr thinks it looks like. This is useful
-for implementing a command which would redraw the screen in case it get messed
-up.
-
-
addch() is getch() which, if
-echo is set, will call 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. Since
-initially the terminal has echoing enabled and is in ordinary ``cooked'' mode,
-one or the other has to changed before calling getch(); otherwise,
-the program's output will be unpredictable.
-
-When you need to accept line-oriented input in a window, the functions
-wgetstr() and friends are available. There is even a wscanw()
-function that can do scanf()(3)-style multi-field parsing on window
-input. These pseudo-line-oriented functions turn on echoing while they
-execute.
-
-The example code above uses the call keypad(stdscr, TRUE) to enable
-support for function-key mapping. With this feature, the getch() code
-watches the input stream for character sequences that correspond to arrow and
-function keys. These sequences are returned as pseudo-character values. The
-#define values returned are listed in the curses.h The
-mapping from sequences to #define values is determined by
-key_ capabilities in the terminal's terminfo entry.
-
-
addch() function (and some others, including box() and
-border()) can accept some pseudo-character arguments which are specially
-defined by ncurses. These are #define values set up in
-the curses.h header; see there for a complete list (look for
-the prefix ACS_).
-
-The most useful of the ACS defines are the forms-drawing characters. You can
-use these to draw boxes and simple graphs on the screen. If the terminal
-does not have such characters, curses.h will map them to a
-recognizable (though ugly) set of ASCII defaults.
-
-
ncurses package supports screen highlights including standout,
-reverse-video, underline, and blink. It also supports color, which is treated
-as another kind of highlight.
-
-Highlights are encoded, internally, as high bits of the pseudo-character type
-(chtype) that curses.h uses to represent the contents of a
-screen cell. See the curses.h header file for a complete list of
-highlight mask values (look for the prefix A_).
-
-There are two ways to make highlights. One is to logical-or the value of the
-highlights you want into the character argument of an addch() call,
-or any other output call that takes a chtype argument.
-
-The other is to set the current-highlight value. This is logical-or'ed with
-any highlight you specify the first way. You do this with the functions
-attron(), attroff(), and attrset(); see the manual
-pages for details.
-
-Color is a special kind of highlight. The package actually thinks in terms
-of color pairs, combinations of foreground and background colors. The sample
-code above sets up eight color pairs, all of the guaranteed-available colors
-on black. Note that each color pair is, in effect, given the name of its
-foreground color. Any other range of eight non-conflicting values could
-have been used as the first arguments of the init_pair() values.
-
-Once you've done an init_pair() that creates color-pair N, you can
-use COLOR_PAIR(N) as a highlight that invokes that particular
-color combination. Note that COLOR_PAIR(N), for constant N,
-is itself a compile-time constant and can be used in initializers.
-
-
ncurses library also provides a mouse interface.
-
-
-NOTE: this facility is specific to ncurses, it is not part of either
-the XSI Curses standard, nor of System V Release 4, nor BSD curses.
-System V Release 4 curses contains code with similar interface definitions,
-however it is not documented. Other than by disassembling the library, we
-have no way to determine exactly how that mouse code works.
-Thus, we recommend that you wrap mouse-related code in an #ifdef using the
-feature macro NCURSES_MOUSE_VERSION so it will not be compiled and linked
-on non-ncurses systems.
-
-
-Presently, mouse event reporting works in the following environments:
-gpm(1), Alessandro
-Rubini's mouse server.
-
-The mouse interface is very simple. To activate it, you use the function
-mousemask(), passing it as first argument a bit-mask that specifies
-what kinds of events you want your program to be able to see. It will
-return the bit-mask of events that actually become visible, which may differ
-from the argument if the mouse device is not capable of reporting some of
-the event types you specify.
-
-Once the mouse is active, your application's command loop should watch
-for a return value of KEY_MOUSE from wgetch(). When
-you see this, a mouse event report has been queued. To pick it off
-the queue, use the function getmouse() (you must do this before
-the next wgetch(), otherwise another mouse event might come
-in and make the first one inaccessible).
-
-Each call to getmouse() fills a structure (the address of which you'll
-pass it) with mouse event data. The event data includes zero-origin,
-screen-relative character-cell coordinates of the mouse pointer. It also
-includes an event mask. Bits in this mask will be set, corresponding
-to the event type being reported.
- -The mouse structure contains two additional fields which may be -significant in the future as ncurses interfaces to new kinds of -pointing device. In addition to x and y coordinates, there is a slot -for a z coordinate; this might be useful with touch-screens that can -return a pressure or duration parameter. There is also a device ID -field, which could be used to distinguish between multiple pointing -devices.
-
-The class of visible events may be changed at any time via mousemask().
-Events that can be reported include presses, releases, single-, double- and
-triple-clicks (you can set the maximum button-down time for clicks). If
-you don't make clicks visible, they will be reported as press-release
-pairs. In some environments, the event mask may include bits reporting
-the state of shift, alt, and ctrl keys on the keyboard during the event.
- -A function to check whether a mouse event fell within a given window is -also supplied. You can use this to see whether a given window should -consider a mouse event relevant to it.
-
-Because mouse event reporting will not be available in all
-environments, it would be unwise to build ncurses
-applications that require the use of a mouse. Rather, you should
-use the mouse as a shortcut for point-and-shoot commands your application
-would normally accept from the keyboard. Two of the test games in the
-ncurses distribution (bs and knight) contain
-code that illustrates how this can be done.
-
-See the manual page curs_mouse(3X) for full details of the
-mouse-interface functions.
-
-
ncurses routines, the routine
-endwin() is provided. It restores tty modes to what they were when
-initscr() was first called, and moves the cursor down to the
-lower-left corner. Thus, anytime after the call to initscr, endwin()
-should be called before exiting.
-
-initscr()
-initscr().
-This will determine the terminal type and
-initialize curses data structures. initscr() also arranges that
-the first call to refresh() will clear the screen. If an error
-occurs a message is written to standard error and the program
-exits. Otherwise it returns a pointer to stdscr. A few functions may be
-called before initscr (slk_init(), filter(),
-ripofflines(), use_env(), and, if you are using multiple
-terminals, newterm().)
-endwin()
-endwin() before exiting or
-shelling out of the program. This function will restore tty modes,
-move the cursor to the lower left corner of the screen, reset the
-terminal into the proper non-visual mode. Calling refresh()
-or doupdate() after a temporary escape from the program will
-restore the ncurses screen from before the escape.
-newterm(type, ofp, ifp)
-newterm() instead of initscr(). newterm() should
-be called once for each terminal. It returns a variable of type
-SCREEN * which should be saved as a reference to that
-terminal.
-(NOTE: a SCREEN variable is not a screen in the sense we
-are describing in this introduction, but a collection of
-parameters used to assist in optimizing the display.)
-The arguments are the type of the terminal (a string) and
-FILE pointers for the output and input of the terminal. If
-type is NULL then the environment variable $TERM is used.
-endwin() should called once at wrapup time for each terminal
-opened using this function.
-set_term(new)
-newterm(). The screen reference for the new terminal
-is passed as the parameter. The previous terminal is returned by the
-function. All other calls affect only the current terminal.
-delscreen(sp)
-newterm(); deallocates the data structures
-associated with a given SCREEN reference.
-refresh() and wrefresh(win)
-wrefresh() copies the named window to the physical
-terminal screen, taking into account what is already
-there in order to do optimizations. refresh() does a
-refresh of stdscr(). Unless leaveok() has been
-enabled, the physical cursor of the terminal is left at the
-location of the window's cursor.
-doupdate() and wnoutrefresh(win)
-wnoutrefresh()), and then calling the routine to update the
-screen (doupdate()). If the programmer wishes to output
-several windows at once, a series of calls to wrefresh will result
-in alternating calls to wnoutrefresh() and doupdate(),
-causing several bursts of output to the screen. By calling
-wnoutrefresh() for each window, it is then possible to call
-doupdate() once, resulting in only one burst of output, with
-fewer total characters transmitted (this also avoids a visually annoying
-flicker at each update).
-setupterm(term, filenum, errret)
-term is the character string representing the name of the terminal
-being used. filenum is the UNIX file descriptor of the terminal to
-be used for output. errret is a pointer to an integer, in which a
-success or failure indication is returned. The values returned can be 1 (all
-is well), 0 (no such terminal), or -1 (some problem locating the terminfo
-database).
-
-The value of term can be given as NULL, which will cause the value of
-TERM in the environment to be used. The errret pointer can
-also be given as NULL, meaning no error code is wanted. If errret is
-defaulted, and something goes wrong, setupterm() will print an
-appropriate error message and exit, rather than returning. Thus, a simple
-program can call setupterm(0, 1, 0) and not worry about initialization
-errors.
-
-After the call to setupterm(), the global variable cur_term is
-set to point to the current structure of terminal capabilities. By calling
-setupterm() for each terminal, and saving and restoring
-cur_term, it is possible for a program to use two or more terminals at
-once. Setupterm() also stores the names section of the terminal
-description in the global character array ttytype[]. Subsequent calls
-to setupterm() will overwrite this array, so you'll have to save it
-yourself if need be.
-
-NOTE: These functions are not part of the standard curses API! -- -
trace()
-TRACE_ defines
-in the curses.h file for details. (It is also possible to set
-a trace level by assigning a trace level value to the environment variable
-NCURSES_TRACE).
-_tracef()
-printf(), only it outputs a newline after the end of arguments.
-The output goes to a file called trace in the current directory.
-ncurses distribution that can alleviate
-this problem somewhat; it compacts long sequences of similar operations into
-more succinct single-line pseudo-operations. These pseudo-ops can be
-distinguished by the fact that they are named in capital letters.
-
-ncurses manual pages are a complete reference for this library.
-In the remainder of this document, we discuss various useful methods that
-may not be obvious from the manual page descriptions.
-
-noraw() or
-nocbreak(), think again and move carefully. It's probably
-better design to use getstr() or one of its relatives to
-simulate cooked mode. The noraw() and nocbreak()
-functions try to restore cooked mode, but they may end up clobbering
-some control bits set before you started your application. Also, they
-have always been poorly documented, and are likely to hurt your
-application's usability with other curses libraries.
-
-Bear in mind that refresh() is a synonym for wrefresh(stdscr).
-Don't try to mix use of stdscr with use of windows declared
-by newwin(); a refresh() call will blow them off the
-screen. The right way to handle this is to use subwin(), or
-not touch stdscr at all and tile your screen with declared
-windows which you then wnoutrefresh() somewhere in your program
-event loop, with a single doupdate() call to trigger actual
-repainting.
-
-You are much less likely to run into problems if you design your screen
-layouts to use tiled rather than overlapping windows. Historically,
-curses support for overlapping windows has been weak, fragile, and poorly
-documented. The ncurses library is not yet an exception to this
-rule.
-
-There is a panels library included in the ncurses
-distribution that does a pretty good job of strengthening the
-overlapping-windows facilities.
-
-Try to avoid using the global variables LINES and COLS. Use
-getmaxyx() on the stdscr context instead. Reason:
-your code may be ported to run in an environment with window resizes,
-in which case several screens could be open with different sizes.
-
-
ncurses.
-
-To leave ncurses mode, call endwin() as you would if you
-were intending to terminate the program. This will take the screen back to
-cooked mode; you can do your shell-out. When you want to return to
-ncurses mode, simply call refresh() or doupdate().
-This will repaint the screen.
-
-There is a boolean function, isendwin(), which code can use to
-test whether ncurses screen mode is active. It returns TRUE
-in the interval between an endwin() call and the following
-refresh(), FALSE otherwise.
- -Here is some sample code for shellout: - -
++ +
In order to use the screen package, the routines must know
+ about terminal characteristics, and the space for
+ curscr and stdscr must be allocated.
+ These function initscr() does both these things.
+ Since it must allocate space for the windows, it can overflow
+ memory when attempting to do so. On the rare occasions this
+ happens, initscr() will terminate the program with
+ an error message. initscr() must 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
+ curscr or 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 nl()
+ and cbreak() should be called after
+ initscr().
Once the screen windows have been allocated, you can set them
+ up for your program. If you want to, say, allow a screen to
+ scroll, use scrollok(). If you want the cursor to be
+ left in place after the last change, use leaveok().
+ If this is not done, refresh() will move the cursor
+ to the window's current (y, x) coordinates after updating it.
You can create new windows of your own using the functions
+ newwin(), derwin(), and
+ subwin(). The routine delwin() will
+ allow you to get rid of old windows. All the options described
+ above can be applied to any window.
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 addch() and move().
+ addch() adds a character at the current (y, x)
+ coordinates. move() changes the current (y, x)
+ coordinates to whatever you want them to be. It returns
+ ERR if you try to move off the window. As mentioned
+ above, you can combine the two into mvaddch() to do
+ both things at once.
The other output functions, such as addstr() and
+ printw(), all call addch() to add
+ characters to the window.
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 refresh(). In order
+ to optimize finding changes, refresh() assumes that
+ any part of the window not changed since the last
+ refresh() of that window has not been changed on the
+ terminal, i.e., that you have not refreshed a portion of the
+ terminal with an overlapping window. If this is not the case, the
+ routine touchwin() is provided to make it look like
+ the entire window has been changed, thus making
+ refresh() check the whole subsection of the terminal
+ for changes.
If you call wrefresh() with curscr
+ as its argument, it will make the screen look like
+ curscr thinks it looks like. This is useful for
+ implementing a command which would redraw the screen in case it
+ get messed up.
The complementary function to addch() is
+ getch() which, if echo is set, will call
+ 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. Since initially the terminal has echoing enabled and is in
+ ordinary “cooked” mode, one or the other has to
+ changed before calling getch(); otherwise, the
+ program's output will be unpredictable.
When you need to accept line-oriented input in a window, the
+ functions wgetstr() and friends are available. There
+ is even a wscanw() function that can do
+ scanf()(3)-style multi-field parsing on window
+ input. These pseudo-line-oriented functions turn on echoing while
+ they execute.
The example code above uses the call keypad(stdscr,
+ TRUE) to enable support for function-key mapping. With
+ this feature, the getch() code watches the input
+ stream for character sequences that correspond to arrow and
+ function keys. These sequences are returned as pseudo-character
+ values. The #define values returned are listed in
+ the curses.h The mapping from sequences to
+ #define values is determined by key_
+ capabilities in the terminal's terminfo entry.
The addch() function (and some others, including
+ box() and border()) can accept some
+ pseudo-character arguments which are specially defined by
+ ncurses. These are #define values set
+ up in the curses.h header; see there for a complete
+ list (look for the prefix ACS_).
The most useful of the ACS defines are the forms-drawing
+ characters. You can use these to draw boxes and simple graphs on
+ the screen. If the terminal does not have such characters,
+ curses.h will map them to a recognizable (though
+ ugly) set of ASCII defaults.
The ncurses package supports screen highlights
+ including standout, reverse-video, underline, and blink. It also
+ supports color, which is treated as another kind of
+ highlight.
Highlights are encoded, internally, as high bits of the
+ pseudo-character type (chtype) that
+ curses.h uses to represent the contents of a screen
+ cell. See the curses.h header file for a complete
+ list of highlight mask values (look for the prefix
+ A_).
There are two ways to make highlights. One is to logical-or
+ the value of the highlights you want into the character argument
+ of an addch() call, or any other output call that
+ takes a chtype argument.
The other is to set the current-highlight value. This is
+ logical-ORed with any highlight you specify the first
+ way. You do this with the functions attron(),
+ attroff(), and attrset(); see the
+ manual pages for details. Color is a special kind of highlight.
+ The package actually thinks in terms of color pairs, combinations
+ of foreground and background colors. The sample code above sets
+ up eight color pairs, all of the guaranteed-available colors on
+ black. Note that each color pair is, in effect, given the name of
+ its foreground color. Any other range of eight non-conflicting
+ values could have been used as the first arguments of the
+ init_pair() values.
Once you have done an init_pair() that creates
+ color-pair N, you can use COLOR_PAIR(N) as a
+ highlight that invokes that particular color combination. Note
+ that COLOR_PAIR(N), for constant N, is itself a
+ compile-time constant and can be used in initializers.
The ncurses library also provides a mouse
+ interface.
+ NOTE: this facility is specific to
+ ncurses, it is not part of either the XSI Curses
+ standard, nor of System V Release 4, nor BSD curses. System V
+ Release 4 curses contains code with similar interface
+ definitions, however it is not documented. Other than by
+ disassembling the library, we have no way to determine exactly
+ how that mouse code works. Thus, we recommend that you wrap
+ mouse-related code in an #ifdef using the feature macro
+ NCURSES_MOUSE_VERSION so it will not be compiled and linked on
+ non-ncurses systems.
+
+
+ Presently, mouse event reporting works in the following + environments:
+ +gpm(1),
+ Alessandro Rubini's mouse server.The mouse interface is very simple. To activate it, you use
+ the function mousemask(), passing it as first
+ argument a bit-mask that specifies what kinds of events you want
+ your program to be able to see. It will return the bit-mask of
+ events that actually become visible, which may differ from the
+ argument if the mouse device is not capable of reporting some of
+ the event types you specify.
Once the mouse is active, your application's command loop
+ should watch for a return value of KEY_MOUSE from
+ wgetch(). When you see this, a mouse event report
+ has been queued. To pick it off the queue, use the function
+ getmouse() (you must do this before the next
+ wgetch(), otherwise another mouse event might come
+ in and make the first one inaccessible).
Each call to getmouse() fills a structure (the
+ address of which you will pass it) with mouse event data. The
+ event data includes zero-origin, screen-relative character-cell
+ coordinates of the mouse pointer. It also includes an event mask.
+ Bits in this mask will be set, corresponding to the event type
+ being reported.
The mouse structure contains two additional fields which may + be significant in the future as ncurses interfaces to new kinds + of pointing device. In addition to x and y coordinates, there is + a slot for a z coordinate; this might be useful with + touch-screens that can return a pressure or duration parameter. + There is also a device ID field, which could be used to + distinguish between multiple pointing devices.
+ +The class of visible events may be changed at any time via
+ mousemask(). Events that can be reported include
+ presses, releases, single-, double- and triple-clicks (you can
+ set the maximum button-down time for clicks). If you do not make
+ clicks visible, they will be reported as press-release pairs. In
+ some environments, the event mask may include bits reporting the
+ state of shift, alt, and ctrl keys on the keyboard during the
+ event.
A function to check whether a mouse event fell within a given + window is also supplied. You can use this to see whether a given + window should consider a mouse event relevant to it.
+ +Because mouse event reporting will not be available in all
+ environments, it would be unwise to build ncurses
+ applications that require the use of a mouse. Rather,
+ you should use the mouse as a shortcut for point-and-shoot
+ commands your application would normally accept from the
+ keyboard. Two of the test games in the ncurses
+ distribution (bs and knight) contain
+ code that illustrates how this can be done.
See the manual page curs_mouse(3X) for full
+ details of the mouse-interface functions.
In order to clean up after the ncurses routines,
+ the routine endwin() is provided. It restores tty
+ modes to what they were when initscr() was first
+ called, and moves the cursor down to the lower-left corner. Thus,
+ anytime after the call to initscr, endwin() should
+ be called before exiting.
We describe the detailed behavior of some important curses + functions here, as a supplement to the manual page + descriptions.
+ +initscr()initscr(). This will determine the terminal type
+ and initialize curses data structures. initscr()
+ also arranges that the first call to refresh()
+ will clear the screen. If an error occurs a message is written
+ to standard error and the program exits. Otherwise it returns a
+ pointer to stdscr. A few functions may be called before initscr
+ (slk_init(), filter(),
+ ripoffline(), use_env(), and, if you
+ are using multiple terminals, newterm().)endwin()endwin()
+ before exiting or shelling out of the program. This function
+ will restore tty modes, move the cursor to the lower left
+ corner of the screen, reset the terminal into the proper
+ non-visual mode. Calling refresh() or
+ doupdate() after a temporary escape from the
+ program will restore the ncurses screen from before the
+ escape.newterm(type, ofp, ifp)newterm() instead of initscr().
+ newterm() should be called once for each terminal.
+ It returns a variable of type SCREEN * which
+ should be saved as a reference to that terminal. (NOTE: a
+ SCREEN variable is not a screen in the sense we are
+ describing in this introduction, but a collection of parameters
+ used to assist in optimizing the display.) The arguments are
+ the type of the terminal (a string) and FILE
+ pointers for the output and input of the terminal. If type is
+ NULL then the environment variable $TERM is used.
+ endwin() should called once at wrapup time for
+ each terminal opened using this function.set_term(new)newterm(). The screen
+ reference for the new terminal is passed as the parameter. The
+ previous terminal is returned by the function. All other calls
+ affect only the current terminal.delscreen(sp)newterm(); deallocates the data
+ structures associated with a given SCREEN
+ reference.refresh() and wrefresh(win)wrefresh() copies the named window to
+ the physical terminal screen, taking into account what is
+ already there in order to do optimizations.
+ refresh() does a refresh of stdscr.
+ Unless leaveok() has been enabled, the physical
+ cursor of the terminal is left at the location of the window's
+ cursor.doupdate() and
+ wnoutrefresh(win)wnoutrefresh()), and then calling the routine to
+ update the screen (doupdate()). If the programmer
+ wishes to output several windows at once, a series of calls to
+ wrefresh will result in alternating calls to
+ wnoutrefresh() and doupdate(),
+ causing several bursts of output to the screen. By calling
+ wnoutrefresh() for each window, it is then
+ possible to call doupdate() once, resulting in
+ only one burst of output, with fewer total characters
+ transmitted (this also avoids a visually annoying flicker at
+ each update).setupterm(term, filenum, errret)term is
+ the character string representing the name of the terminal
+ being used. filenum is the UNIX file descriptor
+ of the terminal to be used for output. errret is
+ a pointer to an integer, in which a success or failure
+ indication is returned. The values returned can be 1 (all is
+ well), 0 (no such terminal), or -1 (some problem locating the
+ terminfo database).
+
+ The value of term can be given as NULL, which
+ will cause the value of TERM in the environment
+ to be used. The errret pointer can also be given
+ as NULL, meaning no error code is wanted. If
+ errret is defaulted, and something goes wrong,
+ setupterm() will print an appropriate error
+ message and exit, rather than returning. Thus, a simple
+ program can call setupterm(0, 1, 0) and not worry about
+ initialization errors.
After the call to setupterm(), the global
+ variable cur_term is set to point to the current
+ structure of terminal capabilities. By calling
+ setupterm() for each terminal, and saving and
+ restoring cur_term, it is possible for a program
+ to use two or more terminals at once.
+ Setupterm() also stores the names section of the
+ terminal description in the global character array
+ ttytype[]. Subsequent calls to
+ setupterm() will overwrite this array, so you
+ will have to save it yourself if need be.
+ NOTE: These functions are not part of the + standard curses API! ++ +
trace()TRACE_
+ defines in the curses.h file for details. (It is
+ also possible to set a trace level by assigning a trace level
+ value to the environment variable
+ NCURSES_TRACE)._tracef()printf(), only it outputs a newline after the end
+ of arguments. The output goes to a file called
+ trace in the current directory.Trace logs can be difficult to interpret due to the sheer
+ volume of data dumped in them. There is a script called
+ tracemunch included with the
+ ncurses distribution that can alleviate this problem
+ somewhat; it compacts long sequences of similar operations into
+ more succinct single-line pseudo-operations. These pseudo-ops can
+ be distinguished by the fact that they are named in capital
+ letters.
The ncurses manual pages are a complete reference
+ for this library. In the remainder of this document, we discuss
+ various useful methods that may not be obvious from the manual
+ page descriptions.
If you find yourself thinking you need to use
+ noraw() or nocbreak(), think again and
+ move carefully. It is probably better design to use
+ getstr() or one of its relatives to simulate cooked
+ mode. The noraw() and nocbreak()
+ functions try to restore cooked mode, but they may end up
+ clobbering some control bits set before you started your
+ application. Also, they have always been poorly documented, and
+ are likely to hurt your application's usability with other curses
+ libraries.
Bear in mind that refresh() is a synonym for
+ wrefresh(stdscr). Do not try to mix use of
+ stdscr with use of windows declared by
+ newwin(); a refresh() call will blow
+ them off the screen. The right way to handle this is to use
+ subwin(), or not touch stdscr at all
+ and tile your screen with declared windows which you then
+ wnoutrefresh() somewhere in your program event loop,
+ with a single doupdate() call to trigger actual
+ repainting.
You are much less likely to run into problems if you design
+ your screen layouts to use tiled rather than overlapping windows.
+ Historically, curses support for overlapping windows has been
+ weak, fragile, and poorly documented. The ncurses
+ library is not yet an exception to this rule.
There is a panels library included in the ncurses
+ distribution that does a pretty good job of strengthening the
+ overlapping-windows facilities.
Try to avoid using the global variables LINES and COLS. Use
+ getmaxyx() on the stdscr context
+ instead. Reason: your code may be ported to run in an environment
+ with window resizes, in which case several screens could be open
+ with different sizes.
Sometimes you will want to write a program that spends most of
+ its time in screen mode, but occasionally returns to ordinary
+ “cooked” mode. A common reason for this is to support
+ shell-out. This behavior is simple to arrange in
+ ncurses.
To leave ncurses mode, call endwin()
+ as you would if you were intending to terminate the program. This
+ will take the screen back to cooked mode; you can do your
+ shell-out. When you want to return to ncurses mode,
+ simply call refresh() or doupdate().
+ This will repaint the screen.
There is a boolean function, isendwin(), which
+ code can use to test whether ncurses screen mode is
+ active. It returns TRUE in the interval between an
+ endwin() call and the following
+ refresh(), FALSE otherwise.
Here is some sample code for shellout:
+
addstr("Shelling out...");
def_prog_mode(); /* save current tty modes */
endwin(); /* restore original tty modes */
system("sh"); /* run shell */
addstr("returned.\n"); /* prepare return message */
refresh(); /* restore save modes, repaint screen */
-
-
-ncurses library provides an experimental signal
-handler, but in general does not catch this signal, because it cannot
-know how you want the screen re-painted. You will usually have to write the
-SIGWINCH handler yourself. Ncurses can give you some help.
-
-The easiest way to code your SIGWINCH handler is to have it do an
-endwin, followed by an refresh and a screen repaint you code
-yourself. The refresh will pick up the new screen size from the
-xterm's environment.
-
-That is the standard way, of course (it even works with some vendor's curses
-implementations).
-Its drawback is that it clears the screen to reinitialize the display, and does
-not resize subwindows which must be shrunk.
-Ncurses provides an extension which works better, the
-resizeterm function. That function ensures that all windows
-are limited to the new screen dimensions, and pads stdscr
-with blanks if the screen is larger.
-
-Finally, ncurses can be configured to provide its own SIGWINCH handler,
-based on resizeterm.
-
-
initscr() function actually calls a function named
-newterm() to do most of its work. If you are writing a program that
-opens multiple terminals, use newterm() directly.
-
-For each call, you will have to specify a terminal type and a pair of file
-pointers; each call will return a screen reference, and stdscr will be
-set to the last one allocated. You will switch between screens with the
-set_term call. Note that you will also have to call
-def_shell_mode and def_prog_mode on each tty yourself.
-
-
ncurses mode. An easy
-way to do this is to call setupterm(), then use the functions
-tigetflag(), tigetnum(), and tigetstr() to do your
-testing.
-
-A particularly useful case of this often comes up when you want to
-test whether a given terminal type should be treated as `smart'
-(cursor-addressable) or `stupid'. The right way to test this is to see
-if the return value of tigetstr("cup") is non-NULL. Alternatively,
-you can include the term.h file and test the value of the
-macro cursor_address.
-
-
addchstr() family of functions for fast
-screen-painting of text when you know the text doesn't contain any
-control characters. Try to make attribute changes infrequent on your
-screens. Don't use the immedok() option!
-
-wresize() function allows you to resize a window in place.
-The associated resizeterm() function simplifies the construction
-of SIGWINCH handlers, for resizing all windows.
-
-The define_key() function allows you
-to define at runtime function-key control sequences which are not in the
-terminal description.
-The keyok() function allows you to temporarily
-enable or disable interpretation of any function-key control sequence.
-
-The use_default_colors() function allows you to construct
-applications which can use the terminal's default foreground and
-background colors as an additional "default" color.
-Several terminal emulators support this feature, which is based on ISO 6429.
- -Ncurses supports up 16 colors, unlike SVr4 curses which defines only 8. -While most terminals which provide color allow only 8 colors, about -a quarter (including XFree86 xterm) support 16 colors. - -
ncurses
-and the (undocumented!) behavior of older curses implementations. These arise
-from ambiguities or omissions in the documentation of the API.
-
-curses versions were often not documented precisely. - -To understand why this is a problem, remember that screen updates are -calculated between two representations of the entire display. The -documentation says that when you refresh a window, it is first copied to to the -virtual screen, and then changes are calculated to update the physical screen -(and applied to the terminal). But "copied to" is not very specific, and -subtle differences in how copying works can produce different behaviors in the -case where two overlapping windows are each being refreshed at unpredictable -intervals.
-
-What happens to the overlapping region depends on what wnoutrefresh()
-does with its argument -- what portions of the argument window it copies to the
-virtual screen. Some implementations do "change copy", copying down only
-locations in the window that have changed (or been marked changed with
-wtouchln() and friends). Some implementations do "entire copy",
-copying all window locations to the virtual screen whether or not
-they have changed.
-
-The ncurses library itself has not always been consistent on this
-score. Due to a bug, versions 1.8.7 to 1.9.8a did entire copy. Versions
-1.8.6 and older, and versions 1.9.9 and newer, do change copy.
-
-For most commercial curses implementations, it is not documented and not known
-for sure (at least not to the ncurses maintainers) whether they do
-change copy or entire copy. We know that System V release 3 curses has logic
-in it that looks like an attempt to do change copy, but the surrounding logic
-and data representations are sufficiently complex, and our knowledge
-sufficiently indirect, that it's hard to know whether this is reliable.
-
-It is not clear what the SVr4 documentation and XSI standard intend. The XSI
-Curses standard barely mentions wnoutrefresh(); the SVr4 documents seem to be
-describing entire-copy, but it is possible with some effort and straining to
-read them the other way.
-
-It might therefore be unwise to rely on either behavior in programs that might
-have to be linked with other curses implementations. Instead, you can do an
-explicit touchwin() before the wnoutrefresh() call to
-guarantee an entire-contents copy anywhere.
-
-The really clean way to handle this is to use the panels library. If,
-when you want a screen update, you do update_panels(), it will
-do all the necessary wnoutrfresh() calls for whatever panel
-stacking order you have defined. Then you can do one doupdate()
-and there will be a single burst of physical I/O that will do
-all your updates.
-
-
ncurses (1.8.7 or
-older) you may be surprised by the behavior of the erase functions. In older
-versions, erased areas of a window were filled with a blank modified by the
-window's current attribute (as set by wattrset(), wattron(),
-wattroff() and friends).
-
-In newer versions, this is not so. Instead, the attribute of erased blanks
-is normal unless and until it is modified by the functions bkgdset()
-or wbkgdset().
-
-This change in behavior conforms ncurses to System V Release 4 and
-the XSI Curses standard.
-
-
ncurses library is intended to be base-level conformant with the
-XSI Curses standard from X/Open. Many extended-level features (in fact, almost
-all features not directly concerned with wide characters and
-internationalization) are also supported. - -One effect of XSI conformance is the change in behavior described under -"Background Erase -- Compatibility with Old Versions".
-
-Also, ncurses meets the XSI requirement that every macro
-entry point have a corresponding function which may be linked (and
-will be prototype-checked) if the macro definition is disabled with
-#undef.
-
-
ncurses library by itself provides good support for screen
-displays in which the windows are tiled (non-overlapping). In the more
-general case that windows may overlap, you have to use a series of
-wnoutrefresh() calls followed by a doupdate(), and be
-careful about the order you do the window refreshes in. It has to be
-bottom-upwards, otherwise parts of windows that should be obscured will
-show through. - -When your interface design is such that windows may dive deeper into the -visibility stack or pop to the top at runtime, the resulting book-keeping -can be tedious and difficult to get right. Hence the panels library.
-
-The panel library first appeared in AT&T System V. The
-version documented here is the panel code distributed
-with ncurses.
-
-
- #include <panel.h> -- -and must be linked explicitly with the panels library using an -
-lpanel argument. Note that they must also link the
-ncurses library with -lncurses. Many linkers
-are two-pass and will accept either order, but it is still good practice
-to put -lpanel first and -lncurses second.
-
-refresh()) that displays all panels in the
-deck in the proper order to resolve overlaps. The standard window,
-stdscr, is considered below all panels. - -Details on the panels functions are available in the man pages. We'll just -hit the highlights here.
-
-You create a panel from a window by calling new_panel() on a
-window pointer. It then becomes the top of the deck. The panel's window
-is available as the value of panel_window() called with the
-panel pointer as argument.
-
-You can delete a panel (removing it from the deck) with del_panel.
-This will not deallocate the associated window; you have to do that yourself.
+
+
+
A resize operation in X sends SIGWINCH to the
+ application running under xterm. The easiest way to handle
+ SIGWINCH is to do an endwin, followed
+ by an refresh and a screen repaint you code
+ yourself. The refresh will pick up the new screen
+ size from the xterm's environment.
That is the standard way, of course (it even works with some
+ vendor's curses implementations). Its drawback is that it clears
+ the screen to reinitialize the display, and does not resize
+ subwindows which must be shrunk. Ncurses provides an
+ extension which works better, the resizeterm
+ function. That function ensures that all windows are limited to
+ the new screen dimensions, and pads stdscr with
+ blanks if the screen is larger.
The ncurses library provides a SIGWINCH signal
+ handler, which pushes a KEY_RESIZE via the wgetch()
+ calls. When ncurses returns that code, it calls
+ resizeterm to update the size of the standard
+ screen's window, repainting that (filling with blanks or
+ truncating as needed). It also resizes other windows, but its
+ effect may be less satisfactory because it cannot know how you
+ want the screen re-painted. You will usually have to write
+ special-purpose code to handle KEY_RESIZE
+ yourself.
The initscr() function actually calls a function
+ named newterm() to do most of its work. If you are
+ writing a program that opens multiple terminals, use
+ newterm() directly.
For each call, you will have to specify a terminal type and a
+ pair of file pointers; each call will return a screen reference,
+ and stdscr will be set to the last one allocated.
+ You will switch between screens with the set_term
+ call. Note that you will also have to call
+ def_shell_mode and def_prog_mode on
+ each tty yourself.
Sometimes you may want to write programs that test for the
+ presence of various capabilities before deciding whether to go
+ into ncurses mode. An easy way to do this is to call
+ setupterm(), then use the functions
+ tigetflag(), tigetnum(), and
+ tigetstr() to do your testing.
A particularly useful case of this often comes up when you
+ want to test whether a given terminal type should be treated as
+ “smart” (cursor-addressable) or “stupid”.
+ The right way to test this is to see if the return value of
+ tigetstr("cup") is non-NULL. Alternatively, you can
+ include the term.h file and test the value of the
+ macro cursor_address.
Use the addchstr() family of functions for fast
+ screen-painting of text when you know the text does not contain
+ any control characters. Try to make attribute changes infrequent
+ on your screens. Do not use the immedok()
+ option!
The wresize() function allows you to resize a
+ window in place. The associated resizeterm()
+ function simplifies the construction of SIGWINCH handlers, for resizing all windows.
The define_key() function allows you to define at
+ runtime function-key control sequences which are not in the
+ terminal description. The keyok() function allows
+ you to temporarily enable or disable interpretation of any
+ function-key control sequence.
The use_default_colors() function allows you to
+ construct applications which can use the terminal's default
+ foreground and background colors as an additional "default"
+ color. Several terminal emulators support this feature, which is
+ based on ISO 6429.
Ncurses supports up 16 colors, unlike SVr4 curses which + defines only 8. While most terminals which provide color allow + only 8 colors, about a quarter (including XFree86 xterm) support + 16 colors.
+ +Despite our best efforts, there are some differences between
+ ncurses and the (undocumented!) behavior of older
+ curses implementations. These arise from ambiguities or omissions
+ in the documentation of the API.
If you define two windows A and B that overlap, and then
+ alternately scribble on and refresh them, the changes made to the
+ overlapping region under historic curses versions
+ were often not documented precisely.
To understand why this is a problem, remember that screen + updates are calculated between two representations of the + entire display. The documentation says that when you + refresh a window, it is first copied to the virtual screen, and + then changes are calculated to update the physical screen (and + applied to the terminal). But "copied to" is not very specific, + and subtle differences in how copying works can produce different + behaviors in the case where two overlapping windows are each + being refreshed at unpredictable intervals.
+ +What happens to the overlapping region depends on what
+ wnoutrefresh() does with its argument -- what
+ portions of the argument window it copies to the virtual screen.
+ Some implementations do "change copy", copying down only
+ locations in the window that have changed (or been marked changed
+ with wtouchln() and friends). Some implementations
+ do "entire copy", copying all window locations to the
+ virtual screen whether or not they have changed.
The ncurses library itself has not always been
+ consistent on this score. Due to a bug, versions 1.8.7 to 1.9.8a
+ did entire copy. Versions 1.8.6 and older, and versions 1.9.9 and
+ newer, do change copy.
For most commercial curses implementations, it is not
+ documented and not known for sure (at least not to the
+ ncurses maintainers) whether they do change copy or
+ entire copy. We know that System V release 3 curses has logic in
+ it that looks like an attempt to do change copy, but the
+ surrounding logic and data representations are sufficiently
+ complex, and our knowledge sufficiently indirect, that it is hard
+ to know whether this is reliable. It is not clear what the SVr4
+ documentation and XSI standard intend. The XSI Curses standard
+ barely mentions wnoutrefresh(); the SVr4 documents seem to be
+ describing entire-copy, but it is possible with some effort and
+ straining to read them the other way.
It might therefore be unwise to rely on either behavior in
+ programs that might have to be linked with other curses
+ implementations. Instead, you can do an explicit
+ touchwin() before the wnoutrefresh()
+ call to guarantee an entire-contents copy anywhere.
The really clean way to handle this is to use the panels
+ library. If, when you want a screen update, you do
+ update_panels(), it will do all the necessary
+ wnoutrefresh() calls for whatever panel stacking
+ order you have defined. Then you can do one
+ doupdate() and there will be a single burst
+ of physical I/O that will do all your updates.
If you have been using a very old versions of
+ ncurses (1.8.7 or older) you may be surprised by the
+ behavior of the erase functions. In older versions, erased areas
+ of a window were filled with a blank modified by the window's
+ current attribute (as set by wattrset(),
+ wattron(), wattroff() and
+ friends).
In newer versions, this is not so. Instead, the attribute of
+ erased blanks is normal unless and until it is modified by the
+ functions bkgdset() or wbkgdset().
This change in behavior conforms ncurses to
+ System V Release 4 and the XSI Curses standard.
The ncurses library is intended to be base-level
+ conformant with the XSI Curses standard from X/Open. Many
+ extended-level features (in fact, almost all features not
+ directly concerned with wide characters and internationalization)
+ are also supported.
One effect of XSI conformance is the change in behavior + described under "Background Erase -- + Compatibility with Old Versions".
+ +Also, ncurses meets the XSI requirement that
+ every macro entry point have a corresponding function which may
+ be linked (and will be prototype-checked) if the macro definition
+ is disabled with #undef.
The ncurses library by itself provides good
+ support for screen displays in which the windows are tiled
+ (non-overlapping). In the more general case that windows may
+ overlap, you have to use a series of wnoutrefresh()
+ calls followed by a doupdate(), and be careful about
+ the order you do the window refreshes in. It has to be
+ bottom-upwards, otherwise parts of windows that should be
+ obscured will show through.
When your interface design is such that windows may dive + deeper into the visibility stack or pop to the top at runtime, + the resulting book-keeping can be tedious and difficult to get + right. Hence the panels library.
+ +The panel library first appeared in AT&T
+ System V. The version documented here is the panel
+ code distributed with ncurses.
Your panels-using modules must import the panels library + declarations with
++ #include <panel.h> ++ +
and must be linked explicitly with the panels library using an
+ -lpanel argument. Note that they must also link the
+ ncurses library with -lncurses. Many
+ linkers are two-pass and will accept either order, but it is
+ still good practice to put -lpanel first and
+ -lncurses second.
A panel object is a window that is implicitly treated as part
+ of a deck including all other panel objects. The deck
+ has an implicit bottom-to-top visibility order. The panels
+ library includes an update function (analogous to
+ refresh()) that displays all panels in the deck in
+ the proper order to resolve overlaps. The standard window,
+ stdscr, is considered below all panels.
Details on the panels functions are available in the man + pages. We will just hit the highlights here.
+ +You create a panel from a window by calling
+ new_panel() on a window pointer. It then becomes the
+ top of the deck. The panel's window is available as the value of
+ panel_window() called with the panel pointer as
+ argument.
You can delete a panel (removing it from the deck) with
+ del_panel. This will not deallocate the associated
+ window; you have to do that yourself. You can replace a panel's
+ window with a different window by calling
+ replace_window. The new window may be of different
+ size; the panel code will re-compute all overlaps. This operation
+ does not change the panel's position in the deck.
To move a panel's window, use move_panel(). The
+ mvwin() function on the panel's window is not
+ sufficient because it does not update the panels library's
+ representation of where the windows are. This operation leaves
+ the panel's depth, contents, and size unchanged.
Two functions (top_panel(),
+ bottom_panel()) are provided for rearranging the
+ deck. The first pops its argument window to the top of the deck;
+ the second sends it to the bottom. Either operation leaves the
+ panel's screen location, contents, and size unchanged.
The function update_panels() does all the
+ wnoutrefresh() calls needed to prepare for
+ doupdate() (which you must call yourself,
+ afterwards).
Typically, you will want to call update_panels()
+ and doupdate() just before accepting command input,
+ once in each cycle of interaction with the user. If you call
+ update_panels() after each and every panel write,
+ you will generate a lot of unnecessary refresh activity and
+ screen flicker.
You should not mix wnoutrefresh() or
+ wrefresh() operations with panels code; this will
+ work only if the argument window is either in the top panel or
+ unobscured by any other panels.
The stsdcr window is a special case. It is
+ considered below all panels. Because changes to panels may
+ obscure parts of stdscr, though, you should call
+ update_panels() before doupdate() even
+ when you only change stdscr.
Note that wgetch automatically calls
+ wrefresh. Therefore, before requesting input from a
+ panel window, you need to be sure that the panel is totally
+ unobscured.
There is presently no way to display changes to one obscured + panel without repainting all panels.
+ +It is possible to remove a panel from the deck temporarily;
+ use hide_panel for this. Use
+ show_panel() to render it visible again. The
+ predicate function panel_hidden tests whether or not
+ a panel is hidden.
The panel_update code ignores hidden panels. You
+ cannot do top_panel() or bottom_panel
+ on a hidden panel(). Other panels operations are applicable.
It is possible to navigate the deck using the functions
+ panel_above() and panel_below. Handed a
+ panel pointer, they return the panel above or below that panel.
+ Handed NULL, they return the bottom-most or top-most
+ panel.
Every panel has an associated user pointer, not used by the
+ panel code, to which you can attach application data. See the man
+ page documentation of set_panel_userptr() and
+ panel_userptr for details.
A menu is a screen display that assists the user to choose
+ some subset of a given set of items. The menu
+ library is a curses extension that supports easy programming of
+ menu hierarchies with a uniform but flexible interface.
replace_window. The new window may be of different size;
-the panel code will re-compute all overlaps. This operation doesn't
-change the panel's position in the deck. +
The menu library first appeared in AT&T
+ System V. The version documented here is the menu
+ code distributed with ncurses.
move_panel(). The
-mvwin() function on the panel's window isn't sufficient because it
-doesn't update the panels library's representation of where the windows are.
-This operation leaves the panel's depth, contents, and size unchanged. +
top_panel(), bottom_panel()) are
-provided for rearranging the deck. The first pops its argument window to the
-top of the deck; the second sends it to the bottom. Either operation leaves
-the panel's screen location, contents, and size unchanged. +
Your menu-using modules must import the menu library + declarations with
++ #include <menu.h> +-The function
update_panels() does all the
-wnoutrefresh() calls needed to prepare for
-doupdate() (which you must call yourself, afterwards).
-
-Typically, you will want to call update_panels() and
-doupdate() just before accepting command input, once in each cycle
-of interaction with the user. If you call update_panels() after
-each and every panel write, you'll generate a lot of unnecessary refresh
-activity and screen flicker.
-
-
wnoutrefresh() or wrefresh()
-operations with panels code; this will work only if the argument window
-is either in the top panel or unobscured by any other panels.
-
-The stsdcr window is a special case. It is considered below all
-panels. Because changes to panels may obscure parts of stdscr,
-though, you should call update_panels() before
-doupdate() even when you only change stdscr.
-
-Note that wgetch automatically calls wrefresh.
-Therefore, before requesting input from a panel window, you need to be sure
-that the panel is totally unobscured.
- -There is presently no way to display changes to one obscured panel without -repainting all panels. - -
hide_panel for this. Use show_panel() to render it
-visible again. The predicate function panel_hidden
-tests whether or not a panel is hidden.
-
-The panel_update code ignores hidden panels. You cannot do
-top_panel() or bottom_panel on a hidden panel().
-Other panels operations are applicable.
-
-
panel_above() and panel_below. Handed a panel
-pointer, they return the panel above or below that panel. Handed
-NULL, they return the bottom-most or top-most panel.
-
-Every panel has an associated user pointer, not used by the panel code, to
-which you can attach application data. See the man page documentation
-of set_panel_userptr() and panel_userptr for
-details.
-
-
menu library is a curses
-extension that supports easy programming of menu hierarchies with a
-uniform but flexible interface.
-
-The menu library first appeared in AT&T System V. The
-version documented here is the menu code distributed
-with ncurses.
-
-
- #include <menu.h> -- -and must be linked explicitly with the menus library using an -
-lmenu argument. Note that they must also link the
-ncurses library with -lncurses. Many linkers
-are two-pass and will accept either order, but it is still good practice
-to put -lmenu first and -lncurses second.
-
-- -The menu can then by posted, that is written to an -associated window. Actually, each menu has two associated windows; a -containing window in which the programmer can scribble titles or -borders, and a subwindow in which the menu items proper are displayed. -If this subwindow is too small to display all the items, it will be a -scrollable viewport on the collection of items.
- -A menu may also be unposted (that is, undisplayed), and finally -freed to make the storage associated with it and its items available for -re-use.
- -The general flow of control of a menu program looks like this: - -
curses.
-new_item().
-new_menu().
-menu_post().
-menu_unpost().
-free_menu().
-free_item().
-curses.
-menu_opts(3x) to see how to change the default).
-Both types always have a current item.
-
-From a single-valued menu you can read the selected value simply by looking
-at the current item. From a multi-valued menu, you get the selected set
-by looping through the items applying the item_value()
-predicate function. Your menu-processing code can use the function
-set_item_value() to flag the items in the select set.
-
-Menu items can be made unselectable using set_item_opts()
-or item_opts_off() with the O_SELECTABLE
-argument. This is the only option so far defined for menus, but it
-is good practice to code as though other option bits might be on.
-
-
set_menu_format() allows you to set the
-maximum size of the viewport or menu page that will be used
-to display menu items. You can retrieve any format associated with a
-menu with menu_format(). The default format is rows=16,
-columns=1. - -The actual menu page may be smaller than the format size. This depends -on the item number and size and whether O_ROWMAJOR is on. This option -(on by default) causes menu items to be displayed in a `raster-scan' -pattern, so that if more than one item will fit horizontally the first -couple of items are side-by-side in the top row. The alternative is -column-major display, which tries to put the first several items in -the first column.
- -As mentioned above, a menu format not large enough to allow all items to fit -on-screen will result in a menu display that is vertically scrollable.
-You can scroll it with requests to the menu driver, which will be described -in the section on menu input handling.
-
-Each menu has a mark string used to visually tag selected items;
-see the menu_mark(3x) manual page for details. The mark
-string length also influences the menu page size.
-
-The function scale_menu() returns the minimum display size
-that the menu code computes from all these factors.
-
-There are other menu display attributes including a select attribute,
-an attribute for selectable items, an attribute for unselectable items,
-and a pad character used to separate item name text from description
-text. These have reasonable defaults which the library allows you to
-change (see the menu_attribs(3x) manual page.
-
-
- -The outer or frame window is not otherwise touched by the menu -routines. It exists so the programmer can associate a title, a -border, or perhaps help text with the menu and have it properly -refreshed or erased at post/unpost time. The inner window or -subwindow is where the current menu page is displayed.
-
-By default, both windows are stdscr. You can set them with the
-functions in menu_win(3x).
-
-When you call menu_post(), you write the menu to its
-subwindow. When you call menu_unpost(), you erase the
-subwindow, However, neither of these actually modifies the screen. To
-do that, call wrefresh() or some equivalent.
-
-
menu_driver() repeatedly. The first argument of this routine
-is a menu pointer; the second is a menu command code. You should write an
-input-fetching routine that maps input characters to menu command codes, and
-pass its output to menu_driver(). The menu command codes are
-fully documented in menu_driver(3x).
-
-The simplest group of command codes is REQ_NEXT_ITEM,
-REQ_PREV_ITEM, REQ_FIRST_ITEM,
-REQ_LAST_ITEM, REQ_UP_ITEM,
-REQ_DOWN_ITEM, REQ_LEFT_ITEM,
-REQ_RIGHT_ITEM. These change the currently selected
-item. These requests may cause scrolling of the menu page if it only
-partially displayed.
-
-There are explicit requests for scrolling which also change the
-current item (because the select location does not change, but the
-item there does). These are REQ_SCR_DLINE,
-REQ_SCR_ULINE, REQ_SCR_DPAGE, and
-REQ_SCR_UPAGE.
-
-The REQ_TOGGLE_ITEM selects or deselects the current item.
-It is for use in multi-valued menus; if you use it with O_ONEVALUE
-on, you'll get an error return (E_REQUEST_DENIED).
-
-Each menu has an associated pattern buffer. The
-menu_driver() logic tries to accumulate printable ASCII
-characters passed in in that buffer; when it matches a prefix of an
-item name, that item (or the next matching item) is selected. If
-appending a character yields no new match, that character is deleted
-from the pattern buffer, and menu_driver() returns
-E_NO_MATCH.
-
-Some requests change the pattern buffer directly:
-REQ_CLEAR_PATTERN, REQ_BACK_PATTERN,
-REQ_NEXT_MATCH, REQ_PREV_MATCH. The latter
-two are useful when pattern buffer input matches more than one item
-in a multi-valued menu.
-
-Each successful scroll or item navigation request clears the pattern
-buffer. It is also possible to set the pattern buffer explicitly
-with set_menu_pattern().
-
-Finally, menu driver requests above the constant MAX_COMMAND
-are considered application-specific commands. The menu_driver()
-code ignores them and returns E_UNKNOWN_COMMAND.
-
-
menu_opts(3x) for
-details.
-
-It is possible to change the current item from application code; this
-is useful if you want to write your own navigation requests. It is
-also possible to explicitly set the top row of the menu display. See
-mitem_current(3x).
-
-If your application needs to change the menu subwindow cursor for
-any reason, pos_menu_cursor() will restore it to the
-correct location for continuing menu driver processing.
-
-It is possible to set hooks to be called at menu initialization and
-wrapup time, and whenever the selected item changes. See
-menu_hook(3x).
-
-Each item, and each menu, has an associated user pointer on which you
-can hang application data. See mitem_userptr(3x) and
-menu_userptr(3x).
-
-
form library is a curses extension that supports easy
-programming of on-screen forms for data entry and program control.
-
-The form library first appeared in AT&T System V. The
-version documented here is the form code distributed
-with ncurses.
-
-
- #include <form.h> -- -and must be linked explicitly with the forms library using an -
-lform argument. Note that they must also link the
-ncurses library with -lncurses. Many linkers
-are two-pass and will accept either order, but it is still good practice
-to put -lform first and -lncurses second.
-
--To make forms, you create groups of fields and connect them with form -frame objects; the form library makes this relatively simple.
- -Once defined, a form can be posted, that is written to an -associated window. Actually, each form has two associated windows; a -containing window in which the programmer can scribble titles or -borders, and a subwindow in which the form fields proper are displayed.
-
-As the form user fills out the posted form, navigation and editing
-keys support movement between fields, editing keys support modifying
-field, and plain text adds to or changes data in a current field. The
-form library allows you (the forms designer) to bind each navigation
-and editing key to any keystroke accepted by curses
-
-Fields may have validation conditions on them, so that they check input
-data for type and value. The form library supplies a rich set of
-pre-defined field types, and makes it relatively easy to define new ones.
- -Once its transaction is completed (or aborted), a form may be -unposted (that is, undisplayed), and finally freed to make -the storage associated with it and its items available for re-use.
- -The general flow of control of a form program looks like this: - -
curses.
-new_field().
-new_form().
-form_post().
-form_unpost().
-free_form().
-free_field().
-curses.
-and must be linked explicitly with the menus library using an
+ -lmenu argument. Note that they must also link the
+ ncurses library with -lncurses. Many
+ linkers are two-pass and will accept either order, but it is
+ still good practice to put -lmenu first and
+ -lncurses second.
+
The menus created by this library consist of collections of + items including a name string part and a description + string part. To make menus, you create groups of these items and + connect them with menu frame objects.
-In forms programs, however, the `process user requests' is somewhat more -complicated than for menus. Besides menu-like navigation operations, -the menu driver loop has to support field editing and data validation. +The menu can then by posted, that is written to an + associated window. Actually, each menu has two associated + windows; a containing window in which the programmer can scribble + titles or borders, and a subwindow in which the menu items proper + are displayed. If this subwindow is too small to display all the + items, it will be a scrollable viewport on the collection of + items.
-A menu may also be unposted (that is, undisplayed), + and finally freed to make the storage associated with it and its + items available for re-use.
+ +The general flow of control of a menu program looks like + this:
-The basic function for creating fields isnew_field():
+ curses.-FIELD *new_field(int height, int width, /* new field size */ - int top, int left, /* upper left corner */ - int offscreen, /* number of offscreen rows */ - int nbuf); /* number of working buffers */ -- -Menu items always occupy a single row, but forms fields may have -multiple rows. So
new_field() requires you to specify a
-width and height (the first two arguments, which mist both be greater
-than zero).
-
-You must also specify the location of the field's upper left corner on
-the screen (the third and fourth arguments, which must be zero or
-greater). Note that these coordinates are relative to the form
-subwindow, which will coincide with stdscr by default but
-need not be stdscr if you've done an explicit
-set_form_window() call.
-
-The fifth argument allows you to specify a number of off-screen rows. If
-this is zero, the entire field will always be displayed. If it is
-nonzero, the form will be scrollable, with only one screen-full (initially
-the top part) displayed at any given time. If you make a field dynamic
-and grow it so it will no longer fit on the screen, the form will become
-scrollable even if the offscreen argument was initially zero.
-
-The forms library allocates one working buffer per field; the size of
-each buffer is ((height + offscreen)*width + 1, one character
-for each position in the field plus a NUL terminator. The sixth
-argument is the number of additional data buffers to allocate for the
-field; your application can use them for its own purposes.
-
-
-FIELD *dup_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ -+
new_item().dup_field() duplicates an existing field at a
-new location. Size and buffering information are copied; some
-attribute flags and status bits are not (see the
-form_field_new(3X) for details).
+ new_menu().-FIELD *link_field(FIELD *field, /* field to copy */ - int top, int left); /* location of new copy */ -+
post_menu().link_field() also duplicates an existing field
-at a new location. The difference from dup_field() is that
-it arranges for the new field's buffer to be shared with the old one. +
+
+
unpost_menu().NULL if
-the field allocation is not possible due to an out-of-memory error or
-out-of-bounds arguments. +
free_menu().free_item().-FORM *new_form(FIELD **fields); -+
curses.Menus may be multi-valued or (the default) single-valued (see
+ the manual page menu_opts(3x) to see how to change
+ the default). Both types always have a current
+ item.
From a single-valued menu you can read the selected value
+ simply by looking at the current item. From a multi-valued menu,
+ you get the selected set by looping through the items applying
+ the item_value() predicate function. Your
+ menu-processing code can use the function
+ set_item_value() to flag the items in the select
+ set.
Menu items can be made unselectable using
+ set_item_opts() or item_opts_off() with
+ the O_SELECTABLE argument. This is the only option
+ so far defined for menus, but it is good practice to code as
+ though other option bits might be on.
The menu library calculates a minimum display size for your + window, based on the following variables:
+ +The function set_menu_format() allows you to set
+ the maximum size of the viewport or menu page that
+ will be used to display menu items. You can retrieve any format
+ associated with a menu with menu_format(). The
+ default format is rows=16, columns=1.
The actual menu page may be smaller than the format size. This + depends on the item number and size and whether O_ROWMAJOR is on. + This option (on by default) causes menu items to be displayed in + a “raster-scan” pattern, so that if more than one + item will fit horizontally the first couple of items are + side-by-side in the top row. The alternative is column-major + display, which tries to put the first several items in the first + column.
+ +As mentioned above, a menu format not large enough to allow + all items to fit on-screen will result in a menu display that is + vertically scrollable.
+ +You can scroll it with requests to the menu driver, which will + be described in the section on menu input + handling.
+ +Each menu has a mark string used to visually tag
+ selected items; see the menu_mark(3x) manual page
+ for details. The mark string length also influences the menu page
+ size.
The function scale_menu() returns the minimum
+ display size that the menu code computes from all these factors.
+ There are other menu display attributes including a select
+ attribute, an attribute for selectable items, an attribute for
+ unselectable items, and a pad character used to separate item
+ name text from description text. These have reasonable defaults
+ which the library allows you to change (see the
+ menu_attribs(3x) manual page.
Each menu has, as mentioned previously, a pair of associated + windows. Both these windows are painted when the menu is posted + and erased when the menu is unposted.
+ +The outer or frame window is not otherwise touched by the menu + routines. It exists so the programmer can associate a title, a + border, or perhaps help text with the menu and have it properly + refreshed or erased at post/unpost time. The inner window or + subwindow is where the current menu page is + displayed.
+ +By default, both windows are stdscr. You can set
+ them with the functions in menu_win(3x).
When you call post_menu(), you write the menu to
+ its subwindow. When you call unpost_menu(), you
+ erase the subwindow, However, neither of these actually modifies
+ the screen. To do that, call wrefresh() or some
+ equivalent.
The main loop of your menu-processing code should call
+ menu_driver() repeatedly. The first argument of this
+ routine is a menu pointer; the second is a menu command code. You
+ should write an input-fetching routine that maps input characters
+ to menu command codes, and pass its output to
+ menu_driver(). The menu command codes are fully
+ documented in menu_driver(3x).
The simplest group of command codes is
+ REQ_NEXT_ITEM, REQ_PREV_ITEM,
+ REQ_FIRST_ITEM, REQ_LAST_ITEM,
+ REQ_UP_ITEM, REQ_DOWN_ITEM,
+ REQ_LEFT_ITEM, REQ_RIGHT_ITEM. These
+ change the currently selected item. These requests may cause
+ scrolling of the menu page if it only partially displayed.
There are explicit requests for scrolling which also change
+ the current item (because the select location does not change,
+ but the item there does). These are REQ_SCR_DLINE,
+ REQ_SCR_ULINE, REQ_SCR_DPAGE, and
+ REQ_SCR_UPAGE.
The REQ_TOGGLE_ITEM selects or deselects the
+ current item. It is for use in multi-valued menus; if you use it
+ with O_ONEVALUE on, you will get an error return
+ (E_REQUEST_DENIED).
Each menu has an associated pattern buffer. The
+ menu_driver() logic tries to accumulate printable
+ ASCII characters passed in in that buffer; when it matches a
+ prefix of an item name, that item (or the next matching item) is
+ selected. If appending a character yields no new match, that
+ character is deleted from the pattern buffer, and
+ menu_driver() returns E_NO_MATCH.
Some requests change the pattern buffer directly:
+ REQ_CLEAR_PATTERN, REQ_BACK_PATTERN,
+ REQ_NEXT_MATCH, REQ_PREV_MATCH. The
+ latter two are useful when pattern buffer input matches more than
+ one item in a multi-valued menu.
Each successful scroll or item navigation request clears the
+ pattern buffer. It is also possible to set the pattern buffer
+ explicitly with set_menu_pattern().
Finally, menu driver requests above the constant
+ MAX_COMMAND are considered application-specific
+ commands. The menu_driver() code ignores them and
+ returns E_UNKNOWN_COMMAND.
Various menu options can affect the processing and visual
+ appearance and input processing of menus. See menu_opts(3x)
+ for details.
It is possible to change the current item from application
+ code; this is useful if you want to write your own navigation
+ requests. It is also possible to explicitly set the top row of
+ the menu display. See mitem_current(3x). If your
+ application needs to change the menu subwindow cursor for any
+ reason, pos_menu_cursor() will restore it to the
+ correct location for continuing menu driver processing.
It is possible to set hooks to be called at menu
+ initialization and wrapup time, and whenever the selected item
+ changes. See menu_hook(3x).
Each item, and each menu, has an associated user pointer on
+ which you can hang application data. See
+ mitem_userptr(3x) and
+ menu_userptr(3x).
The form library is a curses extension that
+ supports easy programming of on-screen forms for data entry and
+ program control.
The form library first appeared in AT&T
+ System V. The version documented here is the form
+ code distributed with ncurses.
Your form-using modules must import the form library + declarations with
++ #include <form.h> ++ +
and must be linked explicitly with the forms library using an
+ -lform argument. Note that they must also link the
+ ncurses library with -lncurses. Many
+ linkers are two-pass and will accept either order, but it is
+ still good practice to put -lform first and
+ -lncurses second.
A form is a collection of fields; each field may be either a + label (explanatory text) or a data-entry location. Long forms may + be segmented into pages; each entry to a new page clears the + screen.
+ +To make forms, you create groups of fields and connect them + with form frame objects; the form library makes this relatively + simple.
+ +Once defined, a form can be posted, that is written + to an associated window. Actually, each form has two associated + windows; a containing window in which the programmer can scribble + titles or borders, and a subwindow in which the form fields + proper are displayed.
+ +As the form user fills out the posted form, navigation and
+ editing keys support movement between fields, editing keys
+ support modifying field, and plain text adds to or changes data
+ in a current field. The form library allows you (the forms
+ designer) to bind each navigation and editing key to any
+ keystroke accepted by curses Fields may have
+ validation conditions on them, so that they check input data for
+ type and value. The form library supplies a rich set of
+ pre-defined field types, and makes it relatively easy to define
+ new ones.
Once its transaction is completed (or aborted), a form may be + unposted (that is, undisplayed), and finally freed to + make the storage associated with it and its items available for + re-use.
+ +The general flow of control of a form program looks like + this:
+ +curses.new_field().new_form().post_form().unpost_form().free_form().+
free_field().new_field() does not copy the pointer array
-into private storage; if you modify the contents of the pointer array
-during forms processing, all manner of bizarre things might happen. Also
-note that any given field may only be connected to one form. +
curses.free_field() and free_form are available
-to free field and form objects. It is an error to attempt to free a field
-connected to a form, but not vice-versa; thus, you will generally free
-your form objects first.
+ Note that this looks much like a menu program; the form + library handles tasks which are in many ways similar, and its + interface was obviously designed to resemble that of the menu library wherever possible.
-In forms programs, however, the “process user + requests” is somewhat more complicated than for menus. + Besides menu-like navigation operations, the menu driver loop has + to support field editing and data validation.
+ +The basic function for creating fields is
+ new_field():
+FIELD *new_field(int height, int width, /* new field size */ + int top, int left, /* upper left corner */ + int offscreen, /* number of offscreen rows */ + int nbuf); /* number of working buffers */ ++ +
Menu items always occupy a single row, but forms fields may
+ have multiple rows. So new_field() requires you to
+ specify a width and height (the first two arguments, which mist
+ both be greater than zero).
You must also specify the location of the field's upper left
+ corner on the screen (the third and fourth arguments, which must
+ be zero or greater). Note that these coordinates are relative to
+ the form subwindow, which will coincide with stdscr
+ by default but need not be stdscr if you have done
+ an explicit set_form_win() call.
The fifth argument allows you to specify a number of
+ off-screen rows. If this is zero, the entire field will always be
+ displayed. If it is nonzero, the form will be scrollable, with
+ only one screen-full (initially the top part) displayed at any
+ given time. If you make a field dynamic and grow it so it will no
+ longer fit on the screen, the form will become scrollable even if
+ the offscreen argument was initially zero.
The forms library allocates one working buffer per field; the
+ size of each buffer is ((height + offscreen)*width +
+ 1, one character for each position in the field plus a NUL
+ terminator. The sixth argument is the number of additional data
+ buffers to allocate for the field; your application can use them
+ for its own purposes.
+FIELD *dup_field(FIELD *field, /* field to copy */ + int top, int left); /* location of new copy */ ++ +
The function dup_field() duplicates an existing
+ field at a new location. Size and buffering information are
+ copied; some attribute flags and status bits are not (see the
+ form_field_new(3X) for details).
+FIELD *link_field(FIELD *field, /* field to copy */ + int top, int left); /* location of new copy */ +-Each form field has a number of location and size attributes -associated with it. There are other field attributes used to control -display and editing of the field. Some (for example, the
O_STATIC bit)
-involve sufficient complications to be covered in sections of their own
-later on. We cover the functions used to get and set several basic
-attributes here. +
The function link_field() also duplicates an
+ existing field at a new location. The difference from
+ dup_field() is that it arranges for the new field's
+ buffer to be shared with the old one.
new_field function are copied from an invisible system
-default field. In attribute-setting and -fetching functions, the
-argument NULL is taken to mean this field. Changes to it persist
-as defaults until your forms application terminates.
+ Besides the obvious use in making a field editable from two + different form pages, linked fields give you a way to hack in + dynamic labels. If you declare several fields linked to an + original, and then make them inactive, changes from the original + will still be propagated to the linked fields.
-As with duplicated fields, linked fields have attribute bits + separate from the original.
-You can retrieve field sizes and locations through: +As you might guess, all these field-allocations return
+ NULL if the field allocation is not possible due to
+ an out-of-memory error or out-of-bounds arguments.
+-To connect fields to a form, use
++FORM *new_form(FIELD **fields); ++ +This function expects to see a NULL-terminated array of field + pointers. Said fields are connected to a newly-allocated form + object; its address is returned (or else NULL if the allocation + fails).
+ +Note that
+ +new_field()does not copy the + pointer array into private storage; if you modify the contents of + the pointer array during forms processing, all manner of bizarre + things might happen. Also note that any given field may only be + connected to one form.The functions
+ +free_field()and +free_formare available to free field and form + objects. It is an error to attempt to free a field connected to a + form, but not vice-versa; thus, you will generally free your form + objects first.Fetching and Changing + Field Attributes
+ +Each form field has a number of location and size attributes + associated with it. There are other field attributes used to + control display and editing of the field. Some (for example, the +
+ +O_STATICbit) involve sufficient complications to be + covered in sections of their own later on. We cover the functions + used to get and set several basic attributes here.When a field is created, the attributes not specified by the +
+ +new_fieldfunction are copied from an invisible + system default field. In attribute-setting and -fetching + functions, the argument NULL is taken to mean this field. Changes + to it persist as defaults until your forms application + terminates.Fetching Size and Location + Data
+ +You can retrieve field sizes and locations through:
+int field_info(FIELD *field, /* field from which to fetch */ int *height, *int width, /* field size */ int *top, int *left, /* upper left corner */ int *offscreen, /* number of offscreen rows */ int *nbuf); /* number of working buffers */ -- -This function is a sort of inverse ofnew_field(); instead of -setting size and location attributes of a new field, it fetches them -from an existing one. +
This function is a sort of inverse of
+ new_field(); instead of setting size and location
+ attributes of a new field, it fetches them from an existing
+ one.
+-It is possible to move a field's location on the screen:
+int move_field(FIELD *field, /* field to alter */ int top, int left); /* new upper-left corner */ -- -You can, of course. query the current location throughfield_info(). +
You can, of course. query the current location through
+ field_info().
+-The mode values accepted and returned by this functions are -preprocessor macrosOne-line fields may be unjustified, justified right, justified + left, or centered. Here is how you manipulate this attribute:
+int set_field_just(FIELD *field, /* field to alter */ int justmode); /* mode to set */ int field_just(FIELD *field); /* fetch mode of field */ -+
NO_JUSTIFICATION, JUSTIFY_RIGHT,
-JUSTIFY_LEFT, or JUSTIFY_CENTER.
+ The mode values accepted and returned by this functions are
+ preprocessor macros NO_JUSTIFICATION,
+ JUSTIFY_RIGHT, JUSTIFY_LEFT, or
+ JUSTIFY_CENTER.
+
For each field, you can set a foreground attribute for entered + characters, a background attribute for the entire field, and a + pad character for the unfilled portion of the field. You can also + control pagination of the form.
-This group of four field attributes controls the visual appearance -of the field on the screen, without affecting in any way the data -in the field buffer. - -+-This group of four field attributes controls the visual + appearance of the field on the screen, without affecting in any + way the data in the field buffer.
+int set_field_fore(FIELD *field, /* field to alter */ chtype attr); /* attribute to set */ @@ -1633,22 +2062,20 @@ int set_new_page(FIELD *field, /* field to alter */ int flag); /* TRUE to force new page */ chtype new_page(FIELD *field); /* field to query */ -- -The attributes set and returned by the first four functions are normal -curses(3x)display attribute values (A_STANDOUT, -A_BOLD,A_REVERSEetc). - -The page bit of a field controls whether it is displayed at the start of -a new form screen. +
The attributes set and returned by the first four functions
+ are normal curses(3x) display attribute values
+ (A_STANDOUT, A_BOLD,
+ A_REVERSE etc). The page bit of a field controls
+ whether it is displayed at the start of a new form screen.
+There is also a large collection of field option bits you can + set to control various aspects of forms processing. You can + manipulate them with these functions:
+int set_field_opts(FIELD *field, /* field to alter */ int attr); /* attribute to set */ @@ -1659,423 +2086,476 @@ int field_opts_off(FIELD *field, /* field to alter */ int attr); /* attributes to turn off */ int field_opts(FIELD *field); /* field to query */ -- -By default, all options are on. Here are the available option bits: -
REQ_PREV_CHOICE and
-REQ_NEXT_CHOICE will fail. Such read-only fields may be useful for
-help messages.
-- -The option values are bit-masks and can be composed with logical-or in -the obvious way. - -
-int set_field_status(FIELD *field, /* field to alter */ - int status); /* mode to set */ +-int field_status(FIELD *field); /* fetch mode of field */ - +
By default, all options are on. Here are the available option + bits:
-Setting this flag under program control can be useful if you use the same -form repeatedly, looking for modified fields each time.+
field_status() on a field not currently selected
-for input will return a correct value. Calling field_status() on a
-field that is currently selected for input may not necessarily give a
-correct field status value, because entered data isn't necessarily copied to
-buffer zero before the exit validation check.
+ field_status() either (1) in the field's exit validation check
-routine, (2) from the field's or form's initialization or termination
-hooks, or (3) just after a REQ_VALIDATION request has been
-processed by the forms driver.
+ -int set_field_userptr(FIELD *field, /* field to alter */ - char *userptr); /* mode to set */ +
(void *) type.
-The (char *) type is retained for System V compatibility.) +
REQ_PREV_CHOICE and REQ_NEXT_CHOICE
+ will fail. Such read-only fields may be useful for help
+ messages.set_field_userptr() call passed a NULL field pointer.)
-When a new field is created, the default-field user pointer is copied
-to initialize the new field's user pointer.
+ +
+
+
A field's options cannot be changed while the field is + currently selected. However, options may be changed on posted + fields that are not current.
+ +The option values are bit-masks and can be composed with + logical-or in the obvious way.
+ +Every field has a status flag, which is set to FALSE when the + field is created and TRUE when the value in field buffer 0 + changes. This flag can be queried and set directly:
++int set_field_status(FIELD *field, /* field to alter */ + int status); /* mode to set */ + +int field_status(FIELD *field); /* fetch mode of field */ ++ +
Setting this flag under program control can be useful if you + use the same form repeatedly, looking for modified fields each + time.
+ +Calling field_status() on a field not currently
+ selected for input will return a correct value. Calling
+ field_status() on a field that is currently selected
+ for input may not necessarily give a correct field status value,
+ because entered data is not necessarily copied to buffer zero
+ before the exit validation check. To guarantee that the returned
+ status value reflects reality, call field_status()
+ either (1) in the field's exit validation check routine, (2) from
+ the field's or form's initialization or termination hooks, or (3)
+ just after a REQ_VALIDATION request has been
+ processed by the forms driver.
Each field structure contains one character pointer slot that + is not used by the forms library. It is intended to be used by + applications to store private per-field data. You can manipulate + it with:
++int set_field_userptr(FIELD *field, /* field to alter */ + char *userptr); /* mode to set */ + +char *field_userptr(FIELD *field); /* fetch mode of field */ +(Properly, this user pointer field ought to have
(void
+*) type. The (char *) type is retained for
+System V compatibility.)
+
+ It is valid to set the user pointer of the default field (with
+ a set_field_userptr() call passed a NULL field
+ pointer.) When a new field is created, the default-field user
+ pointer is copied to initialize the new field's user pointer.
Normally, a field is fixed at the size specified for it at + creation time. If, however, you turn off its O_STATIC bit, it + becomes dynamic and will automatically resize itself + to accommodate data as it is entered. If the field has extra + buffers associated with it, they will grow right along with the + main input buffer.
+ +A one-line dynamic field will have a fixed height (1) but + variable width, scrolling horizontally to display data within the + field area as originally dimensioned and located. A multi-line + dynamic field will have a fixed width, but variable height + (number of rows), scrolling vertically to display data within the + field area as originally dimensioned and located.
+ +Normally, a dynamic field is allowed to grow without limit. + But it is possible to set an upper limit on the size of a dynamic + field. You do it with this function:
+
int set_max_field(FIELD *field, /* field to alter (may not be NULL) */
int max_size); /* upper limit on field size */
-
-
-If the field is one-line, max_size is taken to be a column size
-limit; if it is multi-line, it is taken to be a line size limit. To disable
-any limit, use an argument of zero. The growth limit can be changed whether
-or not the O_STATIC bit is on, but has no effect until it is. - -The following properties of a field change when it becomes dynamic: - -
O_AUTOSKIP and O_NL_OVERLOAD are ignored.
-dup_field() and link_field() calls copy
-dynamic-buffer sizes. If the O_STATIC option is set on one of a
-collection of links, buffer resizing will occur only when the field is
-edited through that link.
-field_info() will retrieve the original static size of
-the field; use dynamic_field_info() to get the actual dynamic size.
-
-
-A field's validation check (if any) is not called when
-set_field_buffer() modifies the input buffer, nor when that buffer
-is changed through a linked field.
-
-The form library provides a rich set of pre-defined validation
-types, and gives you the capability to define custom ones of your own. You
-can examine and change field validation attributes with the following
-functions:
-
-
++ +
If the field is one-line, max_size is taken to be
+ a column size limit; if it is multi-line, it is taken to be a
+ line size limit. To disable any limit, use an argument of zero.
+ The growth limit can be changed whether or not the O_STATIC bit
+ is on, but has no effect until it is.
The following properties of a field change when it becomes + dynamic:
+ +O_AUTOSKIP and
+ O_NL_OVERLOAD are ignored.dup_field() and link_field()
+ calls copy dynamic-buffer sizes. If the O_STATIC
+ option is set on one of a collection of links, buffer resizing
+ will occur only when the field is edited through that
+ link.field_info() will retrieve the
+ original static size of the field; use
+ dynamic_field_info() to get the actual dynamic
+ size.By default, a field will accept any data that will fit in its + input buffer. However, it is possible to attach a validation type + to a field. If you do this, any attempt to leave the field while + it contains data that does not match the validation type will + fail. Some validation types also have a character-validity check + for each time a character is entered in the field.
+ +A field's validation check (if any) is not called when
+ set_field_buffer() modifies the input buffer, nor
+ when that buffer is changed through a linked field.
The form library provides a rich set of
+ pre-defined validation types, and gives you the capability to
+ define custom ones of your own. You can examine and change field
+ validation attributes with the following functions:
int set_field_type(FIELD *field, /* field to alter */
FIELDTYPE *ftype, /* type to associate */
...); /* additional arguments*/
FIELDTYPE *field_type(FIELD *field); /* field to query */
-
+
-The validation type of a field is considered an attribute of the field. As
-with other field attributes, Also, doing set_field_type() with a
-NULL field default will change the system default for validation of
-newly-created fields. +
The validation type of a field is considered an attribute of
+ the field. As with other field attributes, Also, doing
+ set_field_type() with a NULL field
+ default will change the system default for validation of
+ newly-created fields.
Here are the pre-defined validation types:
-+-This field type accepts alphabetic data; no blanks, no digits, + no special characters (this is checked at character-entry time). + It is set up with:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_ALPHA, /* type to associate */ int width); /* maximum width of field */ -- -Thewidthargument sets a minimum width of data. Typically -you'll want to set this to the field width; if it's greater than the -field width, the validation check will always fail. A minimum width -of zero makes field completion optional. +
The width argument sets a minimum width of data.
+ Typically you will want to set this to the field width; if it is
+ greater than the field width, the validation check will always
+ fail. A minimum width of zero makes field completion
+ optional.
+-This field type accepts alphabetic data and digits; no blanks, + no special characters (this is checked at character-entry time). + It is set up with:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_ALNUM, /* type to associate */ int width); /* maximum width of field */ -- -Thewidthargument sets a minimum width of data. As with -TYPE_ALPHA, typically you'll want to set this to the field width; if it's -greater than the field width, the validation check will always fail. A -minimum width of zero makes field completion optional. +
The width argument sets a minimum width of data.
+ As with TYPE_ALPHA, typically you will want to set this to the
+ field width; if it is greater than the field width, the
+ validation check will always fail. A minimum width of zero makes
+ field completion optional.
+-If the value passes its range check, it is padded with as many leading -zero digits as necessary to meet the padding argument.This type allows you to restrict a field's values to be among + a specified set of string values (for example, the two-letter + postal codes for U.S. states). It is set up with:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_ENUM, /* type to associate */ char **valuelist; /* list of possible values */ int checkcase; /* case-sensitive? */ int checkunique); /* must specify uniquely? */ -- -Thevaluelistparameter must point at a NULL-terminated list of -valid strings. Thecheckcaseargument, if true, makes comparison -with the string case-sensitive.- -When the user exits a TYPE_ENUM field, the validation procedure tries to -complete the data in the buffer to a valid entry. If a complete choice string -has been entered, it is of course valid. But it is also possible to enter a -prefix of a valid string and have it completed for you.
- -By default, if you enter such a prefix and it matches more than one value -in the string list, the prefix will be completed to the first matching -value. But the
checkuniqueargument, if true, requires prefix -matches to be unique in order to be valid.- -The
REQ_NEXT_CHOICEandREQ_PREV_CHOICEinput requests -can be particularly useful with these fields. - -TYPE_INTEGER
- -This field type accepts an integer. It is set up as follows: - -++ +The
+ +valuelistparameter must point at a + NULL-terminated list of valid strings. Thecheckcase+ argument, if true, makes comparison with the string + case-sensitive.When the user exits a TYPE_ENUM field, the validation + procedure tries to complete the data in the buffer to a valid + entry. If a complete choice string has been entered, it is of + course valid. But it is also possible to enter a prefix of a + valid string and have it completed for you.
+ +By default, if you enter such a prefix and it matches more + than one value in the string list, the prefix will be completed + to the first matching value. But the
+ +checkunique+ argument, if true, requires prefix matches to be unique in order + to be valid.The
+ +REQ_NEXT_CHOICEand +REQ_PREV_CHOICEinput requests can be particularly + useful with these fields.TYPE_INTEGER
+ +This field type accepts an integer. It is set up as + follows:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_INTEGER, /* type to associate */ int padding, /* # places to zero-pad to */ int vmin, int vmax); /* valid range */ -- -Valid characters consist of an optional leading minus and digits. -The range check is performed on exit. If the range maximum is less -than or equal to the minimum, the range is ignored.+
+
Valid characters consist of an optional leading minus and + digits. The range check is performed on exit. If the range + maximum is less than or equal to the minimum, the range is + ignored.
-ATYPE_INTEGER value buffer can conveniently be interpreted
-with the C library function atoi(3).
+ If the value passes its range check, it is padded with as many + leading zero digits as necessary to meet the padding + argument.
-A TYPE_INTEGER value buffer can conveniently be
+ interpreted with the C library function atoi(3).
+-If the value passes its range check, it is padded with as many trailing -zero digits as necessary to meet the padding argument.This field type accepts a decimal number. It is set up as + follows:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_NUMERIC, /* type to associate */ int padding, /* # places of precision */ double vmin, double vmax); /* valid range */ -- -Valid characters consist of an optional leading minus and digits. possibly -including a decimal point. If your system supports locale's, the decimal point -character used must be the one defined by your locale. The range check is -performed on exit. If the range maximum is less than or equal to the minimum, -the range is ignored.+
+
Valid characters consist of an optional leading minus and + digits. possibly including a decimal point. If your system + supports locale's, the decimal point character used must be the + one defined by your locale. The range check is performed on exit. + If the range maximum is less than or equal to the minimum, the + range is ignored.
-ATYPE_NUMERIC value buffer can conveniently be interpreted
-with the C library function atof(3).
+ If the value passes its range check, it is padded with as many + trailing zero digits as necessary to meet the padding + argument.
-A TYPE_NUMERIC value buffer can conveniently be
+ interpreted with the C library function atof(3).
+-The syntax for regular expressions is that ofThis field type accepts data matching a regular expression. It + is set up as follows:
+int set_field_type(FIELD *field, /* field to alter */ TYPE_REGEXP, /* type to associate */ char *regexp); /* expression to match */ -+
regcomp(3).
-The check for regular-expression match is performed on exit.
+ The syntax for regular expressions is that of
+ regcomp(3). The check for regular-expression match
+ is performed on exit.
+-The chief attribute of a field is its buffer contents. When a + form has been completed, your application usually needs to know + the state of each field buffer. You can find this out with:
+char *field_buffer(FIELD *field, /* field to query */ int bufindex); /* number of buffer to query */ -- -Normally, the state of the zero-numbered buffer for each field is set by -the user's editing actions on that field. It's sometimes useful to be able -to set the value of the zero-numbered (or some other) buffer from your -application: +
+-Normally, the state of the zero-numbered buffer for each field + is set by the user's editing actions on that field. It is + sometimes useful to be able to set the value of the zero-numbered + (or some other) buffer from your application:
+int set_field_buffer(FIELD *field, /* field to alter */ int bufindex, /* number of buffer to alter */ char *value); /* string value to set */ -- -If the field is not large enough and cannot be resized to a sufficiently -large size to contain the specified value, the value will be truncated -to fit.- -Calling
field_buffer()with a null field pointer will raise an -error. Callingfield_buffer()on a field not currently selected -for input will return a correct value. Callingfield_buffer()on a -field that is currently selected for input may not necessarily give a -correct field buffer value, because entered data isn't necessarily copied to -buffer zero before the exit validation check. - -To guarantee that the returned buffer value reflects on-screen reality, -callfield_buffer()either (1) in the field's exit validation -check routine, (2) from the field's or form's initialization or termination -hooks, or (3) just after aREQ_VALIDATIONrequest has been processed -by the forms driver. - -Attributes of Forms
- -As with field attributes, form attributes inherit a default from a -system default form structure. These defaults can be queried or set by -of these functions using a form-pointer argument ofNULL.- -The principal attribute of a form is its field list. You can query -and change this list with: - -
++ +If the field is not large enough and cannot be resized to a + sufficiently large size to contain the specified value, the value + will be truncated to fit.
+ +Calling
+ +field_buffer()with a null field pointer + will raise an error. Callingfield_buffer()on a + field not currently selected for input will return a correct + value. Callingfield_buffer()on a field that is + currently selected for input may not necessarily give a correct + field buffer value, because entered data is not necessarily + copied to buffer zero before the exit validation check. To + guarantee that the returned buffer value reflects on-screen + reality, callfield_buffer()either (1) in the + field's exit validation check routine, (2) from the field's or + form's initialization or termination hooks, or (3) just after a +REQ_VALIDATIONrequest has been processed by the + forms driver.Attributes of + Forms
+ +As with field attributes, form attributes inherit a default + from a system default form structure. These defaults can be + queried or set by of these functions using a form-pointer + argument of
+ +NULL.The principal attribute of a form is its field list. You can + query and change this list with:
+int set_form_fields(FORM *form, /* form to alter */ FIELD **fields); /* fields to connect */ char *form_fields(FORM *form); /* fetch fields of form */ int field_count(FORM *form); /* count connect fields */ -- -The second argument ofset_form_fields()may be a -NULL-terminated field pointer array like the one required by -new_form(). In that case, the old fields of the form are -disconnected but not freed (and eligible to be connected to other -forms), then the new fields are connected.- -It may also be null, in which case the old fields are disconnected -(and not freed) but no new ones are connected.
- -The
field_count()function simply counts the number of fields -connected to a given from. It returns -1 if the form-pointer argument -is NULL. - -Control of Form Display
- -In the overview section, you saw that to display a form you normally -start by defining its size (and fields), posting it, and refreshing -the screen. There is an hidden step before posting, which is the -association of the form with a frame window (actually, a pair of -windows) within which it will be displayed. By default, the forms -library associates every form with the full-screen window -stdscr.- -By making this step explicit, you can associate a form with a declared -frame window on your screen display. This can be useful if you want to -adapt the form display to different screen sizes, dynamically tile -forms on the screen, or use a form as part of an interface layout -managed by panels.
- -The two windows associated with each form have the same functions as -their analogues in the menu library. Both these -windows are painted when the form is posted and erased when the form -is unposted.
- -The outer or frame window is not otherwise touched by the form -routines. It exists so the programmer can associate a title, a -border, or perhaps help text with the form and have it properly -refreshed or erased at post/unpost time. The inner window or subwindow -is where the current form page is actually displayed.
- -In order to declare your own frame window for a form, you'll need to -know the size of the form's bounding rectangle. You can get this -information with: - -
++ +The second argument of
+ +set_form_fields()may be a + NULL-terminated field pointer array like the one required by +new_form(). In that case, the old fields of the form + are disconnected but not freed (and eligible to be connected to + other forms), then the new fields are connected.It may also be null, in which case the old fields are + disconnected (and not freed) but no new ones are connected.
+ +The
+ +field_count()function simply counts the + number of fields connected to a given from. It returns -1 if the + form-pointer argument is NULL.Control of Form + Display
+ +In the overview section, you saw that to display a form you + normally start by defining its size (and fields), posting it, and + refreshing the screen. There is an hidden step before posting, + which is the association of the form with a frame window + (actually, a pair of windows) within which it will be displayed. + By default, the forms library associates every form with the + full-screen window
+ +stdscr.By making this step explicit, you can associate a form with a + declared frame window on your screen display. This can be useful + if you want to adapt the form display to different screen sizes, + dynamically tile forms on the screen, or use a form as part of an + interface layout managed by panels.
+ +The two windows associated with each form have the same + functions as their analogues in the menu + library. Both these windows are painted when the form is + posted and erased when the form is unposted.
+ +The outer or frame window is not otherwise touched by the form + routines. It exists so the programmer can associate a title, a + border, or perhaps help text with the form and have it properly + refreshed or erased at post/unpost time. The inner window or + subwindow is where the current form page is actually + displayed.
+ +In order to declare your own frame window for a form, you will + need to know the size of the form's bounding rectangle. You can + get this information with:
+int scale_form(FORM *form, /* form to query */ int *rows, /* form rows */ int *cols); /* form cols */ -- -The form dimensions are passed back in the locations pointed to by -the arguments. Once you have this information, you can use it to -declare of windows, then use one of these functions: +
+-It is possible to check from your application whether all of a -scrollable field is actually displayed within the menu subwindow. Use -these functions: +The form dimensions are passed back in the locations pointed + to by the arguments. Once you have this information, you can use + it to declare of windows, then use one of these functions:
+int set_form_win(FORM *form, /* form to alter */ WINDOW *win); /* frame window to connect */ @@ -2085,319 +2565,448 @@ int set_form_sub(FORM *form, /* form to alter */ WINDOW *win); /* form subwindow to connect */ WINDOW *form_sub(FORM *form); /* fetch form subwindow of form */ -- -Note that curses operations, includingrefresh(), on the form, -should be done on the frame window, not the form subwindow.+
Note that curses operations, including refresh(),
+ on the form, should be done on the frame window, not the form
+ subwindow.
+-The functionIt is possible to check from your application whether all of a + scrollable field is actually displayed within the menu subwindow. + Use these functions:
+int data_ahead(FORM *form); /* form to be queried */ int data_behind(FORM *form); /* form to be queried */ -+
data_ahead() returns TRUE if (a) the current
-field is one-line and has undisplayed data off to the right, (b) the current
-field is multi-line and there is data off-screen below it. +
The function data_ahead() returns TRUE if (a) the
+ current field is one-line and has undisplayed data off to the
+ right, (b) the current field is multi-line and there is data
+ off-screen below it.
data_behind() returns TRUE if the first (upper
-left hand) character position is off-screen (not being displayed). +
The function data_behind() returns TRUE if the
+ first (upper left hand) character position is off-screen (not
+ being displayed).
+-Finally, there is a function to restore the form window's + cursor to the value expected by the forms driver:
+int pos_form_cursor(FORM *) /* form to be queried */ -- -If your application changes the form window cursor, call this function before -handing control back to the forms driver in order to re-synchronize it. +
If your application changes the form window cursor, call this + function before handing control back to the forms driver in order + to re-synchronize it.
-The functionform_driver() handles virtualized input requests
-for form navigation, editing, and validation requests, just as
-menu_driver does for menus (see the section on menu input handling).
+ +The function
+form_driver()handles virtualized + input requests for form navigation, editing, and validation + requests, just asmenu_driverdoes for menus (see + the section on menu input handling).int form_driver(FORM *form, /* form to pass input to */ int request); /* form request code */ -- -Your input virtualization function needs to take input and then convert it -to either an alphanumeric character (which is treated as data to be -entered in the currently-selected field), or a forms processing request.- -The forms driver provides hooks (through input-validation and -field-termination functions) with which your application code can check -that the input taken by the driver matched what was expected. - -
Page Navigation Requests
- -These requests cause page-level moves through the form, -triggering display of a new form screen. - -
REQ_NEXT_PAGE
-REQ_PREV_PAGE
-REQ_FIRST_PAGE
-REQ_LAST_PAGE
-REQ_NEXT_PAGE
-from the last page goes to the first, and REQ_PREV_PAGE from
-the first page goes to the last.
-
-REQ_NEXT_FIELD
-REQ_PREV_FIELD
-REQ_FIRST_FIELD
-REQ_LAST_FIELD
-REQ_SNEXT_FIELD
-REQ_SPREV_FIELD
-REQ_SFIRST_FIELD
-REQ_SLAST_FIELD
-REQ_LEFT_FIELD
-REQ_RIGHT_FIELD
-REQ_UP_FIELD
-REQ_DOWN_FIELD
-REQ_NEXT_FIELD from the last field goes to the first, and
-REQ_PREV_FIELD from the first field goes to the last. The
-order of the fields for these (and the REQ_FIRST_FIELD and
-REQ_LAST_FIELD requests) is simply the order of the field
-pointers in the form array (as set up by new_form() or
-set_form_fields() - -It is also possible to traverse the fields as if they had been sorted in -screen-position order, so the sequence goes left-to-right and top-to-bottom. -To do this, use the second group of four sorted-movement requests.
- -Finally, it is possible to move between fields using visual directions up, -down, right, and left. To accomplish this, use the third group of four -requests. Note, however, that the position of a form for purposes of these -requests is its upper-left corner.
-
-For example, suppose you have a multi-line field B, and two
-single-line fields A and C on the same line with B, with A to the left
-of B and C to the right of B. A REQ_MOVE_RIGHT from A will
-go to B only if A, B, and C all share the same first line;
-otherwise it will skip over B to C.
-
-
REQ_NEXT_CHAR
-REQ_PREV_CHAR
-REQ_NEXT_LINE
-REQ_PREV_LINE
-REQ_NEXT_WORD
-REQ_PREV_WORD
-REQ_BEG_FIELD
-REQ_END_FIELD
-REQ_BEG_LINE
-REQ_END_LINE
-REQ_LEFT_CHAR
-REQ_RIGHT_CHAR
-REQ_UP_CHAR
-REQ_DOWN_CHAR
-REQ_SCR_FLINE
-REQ_SCR_BLINE
-REQ_SCR_FPAGE
-REQ_SCR_BPAGE
-REQ_SCR_FHPAGE
-REQ_SCR_BHPAGE
-REQ_SCR_FCHAR
-REQ_SCR_BCHAR
-REQ_SCR_HFLINE
-REQ_SCR_HBLINE
-REQ_SCR_HFHALF
-REQ_SCR_HBHALF
-- -The following requests support editing the field and changing the edit -mode: - -
REQ_INS_MODE
-REQ_OVL_MODE
-REQ_NEW_LINE
-REQ_INS_CHAR
-REQ_INS_LINE
-REQ_DEL_CHAR
-REQ_DEL_PREV
-REQ_DEL_LINE
-REQ_DEL_WORD
-REQ_CLR_EOL
-REQ_CLR_EOF
-REQ_CLEAR_FIELD
-REQ_NEW_LINE and REQ_DEL_PREV requests
-is complicated and partly controlled by a pair of forms options.
-The special cases are triggered when the cursor is at the beginning of
-a field, or on the last line of the field.
-
-First, we consider REQ_NEW_LINE:
-
-The normal behavior of REQ_NEW_LINE in insert mode is to break the
-current line at the position of the edit cursor, inserting the portion of
-the current line after the cursor as a new line following the current
-and moving the cursor to the beginning of that new line (you may think
-of this as inserting a newline in the field buffer).
-
-The normal behavior of REQ_NEW_LINE in overlay mode is to clear the
-current line from the position of the edit cursor to end of line.
-The cursor is then moved to the beginning of the next line.
-
-However, REQ_NEW_LINE at the beginning of a field, or on the
-last line of a field, instead does a REQ_NEXT_FIELD.
-O_NL_OVERLOAD option is off, this special action is
-disabled.
-
-Now, let us consider REQ_DEL_PREV:
-
-The normal behavior of REQ_DEL_PREV is to delete the previous
-character. If insert mode is on, and the cursor is at the start of a
-line, and the text on that line will fit on the previous one, it
-instead appends the contents of the current line to the previous one
-and deletes the current line (you may think of this as deleting a
-newline from the field buffer).
-
-However, REQ_DEL_PREV at the beginning of a field is instead
-treated as a REQ_PREV_FIELD.
If the
-O_BS_OVERLOAD option is off, this special action is
-disabled and the forms driver just returns E_REQUEST_DENIED.
- -See Form Options for discussion of how to set -and clear the overload options. - -
REQ_NEXT_CHOICE
-REQ_PREV_CHOICE
-TYPE_ENUM has built-in successor
-and predecessor functions. When you define a field type of your own
-(see Custom Validation Types), you can associate
-our own ordering functions.
-
-curses value
-greater than KEY_MAX and less than or equal to the constant
-MAX_COMMAND. If your input-virtualization routine returns a
-value above MAX_COMMAND, the forms driver will ignore it.
-
--typedef void (*HOOK)(); /* pointer to function returning void */ ++ +
Your input virtualization function needs to take input and + then convert it to either an alphanumeric character (which is + treated as data to be entered in the currently-selected field), + or a forms processing request.
+ +The forms driver provides hooks (through input-validation and + field-termination functions) with which your application code can + check that the input taken by the driver matched what was + expected.
+ +These requests cause page-level moves through the form, + triggering display of a new form screen.
+ +REQ_NEXT_PAGEREQ_PREV_PAGEREQ_FIRST_PAGEREQ_LAST_PAGEThese requests treat the list as cyclic; that is,
+ REQ_NEXT_PAGE from the last page goes to the first,
+ and REQ_PREV_PAGE from the first page goes to the
+ last.
These requests handle navigation between fields on the same + page.
+ +REQ_NEXT_FIELDREQ_PREV_FIELDREQ_FIRST_FIELDREQ_LAST_FIELDREQ_SNEXT_FIELDREQ_SPREV_FIELDREQ_SFIRST_FIELDREQ_SLAST_FIELDREQ_LEFT_FIELDREQ_RIGHT_FIELDREQ_UP_FIELDREQ_DOWN_FIELDThese requests treat the list of fields on a page as cyclic;
+ that is, REQ_NEXT_FIELD from the last field goes to
+ the first, and REQ_PREV_FIELD from the first field
+ goes to the last. The order of the fields for these (and the
+ REQ_FIRST_FIELD and REQ_LAST_FIELD
+ requests) is simply the order of the field pointers in the form
+ array (as set up by new_form() or
+ set_form_fields()
It is also possible to traverse the fields as if they had been + sorted in screen-position order, so the sequence goes + left-to-right and top-to-bottom. To do this, use the second group + of four sorted-movement requests.
+ +Finally, it is possible to move between fields using visual + directions up, down, right, and left. To accomplish this, use the + third group of four requests. Note, however, that the position of + a form for purposes of these requests is its upper-left + corner.
+ +For example, suppose you have a multi-line field B, and two
+ single-line fields A and C on the same line with B, with A to the
+ left of B and C to the right of B. A REQ_MOVE_RIGHT
+ from A will go to B only if A, B, and C all share the
+ same first line; otherwise it will skip over B to C.
These requests drive movement of the edit cursor within the + currently selected field.
+ +REQ_NEXT_CHARREQ_PREV_CHARREQ_NEXT_LINEREQ_PREV_LINEREQ_NEXT_WORDREQ_PREV_WORDREQ_BEG_FIELDREQ_END_FIELDREQ_BEG_LINEREQ_END_LINEREQ_LEFT_CHARREQ_RIGHT_CHARREQ_UP_CHARREQ_DOWN_CHAREach word is separated from the previous and next + characters by whitespace. The commands to move to beginning and + end of line or field look for the first or last non-pad character + in their ranges.
+ +Fields that are dynamic and have grown and fields explicitly + created with offscreen rows are scrollable. One-line fields + scroll horizontally; multi-line fields scroll vertically. Most + scrolling is triggered by editing and intra-field movement (the + library scrolls the field to keep the cursor visible). It is + possible to explicitly request scrolling with the following + requests:
+ +REQ_SCR_FLINEREQ_SCR_BLINEREQ_SCR_FPAGEREQ_SCR_BPAGEREQ_SCR_FHPAGEREQ_SCR_BHPAGEREQ_SCR_FCHARREQ_SCR_BCHARREQ_SCR_HFLINEREQ_SCR_HBLINEREQ_SCR_HFHALFREQ_SCR_HBHALFFor scrolling purposes, a page of a field is the + height of its visible part.
+ +When you pass the forms driver an ASCII character, it is + treated as a request to add the character to the field's data + buffer. Whether this is an insertion or a replacement depends on + the field's edit mode (insertion is the default.
+ +The following requests support editing the field and changing + the edit mode:
+ +REQ_INS_MODEREQ_OVL_MODEREQ_NEW_LINEREQ_INS_CHARREQ_INS_LINEREQ_DEL_CHARREQ_DEL_PREVREQ_DEL_LINEREQ_DEL_WORDREQ_CLR_EOLREQ_CLR_EOFREQ_CLEAR_FIELDThe behavior of the REQ_NEW_LINE and
+ REQ_DEL_PREV requests is complicated and partly
+ controlled by a pair of forms options. The special cases are
+ triggered when the cursor is at the beginning of a field, or on
+ the last line of the field.
First, we consider REQ_NEW_LINE:
The normal behavior of REQ_NEW_LINE in insert
+ mode is to break the current line at the position of the edit
+ cursor, inserting the portion of the current line after the
+ cursor as a new line following the current and moving the cursor
+ to the beginning of that new line (you may think of this as
+ inserting a newline in the field buffer).
The normal behavior of REQ_NEW_LINE in overlay
+ mode is to clear the current line from the position of the edit
+ cursor to end of line. The cursor is then moved to the beginning
+ of the next line.
However, REQ_NEW_LINE at the beginning of a
+ field, or on the last line of a field, instead does a
+ REQ_NEXT_FIELD. O_NL_OVERLOAD option is
+ off, this special action is disabled.
Now, let us consider REQ_DEL_PREV:
The normal behavior of REQ_DEL_PREV is to delete
+ the previous character. If insert mode is on, and the cursor is
+ at the start of a line, and the text on that line will fit on the
+ previous one, it instead appends the contents of the current line
+ to the previous one and deletes the current line (you may think
+ of this as deleting a newline from the field buffer).
However, REQ_DEL_PREV at the beginning of a field
+ is instead treated as a REQ_PREV_FIELD.
If the O_BS_OVERLOAD option is off, this special
+ action is disabled and the forms driver just returns
+ E_REQUEST_DENIED.
See Form Options for discussion of + how to set and clear the overload options.
+ +If the type of your field is ordered, and has associated + functions for getting the next and previous values of the type + from a given value, there are requests that can fetch that value + into the field buffer:
+ +REQ_NEXT_CHOICEREQ_PREV_CHOICEOf the built-in field types, only TYPE_ENUM has
+ built-in successor and predecessor functions. When you define a
+ field type of your own (see Custom Validation
+ Types), you can associate our own ordering functions.
Form requests are represented as integers above the
+ curses value greater than KEY_MAX and
+ less than or equal to the constant MAX_COMMAND. If
+ your input-virtualization routine returns a value above
+ MAX_COMMAND, the forms driver will ignore it.
It is possible to set function hooks to be executed whenever + the current field or form changes. Here are the functions that + support this:
+
+typedef void (*HOOK)(); /* pointer to function returning void */
int set_form_init(FORM *form, /* form to alter */
HOOK hook); /* initialization hook */
@@ -2418,53 +3027,66 @@ int set_field_term(FORM *form, /* form to alter */
HOOK hook); /* termination hook */
HOOK field_term(FORM *form); /* form to query */
-
-
-These functions allow you to either set or query four different hooks.
-In each of the set functions, the second argument should be the
-address of a hook function. These functions differ only in the timing
-of the hook call.
-
-set_current_field() call
-set_form_page() call
-- -You can set a default hook for all fields by passing one of the set functions -a NULL first argument.
- -You can disable any of these hooks by (re)setting them to NULL, the default -value. - -
++ +
These functions allow you to either set or query four + different hooks. In each of the set functions, the second + argument should be the address of a hook function. These + functions differ only in the timing of the hook call.
+ +Calls to these hooks may be triggered
+ +set_current_field() callset_form_page() callSee Field Change Commands for + discussion of the latter two cases.
+ +You can set a default hook for all fields by passing one of + the set functions a NULL first argument.
+ +You can disable any of these hooks by (re)setting them to + NULL, the default value.
+ +Normally, navigation through the form will be driven by the + user's input requests. But sometimes it is useful to be able to + move the focus for editing and viewing under control of your + application, or ask which field it currently is in. The following + functions help you accomplish this:
+
int set_current_field(FORM *form, /* form to alter */
FIELD *field); /* field to shift to */
@@ -2472,33 +3094,33 @@ FIELD *current_field(FORM *form); /* form to query */
int field_index(FORM *form, /* form to query */
FIELD *field); /* field to get index of */
-
-
-The function field_index() returns the index of the given field
-in the given form's field array (the array passed to new_form() or
-set_form_fields()).
+
-The initial current field of a form is the first active field on the
-first page. The function set_form_fields() resets this.
+
The function field_index() returns the index of
+ the given field in the given form's field array (the array passed
+ to new_form() or
+ set_form_fields()).
The initial current field of a form is the first active field
+ on the first page. The function set_form_fields()
+ resets this.
+-It is also possible to move around by pages.
+int set_form_page(FORM *form, /* form to alter */ int page); /* page to go to (0-origin) */ int form_page(FORM *form); /* return form's current page */ -- -The initial page of a newly-created form is 0. The function -set_form_fields()resets this. +
The initial page of a newly-created form is 0. The function
+ set_form_fields() resets this.
+-By default, all options are on. Here are the available option bits: +Like fields, forms may have control option bits. They can be + changed or queried with these functions:
+int set_form_opts(FORM *form, /* form to alter */ int attr); /* attribute to set */ @@ -2509,179 +3131,206 @@ int form_opts_off(FORM *form, /* form to alter */ int attr); /* attributes to turn off */ int form_opts(FORM *form); /* form to query */ -+
By default, all options are on. Here are the available option + bits:
-REQ_NEW_LINE as described in Editing Requests. The value of this option is
-ignored on dynamic fields that have not reached their size limit;
-these have no last line, so the circumstances for triggering a
-REQ_NEXT_FIELD never arise.
-REQ_DEL_PREV as described in
-Editing Requests.
-REQ_NEW_LINE as
+ described in Editing Requests. The value
+ of this option is ignored on dynamic fields that have not
+ reached their size limit; these have no last line, so the
+ circumstances for triggering a REQ_NEXT_FIELD
+ never arise.form library gives you the capability to define custom
-validation types of your own. Further, the optional additional arguments
-of set_field_type effectively allow you to parameterize validation
-types. Most of the complications in the validation-type interface have to
-do with the handling of the additional arguments within custom validation
-functions.
+ REQ_DEL_PREV as
+ described in Editing Requests.The option values are bit-masks and can be composed with + logical-or in the obvious way.
-The simplest way to create a custom data type is to compose it from two -preexisting ones: ++-This function creates a field type that will accept any of the values -legal for either of its argument field types (which may be either -predefined or programmer-defined). +The
+ +formlibrary gives you the capability to + define custom validation types of your own. Further, the optional + additional arguments ofset_field_typeeffectively + allow you to parameterize validation types. Most of the + complications in the validation-type interface have to do with + the handling of the additional arguments within custom validation + functions.Union Types
+ +The simplest way to create a custom data type is to compose it + from two preexisting ones:
+FIELD *link_fieldtype(FIELDTYPE *type1, FIELDTYPE *type2); -+
This function creates a field type that will accept any of the
+ values legal for either of its argument field types (which may be
+ either predefined or programmer-defined). If a
+ set_field_type() call later requires arguments, the
+ new composite type expects all arguments for the first type, than
+ all arguments for the second. Order functions (see Order Requests) associated with the component types
+ will work on the composite; what it does is check the validation
+ function for the first type, then for the second, to figure what
+ type the buffer contents should be treated as.
set_field_type() call later requires arguments, the new
-composite type expects all arguments for the first type, than all arguments
-for the second. Order functions (see Order Requests)
-associated with the component types will work on the composite; what it does
-is check the validation function for the first type, then for the second, to
-figure what type the buffer contents should be treated as.
+ To create a field type from scratch, you need to specify one + or both of the following things:
-To create a field type from scratch, you need to specify one or both of the -following things: +-typedef int (*HOOK)(); /* pointer to function returning int */ ++ +Here is how you do that:
++typedef int (*HOOK)(); /* pointer to function returning int */ FIELDTYPE *new_fieldtype(HOOK f_validate, /* field validator */ HOOK c_validate) /* character validator */ int free_fieldtype(FIELDTYPE *ftype); /* type to free */ -+
At least one of the arguments of new_fieldtype()
+ must be non-NULL. The forms driver will automatically call the
+ new type's validation functions at appropriate points in
+ processing a field of the new type.
The function free_fieldtype() deallocates the
+ argument fieldtype, freeing all storage associated with it.
Normally, a field validator is called when the user attempts + to leave the field. Its first argument is a field pointer, from + which it can get to field buffer 0 and test it. If the function + returns TRUE, the operation succeeds; if it returns FALSE, the + edit cursor stays in the field.
+ +A character validator gets the character passed in as a first + argument. It too should return TRUE if the character is valid, + FALSE otherwise.
+ +Your field- and character- validation functions will be passed
+ a second argument as well. This second argument is the address of
+ a structure (which we will call a pile) built from any
+ of the field-type-specific arguments passed to
+ set_field_type(). If no such arguments are defined
+ for the field type, this pile pointer argument will be NULL.
In order to arrange for such arguments to be passed to your
+ validation functions, you must associate a small set of
+ storage-management functions with the type. The forms driver will
+ use these to synthesize a pile from the trailing arguments of
+ each set_field_type() argument, and a pointer to the
+ pile will be passed to the validation functions.
Here is how you make the association:
++typedef char *(*PTRHOOK)(); /* pointer to function returning (char *) */ +typedef void (*VOIDHOOK)(); /* pointer to function returning void */ -At least one of the arguments of-The functionnew_fieldtype()must be -non-NULL. The forms driver will automatically call the new type's -validation functions at appropriate points in processing a field of -the new type.+int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ + PTRHOOK make_str, /* make structure from args */ + PTRHOOK copy_str, /* make copy of structure */ + VOIDHOOK free_str); /* free structure storage */ +
free_fieldtype() deallocates the argument
-fieldtype, freeing all storage associated with it. +
Here is how the storage-management hooks are used:
-Normally, a field validator is called when the user attempts to -leave the field. Its first argument is a field pointer, from which it -can get to field buffer 0 and test it. If the function returns TRUE, -the operation succeeds; if it returns FALSE, the edit cursor stays in -the field.+
make_strset_field_type().
+ It gets one argument, a va_list of the
+ type-specific arguments passed to
+ set_field_type(). It is expected to return a pile
+ pointer to a data structure that encapsulates those
+ arguments.copy_strset_field_type(). If
-no such arguments are defined for the field type, this pile pointer
-argument will be NULL. +
set_field_type() argument, and
-a pointer to the pile will be passed to the validation functions. +
free_str-typedef char *(*PTRHOOK)(); /* pointer to function returning (char *) */ -typedef void (*VOIDHOOK)(); /* pointer to function returning void */ +- -Here is how the storage-management hooks are used: - -The
-int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ - PTRHOOK make_str, /* make structure from args */ - PTRHOOK copy_str, /* make copy of structure */ - VOIDHOOK free_str); /* free structure storage */ -make_strandcopy_strfunctions + may return NULL to signal allocation failure. The library + routines will that call them will return error indication when + this happens. Thus, your validation functions should never see a + NULL file pointer and need not check specially for it.
make_str
-set_field_type(). It gets one
-argument, a va_list of the type-specific arguments passed to
-set_field_type(). It is expected to return a pile pointer to a data
-structure that encapsulates those arguments.
-copy_str
-free_str
-make_str and copy_str functions may return NULL to
-signal allocation failure. The library routines will that call them will
-return error indication when this happens. Thus, your validation functions
-should never see a NULL file pointer and need not check specially for it.
-
-TYPE_ENUM is. For such types, it is possible to define
-successor and predecessor functions to support the REQ_NEXT_CHOICE
-and REQ_PREV_CHOICE requests. Here's how:
-
--typedef int (*INTHOOK)(); /* pointer to function returning int */ ++ +Order Functions For + Custom Types
+ +Some custom field types are simply ordered in the same + well-defined way that
+TYPE_ENUMis. For such types, + it is possible to define successor and predecessor functions to + support theREQ_NEXT_CHOICEand +REQ_PREV_CHOICErequests. Here is how:+typedef int (*INTHOOK)(); /* pointer to function returning int */ int set_fieldtype_arg(FIELDTYPE *type, /* type to alter */ INTHOOK succ, /* get successor value */ INTHOOK pred); /* get predecessor value */ -- -The successor and predecessor arguments will each be passed two arguments; -a field pointer, and a pile pointer (as for the validation functions). They -are expected to use the functionfield_buffer()to read the -current value, andset_field_buffer()on buffer 0 to set the next -or previous value. Either hook may return TRUE to indicate success (a -legal next or previous value was set) or FALSE to indicate failure. - -Avoiding Problems
- -The interface for defining custom types is complicated and tricky. -Rather than attempting to create a custom type entirely from scratch, -you should start by studying the library source code for whichever of -the pre-defined types seems to be closest to what you want.- -Use that code as a model, and evolve it towards what you really want. -You will avoid many problems and annoyances that way. The code -in the
ncurseslibrary has been specifically exempted from -the package copyright to support this.- -If your custom type defines order functions, have do something intuitive -with a blank field. A useful convention is to make the successor of a -blank field the types minimum value, and its predecessor the maximum. - - +
The successor and predecessor arguments will each be passed
+ two arguments; a field pointer, and a pile pointer (as for the
+ validation functions). They are expected to use the function
+ field_buffer() to read the current value, and
+ set_field_buffer() on buffer 0 to set the next or
+ previous value. Either hook may return TRUE to indicate success
+ (a legal next or previous value was set) or FALSE to indicate
+ failure.
The interface for defining custom types is complicated and + tricky. Rather than attempting to create a custom type entirely + from scratch, you should start by studying the library source + code for whichever of the pre-defined types seems to be closest + to what you want.
+ +Use that code as a model, and evolve it towards what you
+ really want. You will avoid many problems and annoyances that
+ way. The code in the ncurses library has been
+ specifically exempted from the package copyright to support
+ this.
If your custom type defines order functions, have do something + intuitive with a blank field. A useful convention is to make the + successor of a blank field the types minimum value, and its + predecessor the maximum.
+ +