Inside Macintosh: Macintosh Toolbox Essentials /

Glossary

action procedure A procedure that performs an action in response to the user holding the mouse button down while the cursor is in a control.

activate event A type of event that indicates that a window is becoming active or inactive. Each activate event specifies the window
to be changed and the direction of the change (that is, whether it's becoming active or becoming inactive).

active control A control in which the Control Manager responds to a user's mouse actions by providing visual feedback.

active window The frontmost window on the desktop, the one in which the user is currently working. The active window is designated by racing stripes in the title bar, active controls, and highlighted selections.

A5 world An area of memory in an application's partition that contains the QuickDraw
gloabl variables, the application global variables, the application parameters, and the jump table--all of which are accessed through the A5 register.

alert An alert sound, an alert box, or both. Alerts warn the user of an unusual or a potentially undesirable situation occurring within an application. See also alert box and
alert sound.

alert box A window that an application displays on the screen to warn the user or to report an error to the user. An alert box typically consists of text describing the situation and buttons that require the user to acknowledge or rectify the problem. An alert box may or may not be accompanied by an alert sound. See also caution alert, note alert, and stop alert.

alert color table resource A resource (of type 'actb') that lets an application display an alert box using colors other than the system's default window colors.

alert resource A resource (of type 'ALRT') that specifies alert sounds, a display rectangle, and an item list for an alert box.

alert sound An audible signal from the Macintosh speaker that warns the user of an unusual or a potentially undesirable situation occurring within an application. An alert sound may or may not be accompanied by an alert box.

alias An object that represents another file, directory, or volume.

alias file A file that contains a record that points to another file, directory, or volume. An alias file is displayed by the Finder as an alias.

alias record A data structure created by the Alias Manager to identify a file, directory,
or volume.

alias target The file, directory, or volume described by the alias record.

Apple event A high-level event whose structure and interpretation are determined by the Apple Event Interprocess Messaging Protocol.

Apple Menu Items folder A directory located in the System Folder for storing desk accessories, applications, folders, and aliases that the
user wants to display in and access from the Apple menu.

application heap An area of memory in
the application heap zone in which memory is dynamically allocated and released on demand. The heap contains the application's 'CODE' segment 1, data structures, resource map, and other code segments as needed.

application partition A partition of memory
reserved for use by an application. The application partition consists of free space, the
application heap, the application's stack, and
the application's A5 world.

auto-key event An event indicating that a
key is still down after a certain amount of time has elapsed.

auxiliary window record A data structure that the Window Manager uses to tie together a list of windows and their corresponding window color information tables.

background process A process that isn't currently interacting with the user. Compare foreground process.

bundle bit A flag in a file's Finder information record that informs the Finder that a bundle ('BNDL') resource exists for the file. A file's Finder information record is stored in a volume's catalog file. The Finder uses the information
in the bundle resource to associate icons with
the file.

button A control that appears on the screen as a rounded rectangle with a title centered inside. When the user clicks a button, the application performs the action described by the button's title. Button actions are usually performed instantaneously. Examples include completing operations defined by a dialog box and acknowledging an error message in an alert box.

catalog file A special file, located on a volume, that contains information about the hierarchical organization of files and folders on that volume.

caution alert An alert box that warns the user of an operation that may have undesirable results if it's allowed to continue. A caution alert gives the user the choice of continuing the action (by clicking the OK button) or stopping the action (by clicking the Cancel button). A caution alert is identified by an icon bearing an exclamation point in the upper-left corner of the alert box. See also note alert and stop alert.

character code A value that represents a particular character. The character code that is generated depends on the virtual key code and the state of the modifier keys. In the Roman script system, character codes are specified in
the extended version of ASCII (the American Standard Code for Information Interchange).

checkbox A control that appears onscreen as a small square with an accompanying title. A checkbox displays one of two settings: on (indicated by an X inside the box) or off. When the user clicks a checkbox, the application reverses its setting. See also radio button.

close box The small white box on the left side of the title bar of an active window. Clicking it closes the window.

close region The area occupied by a window's close box. See also close box.

Command-key equivalent Refers specifically to a keyboard equivalent that the user invokes by holding down the Command key and pressing another key (other than a modifier key) at the same time.

content region The part of a window in which the contents of a document, the size box, and
the window controls (including the scroll bars) are displayed.

context The information about a process maintained by the Process Manager. This information includes the current state of the process, the address and size of its partition, its type, its creator, a copy of its low-memory global variables, information about its 'SIZE' resource, and a process serial number.

control An onscreen object that the user can manipulate with the mouse. By manipulating a control, the user can take an immediate action or change a setting to modify a future action.

control color table In an item color table resource, a specification for the colors used to draw the various parts of a control.

control definition function A function that defines the appearance and behavior of a control. A control definition function, for example, draws the control. See also standard control definition functions.

control definition ID A number passed to control-creation routines to indicate the type of control. It consists of the control definition function's resource ID and a variation code.

control list A series of entries pointing to the descriptions of the controls associated with
the window.

Control Manager A collection of routines that applications use to create and manipulate controls, especially those in windows.

Control Panels folder A directory located in the System Folder for storing control panels, which allow users to modify the work environment of their Macintosh computer.

control record A data structure of type ControlRecord, which the Control Manager uses to store all the information it needs for its operations on a control.

current menu list A data structure that contains handles to the menu records of all menus in the current menu bar and the menu records of any submenus or pop-up menus that an application inserts into the list.

current process The process that is currently executing and whose A5 world is valid; this process can be in the background or the foreground.

cursor Any 256-bit image, defined by a 16-by-16 bit square. The mouse driver displays the current cursor and maps the movement
of the mouse to relative locations on the screen
as the user moves the mouse.

custom alert box An alert box whose upper-left corner contains blank space or displays an icon other than those used by caution alerts, stop alerts, or note alerts.

customized icon An icon created by the user or by an application and stored with a resource ID of -16455 in the resource fork of a file. A file with a customized icon has the hasCustomIcon bit set in its Finder flags field.

data fork The part of a file that contains data accessed using the File Manager. The data usually corresponds to data entered by the user; the application creating a file can store and interpret the data in the data fork in whatever manner is appropriate.

default button In an alert box or a dialog box, the button whose action is invoked when the user presses the Return key or the Enter key. The Dialog Manager automatically draws a bold outline around the default button in alert boxes; applications should draw a bold outline around the default button in dialog boxes. The default button should invoke the preferred action, which, whenever possible, should be a "safe" action--that is, one that doesn't cause loss of data.

desktop The working environment displayed on the Macintosh computer: the gray background area on the screen.

desktop database A Finder-maintained database of icons, file types, applications, version data, and comments for all volumes over 2 MB. Compare Desktop file.

Desktop file A resource file in which the Finder stores icons, file types, applications, version data, and comments for all volumes less than 2 MB. Compare desktop database.

Desktop Folder A directory, located at the root level of each volume, used by the Finder for storing information about the icons that appear on the desktop area of the screen. The Desktop Folder is invisible to the user. What the user sees onscreen is the union of the contents of Desktop Folders for all mounted volumes.

dial A control, similar to a scroll bar, that graphically represents the ranges of values that
a user can set or that simply displays the value, magnitude, or position of something, typically in some pseudo-analog form.

dialog box A window that an application displays on the screen to solicit information
from the user before the application carries
out the user's command. See also modal dialog box, modeless dialog box, and movable modal dialog box.

dialog color table resource A resource (of type 'dctb') that lets an application display a dialog box using colors other than the system's default window colors.

Dialog Manager A collection of routines that applications use to implement alerts and dialog boxes.

dialog record A data structure of type DialogRecord that the Dialog Manager
uses to create dialog boxes and alerts.

dialog resource A resource (of type 'DLOG') that specifies the window type, display rectangle, and item list for a dialog box.

disabled item In an alert box or a dialog box, an item for which the Dialog Manager does
not report user events. An example of a disabled item is static text, which typically does not respond to clicks.

disk-inserted event An event indicating that a disk has been inserted into a disk drive.

display rectangle A rectangle that defines the size and location of an item in an alert box or a dialog box. The display rectangle is specified in an item list and uses coordinates local to the alert box or dialog box.

divider A gray line used in menus to separate groups of menu items.

document window A window in which the user enters text, draws graphics, or otherwise enters or manipulates data.

drag region The area occupied by a window's title bar, except for the close box and zoom box. The user can move a window on the desktop by dragging the drag region.

edition The data written to an edition container by a publisher. A publisher writes data to an edition whenever a user saves a document that contains a publisher, and subscribers in other documents may read the data from the edition whenever it is updated.

enabled item In an alert box or a dialog box, an item for which the Dialog Manager reports user events. For example, the Dialog Manager reports clicks in an enabled OK button.

event The means by which the Event Manager communicates information about user actions, changes in the processing status of the application, and other occurrences that require a response from the application.

event filter function An application-defined routine that supplements the Dialog Manager's ability to handle events--for example, an event filter function can test for disk-inserted events and can allow background applications to receive update events.

Event Manager The collection of routines that an application can use to receive information about actions performed by the user, to receive notice of changes in the processing status of
the application, and to communicate with
other applications.

event mask An integer with one bit position for each event type. You specify an event mask as a parameter to Event Manager routines to specify the event types you want your application to receive, thereby disabling (or "masking out") the events you are not interested in receiving.

event record A data structure of type
EventRecord that your application uses when retrieving information about an event. The Event Manager returns, in an event record, information about what type of event occurred (a mouse click or keypress, for example) and additional information associated with the event.

Extensions folder A directory located in the System Folder for storing system extension files such as printer and network drivers and files of types 'INIT', 'scri', and 'appe'.

file A named, ordered sequence of bytes stored on a Macintosh volume, divided into a data fork and a resource fork.

Finder An application that works with the system software to keep track of files and manage the user's desktop display.

Fonts folder A directory located in the System Folder for storing fonts.

foreground process The process currently interacting with the user; it appears to the user as the active application. The foreground process displays its menu bar, and its windows are in front of the windows of other applications. Compare background process.

frame The part of a window drawn automatically by the Window Manager, namely, the title bar, including the close box and zoom box, and the window's outline.

global coordinate system The coordinate system that represents all potential QuickDraw drawing space. The origin of the global coordinate system--that is, the point (0,0)--
is at the upper-left corner of the main screen. Compare local coordinate system.

graphics port A complete, individual drawing environment with an independent coordinate system. Each window is drawn in a graphics port.

gray area The area within a scroll bar, excluding the scroll arrows and the scroll box. When the user clicks the gray area of a scroll bar, the application moves the displayed area of the document by an entire window less one line (or column, row, or character).

gray region A region that represents all available desktop area--that is, a collection
of rounded-corner rectangles representing
the display areas of all monitors available to
a computer.

grow image An outline of a window's new frame, drawn on the screen while the user is resizing the window with the size box.

help balloon A rounded-rectangle window that contains explanatory information for the user. With tips pointing at the objects they annotate, help balloons look like bubbles used for dialog in comic strips. Help balloons are turned on by the user from the Help menu; when Balloon Help assistance is on, a help balloon appears whenever the user moves the cursor over an area that is associated with it.

hierarchical menu A menu to which a submenu is attached.

high-level event An event sent from one application to another requesting transfer of information or performance of some action.

high-level event queue A separate queue that the Event Manager maintains to store high-level events transmitted to an application. The Event Manager maintains a high-level event queue for each open application capable of receiving high-level events.

hot spot A point that the mouse driver uses to align the cursor with the mouse location.

icon An image that represents an object, a concept, or a message.

icon family The set of icons that represent an object--such as an application or a document--displayed by the Finder. An entire icon family consists of large (32-by-32 pixel) and small (16-by-16 pixel) icons, each with a mask, and each available in three different versions of color: black and white, 4 bits of color data per pixel, and 8 bits of color data per pixel.

inactive control A control that has no meaning or effect in the current context--for example, the scroll bars in an empty window. The Control Manager dims inactive controls or otherwise visually indicates their inactive state.

inactive window A window in which the user is not working.

indicator A moving part in a dial or slider control. A user moves an indicator to set a value, and an application moves it to indicate the current setting of the control. In a scroll bar, the scroll box is the indicator.

item color table resource A resource (of type 'ictb') that an application can use to display an alert box or a dialog box with items using a typeface, font style, font size, or colors other
than the system's default font and colors. (For
an application to use a nonstandard typeface, font style, or font size, the user must have a
color monitor.)

item list A resource (of type 'DITL') that specifies the items--such as buttons and static text--to display in an alert box or a dialog box.

item number An integer that identifies an item in either a menu or a dialog box. Menu items
are assigned item numbers starting with 1 for
the first menu item in the menu, 2 for the second menu item in the menu, and so on, up to the number of the last menu item in the menu. Dialog items are assigned numbers that correspond to the item's position in its item list. For example, the first item listed in a dialog item list is item number 1.

keyboard equivalent A keyboard combination of one or more modifier keys and another key that invokes a corresponding menu command when pressed by the user.

key-down event An event indicating that the user pressed a key on the keyboard.

key-up event An event indicating that the user released a key on the keyboard.

local coordinate system The coordinate system defined by the port rectangle of a graphics port. When the Window Manager creates a window, it places the origin of the local coordinate system at the upper-left corner of the window's port rectangle. Compare global coordinate system.

location name An identifier for the network location of the computer on which a PPC port resides. A location name consists of an object string, a type string, and a zone.

low-level event The type of event returned by the Event Manager to report very low level hardware and software occurrences. Low-level events report actions by the user, changes in windows on the screen, and that the Event Manager has no other events to report. Compare high-level event, operating-system event.

major switch A change of the foreground process. The Process Manager switches the context of the foreground process with the context of a background process (including the A5 worlds and low-memory global variables) and brings the background process to the front, sending the previous foreground process to the background. See also context.

menu A user interface element you can use in your application to allow the user to view or choose an item from a list of choices and commands that your application provides.
See also hierarchical menu, pop-up menu, pull-down menu, and submenu.

menu bar A white rectangle that is tall enough to display menu titles in the height of the system font and system font size, and with a black lower border that is one pixel tall. The menu bar extends across the top of the startup screen and contains the title of each available pull-down menu.

menu bar definition function A function that draws the menu bar and performs most of the drawing activities related to the display of menus when the user moves the cursor between menus. This function, in conjunction with the menu definition procedure, defines the general appearance and behavior of menus.

menu bar entry A menu color entry record that contains 0 in both the mctID and mctItem fields. A menu bar entry defines the color for an application's menu bar and defines default colors for its menu titles, menu items, and background color of menus.

menu bar resource A resource (of type 'MBAR') that specifies the order and resource ID of each menu in a menu bar.

menu color entry record A data structure of type MCEntry that defines the colors for an application's menu bar, menus, or menu items. The first two fields of a menu color entry record, mctID and mctItem, define whether the entry
is a menu bar entry, a menu title entry, or a menu item entry.

menu color information table An array of menu color entry records, maintained by the Menu Manager, that define the standard color
for the menu bar, titles of menus, text and characteristics of menu items, and background color of a displayed menu. If you do not add
any entries to this table, the Menu Manager draws your menus using the default colors, black on white.

menu color information table resource A resource (of type 'mctb') that specifies the colors for an application's menu bar, menus,
and menu items.

menu definition procedure A procedure that performs all the drawing of menu items within
a specific menu. This procedure, in conjunction with the menu bar definition function, defines the general appearance and behavior of menus.

menu ID A number that you assign to a menu in your application. Each menu in your application must have a unique menu ID.

menu item In a menu, a rectangle with text and other characteristics identifying a command that the user can choose.

menu item entry A menu color entry record that contains nonzero values in both the mctID and mctItem fields. A menu item entry defines colors for the mark, text, and keyboard equivalent of items in a specific menu. It also defines the default background color of a menu.

menu list A data structure that contains handles to the menu records of one or more menus (although a menu list can be empty). Compare current menu list.

Menu Manager The collection of routines that an application can use to create, display, and manage its menus.

menu record A data structure of type MenuInfo that the Menu Manager uses to maintain information about a menu.

menu resource A resource (of type 'MENU') that specifies the menu title and the individual characteristics of items in a menu.

menu title entry A menu color entry record that contains a nonzero value in the mctID
field and contains 0 in the mctItem field. A menu title entry defines colors for the title,
items, and background color of a specific menu. It also defines the default menu bar color.

minimum partition size The actual partition size limit below which an application cannot run.

minor switch A change in the context of a process. The Process Manager switches the context of a process to give time to a background process without bringing the background process to the front.

modal dialog box A dialog box that puts the user in the state or "mode" of being able to work only inside the dialog box. A modal dialog box resembles an alert box. The user cannot move a modal dialog box and can dismiss it only by clicking its buttons. See also modeless dialog box and movable modal dialog box.

modeless dialog box A dialog box that looks like a document window without a size box or scroll bars. The user can move a modeless dialog box, make it inactive and active again, and close it like any document window. See also modal dialog box and movable modal dialog box.

modifier keys The Shift, Option, Command, Control, and Caps Lock keys.

mouse-down event An event indicating that the user pressed the mouse button.

mouse location The location of the cursor at the time the event occurred.

mouse-moved event An event indicating that the cursor is outside of a specified region.

mouse-up event An event indicating that the user released the mouse button.

movable modal dialog box A modal dialog box that has a title bar (with no close box) by which the user can drag the dialog box. See also dialog box, modal dialog box, and modeless dialog box.

note alert An alert box that informs users of a minor mistake that won't have any disastrous consequences if left as is. Usually a note alert simply offers information, and the user responds by clicking the OK button. A note alert is identified by an icon bearing a face and a cartoonlike dialog balloon in the upper-left corner of the alert box. See also caution alert and stop alert.

null event An event indicating that no events of the requested types exist in the application's event stream.

offset point The point in a region whose horizontal and vertical offsets from the upper-left corner of the region's enclosing rectangle are the same as the offsets of a specified point. The DrayGrayRgn function uses an offset point to limit the motion of a region and to calculate the distance a region has moved.

operating-system event An event returned by the Event Manager to communicate information about changes in the operating status of applications (suspend and resume events) and to report that the user has moved the cursor outside of an area specified by the application (mouse- moved events). Compare low-level event, high-level event.

Operating System Event Manager The collection of low-level routines that manage the Operating System event queue.

Operating System event queue A queue that the Operating System Event Manager creates and maintains. The Operating System Event Manager detects and reports low-level hardware-related events such as mouse clicks, keypresses, and disk insertions and places these events in the Operating System event queue.

part code An integer from 1 through 253 that stands for a particular part of a control. The FindControl and TrackControl functions return a part code to indicate the location of the cursor when the user presses the mouse button.

pop-up menu A menu that appears elsewhere than the menu bar. The Control Manager provides a control definition function for applications to use when implementing pop-
up menus.

port name A unique identifier for a particular application on a computer, used for the purposes of communication between applications. A port name consists of a name string, a type string, and a script code.

port rectangle An entry in the graphics port data structure, described in Inside Macintosh: Imaging. Ordinarily, the port rectangle represents the area of a graphics port available for drawing--that is, the content region of a window.

Preferences folder A directory located in the System Folder for holding files that record users' configuration settings for applications on a particular Macintosh computer.

preferred partition size The partition size at which an application can run most effectively. The Operating System attempts to secure this partition size upon launch of the application.

PrintMonitor Documents folder A directory located in the System Folder for storing spooled documents waiting to be printed.

process An open application or, in some cases, an open desk accessory. (Only desk accessories that are not opened in the context of another application are considered processes.)

process serial number A number assigned by the Process Manager to identify a particular instance of an application during a single boot
of the local machine.

pull-down menu A menu that is identified by a menu title (a word or an icon) in the menu bar.

query document A file of file type 'qery' containing commands and data in a format appropriate for a database or other data source. An application uses high-level Data Access Manager routines to open a query document.

radio button A control that appears onscreen as a small circle. A radio button displays one of two settings: on (indicated by a black dot inside the circle) or off. A radio button is always a part of a group of related radio buttons in which only one button can be on at a time. When the user clicks an unmarked radio button, the application turns that button on and turns the other buttons in its group off.

Rescued Items from volume name folder A directory located in the Trash directory and created by the Finder at system startup, restart, or shutdown only when it finds items in the Temporary Items folder, usually after a system crash. The Rescued Items from volume name folder is named for the volume on which the Temporary Items folder exists. When a user empties the Trash, all Rescued Items folders disappear.

resource Any data stored according to a defined structure in a resource fork of a file; the data in a resource is interpreted according to its resource type.

resource fork The part of a file that contains the files' resources. A resource fork consists of a resource map and resources.

resource ID A number that identifies a specific resource of a given resource type.

resource type A sequence of four characters that uniquely identifies a specific type of resource.

resume event An event indicating that an application has been switched back into the foreground and can resume interacting with
the user.

return receipt A high-level event that indicates whether the other application accepted the high-level event sent to it by your application.

scroll arrow An arrow at either end of a scroll bar. When the user clicks a scroll arrow, the application moves a document or list one line
(or some similar measure) in the direction of the arrow. When the user holds the mouse button down while the cursor is over a scroll arrow,
the application moves the document or list continuously in the direction of the arrow.

scroll bar A control with which the user can change the portion of a document displayed within a window. A scroll bar is a light gray rectangle with scroll arrows at each end. Windows can have a horizontal scroll bar, a vertical scroll bar, or both. A vertical scroll bar lies along the right side of a window. A horizontal scroll bar runs along the bottom of
a window. Inside the scroll bar is a rectangle called the scroll box. The rest of the scroll bar
is called the gray area. The user can move through a document by manipulating the parts
of the scroll bar.

scroll box A box that slides up and down or back and forth across a scroll bar. The position of the scroll box in a scroll bar indicates the position of the window contents relative to the entire document. When the user drags the scroll box, the application displays a different portion of
the document.

signature A resource whose type is defined by a four-character sequence that uniquely identifies an application to the Finder. A signature is located in an application's resource fork.

size box A box in the lower-right corner of windows that can be resized. Dragging the size box resizes the window.

size region The area occupied by a window's size box. See also size box.

size resource A resource (of type 'SIZE') that specifies the operating characteristics, minimum partition size, and preferred partition size of
an application.

slider A control, such as a scroll bar, that graphically represent the ranges of values that
a user can set or that simply displays the value, magnitude, or position of something, typically
in some pseudo-analog form.

standard control definition functions Three control definition functions, stored as 'CDEF' resources in the System file. The 'CDEF' resource with resource ID 0 defines the look and behavior of buttons, checkboxes, and radio buttons; the 'CDEF' resource with resource ID 1 defines the look and behavior of scroll bars; and the 'CDEF' resource with resource ID 63 defines the look and behavior of pop-up menus.

standard state The size and location that
an application deems the most convenient for
a window.

Startup Items folderA directory located in the System Folder for storing applications and desk accessories that the user wants started up every time the Finder starts up.

stationery pad A document that a user creates to serve as a template for other documents. The Finder tags a document as a stationery pad by setting the isStationery bit in the Finder
flags field of the file's file information record.
An application that is asked to open a stationery pad should copy the template's contents into a new document and open the document in an untitled window.

stop alert An alert box that informs the user of a problem or situation so serious that the user's desired action cannot be completed. Stop alerts typically have only a single button (OK), because all the user can do is acknowledge that the action cannot be completed. A stop alert is identified by an icon of an upraised hand in the upper-left corner of the alert box. See also caution alert and note alert.

structure region The entire screen area occupied by a window, including both the window frame and the content region.

submenu A menu that is attached to
another menu.

suspend event An event indicating that the execution of your application is about to be suspended as the result of a major switch.
The application is suspended at the application's next call to WaitNextEvent or EventAvail.

system alert sound A sound resource that is stored in the System file and played whenever system software or an application uses the Sound Manager procedure SysBeep. With the Sound control panel, the user can select which sound
to use.

System file A file, located in the System Folder, that contains the basic system software plus some system resources, such as sound and keyboard resources.The System file behaves like a folder in this regard: although it looks like a suitcase icon,

double-clicking it opens a window that reveals movable resource files (such as sounds, keyboard layouts, and script system resource collections) stored in the System file.

System Folder A directory containing the software that Macintosh computers use to start up. The System Folder includes a set of folders for storing related files, such as preferences files that an application might need when starting up.

Temporary Items folder A directory located at the root level of a volume for storing temporary buffer files created by applications. The Temporary Items folder is invisible to the user.

text style table In an item color table resource, a specification for the typeface, font style, font size, and color of text in an editable text item or a static text item.

title bar The bar at the top of a window that displays the window name, contains the close and zoom boxes, and indicates whether the window is active.

Toolbox Event Manager See Event Manager.

Trash folder A directory at the root level of a volume for storing files that the user has moved to the Trash icon. After opening the Trash icon, the user sees the collection of all items that the user has moved to the Trash icon--that is, the union of appropriate Trash directories from
all mounted volumes. A Macintosh computer
set up to share files among users in a network environment maintains separate Trash subdirectories for remote users within its shared Trash directory. The Finder empties a Trash directory (or, in the case of a file server, a Trash subdirectory) only when the user of that directory chooses the Empty Trash command.

update event An event indicating that the contents of a window need updating.

update region A region maintained by the Window Manager that includes the parts of a window's content region that need updating.
The Event Manager generates update events
as necessary, based on the contents of the
update region, telling your application to update a window.

user state The size and location that the user has established for a window.

variation code A number that selects among variations supported by a single window defintion function or control definition function. The variation code is stored in the low-order 4 bits of the window definition ID or control definition ID. See also control definition function, control definition ID, window definition function, and window definition ID.

virtual key code A value that represents the key pressed or released by the user; this value is always the same for a specific physical key on a keyboard. Compare character code.

visible region The part of a window's graphics port that's actually visible on the screen--that is, the part that's not covered by other windows.

window An area on the screen that displays information, including user documents as well
as communications such as alert boxes and dialog boxes. The user can open or close a window; move it around on the desktop; and sometimes change its size, scroll through it, and edit its contents.

window color table The data structure in which the Window Manager stores the colors
to be used for drawing a window's frame and
for highlighting selected text.

window definition function A function that defines the general appearance and behavior of a window. The Window Manager calls the window definition function to draw the window's frame, determine what region of the window the cursor is in, draw the window's size box, draw the window's zoom box, move and resize the window, and calculate the window's structure and content regions.

window definition ID An integer that specifies the resource ID of a window definition function in the upper 12 bits and an optional variation code in the lower 4 bits. When creating a new window, your application supplies a window definition ID either as a field in the 'WIND' resource or as a parameter to the NewWindow or NewCWindow function.

window list A list maintained by the Window Manager of all windows on the desktop. The frontmost window is first in the window list, and the remaining windows appear in the order in which they are layered on the desktop.

Window Manager port A graphics port that represents the desktop area on the main monitor--that is, a rounded-corner rectangle that occupies all of the main monitor except for the area occupied by the title bar.

window origin The upper-left corner of a window. Usually specified as (0,0), the window origin is expressed in coordinates local to
the window.

window record A data structure of type
WindowRecord (or CWindowRecord) in which the Window Manager stores a window's characteristics, including the window's graphics port,
title, visibility status, and control list.

window region Special-purpose region of a window. See also close region, content region, drag region, size region, and zoom region.

window type A collection of characteristics--such as the shape of the window's frame and the features of its title bar--that describe a window.

zoom box A box in the right side of a window's title bar that the user can click to alternate between two different window sizes (the user state and the standard state).

zoom region The area occupied by a window's zoom box. See also zoom box.