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Legacy Document

Important: The Event Manager is a legacy System 7 technology. You should use the Mac OS X Carbon Event Manager instead. See Carbon Event Manager Programming Guide.

Event Manager Reference (Not Recommended)

Framework	Carbon/Carbon.h
Declared in	CarbonEvents.h CarbonEventsCore.h Events.h

Overview

Important: The Event Manager is a legacy System 7 technology. You should use the Mac OS X Carbon Event Manager instead. See Carbon Event Manager Programming Guide.

The Event Manager is a legacy System 7 technology that was created to support the cooperative, multitasking environment available on Macintosh computers at the time. This environment allowed users to switch between many open applications and allows other applications to receive background processing time.

The Carbon Event Manager, introduced in Mac OS X, offers a simple yet flexible approach to event handling that greatly reduces the amount of code needed to write a basic application. Moreover, the Carbon Event Manager's streamlined event handling enhances system performance on Mac OS X through more efficient allocation of processing time. Applications that use the Carbon Event Manager not only run better on Mac OS X, they help improve overall performance and responsiveness.

Since the introduction of the Macintosh computer, Mac applications have used the Event Manager to receive information about actions performed by the user, to receive notices of changes in their processing, and to communicate with other applications. For example, an application can retrieve information from the Event Manager about whether the user has pressed a key or the mouse button, whether one of the application’s windows needs updating, or whether some other hardware-related or software-related action requires a response from the application.

Applications also used the Event Manager to support the cooperative, multitasking environment available on versions of the Mac OS that preceded Mac OS X. This environment allows users to switch between many open applications and allows other applications to receive background processing time. By using Event Manager routines, an application allowed the system software to coordinate the scheduling of processing time between it and other applications.

Carbon supports the majority of the Event Manager.

High-level events APIs (as contained in EPPC.h) are not supported. You should use Apple events instead.

Carbon does not support the diskEvt event. Support for volume mount and unmount events will be available in the Carbon Event Manager.

Carbon does not set the convertClipboardFlag in the EventRecord to indicate that the scrap has changed while the application was suspended. You should call the Scrap Manager function GetCurrentScrap instead.

Low-level event queue functions, such as GetEvQHdr and PPostEvent, are no longer supported.

Application-defined function-key procedures are not supported in Carbon.

Functions by Task

Accessors for Low-Memory Globals

Getting Timing Information

Making Keyboard Settings

Reading the Keyboard

Receiving Events

Sending Events

Miscellaneous

Functions

CheckEventQueueForUserCancel

Checks the event queue for an user-cancel event.

Boolean CheckEventQueueForUserCancel (
   void
);

Return Value

Returns true if a user-cancel event is in the queue, false otherwise.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CarbonEvents.h

EventAvail

Retrieves the next available event from the Event Manager without removing the returned event from your application’s event stream.

Boolean EventAvail (
   EventMask eventMask,
   EventRecord *theEvent
);

Parameters

eventMask: A value that indicates which kinds of events are to be returned; this parameter is interpreted as a sum of event mask constants. You specify the event mask using one or more of the values defined by the “Event Mask Constants.” If no event of any of the designated types is available, EventAvail returns a null event.
theEvent: A pointer to an event structure for the next available event of the specified type or types. The EventAvail function does not remove the returned event from the event stream, but does return the information about the event in an event structure. The event structure includes the type of event received and other information.

Return Value

EventAvail returns false as its function result if the event being returned is a null event; otherwise, EventAvail returns true.

Special Considerations

If EventAvail returns a low-level event from the Operating System event queue, the event will not be accessible later if, in the meantime, the event queue becomes full and the event is discarded from it; however, this is not a common occurrence.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Related Sample Code

Simple DrawSprocket

Declared In

Events.h

FlushEvents

Removes low-level events from the Operating System event queue.

void FlushEvents (
   EventMask whichMask,
   EventMask stopMask
);

Parameters

whichMask: A value that indicates which kinds of low-level events are to be removed from the Operating System event queue; this parameter is interpreted as a sum of event mask constants. You specify the event mask using one or more of the values defined in “Event Mask Constants.” The whichMask and stopMask parameters together specify which events to remove.
stopMask: A value that limits which low-level events are to be removed from the Operating System event queue; this parameter is interpreted as a sum of event mask constants. You specify the event mask using one or more of the values defined in “Event Mask Constants.” FlushEvents does not remove any low-level events that are specified by the stopMask parameter. To remove all events specified by the whichMask parameter, specify 0 as the stopMask parameter.

Discussion

FlushEvents removes only low-level events stored in the Operating System event queue; it does not remove activate, update, operating-system, or high-level events. FlushEvents does not remove any types of events not stored in the Operating System event queue.

You can choose to use the FlushEvents function when your application first starts to empty the Operating System event queue of any keystrokes or mouse events generated by the user while the Finder loaded your application. In general, however, your application should not empty the queue at any other time as this loses user actions and makes your application and the computer appear unresponsive to the user.

You specify which low-level events to remove using the whichMask and stopMask parameters. FlushEvents removes the low-level events specified by the whichMask parameter, up to but not including the first event of any type specified by the stopMask parameter.

If the event queue doesn’t contain any of the events specified by the whichMask parameter, FlushEvents does not remove any events from the queue.

Availability

Available in Mac OS X v10.0 and later.

Related Sample Code

Declared In

Events.h

GetCaretTime

Obtains the suggested difference in ticks that should exist between blinks of the caret (usually a vertical bar marking the insertion point) in editable text.

UInt32 GetCaretTime (
   void
);

Return Value

The blink delay, in ticks.

Discussion

If your application supports editable text, your application should use the value returned by GetCaretTime to determine how often to blink the caret. If your application uses only TextEdit, you can use TextEdit functions to automatically blink the caret at the time interval that the user specifies in the General Controls panel.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

GetCurrentKeyModifiers

Returns the current state of the keyboard modifier keys.

UInt32 GetCurrentKeyModifiers (
   void
);

Parameters

Return Value

A bit mask indicating which keyboard modifier keys are pressed. See “Event Modifier Constants” for a list of possible values.

Discussion

GetCurrentKeyModifiers provides a more convenient way to get the modifier key state than calling GetNextEvent. It returns a value whose individual bits indicate which keyboard modifier keys are currently being pressed. You can test for the Caps Lock, Shift, Control, Option, and Command keys.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CarbonEventsCore.h

GetDblTime

Determines whether a sequence of mouse events constitutes a double click.

UInt32 GetDblTime (
   void
);

Return Value

The suggested maximum elapsed time, in ticks, between a mouse-up event and a mouse-down event.

Discussion

The GetDblTime function returns the suggested maximum elapsed time, in ticks, between a mouse-up event and a mouse-down event. The user can adjust this value using the Mouse control panel.

If your application distinguishes a double click of the mouse from a single click, your application should use the value returned by GetDblTime to make this distinction. If your application uses TextEdit, the TextEdit functions automatically recognize and handle double clicks of text within a TextEdit edit structure by appropriately highlighting or unhighlighting the selection.

The ratio of ticks to value in the DoubleTime global variable is 1:1. However, the Finder multiplies DoubleTime by 2 to determine double click time because it needs to account for user problems that typically occur during icon arrangement. Therefore, the Finder uses DoubleTime*2 whereas the rest of the system uses DoubleTime.

Incidentally, the Finder does not limit the DoubleTime to 64 ticks. In most places, it treats it like a byte although in some others it treats it like a longword. The best method would be to provide a one-second double-byte (two seconds in the Finder).

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

GetGlobalMouse

Obtains the position of the mouse, in global coordinates.

void GetGlobalMouse (
   Point *globalMouse
);

Parameters

globalMouse: The position of the mouse, as a global point.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

CarbonEventsCore.h

GetKeys

Obtains the current state of the keyboard.

void GetKeys (
   KeyMap theKeys
);

Parameters

theKeys: On output, the current state of the keyboard, including the keypad, if any.

Discussion

You can use the GetKeys function to determine the current state of the keyboard at any time. For example, you can determine whether one of the modifier keys is down by itself or in combination with another key using the GetKeys function.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

GetNextEvent

Retrieves events one at a time from the Event Manager.

Boolean GetNextEvent (
   EventMask eventMask,
   EventRecord *theEvent
);

Parameters

eventMask: A value that indicates which kinds of events are to be returned; this parameter is interpreted as a sum of event mask constants. You specify the event mask using one or more of the values defined in “Event Mask Constants.” If no event of any of the designated types is available, GetNextEvent returns a null event.
theEvent: A pointer to an event structure for the next available event of the specified type or types. The GetNextEvent function removes the returned event from the event stream and returns the information about the event in an event structure. The event structure includes the type of event received and other information.

Return Value

Discussion

GetNextEvent returns false as its function result if the event being returned is a null event or if GetNextEvent has intercepted the event; otherwise, GetNextEvent returns true. The GetNextEvent function calls the Operating System Manager function SystemEvent to determine whether the event should be handled by the application or the Operating System.

The GetNextEvent function also intercepts Command–Shift–number key sequences and calls the corresponding 'FKEY' resource to perform the associated action. The Event Manager’s processing of Command–Shift–number key sequences with numbers 3 through 9 can be disabled by setting the ScrDmpEnable global variable (a byte) to 0.

Special Considerations

For greater support of the multitasking environment, your application should use WaitNextEvent instead of GetNextEvent whenever possible.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

IsCmdChar

Tests whether the Command key is pressed in conjunction with another key (or keys) that could generate the specified test character.

Boolean IsCmdChar (
   const EventRecord *event,
   short test
);

Parameters

event: The event record for a key-down or auto-key event with the Command key down.
test: The character you want to test.

Return Value

The function returns TRUE if the test character is produced with the current modifier keys, or if it would be produced by changing the current modifier key bits in either or both of the following ways: (1) turning the Command bit off or (2) toggling the Shift bit.

Discussion

This function tests whether the Command key is pressed in conjunction with another key (or keys) that could generate the test character for some combination of Command up or down and Shift up or down. This accommodates European keyboards that may have the test character as a shifted character, and non-Roman keyboards that will only generate the test character if the Command key is pressed. It's most useful for testing for Command-period, but it can test for command-AnyCharacter.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

KeyTranslate

Converts a virtual key code to a character code based on a 'KCHR' resource.

UInt32 KeyTranslate (
   const void *transData,
   UInt16 keycode,
   UInt32 *state
);

Parameters

transData: A pointer to the 'KCHR' resource that you want the KeyTranslate function to use when converting the key code to a character code.
keycode: A 16-bit value that your application should set so that bits 0–6 contain the virtual key code and bit 7 contains either 1 to indicate an up stroke or 0 to indicate a down stroke of the key. Bits 8–15 have the same interpretation as the high byte of the modifiers field of the event structure and should be set according to the needs of your application.
state: A pointer to a value that your application should set to 0 the first time it calls KeyTranslate or any time your application calls KeyTranslate with a different 'KCHR' resource. Thereafter, your application should pass the same value in the state parameter as KeyTranslate returned in the previous call.

Return Value

A 32-bit value that gives the character code for the virtual key code specified by the keycode parameter.

Discussion

The KeyTranslate function returns the values that correspond to one or possibly two characters that are generated by the specified virtual key code. The following diagram shows the structure of the 32-bit number that KeyTranslate returns.

31             24 23            16 15             8 7               0

---------------------------------------------------------------------

|                |                |                |                |

---------------------------------------------------------------------

    Reserved 1    Character code 1    Reserved 2    Character code 2

For example, a given virtual key code might correspond to an alphabetic character with a separate accent character. When the user presses Option-E followed by E, you can map this through the KeyTranslate function using the U.S. 'KCHR' resource to produce é, which KeyTranslate returns as two characters in the bytes labeled Character code 1 and Character code 2.

If KeyTranslate returns only one character code, it is always in the byte labeled Character code 2. However, your application should always check both bytes labeled Character code 1 and Character code 2 for possible values that map to the virtual key code.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

LMGetKbdLast

Returns a value that specifies the last physical keyboard type used.

UInt8 LMGetKbdLast (
   void
);

Return Value

The last physical keyboard type used.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

LMGetKbdType

Returns a value that specifies the physical keyboard type.

UInt8 LMGetKbdType (
   void
);

Return Value

The physical keyboard type.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

LMGetKeyRepThresh

Returns the low-memory auto-key rate.

SInt16 LMGetKeyRepThresh (
   void
);

Return Value

The auto-key rate, that is, the amount of time, in ticks, that must elapse before the Event Manager generates a subsequent auto-key event.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

LMGetKeyThresh

Returns the low-memory auto-key threshold.

SInt16 LMGetKeyThresh (
   void
);

Return Value

Returns the auto-key threshold, that is, the amount of time, in ticks, that must elapse before the Event Manager generates an auto-key event.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

LMSetKbdLast

Sets a value that specifies the last physical keyboard type used.

void LMSetKbdLast (
   UInt8 value
);

Parameters

value: The physical keyboard type you want to set.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

LMSetKbdType

Sets the keyboard type.

void LMSetKbdType (
   UInt8 value
);

Parameters

value: The physical keyboard type you want to set.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

LMSetKeyRepThresh

Sets the low-memory auto-key rate.

void LMSetKeyRepThresh (
   SInt16 value
);

Parameters

value: The low-memory auto-key rate you want to set.

Discussion

LMSetKeyRepThresh sets the low-memory auto-key rate, that is, the amount of time, in ticks, that must elapse before the Event Manager generates a subsequent auto-key event.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

LMSetKeyThresh

Sets the low-memory auto-key threshold.

void LMSetKeyThresh (
   SInt16 value
);

Parameters

value: The low-memory auto-key threshold you want to set.

Discussion

LMSetKeyThresh sets the low-memory auto-key threshold, that is, the amount of time, in ticks, that must elapse before the Event Manager generates an auto-key event.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

PostEvent

Posts events into the Operating System event queue.

OSErr PostEvent (
   EventKind eventNum,
   UInt32 eventMsg
);

Parameters

eventNum: A value that indicates the type of event to post into the Operating System event queue. You specify the event kind using one or more of these values defined in “Event Mask Constants”: mouseDown, mouseUp, keyDown, keyUp, autoKey, and diskEvt. Do not attempt to post any other type of event in the Operating System event queue.
eventMsg: An unsigned integer that contains the contents of the message field for the event that PostEvent should post in the queue.

Return Value

A result code. See “Event Manager Result Codes.”

Discussion

In the eventNum and eventMsg parameters, you specify the value for the what and message fields of the event’s event structure. The PostEvent function fills out the when, where, and modifiers fields of the event structure with the current time, current mouse location, and current state of the modifier keys and mouse button.

The PostEvent function posts only events that are enabled by the system event mask. If the event queue is full, PostEvent removes the oldest event in the queue and posts the new event.

Note that if you use PostEvent to repost an event, the PostEvent function fills out the when, where, and modifier fields of the event structure, giving these fields of the reposted event different values from the values contained in the original event.

Do not post any events other than mouse-down, mouse-up, key-down, key-up, auto-key, and disk-inserted events in the Operating System event queue. Attempting to post other events into the Operating System event queue interferes with the internal operation of the Event Manager.

In most cases, your application should not call the PostEvent function.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

SetEventMask

Sets the system event mask of your application to the specified mask.

void SetEventMask (
   EventMask value
);

Parameters

value: A value that specifies which events should be posted in the Operating System event queue. You specify the event mask using one or more of the values defined in “Event Mask Constants.”

Discussion

Your application should not call the SetEventMask function to disable any event types from being posted. Use SetEventMask only to enable key-up events if your application needs to respond to key-up events.

The SetEventMask function sets the system event mask of your application according to the parameter value. The Operating System Event Manager posts only low-level events (other than update or activate events) corresponding to bits in the system event mask of the current process when posting events in the Operating System event queue. The system event mask of an application is initially set to post mouse-up, mouse-down, key-down, auto-key, and disk-inserted events into the Operating System event queue.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Declared In

Events.h

WaitNextEvent

Retrieves events one at a time from the Event Manager.

Boolean WaitNextEvent (
   EventMask eventMask,
   EventRecord *theEvent,
   UInt32 sleep,
   RgnHandle mouseRgn
);

Parameters

eventMask

A value that indicates which kinds of events are to be returned. This parameter is interpreted as a sum of event mask constants. You specify the event mask using values defined in “Event Mask Constants.” To accept all events, you can specify the everyEvent constant as the event mask.

If no event of any of the designated types is available, WaitNextEvent returns a null event. WaitNextEvent determines the next available event to return based on the eventMask parameter and the priority of the event.

Events not designated by the event mask remain in the event stream until retrieved by an application. Low-level events in the Operating System event queue are kept in the queue until they are retrieved by your application or another application or until the queue becomes full. Once the queue becomes full, the Operating System Event Manager begins discarding the oldest events in the queue.

theEvent

A pointer to an event structure for the next available event of the specified type or types. The WaitNextEvent function removes the returned event from the event stream and returns the information about the event in an event structure. The event structure includes the type of event received and other information.

In addition to the event structure, high-level events can contain additional data; use the Apple Event Manager AEProcessAppleEvent function to get additional data associated with these events.

sleep

The number of ticks (a tick is approximately 1/60 of a second) indicating the amount of time your application is willing to relinquish the processor if no events are pending for your application. If you specify a value greater than 0 for the sleep parameter, your application relinquishes the processor for the specified time or until an event occurs.

You should not set the sleep parameter to a value greater than the number of ticks returned by GetCaretTime if your application provides text-editing capabilities. When the specified time expires, and if there are no pending events for your application, WaitNextEvent returns a NULL event in the parameter theEvent.

When running on Mac OS X, a Carbon application will block for the entire duration of the sleep parameter if there are no events to be delivered. This is slightly different behavior than on Mac OS 9, where the application will often receive NULL events before the sleep duration has elapsed.

mouseRgn

A handle to a region that specifies a region inside of which mouse movement does not cause mouse-moved events. In other words, your application receives mouse-moved events only when the cursor is outside the specified region. You should specify the region in global coordinates. If you pass an empty region or a null region handle, the Event Manager does not report mouse-moved events to your application. Note that your application should recalculate the mouseRgn parameter when it receives a mouse-moved event, or it will continue to receive mouse-moved events as long as the cursor position is outside the original mouseRgn.

Return Value

The WaitNextEvent function returns false as its function result if the event being returned is a null event or if WaitNextEvent has intercepted the event; otherwise, WaitNextEvent returns true.

Discussion

The WaitNextEvent function calls the Operating System Event Manager function SystemEvent to determine whether the event should be handled by the application or the Operating System.

If no events are pending for your application, WaitNextEvent waits for a specified amount of time for an event. (During this time, processing time may be allocated to background processes.) If an event occurs, it is returned through the parameter theEvent, and WaitNextEvent returns a function result of true. If the specified time expires and there are no pending events for your application, WaitNextEvent returns a null event in theEvent and a function result of false.

Before returning an event to your application, WaitNextEvent performs other processing and may intercept the event.

The WaitNextEvent function intercepts Command–Shift–number key sequences and calls the corresponding ' FKEY ' resource to perform the associated action. The Event Manager’s processing of Command–Shift–number key sequences with numbers 3 through 9 can be disabled by setting the ScrDmpEnable global variable (a byte) to 0.

If the returned event is a high-level event and your application supports Apple events, use the Apple Event Manager function AEProcessAppleEvent to respond to the Apple event and to get additional information associated with the Apple event.

To retrieve an event without removing it from the event stream, use EventAvail.

Availability

Available in Mac OS X v10.0 and later.
Not available to 64-bit applications.

Related Sample Code

Declared In

Events.h

Data Types

EventRecord

Contains information associated with an event.

struct EventRecord {
   EventKind what;
   UInt32 message;
   UInt32 when;
   Point where;
   EventModifiers modifiers;
};
typedef struct EventRecord EventRecord;

Fields

what

The kind of event received. The Event Manager specifies the kind of event with one of the values defined by the EventKind enumeration.

message

Additional information associated with the event. The interpretation of this information depends on the event type. The contents of the message field for each event type are summarized here:

For a null, mouse-up, or mouse-down event, the event message is:Undefined.
For a key-up, key-down, or auto-key event, the event message is:The low-order word contains the character code and virtual key code, which you can access with the constants charCodeMask and keyCodeMask, respectively. For Apple Desktop Bus (ADB) keyboards, the low byte of the high-order word contains the ADB address of the keyboard where the keyboard event occurred. The high byte of the high-order word is reserved.
For an update or activate event, the event message is:A pointer to the window to update, activate, or deactivate.
For a disk-inserted event, the event message is:The drive number in the low-order word, the File Manager result code in the high-order word.
For a resume event, the event message is:The suspendResumeMessage enumerator in bits 24–31 and a 1 (the resumeFlag enumerator) in bit 0 indicate the event is a resume event. Bit 1 contains a 1 (the convertClipBoardFlag enumerator) if Clipboard conversion is required, and bits 2–23 are reserved.
For a suspend event, the event message is:The suspendResumeMessage enumerator in bits 24–31 and a 0 in bit 0 to indicate the event is a suspend event. Bit 1 is undefined, and bits 2–23 are reserved.
For a mouse-moved event, the event message is:The mouseMovedMessage enumerator in bits 24–31. Bits 2–23 are reserved, and bit 0 and bit 1 are undefined.
For a high-level event, the event message is:
The class of events to which the high-level event belongs. The message and where fields of a high-level event define the specific type of high-level event received.

when

The when field indicates the time when the event was posted (in ticks since system startup).

where

For low-level events and operating-system events, the where field contains the location of the cursor at the time the event was posted (in global coordinates).

For high-level events, the where field contains a second event specifier, the event ID. The event ID defines the particular type of event within the class of events defined by the message field of the high-level event. For high-level events, you should interpret the where field as having the data type OSType, not Point.

modifiers

The modifiers field contains information about the state of the modifier keys and the mouse button at the time the event was posted. For activate events, this field also indicates whether the window should be activated or deactivated. In System 7 it also indicates whether the mouse-down event caused your application to switch to the foreground.

Each of the modifier keys is represented by a specific bit in the modifiers field of the event structure. The modifier keys include the Option, Command, Caps Lock, Control, and Shift keys. If your application attaches special meaning to any of these keys in combination with other keys or when the mouse button is down, you can test the state of the modifiers field to determine the action your application should take. For example, you can use this information to determine whether the user pressed the Command key and another key to make a menu choice.

Discussion

When your application uses an Event Manager function to retrieve an event, the Event Manager returns information about the retrieved event in an event structure, which is a structure of type EventRecord.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

EvQEl

Defines an event queue entry.

struct EvQEl {
   QElemPtr qLink;
   SInt16 qType;
   EventKind evtQWhat;
   UInt32 evtQMessage;
   UInt32 evtQWhen;
   Point evtQWhere;
   EventModifiers evtQModifiers;
};
typedef struct EvQEl EvQEl;
typedef EvQEl * EvQElPtr;

Fields

qLink: Next queue entry.
qType: Queue type (evType).
evtQWhat: Event code.
evtQMessage: Event message.
evtQWhen: Ticks since startup.
evtQWhere: Mouse location.
evtQModifiers: Modifier flags.

Discussion

A structure of type EvQEl defines an entry in the Operating System event queue. Each entry in the event queue begins with 4 bytes of flags followed by a pointer to the next queue entry. The flags are maintained by and internal to the Operating System Event Manager. The queue entries are linked by pointers, and the first field of the EvQEl data type, which represents the structure of a queue entry, begins with a pointer to the next queue entry. Thus, you cannot directly access the flags using the EvQEl data type.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

KeyMap

Contains information about the current state of the keyboard.

typedef BigEndianLong KeyMap[4];

Discussion

The type KeyMap is used in GetKeys to return the current state of the keyboard, including the keypad, if any. The KeyMap type is interpreted as an array of 128 elements, each having a Boolean value. Each key on the keyboard or keypad corresponds to an element in the KeyMap array. A KeyMap element is true if the corresponding key is down and false if it isn’t. The maximum number of keys that can be down simultaneously is two character keys plus any combination of the five modifier keys.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

KeyMapByteArray

Contains information about the current state of the keyboard.

typedef UInt8 KeyMapByteArray[16];

Discussion

The type KeyMapByteArray is an alternate version of the type KeyMap for use on little endian platforms.

Availability

Available in Mac OS X v10.0 and later.

Declared In

Events.h

Constants

Event Modifier Constants

Define modifiers for event types.

enum {
   activeFlagBit = 0,
   btnStateBit = 7,
   cmdKeyBit = 8,
   shiftKeyBit = 9,
   alphaLockBit = 10,
   optionKeyBit = 11,
   controlKeyBit = 12,
   rightShiftKeyBit = 13,
   rightOptionKeyBit = 14,
   rightControlKeyBit = 15
};
typedef UInt16 EventModifiers;

Constants

activeFlagBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

btnStateBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

cmdKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

shiftKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

alphaLockBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

optionKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

controlKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightShiftKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightOptionKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightControlKeyBit

Available in Mac OS X v10.0 and later.

Declared in Events.h.

charCodeMask

enum {
   charCodeMask = 0x000000FF,
   keyCodeMask = 0x0000FF00,
   adbAddrMask = 0x00FF0000,
   osEvtMessageMask = 0xFF000000
};

Constants

charCodeMask

The enumerator indicating you want your application to receive a character-code keyboard event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

keyCodeMask

The enumerator indicating you want your application to receive a key-code keyboard event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

adbAddrMask

The enumerator indicating you want your application to receive an ADB address if there is an ADB keyboard.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

osEvtMessageMask

The enumerator indicating you want your application to receive a keyboard event that can be used to extract a message code.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

convertClipboardFlag

Obsolete in Carbon.

enum {
   convertClipboardFlag = 2
};

Constants

convertClipboardFlag

Available in Mac OS X v10.0 and later.

Declared in Events.h.

Discussion

Obsolete in Carbon. To determine if the clipboard has changed while your application was suspended, use the Scrap Manager function GetCurrentScrap.

Carbon Porting Notes

Unsupported. To determine if the clipboard has changed while your application was suspended, use the Scrap Manager function GetCurrentScrap.

Event Modifier Bits

Modifer bits for events.

enum {
   activeFlag = 1 << activeFlagBit,
   btnState = 1 << btnStateBit,
   cmdKey = 1 << cmdKeyBit,
   shiftKey = 1 << shiftKeyBit,
   alphaLock = 1 << alphaLockBit,
   optionKey = 1 << optionKeyBit,
   controlKey = 1 << controlKeyBit,
   rightShiftKey = 1 << rightShiftKeyBit,
   rightOptionKey = 1 << rightOptionKeyBit,
   rightControlKey = 1 << rightControlKeyBit
};

Constants

activeFlag

The enumerator that indicates a window is being activated or that a mouse-down event caused a foreground switch.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

btnState

The enumerator indicating that the mouse button has been released.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

cmdKey

The enumerator indicating that the Command key is being pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

shiftKey

The enumerator indicating that the Shift key is being pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

alphaLock

The enumerator indicating that the Caps Lock key is being pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

optionKey

The enumerator indicating that the Option key is being pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

controlKey

The enumerator indicating that the Control key is being pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightShiftKey

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightOptionKey

Available in Mac OS X v10.0 and later.

Declared in Events.h.

rightControlKey

Available in Mac OS X v10.0 and later.

Declared in Events.h.

HighLevelEventMsgClass

enum {
   HighLevelEventMsgClass = 'jaym',
   rtrnReceiptMsgID = 'rtrn'
};

Constants

HighLevelEventMsgClass: The enumerator indicating a high-level event message class for return receipt.
rtrnReceiptMsgID: The posting enumerator indicating the return receipt message ID.

Character Codes

Define character codes for events.

enum {
   kNullCharCode = 0,
   kHomeCharCode = 1,
   kEnterCharCode = 3,
   kEndCharCode = 4,
   kHelpCharCode = 5,
   kBellCharCode = 7,
   kBackspaceCharCode = 8,
   kTabCharCode = 9,
   kLineFeedCharCode = 10,
   kVerticalTabCharCode = 11,
   kPageUpCharCode = 11,
   kFormFeedCharCode = 12,
   kPageDownCharCode = 12,
   kReturnCharCode = 13,
   kFunctionKeyCharCode = 16,
   kCommandCharCode = 17,
   kCheckCharCode = 18,
   kDiamondCharCode = 19,
   kAppleLogoCharCode = 20,
   kEscapeCharCode = 27,
   kClearCharCode = 27,
   kLeftArrowCharCode = 28,
   kRightArrowCharCode = 29,
   kUpArrowCharCode = 30,
   kDownArrowCharCode = 31,
   kSpaceCharCode = 32,
   kDeleteCharCode = 127,
   kBulletCharCode = 165,
   kNonBreakingSpaceCharCode = 202
};

Constants

kNullCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kHomeCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kEnterCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kEndCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kHelpCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kBellCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kBackspaceCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kTabCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kLineFeedCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kVerticalTabCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kPageUpCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kFormFeedCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kPageDownCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kReturnCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kFunctionKeyCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kCommandCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kCheckCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kDiamondCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kAppleLogoCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kEscapeCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kClearCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kLeftArrowCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kRightArrowCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kUpArrowCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kDownArrowCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kSpaceCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kDeleteCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kBulletCharCode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kNonBreakingSpaceCharCode

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kShiftUnicode

enum {
   kShiftUnicode = 0x21E7,
   kControlUnicode = 0x2303,
   kOptionUnicode = 0x2325,
   kCommandUnicode = 0x2318,
   kPencilUnicode = 0x270E,
   kCheckUnicode = 0x2713,
   kDiamondUnicode = 0x25C6,
   kBulletUnicode = 0x2022,
   kAppleLogoUnicode = 0xF8FF
};

Constants

kShiftUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kControlUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kOptionUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kCommandUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kPencilUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kCheckUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kDiamondUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kBulletUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

kAppleLogoUnicode

Available in Mac OS X v10.1 and later.

Declared in Events.h.

Event Mask Constants

Define constants you can use in the event mask.

enum {
   mDownMask = 1 << mouseDown,
   mUpMask = 1 << mouseUp,
   keyDownMask = 1 << keyDown,
   keyUpMask = 1 << keyUp,
   autoKeyMask = 1 << autoKey,
   updateMask = 1 << updateEvt,
   diskMask = 1 << diskEvt,
   activMask = 1 << activateEvt,
   highLevelEventMask = 0x0400,
   osMask = 1 << osEvt,
   everyEvent = 0xFFFF
};
typedef UInt16 EventMask;

Constants

mDownMask

The enumerator indicating you want your application to receive a mouse-down event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

mUpMask

The enumerator indicating you want your application to receive a mouse-up event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

keyDownMask

The enumerator indicating you want your application to receive a key-down event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

keyUpMask

The enumerator indicating you want your application to receive a key-up event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

autoKeyMask

The enumerator indicating you want your application to receive an auto-key event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

updateMask

The enumerator indicating you want your application to receive an update event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

diskMask

The enumerator indicating you want your application to receive a disk-inserted event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

activMask

The enumerator indicating you want your application to receive an activate event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

highLevelEventMask

The enumerator indicating you want your application to receive a high-level event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

osMask

The enumerator indicating you want your application to receive an operating-system event

Available in Mac OS X v10.0 and later.

Declared in Events.h.

everyEvent

The enumerator indicating you want your application to receive every event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

mouseMovedMessage

enum {
   mouseMovedMessage = 0x00FA,
   suspendResumeMessage = 0x0001
};

Constants

mouseMovedMessage

The message code indicating the mouse-moved operating-system event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

suspendResumeMessage

The message code indicating a suspend or resume operating-system event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

msgWasPartiallyAccepted

enum {
   msgWasPartiallyAccepted = 2,
   msgWasFullyAccepted = 1,
   msgWasNotAccepted = 0
};

Constants

msgWasPartiallyAccepted: The posting enumerator value in the return receipt that indicates the message was partially accepted.
msgWasFullyAccepted: The posting enumerator value in the return receipt that indicates the message was fully accepted.
msgWasNotAccepted: The posting enumerator value in the return receipt that indicates the message was fully accepted.

networkEvt

enum {
   networkEvt = 10,
   driverEvt = 11,
   app1Evt = 12,
   app2Evt = 13,
   app3Evt = 14,
   app4Evt = 15,
   networkMask = 0x0400,
   driverMask = 0x0800,
   app1Mask = 0x1000,
   app2Mask = 0x2000,
   app3Mask = 0x4000,
   app4Mask = 0x8000
};

Constants

networkEvt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

driverEvt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app1Evt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app2Evt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app3Evt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app4Evt

Available in Mac OS X v10.0 and later.

Declared in Events.h.

networkMask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

driverMask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app1Mask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app2Mask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app3Mask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

app4Mask

Available in Mac OS X v10.0 and later.

Declared in Events.h.

Event Kind Constants

Define event kinds.

enum {
   nullEvent = 0,
   mouseDown = 1,
   mouseUp = 2,
   keyDown = 3,
   keyUp = 4,
   autoKey = 5,
   updateEvt = 6,
   diskEvt = 7,
   activateEvt = 8,
   osEvt = 15,
   kHighLevelEvent = 23
};
typedef UInt16 EventKind;

Constants

nullEvent

The event code indicating that there are no other pending events.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

mouseDown

The event code indicating that the mouse button has been pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

mouseUp

The event code indicating that the mouse button has been released.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

keyDown

The event code indicating that a key has been pressed.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

keyUp

The event code indicating that a key has been released.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

autoKey

The event code indicating that a key has been repeatedly held down.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

updateEvt

The event code indicating that a window needs updating.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

diskEvt

The event code indicating that a disk has been inserted.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

activateEvt

The event code indicating that a window has been activated or deactivated.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

osEvt

The event code indicating a suspend, resume, or mouse-moved operating-system event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

kHighLevelEvent

A high-level event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

resumeFlag

Indicates a resume event.

enum {
   resumeFlag = 1
};

Constants

resumeFlag

Flag for a resume event.

Available in Mac OS X v10.0 and later.

Declared in Events.h.

Result Codes

Result codes defined for the Event Manager are listed below.

Result Code Value Description

Result Code	Value	Description
`evtNotEnb`	1	Event not enabled for `PostEvent`. Available in Mac OS X v10.0 and later.

evtNotEnb

Event not enabled for PostEvent.

Available in Mac OS X v10.0 and later.

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