25.5.2 Contents of the Different Types of Events

Every event, no matter what type it is, contains a timestamp (which is typically an offset in milliseconds from when the X server was started) indicating when the event occurred. In addition, many events contain a channel, which specifies which frame the event occurred on, and/or a value indicating which modifier keys (shift, control, etc.) were held down at the time of the event.

The contents of each event are as follows:

key-press event

channel

timestamp

key

Which key was pressed. This is an integer (in the printing ASCII range: >32 and <127) or a symbol such as left or right.

Note: Many physical keys are actually treated as two separate keys, depending on whether the shift key is pressed; for example, the “a” key is treated as either “a” or “A” depending on the state of the shift key, and the “1” key is similarly treated as either “1” or “!” on most keyboards.

In such cases, the shift key does not show up in the modifier list. For other keys, such as backspace, the shift key shows up as a regular modifier.

modifiers

Which modifier keys were pressed. As mentioned above, the shift key is not treated as a modifier for many keys and will not show up in this list in such cases.

button-press event

button-release event

channel

timestamp

button

What button went down or up. Buttons are numbered starting at 1.

modifiers

Which modifier keys were pressed. The special business mentioned above for the shift key does not apply to mouse events.

x

y

The position of the pointer (in pixels) at the time of the event.

pointer-motion event

channel

timestamp

x

y

The position of the pointer (in pixels) after it moved.

modifiers

Which modifier keys were pressed. The special business mentioned above for the shift key does not apply to mouse events.

misc-user event

timestamp

function

The elisp function to call for this event. This is normally either eval or call-interactively.

object

The object to pass to the function. This is normally the callback that was specified in the menu description.

button

What button went down or up. Buttons are numbered starting at 1.

modifiers

Which modifier keys were pressed. The special business mentioned above for the shift key does not apply to mouse events.

x

y

The position of the pointer (in pixels) at the time of the event.

process_event

timestamp

process

The Emacs “process” object in question.

timeout event

timestamp

function

The elisp function to call for this timeout. It is called with one argument, the event.

object

Some Lisp object associated with this timeout, to make it easier to tell them apart. The function and object for this event were specified when the timeout was set.

magic event

timestamp

The rest of the information in this event is not user-accessible.

eval event

timestamp

function

An elisp function to call when this event is dispatched.

object

The object to pass to the function. The function and object are set when the event is created.

Function: event-type event

Return the type of event.

This will be a symbol; one of

key-press

A key was pressed.

button-press

A mouse button was pressed.

button-release

A mouse button was released.

motion

The mouse moved.

misc-user

Some other user action happened; typically, this is a menu selection, scrollbar action, or drag and drop action.

process

Input is available from a subprocess.

timeout

A timeout has expired.

eval

This causes a specified action to occur when dispatched.

magic

Some window-system-specific event has occurred.