— A clipboard function that sets up a storage
and data structure
int XmClipboardStartCopy ( display, window, clip_label,
timestamp, widget, callback, item_id)
Display * display;
long * item_id;
sets up storage and data structures to receive
clipboard data. An application calls this function during a cut or copy
operation. The data item that these structures receive then becomes the next
data item in the clipboard.
Copying a large piece of data to the clipboard can take a long time. It is
possible that, once the data is copied, no application will ever request that
data. The Motif Toolkit provides a mechanism so that an application does not
need to actually pass data to the clipboard until the data has been requested
by some application.
Instead, the application passes format and length information in
to the clipboard functions, along with a widget ID and
a callback function address that is passed in XmClipboardStartCopy
widget ID is necessary for communications between the clipboard functions in
the application that owns the data and the clipboard functions in the
application that requests the data.
The callback functions are responsible for copying the actual data to the
clipboard through XmClipboardCopyByName
. The callback function is also
called if the data item is removed from the clipboard and the actual data is
no longer needed.
- Specifies a pointer to the Display structure that was returned in a
previous call to XOpenDisplay or XtDisplay.
- Specifies the window ID of a widget that relates the application window to
the clipboard. The widget's window ID can be obtained through
XtWindow. The same application instance should pass the same window
ID to each of the clipboard functions that it calls.
- Specifies the label to be associated with the data item. This argument is
used to identify the data item, as in a clipboard viewer. An example of a
label is the name of the application that places the data in the
- Specifies the time of the event that triggered the copy. A valid timestamp
must be supplied; it is not sufficient to use CurrentTime.
- Specifies the ID of the widget that receives messages requesting data
previously passed by name. This argument must be present in order to pass
data by name. Any valid widget ID in your application can be used for this
purpose and all the message handling is taken care of by the cut and paste
- Specifies the address of the callback function that is called when the
clipboard needs data that was originally passed by name. This is also the
callback to receive the delete message for items that were
originally passed by name. This argument must be present in order to pass
data by name.
- Specifies the number assigned to this data item. The application uses this
number in calls to XmClipboardCopy, XmClipboardEndCopy, and
For more information on passing data by name, see XmClipboardCopy
arguments must be present in order to pass
data by name. The callback format is as follows:
void (* callback) (widget, data_id, private, reason)
long * data_id;
long * private;
int * reason;
- Specifies the ID of the widget passed to this function.
- Specifies the identifying number returned by XmClipboardCopy, which
identifies the pass-by-name data.
- Specifies the private information passed to XmClipboardCopy.
- Specifies the reason. XmCR_CLIPBOARD_DATA_DELETE or
XmCR_CLIPBOARD_DATA_REQUEST are the possible values.
- The function was successful.
- The function failed because the clipboard was locked by another
application. The application can continue to call the function again with
the same parameters until the lock goes away. This gives the application
the opportunity to ask if the user wants to keep trying or to give up on
(3), and XmClipboardWithdrawFormat