XmClipboardStartCopy - 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;
XmClipboardStartCopy 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 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
the clipboard functions, along with a widget ID and a callback
function address that is passed in
XmClipboardStartCopy. The widget ID is needed 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 via XmClipboardCopyByName. The
callback function is also called if the data item is removed from the
clipboard, and the actual data is therefore no longer needed.
- Specifies a pointer to the Display structure
that was returned in a previous call to XOpenDisplay
- Specifies a widget's window ID that relates the application
window to the clipboard. The widget's window ID can be obtained by
using XtWindow. The same application instance should
pass the same window ID to each of the clipboard functions that it
- Specifies the label to be associated with the data item. This
argument is used to identify the data item, for example, in a
clipboard viewer. An example of a label is the name of the
application that places the data in the clipboard.
- Specifies the time of the event that triggered the copy. A
valid timestamp must be supplied; it is not sufficient to use
- 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 functions.
- 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(3X) and
The widget and callback arguments must be present
in order to pass data by name. The callback format is as follows:
void (*callback) (widget, data_id, private, 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, which is either
- The function is 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 the operation.