XmClipboardStartCopy(Xm)

Syntax

#include <Xm/Xm.h>
#include <Xm/CutPaste.h>

int XmClipboardStartCopy (display, window, clip_label, timestamp, widget,
			  callback, item_id)
Display * display;
Window window;
XmString clip_label;
Time timestamp;
Widget widget;
XmCutPasteProc callback;
long * item_id;

Description

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 XmClipboardCopy to 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.

display

Specifies a pointer to the Display structure that was returned in a previous call to XOpenDisplay or XtDisplay.

window

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 calls.

clip_label

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.

timestamp

Specifies the time of the event that triggered the copy. A valid timestamp must be supplied; it is not sufficient to use CurrentTime.

widget

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.

callback

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.

item_id

Specifies the number assigned to this data item. The application uses this number in calls to XmClipboardCopy, XmClipboardEndCopy, and XmClipboardCancelCopy.

For more information on passing data by name, see XmClipboardCopy(Xm) and XmClipboardCopyByName(Xm).

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)
   Widget	widget;
   int	*data_id;
   int	*private;
   int	*reason;

widget

Specifies the ID of the widget passed to this function.

data_id

Specifies the identifying number returned by XmClipboardCopy, which identifies the pass-by-name data.

private

Specifies the private information passed to XmClipboardCopy.

reason

Specifies the reason, which is either XmCR_CLIPBOARD_DATA_DELETE or XmCR_CLIPBOARD_DATA_REQUEST.

Return value

ClipboardSuccess

The function is successful.

ClipboardLocked

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.

See also