XmClipboardInquireLength returns the length of the data stored
under a specified format name for the clipboard data item. If no data
is found for the specified format, or if there is no item on the
clipboard, this function returns a value of 0
(zero) in the length argument.
Any format passed by name is assumed to have length passed in
a call to XmClipboardCopy, even though the data has not yet been
transferred to the clipboard in that format.
display
Specifies a pointer to the Display structure that was returned in a
previous call to XOpenDisplay or XtDisplay.
window
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.
format_name
Specifies the name of the format for the data item.
length
Specifies the length of the next data item in the specified format. This
argument equals 0 (zero) if no data is found for the specified format,
or if there is no item on the clipboard.
RETURN
XmClipboardSuccess
The function was successful.
XmClipboardLocked
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.
XmClipboardNoData
The function could not find data on the clipboard corresponding to the
format requested. This could occur because the clipboard is empty;
there is data on the clipboard, but not in the requested format; or
the data in the requested format was passed by name and is no longer
available.