XmClipboardInquireLength — A clipboard function that returns
the length of the stored data

     #include <Xm/CutPaste.h>
int XmClipboardInquireLength (display, window, format_name, length)
        Display * display;
        Window  window;
        char    * format_name;
        unsigned long   * length;

     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

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

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.

          Specifies the name of the format for the data

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.

          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 the

          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.

     XmClipboardCopy(3) and XmClipboardStartCopy(3).