XmDataFieldCopy man page
XmDataFieldCopy — A DataField function that copies the primary selection to the clipboard
#include <Xm/DataF.h> Boolean XmDataFieldCopy( Widget widget, Time time);
XmDataFieldCopy copies the primary selected text to the clipboard.
This routine calls the XmNconvertCallback procedures, possibly multiple times, with the selection member of the XmConvertCallbackStruct set to CLIPBOARD and with the parm member set to XmCOPY.
Specifies the DataField widget ID.
Specifies the time at which the selection value is to be modified. This should be the time of the event that triggered this request.
For a complete definition of DataField and its associated resources, see XmDataField(3).
This function returns False if the primary selection is NULL, if the widget does not own the primary selection, if the function is unable to gain ownership of the clipboard selection, or if no data is placed on the clipboard. Otherwise, it returns True.