* name of the hook to use, the second is the full path name of a mail message.
* The third argument is also the full path name of a mail message, or a NULL
* pointer if it isn't needed. Look in the context for an error message if
* name of the hook to use, the second is the full path name of a mail message.
* The third argument is also the full path name of a mail message, or a NULL
* pointer if it isn't needed. Look in the context for an error message if