void user_dg_process_message(void *user, window *win, FILE *write_to)
The user has to process whatever user-defined messages are sent to the process. A write-to pipe to the wish process is provided so that the user can directly issue commands there.
|void *user||INOUT||Pointer to the user-defined data structure.|
|window *win||INOUT||The window that received the message.|
|FILE *write_to||IN||Pipe to the wish process.|
|USER_ERROR||Error. Message ignored.|
|USER_SUCCESS||The user processed the message.|