typedef void (*zip_cancel_callback)(zip_t *, double, void *);
(*ud_free)(void *), void
registers a callback function callback for the zip
archive archive. The ud_free
function is called during cleanup for deleting the userdata supplied in
The callback function is called during zip_close(3) in regular intervals (after every zip archive entry that's completely written to disk, and while writing data for entries) with zip archive archive, the current progress state (see zip_register_progress_callback_with_state(3)) as a double, and the user-provided user-data ud as arguments. The progress state is a double in the range from 0.0 to 1.0.
The callback function should be fast, since it will be called often.
zip_register_cancel_callback_with_state() was added in libzip 1.6.0.