If 'threads' is already pointing at the last thread then the
iterator will be moved to a point just beyond that last thread,
(where notmuch_threads_valid will return FALSE and
notmuch_threads_get will return NULL).
See the documentation of notmuch_query_search_threads for example
code showing how to iterate over a notmuch_threads_t object.
Move the 'threads' iterator to the next thread.
If 'threads' is already pointing at the last thread then the iterator will be moved to a point just beyond that last thread, (where notmuch_threads_valid will return FALSE and notmuch_threads_get will return NULL).
See the documentation of notmuch_query_search_threads for example code showing how to iterate over a notmuch_threads_t object.