The subject is taken from the first message (according to the query
order---see notmuch_query_set_sort) in the query results that
belongs to this thread.
The returned string belongs to 'thread' and as such, should not be
modified by the caller and will only be valid for as long as the
thread is valid, (which is until notmuch_thread_destroy or until
the query from which it derived is destroyed).
Get the subject of 'thread' as a UTF-8 string.
The subject is taken from the first message (according to the query order---see notmuch_query_set_sort) in the query results that belongs to this thread.
The returned string belongs to 'thread' and as such, should not be modified by the caller and will only be valid for as long as the thread is valid, (which is until notmuch_thread_destroy or until the query from which it derived is destroyed).