*value* is set to a string owned by the message or NULL if there is
no such key. In the case of multiple values for the given key, the
first one is retrieved.
@returns
- NOTMUCH_STATUS_NULL_POINTER: *value* may not be NULL.
- NOTMUCH_STATUS_SUCCESS: No error occured.
@since libnotmuch 4.4 (notmuch 0.23)
Retrieve the value for a single property key
*value* is set to a string owned by the message or NULL if there is no such key. In the case of multiple values for the given key, the first one is retrieved.
@returns - NOTMUCH_STATUS_NULL_POINTER: *value* may not be NULL. - NOTMUCH_STATUS_SUCCESS: No error occured. @since libnotmuch 4.4 (notmuch 0.23)