mongoc_collection_watch()¶
Synopsis¶
mongoc_change_stream_t*
mongoc_collection_watch (const mongoc_collection_t *coll,
const bson_t *pipeline,
const bson_t *opts);
A helper function to create a change stream. It is preferred to call this function over using a raw aggregation to create a change stream.
This function uses the read preference and read concern of the collection. If the change stream needs to re-establish connection, the same read preference will be used. This may happen if the change stream encounters a resumable error.
Warning
A change stream is only supported with majority read concern.
Parameters¶
coll: A mongoc_collection_t specifying the collection which the change stream listens to.pipeline: Abson_trepresenting an aggregation pipeline appended to the change stream. This may be an empty document.opts: Abson_tcontaining change stream options orNULL.
opts may be NULL or a document consisting of any subset of the following
parameters:
batchSizeAnint32representing number of documents requested to be returned on each call to mongoc_change_stream_next()resumeAfterADocumentrepresenting the starting point of the change streammaxAwaitTimeMSAnint64representing the maximum amount of time a call to mongoc_change_stream_next() will block waiting for datacollationA Collation Document
Returns¶
A newly allocated mongoc_change_stream_t which must be freed with
mongoc_change_stream_destroy() when no longer in use. The returned
mongoc_change_stream_t is never NULL. If there is an error, it can
be retrieved with mongoc_change_stream_error_document(), and subsequent
calls to mongoc_change_stream_next() will return false.