mongoc_collection_read_command_with_opts()¶

Synopsis¶

bool
mongoc_collection_read_command_with_opts (mongoc_collection_t *collection,
                                          const bson_t *command,
                                          const mongoc_read_prefs_t *read_prefs,
                                          const bson_t *opts,
                                          bson_t *reply,
                                          bson_error_t *error);

Execute a command on the server, applying logic that is specific to commands that read, and taking the MongoDB server version into account. To send a raw command to the server without any of this logic, use mongoc_collection_command_simple().

Use this function for commands that read such as “count” or “distinct”. Read concern is applied from opts or else from collection. Collation is applied from opts (see example for). Read concern and collation both require MongoDB 3.2 or later, otherwise an error is returned. Read preferences are applied from read_prefs or else from collection. No write concern is applied.

To target a specific server, include an integer “serverId” field in opts with an id obtained first by calling mongoc_client_select_server(), then mongoc_server_description_id() on its return value.

reply is always initialized, and must be freed with bson_destroy().

Parameters¶

collection: A mongoc_collection_t.
command: A bson_t containing the command specification.
read_prefs: An optional mongoc_read_prefs_t.
opts: A bson_t containing additional options.
reply: A location for the resulting document.
error: An optional location for a bson_error_t or NULL.

Errors¶

Errors are propagated via the error parameter.

Returns¶

Returns true if successful. Returns false and sets error if there are invalid arguments or a server or network error.

Example¶

See the example code for mongoc_client_read_command_with_opts().