SYNOPSIS

       New in MongoDB 3.2.

       The  mongoc_read_concern_t  allows  clients  to choose a level of isolation for their reads. The default,
       MONGOC_READ_CONCERN_LEVEL_LOCAL, is right for the great majority of applications.

       You can specify a read concern on connection objects, database objects, or collection objects.

       See readConcern on the MongoDB website for more information.

       Read Concern is only sent to MongoDB when it has explicitly been set  by  mongoc_read_concern_set_level()
       to anything other than NULL.

READ CONCERN LEVELS

            ┌───────────────────────────────────────┬─────────────────────────────┬───────────────────────┐
            │Macro                                  │ Description                 │ First MongoDB version │
            ├───────────────────────────────────────┼─────────────────────────────┼───────────────────────┤
            │MONGOC_READ_CONCERN_LEVEL_LOCAL        │ Level "local", the default. │ 3.2                   │
            ├───────────────────────────────────────┼─────────────────────────────┼───────────────────────┤
            │MONGOC_READ_CONCERN_LEVEL_MAJORITY     │ Level "majority".           │ 3.2                   │
            ├───────────────────────────────────────┼─────────────────────────────┼───────────────────────┤
            │MONGOC_READ_CONCERN_LEVEL_LINEARIZABLE │ Level "linearizable".       │ 3.4                   │
            ├───────────────────────────────────────┼─────────────────────────────┼───────────────────────┤
            │MONGOC_READ_CONCERN_LEVEL_AVAILABLE    │ Level "available".          │ 3.6                   │
            ├───────────────────────────────────────┼─────────────────────────────┼───────────────────────┤
            │MONGOC_READ_CONCERN_LEVEL_SNAPSHOT     │ Level "snapshot".           │ 4.0                   │
            └───────────────────────────────────────┴─────────────────────────────┴───────────────────────┘

       For the sake of compatibility with future versions of MongoDB, mongoc_read_concern_set_level() allows any
       string, not just this list of known read concern levels.

       See  Read  Concern  Levels  in  the MongoDB manual for more information about the individual read concern
       levels.

AUTHOR

       MongoDB, Inc

COPYRIGHT

       2017-present, MongoDB, Inc