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MONGOC_DATABASE_READ_COMMAND_WITH_OPTS(3) libmongoc MONGOC_DATABASE_READ_COMMAND_WITH_OPTS(3)

SYNOPSIS

bool
mongoc_database_read_command_with_opts (mongoc_database_t *database,


                                        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_database_command_simple() <>.

Use this function for commands that read such as "count" or "distinct".

Read preferences, read concern, and collation can be overridden by various sources. In a transaction, read concern and write concern are prohibited in opts and the read preference must be primary or NULL. The highest-priority sources for these options are listed first in the following table. No write concern is applied.

Read Preferences Read Concern Collation
read_prefs opts opts
Transaction Transaction
database

See the example for transactions <#mongoc-client-session-start-transaction-example> and for the "distinct" command with opts <#mongoc-client-read-command-with-opts-example>.

reply is always initialized, and must be freed with bson_destroy() <https://www.mongoc.org/libbson/current/bson_destroy.html>.

This function is considered a retryable read operation. Upon a transient error (a network error, errors due to replica set failover, etc.) the operation is safely retried once. If retryreads is false in the URI (see mongoc_uri_t <>) the retry behavior does not apply.

Retry logic occurs regardless of the underlying command. Retrying mapReduce has the potential for degraded performance. Retrying a getMore command has the potential to miss results. For those commands, use generic command helpers (like mongoc_database_command_with_opts() <>) instead.

PARAMETERS


opts may be NULL or a BSON document with additional command options:

  • readConcern: Construct a mongoc_read_concern_t <> and use mongoc_read_concern_append() <> to add the read concern to opts. See the example code for mongoc_client_read_command_with_opts() <>. Read concern requires MongoDB 3.2 or later, otherwise an error is returned.
  • sessionId: First, construct a mongoc_client_session_t <> with mongoc_client_start_session() <>. You can begin a transaction with mongoc_client_session_start_transaction() <>, optionally with a mongoc_transaction_opt_t <> that overrides the options inherited from database, and use mongoc_client_session_append() <> to add the session to opts. See the example code for mongoc_client_session_t <>.
  • collation: Configure textual comparisons. See Setting Collation Order <https://www.mongodb.com/docs/languages/c/c-driver/current/libmongoc/guides/bulk/#setting-collation-order>, and the MongoDB Manual entry on Collation <https://www.mongodb.com/docs/manual/reference/collation/>. Collation requires MongoDB 3.2 or later, otherwise an error is returned.
  • serverId: To target a specific server, include an int32 "serverId" field. Obtain the id by calling mongoc_client_select_server() <>, then mongoc_server_description_id() <> on its return value.

Consult the MongoDB Manual entry on Database Commands <https://www.mongodb.com/docs/manual/reference/command/> for each command's arguments.

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() <>.

Author

MongoDB, Inc

Copyright

2009-present, MongoDB, Inc.

November 26, 2025 2.2.0