mongoc_database_read_write_command_with_opts (
   mongoc_database_t *database,
   const bson_t *command,
   const mongoc_read_prefs_t *read_prefs /* UNUSED */,
   const bson_t *opts,
   bson_t *reply,
   bson_error_t *error);

Execute a command on the server, applying logic for commands that both read and write, 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 both read and write, such as “mapReduce” with an output collection.

Read and write concern and collation can be overridden by various sources. In a transaction, read concern and write concern are prohibited in opts. The highest-priority sources for these options are listed first in the following table. Read preferences are not applied. The write concern is omitted for MongoDB before 3.4.

Read Concern Write Concern Collation
opts opts opts
Transaction Transaction  
database database  

See the example for transactions and for the “distinct” command with opts.

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

(The mongoc_read_prefs_t parameter was included by mistake when this function was introduced in libmongoc 1.5. A command that writes must not obey a read preference.)


  • database: A mongoc_database_t.
  • command: A bson_t containing the command specification.
  • read_prefs: Ignored.
  • 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.

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

Consult the MongoDB Manual entry on Database Commands for each command’s arguments.


Errors are propagated via the error parameter.


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

A write concern timeout or write concern error is considered a failure.


See the example code for mongoc_client_read_command_with_opts().