# mongoc_collection_read_write_command_with_opts()

## Synopsis

    bool
    mongoc_collection_read_write_command_with_opts (
       mongoc_collection_t *collection,
       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_collection_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 |
`collection` | `collection` |

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.)

## Parameters

- `collection`: A mongoc_collection_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:

- `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.

- `writeConcern`: Construct a mongoc_write_concern_t and use mongoc_write_concern_append() to add the write concern to `opts`. See the example code for mongoc_client_write_command_with_opts().

- `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 `collection`, 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, and the MongoDB Manual entry on 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 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.

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

## Example

See the example code for mongoc_client_read_command_with_opts().