mongoc_collection_command_simple() — MongoDB C Driver 1.6.3

- MongoDB C Driver 1.6.3 »
- API Reference »
- mongoc_collection_t

# mongoc_collection_command_simple()

## Synopsis

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

## Parameters

- `collection`: A mongoc_collection_t.
- `command`: A `bson_t` containing the command to execute.
- `read_prefs`: An optional mongoc_read_prefs_t. Otherwise, the command uses mode `MONGOC_READ_PRIMARY`.
- `reply`: A location to initialize a `bson_t`. This should be on the stack.
- `error`: An optional location for a bson_error_t or `NULL`.

## Description

This is a simplified version of mongoc_collection_command() that returns the first result document in `reply`. The collection's read preference, read concern, and write concern are not applied to the command. The parameter `reply` is initialized even upon failure to simplify memory management.

This function tries to unwrap an embedded error in the command when possible. The unwrapped error will be propagated via the `error` parameter. Additionally, the result document is set in `reply`.

## Errors

Errors are propagated via the `error` parameter.

## Returns

`true` if successful, otherwise `false`.

This function does not check the server response for a write concern error or write concern timeout.

## Example

The following is an example of executing the collection stats command.

    #include <mongoc.h>
    #include <bcon.h>
    #include <stdio.h>

    static void
    print_collection_stats (mongoc_collection_t *collection)
    {
       bson_error_t error;
       const char *name;
       bson_t *cmd;
       bson_t reply;

       name = mongoc_collection_get_name (collection);
       cmd = BCON_NEW ("collStats", BCON_UTF8 (name));

       if (mongoc_collection_command_simple (
              collection, cmd, NULL, &reply, &error)) {
          str = bson_as_json (&reply, NULL);
          printf ("%s\n", str);
          bson_free (str);
       } else {
          fprintf (stderr, "%s\n", error.message);
       }

       bson_destroy (&reply);
       bson_destroy (cmd);
    }

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