mongoc_collection_command_simple man page

mongoc_collection_command_simple() — 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.

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 MONGOC_READ_PRIMARY
reply
A location to initialize a bson_t
error
An optional location for a bson_error_t or NULL

Description

This is a simplified version of mongoc_collection_command(3) that returns the first result document in reply 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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2016‐11‐07 MongoDB C Driver